WO2017113754A1

WO2017113754A1 - Method for detecting dynamic reactive power of grid and reactive power detector

Info

Publication number: WO2017113754A1
Application number: PCT/CN2016/090198
Authority: WO
Inventors: 曾晓生; 郭海滨; 辛凯
Original assignee: 华为技术有限公司
Priority date: 2015-12-28
Filing date: 2016-07-15
Publication date: 2017-07-06
Also published as: CN106918737A

Abstract

A method for detecting dynamic reactive power of a grid and a reactive power detector, used for detecting the reactive power demand in a grid so as to avoid inaccurate data caused by communication delays. The method comprises: a reactive power detector acquires an impedance of an access line in the previous detection period (201), the first detection period being a detection period prior to the current detection period; the reactive power detector acquires a voltage, a current and a phase difference of an inverter in the current detection period (202); the reactive power detector calculates the voltage, current and phase difference of the grid according to the impedance of the access line in the current detection period and the voltage, current and phase difference of the inverter in the current detection period (203); and the reactive power detector calculates a reactive power of the grid according to the calculated voltage, current and phase difference of the grid (203).

Description

一种检测电网动态无功功率的方法以及无功功率检测装置Method for detecting dynamic reactive power of power grid and reactive power detecting device

本申请要求于2015年12月28日提交中国专利局、申请号为201510998926.9、发明名称为“一种检测电网动态无功功率的方法以及无功功率检测装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。This application claims priority to Chinese Patent Application No. 201510998926.9, entitled "Method for Detecting Dynamic Reactive Power of Grid and Reactive Power Detection Device", filed on December 28, 2015, The entire contents are incorporated herein by reference.

技术领域Technical field

本发明涉及强电领域，尤其涉及一种检测电网动态无功功率的方法以及无功功率检测装置。The invention relates to the field of strong electricity, in particular to a method for detecting dynamic reactive power of a power grid and a reactive power detecting device.

背景技术Background technique

无功补偿在电力供电***中起提高电网的功率因数的作用，降低供电变压器及输送线路的损耗，提高供电效率，改善供电环境，所以无功功率补偿装置在电力供电***中处在一个不可缺少的非常重要的位置。Reactive power compensation plays a role in improving the power factor of the power grid in the power supply system, reducing the loss of the power supply transformer and the transmission line, improving the power supply efficiency, and improving the power supply environment. Therefore, the reactive power compensation device is indispensable in the power supply system. Very important location.

合理的选择补偿装置，可以做到最大限度的减少电网的损耗，使电网质量提高。反之，如选择或使用不当，可能造成供电***，电压波动，谐波增大等诸多因素。传统应用上采用专门的无功补偿装置进行电网的无功补偿，然而随着并网逆变器，特别是光伏并网逆变器大量接入电网之后，逆变器可以充当无功补偿装置，为电网提供无功功率。Reasonable selection of compensation devices can minimize the loss of the power grid and improve the quality of the power grid. Conversely, if selected or used improperly, it may cause many factors such as power supply system, voltage fluctuation, harmonic increase and so on. In the traditional application, a special reactive power compensation device is used to perform reactive power compensation of the power grid. However, after the grid-connected inverter, especially the photovoltaic grid-connected inverter, is connected to the power grid in large quantities, the inverter can act as a reactive power compensation device. Provide reactive power to the grid.

不管是传统的无功补偿装置，还是带有无功补偿功能的并网逆变器，检测电网无功功率需求的方法是直接采集电网的电压、电流、相位或有功功率、无功功率等信息而计算得到。Whether it is a traditional reactive power compensation device or a grid-connected inverter with reactive power compensation function, the method for detecting the reactive power demand of the power grid is to directly collect the voltage, current, phase or active power, reactive power and other information of the power grid. And calculated.

当电网的电压、电流、相位或有功功率、无功功率等信息被传输到并网逆变器而被采集到并网逆变器根据数据进行计算其无功功率时，由于通信线路的延迟，并不能准确地作为当前检测周期的无功功率需求。When the voltage, current, phase or active power, reactive power and other information of the grid are transmitted to the grid-connected inverter and collected to the grid-connected inverter to calculate its reactive power according to the data, due to the delay of the communication line, It cannot be accurately used as the reactive power demand of the current detection cycle.

发明内容Summary of the invention

本发明实施例提供了一种检测电网动态无功功率的方法以及无功功率检测装置，用于检测电网中的无功功率需求,能够避免由于通信延迟产生的数据不准确，提高无功功率检测的准确性。Embodiments of the present invention provide a method for detecting dynamic reactive power of a power grid and a reactive power detecting device for detecting reactive power demand in a power grid, which can avoid data inaccuracy due to communication delay, and improve reactive power detection. The accuracy.

有鉴于此，本发明实施例第一方面提供了一种检测电网动态无功功率的方法，该方法用于电网***，该电网***包括电网以及通过接入线路接入该电网的逆变器，该逆变器把直流电转变成交流电通过该接入线路并入该电网中，该方法包括：获取该接入线路在上一检测周期的阻抗，该上一检测周期是指当前检测周期以前的一个检测周期；获取该逆变器在当前检测周期的电压、电流及相位差；根据该接入线路在上一检测周期的阻抗以及该逆变器在当前检测周期的电压、电流及相位差，计算该电网的电压、电流及相位差；且根据该计算得到的电网的电压、电流及相位差计算该电网的无功功率。本发明实施例将接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，并及时获取当前检测周期逆变器端的电压、电流，避免了通讯延迟对于数据获取的影响，因此无功功率检测装置通过这些数据计算得出的无功功率需求可以较为准确地作为电网当前检测周期的无功功率需求。In view of this, the first aspect of the embodiments of the present invention provides a method for detecting dynamic reactive power of a power grid. Method for a grid system, the grid system comprising a grid and an inverter connected to the grid via an access line, the inverter converting the direct current into an alternating current into the grid through the access line, the method The method includes: obtaining an impedance of the access line in a previous detection period, where the previous detection period refers to a detection period before the current detection period; acquiring a voltage, a current, and a phase difference of the inverter during the current detection period; Calculating the voltage, current and phase difference of the grid during the impedance of the previous detection period and the voltage, current and phase difference of the inverter during the current detection period; and calculating the voltage and current of the grid according to the calculation The phase difference calculates the reactive power of the grid. In the embodiment of the present invention, the impedance of the current detection period of the access line is approximated to the impedance of the previous detection period, and the voltage and current of the inverter end of the current detection period are obtained in time, thereby avoiding the influence of the communication delay on the data acquisition, and thus the reactive power The reactive power demand calculated by the power detecting device through these data can be more accurately used as the reactive power demand of the current detection period of the power grid.

结合本发明实施例的第一方面，在本发明实施例的第一方面的第一种实施方式中，获取该接入线路在上一检测周期的阻抗，包括：获取该接入线路在上一检测周期的电压、电流及相位差；根据该接入线路在上一检测周期的电压、电流及相位差，计算该接入线路的阻抗。With reference to the first aspect of the embodiments of the present invention, in a first implementation manner of the first aspect of the embodiment, the acquiring the impedance of the access line in the previous detection period includes: acquiring the access line in the previous The voltage, current, and phase difference of the detection period are calculated; the impedance of the access line is calculated according to the voltage, current, and phase difference of the access line during the previous detection period.

结合本发明实施例的第一方面的第一种具体实施方式，在本发明实施例的第一方面的第二种具体实施方式中，该接入线路包括串联的多级变压器；获取该接入线路在该上一检测周期的电压、电流及相位差，包括：获取该多级变压器中的每一级变压器在上一检测周期的电压、电流及相位差；根据该接入线路在上一检测周期的电压、电流及相位差，计算该接入线路的阻抗，包括：根据每一级变压器在上一检测周期的电压、电流及相位差，计算每一级变压器的阻抗，并对每一级变压器的阻抗求和，得到该接入线路的阻抗，具体的，根据每一级变压器在上一检测周期的相位差θ，作为该级变压器的阻抗角，并采用下述公式计算该级变压器的阻抗：With reference to the first embodiment of the first aspect of the embodiments of the present invention, in a second specific implementation manner of the first aspect of the embodiments, the access line includes a multi-stage transformer connected in series; The voltage, current and phase difference of the line in the last detection period include: obtaining voltage, current and phase difference of the transformer in each stage of the multi-stage transformer in the previous detection period; and detecting the previous line according to the access line The voltage, current and phase difference of the cycle, calculate the impedance of the access line, including: calculating the impedance of each stage transformer according to the voltage, current and phase difference of the transformer in each stage of the previous detection period, and for each stage The impedance of the transformer is summed to obtain the impedance of the access line. Specifically, according to the phase difference θ of the transformer in each stage of the previous detection period, the impedance angle of the transformer is used, and the following formula is used to calculate the transformer of the stage. impedance:

在上述公式中，Z为该级变压器的阻抗，U为该级变压器的电压有效值，I为该级变压器的电流有效值，θ为该级变压器的阻抗角。无功功率检测装置将该多级变压器的阻抗进行求和，得到接入线路的阻抗。由于在发明中，接入线路被看成是串联的变压器组成的，因此接入线路的阻抗可以看成为接入线路中所有串联的变压器的阻抗之和，所以直接通过计算串联的多级变压器在进行求和，可以直接得到准确的接入线路的阻抗数据。In the above formula, Z is the impedance of the transformer of the stage, U is the voltage effective value of the transformer of the stage, I is the current effective value of the transformer of the stage, and θ is the impedance angle of the transformer of the stage. The reactive power detecting device sums the impedances of the multi-stage transformers to obtain the impedance of the access line. Since in the invention, the access line is considered to be composed of a series of transformers, the impedance of the access line can be regarded as the sum of the impedances of all the series connected transformers in the access line, so directly by calculating the series of multi-stage transformers get on Summing, you can directly get the impedance data of the access line.

结合本发明实施例的第一方面，在本发明实施例的第一方面的第三种实施方式中，获取该接入线路在上一检测周期的阻抗，包括：获取该接入线路在上一检测周期的阻抗，包括：获取该电网在上一检测周期的电压、电流以及该逆变器在上一检测周期的电压、电流；根据该电网在上一检测周期的电压、电流以及该逆变器在上一检测周期的电压、电流，计算该接入线路的阻抗。In conjunction with the first aspect of the embodiments of the present invention, in a third implementation manner of the first aspect of the embodiment of the present invention, obtaining an impedance of the access line in a previous detection period includes: acquiring the access line in a previous The impedance of the detection period includes: obtaining the voltage and current of the grid during the last detection period and the voltage and current of the inverter during the last detection period; the voltage, current and the inverter according to the grid during the last detection period The voltage and current of the previous detection period are used to calculate the impedance of the access line.

结合本发明实施例的第一方面的第三种具体实施方式，在本发明实施例的第一方面的第四种具体实施方式中，包括：根据该电网在上一检测周期的电压、电流和该逆变器在上一检测周期的电压、电流计算该接入线路的阻抗，采用下述公式计算该接入线路的阻抗：With reference to the third embodiment of the first aspect of the embodiments of the present invention, in a fourth implementation manner of the first aspect of the embodiments of the present invention, the method includes: according to the voltage, current, and current of the power grid in the previous detection period The inverter calculates the impedance of the access line by the voltage and current of the previous detection period, and calculates the impedance of the access line by the following formula:

在上述公式中，

为接入线路的电压，

为接入线路的电流，Z_line为接入线路的阻抗，

为电网的电流，

为逆变器的电压。无功功率检测装置根据计算得到的当前检测周期电网的无功功率指示逆变器控制电信号中电压、电流，以使得电网得到该无功功率作为无功补偿。由于使用了动态无功功率作为动态无功功率补偿，因此无功功率检测装置能及时为当前检测周期的电网提供恰当的、准确的无功无功功率。由于根据电网和逆变器的数据计算得到的接入线路的阻抗，而不是根据变压器的数据计算的，变压器的数量比较多，所使用到的数据比较多，而使用逆变器和电网的数据计算更加简便，使用的数据更少，减轻无功功率检测装置的处理的负担。In the above formula,

To access the voltage of the line,

For the current to the _line , Z _line is the impedance of the access line.

Current for the grid,

The voltage for the inverter. The reactive power detecting device instructs the inverter to control the voltage and current in the electrical signal according to the calculated reactive power of the current detection period, so that the grid obtains the reactive power as reactive power compensation. Since the dynamic reactive power is used as the dynamic reactive power compensation, the reactive power detecting device can timely provide the proper and accurate reactive power and reactive power for the grid of the current detection period. Since the impedance of the access line calculated from the data of the grid and the inverter is calculated based on the data of the transformer, the number of transformers is relatively large, and the data used is relatively large, and the data of the inverter and the grid are used. The calculation is simpler and uses less data, reducing the burden of processing the reactive power detection device.

结合本发明实施例的第一方面，在本发明实施例的第一方面的第五种具体实施方式中，包括：根据该接入线路在上一检测周期的阻抗以及该逆变器在当前检测周期的电压、电流及相位差，计算该电网的电压、电流及相位差，包括：采用下述公式计算该电网的电压、电流及相位差； With reference to the first aspect of the embodiments of the present invention, in a fifth implementation manner of the first aspect of the embodiments of the present invention, the method includes: determining, according to the access line, an impedance of a previous detection period and the current detection of the inverter The voltage, current and phase difference of the cycle are calculated, and the voltage, current and phase difference of the power grid are calculated, including: calculating the voltage, current and phase difference of the power grid by using the following formula;

θ_grid＝θ_live+θ_inv，θ _grid =θ _live +θ _inv ,

在上述公式中，

为该电网的电压，

为该逆变器的电压，Z_line为该接入线路的阻抗，

为该电网的电流，

为该逆变器的电流，θ_grid为该电网的电压和电流的相位差，θ_inv为该逆变器电压和电流的相位差，θ_line为Z_line的阻抗角。In the above formula,

For the voltage of the grid,

For the voltage of the inverter, Z _{line is} the impedance of the access line,

For the current of the grid,

For the current of the inverter, θ _grid is the phase difference between the voltage and current of the grid, θ _{inv is} the phase difference between the voltage and current of the inverter, and θ _line is the impedance angle of Z _line .

结合本发明实施例的第一方面，在本发明实施例的第一方面的第六种具体实施方式中，包括：根据该计算得到的该电网的电压、电流及相位差，计算该电网的无功功率，包括：根据该电网的电压计算该电网的电压有效值，根据该电网的电流计算该电网的电流有效值，并采用下述公式计算该电网的无功功率：With reference to the first aspect of the embodiments of the present invention, in a sixth implementation manner of the first aspect of the embodiments of the present invention, the method includes: calculating, according to the calculated voltage, current, and phase difference of the power grid, The power of the power includes: calculating a voltage effective value of the power grid according to the voltage of the power grid, calculating a current effective value of the power grid according to the current of the power grid, and calculating a reactive power of the power grid by using the following formula:

Q_grid＝U_grid×I_grid×sinθ_grid， _{_{_{Q grid = U grid × I grid}}} × sinθ grid,

在上述公式中，Q_grid为当前检测周期电网的动态无功功率，U_grid为电网的电压有效值，I_grid为电网的电流有效值，θ_grid为电网的电压和电流的相位差。In the above formula, Q _grid dynamic reactive power, U _grid RMS current detection period of the grid voltage of the grid, I _grid is a grid current effective value, θ _grid phase voltage and current of the grid.

应理解，根据上述方法不同的具体实施方式，上一检测周期指与当前检测周期相邻的前一个检测周期，或者当前检测周期前预置时间范围内的任一检测周期，或者当前检测周期前制定的某检测周期，不作限定。It should be understood that, according to different embodiments of the foregoing method, the previous detection period refers to a previous detection period adjacent to the current detection period, or any detection period within a preset time range before the current detection period, or before the current detection period. A certain test cycle is not limited.

从以上技术方案可以看出，本发明实施例具有以下优点：It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

无功功率检测装置通过获取接入线路的阻抗以及逆变器在当前检测周期的电压、电流，并使之用于计算电网在当前检测周期的无功功率。本发明实施例将接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，并及时获取当前检测周期逆变器端的电压、电流，避免了通讯延迟对于数据获取的影响，因此无功功率检测装置通过这些数据计算得出的无功功率需求可以较为准确地作为电网当前检测周期的无功功率需求。The reactive power detecting device obtains the impedance of the access line and the voltage and current of the inverter during the current detection period, and uses it to calculate the reactive power of the power grid during the current detection period. In the embodiment of the present invention, the impedance of the current detection period of the access line is approximated to the impedance of the previous detection period, and the voltage and current of the inverter end of the current detection period are obtained in time, thereby avoiding the influence of the communication delay on the data acquisition, and thus the reactive power The reactive power demand calculated by the power detecting device through these data can be more accurately used as the reactive power demand of the current detection period of the power grid.

本发明实施例第二方面提供了一种无功功率检测装置，该装置用于电网***，该电网***包括电网以及通过接入线路接入该电网的逆变器，该逆变器把直流电转变成交流电通过该接入线路并入该电网中，该装置包括：第一获取模块，用于获取该接入线路在上一检测周期的阻抗，该上一检测周期是指当前检测周期以前的一个检测周期；第二获取模块，用于获取该逆变器在当前检测周期的电压、电流及相位差；第一计算模块，用于根据该第一获取模块获取的该接入线路在上一检测周期的阻抗以及该第二获取模块获取的该逆变器在当前检测周期的电压、电流及相位差，计算该电网的电压、电流及相位差；第二计算模块，用于根据该计算模块计算得到的该电网的电压、电流及相位差计算该电网的无功功率。A second aspect of the embodiments of the present invention provides a reactive power detecting apparatus for a power grid system, the power grid system including a power grid and an inverter connected to the power grid through an access line, the inverter The DC power is converted into an AC power and integrated into the power grid through the access line. The device includes: a first acquiring module, configured to acquire an impedance of the access line in a previous detection period, where the previous detection period refers to a current detection period. a second detection module, configured to acquire a voltage, a current, and a phase difference of the inverter during a current detection period; and a first calculation module, configured to acquire the access line according to the first acquisition module a voltage of a detection period and a voltage, a current, and a phase difference of the inverter in the current detection period acquired by the second acquisition module, and calculating a voltage, a current, and a phase difference of the power grid; and a second calculation module, configured to calculate according to the The voltage, current and phase difference of the grid calculated by the module calculate the reactive power of the grid.

本发明实施例将接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，并及时获取当前检测周期逆变器端的电压、电流，避免了通讯延迟对于数据获取的影响，因此无功功率检测装置通过这些数据计算得出的无功功率需求可以较为准确地作为电网当前检测周期的无功功率需求。In the embodiment of the present invention, the impedance of the current detection period of the access line is approximated to the impedance of the previous detection period, and the voltage and current of the inverter end of the current detection period are obtained in time, thereby avoiding the influence of the communication delay on the data acquisition, and thus the reactive power The reactive power demand calculated by the power detecting device through these data can be more accurately used as the reactive power demand of the current detection period of the power grid.

结合本发明实施例的第二方面，在本发明实施例的第二方面的第一种实施方式中，该第一获取模块包括：第一获取单元，用于获取该接入线路在上一检测周期的电压、电流及相位差；第一计算单元，用于根据该第一获取单元获取的该接入线路在上一检测周期的电压、电流及相位差计算该接入线路的阻抗。With reference to the second aspect of the embodiments of the present invention, in a first implementation manner of the second aspect of the embodiments, the first acquiring module includes: a first acquiring unit, configured to acquire the access line in the previous detection a voltage, a current, and a phase difference of the cycle; the first calculating unit is configured to calculate an impedance of the access line according to a voltage, a current, and a phase difference of the access line acquired by the first acquiring unit according to a previous detection period.

结合本发明实施例的第二方面的第一种具体实施方式，在本发明实施例的第二方面的第二种具体实施方式中，包括：该第一获取单元，具体用于获取该多级变压器中的每一级变压器在上一检测周期的电压、电流及相位差；该第一计算单元，具体用于根据该第一获取单元获取的每一级变压器在上一检测周期的电压、电流及相位差，计算每一级变压器的阻抗，并对每一级变压器的阻抗求和，得到该接入线路的阻抗，具体的，根据每一级变压器在上一检测周期的相位差θ，作为该级变压器的阻抗角，并采用下述公式计算该级变压器的阻抗：With reference to the first embodiment of the second aspect of the embodiments of the present invention, in a second implementation manner of the second aspect of the embodiment of the present invention, the first acquiring unit is specifically configured to obtain the multi-level a voltage, a current, and a phase difference of each stage of the transformer in the last detection period; the first calculation unit is specifically configured to use the voltage and current of the previous detection period of each stage of the transformer obtained according to the first acquisition unit And the phase difference, calculate the impedance of each stage of the transformer, and sum the impedance of each stage of the transformer to obtain the impedance of the access line. Specifically, according to the phase difference θ of the previous detection period of each stage of the transformer, The impedance angle of the transformer of this stage, and calculate the impedance of the transformer of this stage by the following formula:

在上述公式中，Z为该级变压器的阻抗，U为该级变压器的电压有效值，I为该级变压器的电流有效值，θ为该级变压器的阻抗角。无功功率检测装置将该多级变压器的阻抗进行求和，得到接入线路的阻抗。由于在发明中，接入线路被看成是串联的变压器组成的，因此接入线路的阻抗可以看成为接入线路中所有串联的变压器的阻抗之和，所以直接通过计算串联的多级变压器在进行求和，可以直接得到准确的接入线路的阻抗数据。 In the above formula, Z is the impedance of the transformer of the stage, U is the voltage effective value of the transformer of the stage, I is the current effective value of the transformer of the stage, and θ is the impedance angle of the transformer of the stage. The reactive power detecting device sums the impedances of the multi-stage transformers to obtain the impedance of the access line. Since in the invention, the access line is considered to be composed of a series of transformers, the impedance of the access line can be regarded as the sum of the impedances of all the series connected transformers in the access line, so directly by calculating the series of multi-stage transformers By summing, the impedance data of the access line can be directly obtained.

结合本发明实施例的第二方面，在本发明实施例的第二方面的第三种实施方式中，该第一获取模块包括：第一获取单元，用于获取该接入线路在上一检测周期的电压、电流及相位差；第一计算单元，用于根据该第一获取单元获取的该接入线路在上一检测周期的电压、电流及相位差计算该接入线路的阻抗。With reference to the second aspect of the embodiments of the present invention, in a third implementation manner of the second aspect of the embodiment, the first acquiring module includes: a first acquiring unit, configured to acquire the access line in the previous detection a voltage, a current, and a phase difference of the cycle; the first calculating unit is configured to calculate an impedance of the access line according to a voltage, a current, and a phase difference of the access line acquired by the first acquiring unit according to a previous detection period.

结合本发明实施例的第二方面的第三种具体实施方式，在本发明实施例的第二方面的第四种具体实施方式中，该第一获取模块包括：第二获取单元，用于获取该电网在上一检测周期的电压、电流以及该逆变器在上一检测周期的电压、电流；第二计算单元，用于根据该第二获取单元获取的该电网在上一检测周期的电压、电流以及该逆变器在上一检测周期的电压、电流，计算该接入线路的阻抗，采用下述公式计算该接入线路的阻抗：With reference to the third embodiment of the second aspect of the embodiments of the present invention, in a fourth implementation manner of the second aspect of the embodiment, the first acquiring module includes: a second acquiring unit, configured to obtain The voltage and current of the grid during the last detection period and the voltage and current of the inverter during the last detection period; the second calculation unit is configured to obtain the voltage of the grid during the last detection period according to the second acquisition unit , the current and the voltage and current of the inverter during the last detection period, calculate the impedance of the access line, and calculate the impedance of the access line by the following formula:

在上述公式中，

为接入线路的电压，

为接入线路的电流，Z_line为接入线路的阻抗，

为电网的电流，

To access the voltage of the line,

For the current to the _line , Z _line is the impedance of the access line.

Current for the grid,

结合本发明实施例的第二方面，在本发明实施例的第二方面的第五种具体实施方式中，该第一计算模块具体用于采用下述公式计算该电网的电压、电流及相位差：With reference to the second aspect of the embodiments of the present invention, in a fifth implementation manner of the second aspect of the embodiment, the first calculation module is specifically configured to calculate a voltage, a current, and a phase difference of the power grid by using the following formula: :

θ_grid＝θ_live+θ_inv，θ _grid =θ _live +θ _inv ,

在上述公式中，

为该电网的电压，

为该逆变器的电压，Z_line为该接入线路的阻抗，

为该电网的电流，

For the voltage of the grid,

For the voltage of the inverter, Z _{line is} the impedance of the access line,

For the current of the grid,

结合本发明实施例的第二方面，在本发明实施例的第二方面的第六种具体实施方式中，该第二计算模块具体用于根据该电网的电压计算该电网的电压有效值，根据该电网的电流计算该电网的电流有效值，并采用下述公式计算该电网的无功功率：With reference to the second aspect of the embodiments of the present invention, in a sixth implementation manner of the second aspect of the embodiment, the second calculating module is specifically configured to calculate a voltage effective value of the power grid according to a voltage of the power grid, according to The current of the grid calculates the current rms value of the grid and calculates the reactive power of the grid using the following formula:

Q_grid＝U_grid×I_grid×sinθ_grid，Q _grid =U _grid ×I _grid ×sinθ _grid ,

本发明实施例第三方面提供一种无功功率检测装置，用于电网***，该电网***包括电网以及通过接入线路接入该电网的逆变器，该逆变器把直流电转变成交流电通过该接入线路并入该电网中；该无功功率检测装置包括A third aspect of the embodiments of the present invention provides a reactive power detecting apparatus for a power grid system, where the power grid system includes a power grid and an inverter that accesses the power grid through an access line, and the inverter converts the direct current into an alternating current The access line is incorporated into the power grid; the reactive power detecting device includes

处理单元和采集器；该采集器用于获取逆变器在当前检测周期的电压、电流及相位差；该处理单元，用于根据接入线路在上一检测周期的阻抗以及逆变器在当前检测周期的电压、电流及相位差，计算电网的电压、电流及相位差；且根据计算得到的电网的电压、电流及相位差计算电网的无功功率。Processing unit and collector; the collector is used to obtain voltage and electricity of the inverter during the current detection period Flow and phase difference; the processing unit is configured to calculate a voltage, a current, and a phase difference of the power grid according to an impedance of the access line during a previous detection period and a voltage, a current, and a phase difference of the current detection period of the inverter; Calculate the reactive power of the grid by calculating the voltage, current and phase difference of the grid.

结合本发明实施例的第三方面，根据无功功率检测装置获取接入线路的阻抗的不同方式，分别进行表述，其中，本发明实施例的第三方面的第一种实施方式中，该采集器还用于获取接入线路在上一检测周期的电压、电流及相位差；该处理单元还用于根据接入线路在上一检测周期的电压、电流及相位差，计算接入线路在上一检测周期的阻抗。With reference to the third aspect of the embodiment of the present invention, the representation is respectively performed according to different manners in which the reactive power detecting device acquires the impedance of the access line, wherein in the first embodiment of the third aspect of the embodiment of the present invention, the collecting The device is further configured to obtain the voltage, current, and phase difference of the access line during the previous detection period; the processing unit is further configured to calculate the access line according to the voltage, current, and phase difference of the access line during the previous detection period. The impedance of a detection cycle.

本发明实施例的第三方面的第二种实施方式中，该采集器还用于获取电网在上一检测周期的电压、电流以及逆变器在上一检测周期的电压、电流；该处理单元还用于根据电网在上一检测周期的电压、电流以及逆变器在上一检测周期的电压、电流，计算接入线路在上一检测周期的阻抗。In the second implementation manner of the third aspect of the embodiment of the present invention, the collector is further configured to obtain voltage and current of the power grid during the last detection period, and voltage and current of the inverter during the last detection period; the processing unit It is also used to calculate the impedance of the access line during the last detection period according to the voltage and current of the grid during the last detection period and the voltage and current of the inverter during the last detection period.

本发明实施例第三方面提供的无功功率检测装置，将接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，并及时获取当前检测周期逆变器端的电压、电流，避免了通讯延迟对于数据获取的影响，因此无功功率检测装置通过这些数据计算得出的无功功率需求可以较为准确地作为电网当前检测周期的无功功率需求。The reactive power detecting apparatus provided by the third aspect of the present invention approximates the impedance of the current detection period of the access line to the impedance of the previous detection period, and timely acquires the voltage and current of the inverter end of the current detection period, thereby avoiding The influence of communication delay on data acquisition, so the reactive power demand calculated by the reactive power detection device through these data can be more accurately used as the reactive power demand of the current detection period of the power grid.

本发明实施例第四方面提供一种逆变器，用于电网***，该电网***包括电网以及通过接入线路接入该电网的逆变器，该逆变器把直流电转变成交流电通过该接入线路并入该电网中；该逆变器包括：无功功率检测模块和电流转换模块；该电流转换模块用于把输入的直流电转换为交流电输出；该无功功率检测模块采用与本发明实施例第三方面所提供的无功功率检测装置相同的结构，执行相同的功能。，根据本发明的第四方面的逆变器，将无功功率检测模块集成于传统的逆变器内，简化了***的结构。A fourth aspect of the embodiments of the present invention provides an inverter for a power grid system, where the power grid system includes a power grid and an inverter that accesses the power grid through an access line, and the inverter converts the direct current into an alternating current through the connection. The incoming circuit is incorporated into the power grid; the inverter includes: a reactive power detecting module and a current converting module; the current converting module is configured to convert the input direct current into an alternating current output; the reactive power detecting module is implemented by the present invention The reactive power detecting device provided in the third aspect of the example has the same structure and performs the same function. According to the inverter of the fourth aspect of the invention, the reactive power detecting module is integrated in the conventional inverter, which simplifies the structure of the system.

结合本发明实施例的第四方面，本发明实施例的第四方面的另一种实施方式中，该逆变器的无功功率检测模块还包括通讯单元，用于接收远程采集的电路参数的数据，供给无功功率检测模块中的处理单元使用。根据本实施方式中的逆变器，进一步的，通过接收远程采集的电路参数数据，更方便操作。In conjunction with the fourth aspect of the embodiments of the present invention, in another implementation manner of the fourth aspect of the embodiments, the reactive power detection module of the inverter further includes a communication unit, configured to receive remotely collected circuit parameters. The data is supplied to the processing unit in the reactive power detection module for use. According to the inverter in the present embodiment, further, it is more convenient to operate by receiving remotely collected circuit parameter data.

本发明实施例将接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，并及时获取当前检测周期逆变器端的电压、电流，避免了通讯延迟对于数据获取的影响，因此无功功率检测装置通过这些数据计算得出的无功功率需求可以较为准确地作为电网当前检测周期的无功功率需求。In the embodiment of the present invention, the impedance of the current detection period of the access line is approximated to the impedance of the previous detection period, and the voltage and current of the inverter end of the current detection period are obtained in time to avoid the communication delay. The impact of data acquisition, so the reactive power demand calculated by the reactive power detection device through these data can be more accurately used as the reactive power demand of the current detection period of the power grid.

附图说明DRAWINGS

图1为本发明实施例中电网***的架构示意图；1 is a schematic structural diagram of a power grid system according to an embodiment of the present invention;

图2为本发明实施例中检测电网动态无功功率的方法一个实施例的流程示意图；2 is a schematic flowchart of a method for detecting dynamic reactive power of a power grid according to an embodiment of the present invention;

图3为本发明实施例中检测电网动态无功功率的方法另一个实施例的流程示意图；3 is a schematic flowchart of another embodiment of a method for detecting dynamic reactive power of a power grid according to an embodiment of the present invention;

图4为本发明实施例中检测电网动态无功功率的方法另一个实施例的流程示意图；4 is a schematic flowchart of another embodiment of a method for detecting dynamic reactive power of a power grid according to an embodiment of the present invention;

图5为本发明实施例中无功功率检测装置一个实施例的结构示意图；FIG. 5 is a schematic structural diagram of an embodiment of a reactive power detecting apparatus according to an embodiment of the present invention; FIG.

图6为本发明实施例中无功功率检测装置另一个实施例的结构示意图；6 is a schematic structural diagram of another embodiment of a reactive power detecting apparatus according to an embodiment of the present invention;

图7为本发明实施例中无功功率检测装置另一个实施例的结构示意图；FIG. 7 is a schematic structural diagram of another embodiment of a reactive power detecting apparatus according to an embodiment of the present invention; FIG.

图8为本发明实施例中无功功率检测装置另一个实施例的结构示意图；FIG. 8 is a schematic structural diagram of another embodiment of a reactive power detecting apparatus according to an embodiment of the present invention; FIG.

图9为本发明实施例中无功功率检测装置另一个实施例的结构示意图；FIG. 9 is a schematic structural diagram of another embodiment of a reactive power detecting apparatus according to an embodiment of the present invention; FIG.

图10为本发明实施例中无功功率检测装置另一个实施例的结构示意图；FIG. 10 is a schematic structural diagram of another embodiment of a reactive power detecting apparatus according to an embodiment of the present invention; FIG.

图11为本发明实施例中无功功率检测装置另一个实施例的结构示意图；FIG. 11 is a schematic structural diagram of another embodiment of a reactive power detecting apparatus according to an embodiment of the present invention; FIG.

图12为本发明实施例中无功功率检测装置一个实施例的电路结构示意图；FIG. 12 is a schematic structural diagram of a circuit of an embodiment of a reactive power detecting apparatus according to an embodiment of the present invention; FIG.

图13为本发明实施例中无功功率检测装置另一个实施例的电路结构示意图。FIG. 13 is a schematic structural diagram of a circuit of another embodiment of a reactive power detecting apparatus according to an embodiment of the present invention.

具体实施方式detailed description

本发明实施例公开了一种检测电网动态无功功率的方法以及无功功率检测装置，用于检测电网中的无功功率需求。The embodiment of the invention discloses a method for detecting dynamic reactive power of a power grid and a reactive power detecting device for detecting reactive power demand in the power grid.

为了使本技术领域的人员更好地理解本发明实施例方案，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分的实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都应当属于本发明保护的范围。For a better understanding of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. The examples are only a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention.

本发明的说明书和权利要求书及上述附图中的术语“第一”、“第二”、“第三”、“第四”等(如果存在)是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的数据在适当情况下可以互换，以便这里描述的实施例能够以除了在这里图示或描述的内容以外的顺序实施。此外，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、***、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过程、方法、产品或设备固有的其它步骤或单元。The terms "first", "second", "first" in the specification and claims of the present invention and the above drawings "three", "fourth", etc. (if present) are used to distinguish similar objects, and are not necessarily used to describe a particular order or order. It should be understood that the data so used may be interchanged where appropriate, as described herein. The embodiments can be implemented in a sequence other than what is illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover a non-exclusive inclusion, for example, including a series of steps or The process, method, system, product, or device of the unit is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not explicitly listed or inherent to such processes, methods, products, or devices.

如图1所示，是一种电网***的示意图，电网***包括电网以及通过接入线路接入电网的逆变器，逆变器把直流电转变成交流电通过接入线路并入电网中；接入线路通常包括多级变压器。该电网***还包括一无功功率检测装置，该无功功率检测装置可以是安装在逆变器上的元件，也可以是逆变器本身，也可以是与逆变器串联的一个检测装置，此处不作限定。该无功功率检测装置分别与逆变器、电网以及每一级变压器连接，可以采集逆变器、电网以及每一级变压器的电信号，例如，电压、电流以及相位差。贯穿本说明书，术语“相位差”是指电压和电流的相位差。电网、多级变压器以及逆变器可以组成一个无功补偿***，在该无功补偿***中逆变器可以获取逆变器、变压器以及电网的数据信息，并通过计算得到电网所需要的无功功率。As shown in FIG. 1 , it is a schematic diagram of a power grid system including a power grid and an inverter connected to the power grid through an access line, and the inverter converts the direct current into an alternating current and is integrated into the power grid through the access line; The line usually includes a multi-stage transformer. The grid system further includes a reactive power detecting device, which may be an element mounted on the inverter, or the inverter itself, or a detecting device connected in series with the inverter. This is not a limitation. The reactive power detecting device is respectively connected to the inverter, the power grid and each stage of the transformer, and can collect the electrical signals of the inverter, the power grid and the transformer of each stage, for example, voltage, current and phase difference. Throughout this specification, the term "phase difference" refers to the phase difference between voltage and current. The power grid, multi-stage transformer and inverter can form a reactive power compensation system. In the reactive power compensation system, the inverter can obtain the data information of the inverter, the transformer and the power grid, and calculate the reactive power required by the power grid. power.

无功功率补偿，简称无功补偿，在电力供电***中起提高电网的功率因数的作用，降低供电变压器及输送线路的损耗，提高供电效率，改善供电环境。所以无功功率补偿装置在电力供电***中处在一个不可缺少的非常重要的位置。合理的选择补偿装置，可以做到最大限度的减少电网的损耗，使电网质量提高。反之，如选择或使用不当，可能造成供电***，电压波动，谐波增大等诸多因素。Reactive power compensation, referred to as reactive power compensation, plays a role in improving the power factor of the power grid in the power supply system, reducing the loss of the power supply transformer and the transmission line, improving the power supply efficiency, and improving the power supply environment. Therefore, the reactive power compensation device is in an indispensable and important position in the power supply system. Reasonable selection of compensation devices can minimize the loss of the power grid and improve the quality of the power grid. Conversely, if selected or used improperly, it may cause many factors such as power supply system, voltage fluctuation, harmonic increase and so on.

从应用市场来看，无功补偿装置行业在国内外飞速发展，已经渗透到电能的产生、输送、分配和应用的各个环节，广泛应用到工业***、电力***、交通***、通信***、计算机***、新能源***和日常生活中，是使用电能的其他所有产业的基础技术。传统应用上采用专门的无功补偿装置进行电网的无功补偿。From the perspective of the application market, the reactive power compensation device industry has developed rapidly at home and abroad, and has penetrated into all aspects of the generation, transmission, distribution and application of electric energy, and is widely applied to industrial systems, power systems, transportation systems, communication systems, and computer systems. New energy systems and everyday life are the basic technologies of all other industries that use electrical energy. In the traditional application, a special reactive power compensation device is used to perform reactive power compensation of the power grid.

然而随着并网逆变器，特别是光伏并网逆变器大量接入电网之后，逆变器可以充当无功补偿装置，为电网提供无功功率。具有无功补偿功能的光伏并网***的并网发电的工作运行不仅可以有效地提供电网有功电能，而且可以补偿电网中所需要的无功功率，有利于电网供电能力和质量的进一步提高。However, with grid-connected inverters, especially photovoltaic grid-connected inverters, a large number of inverters are connected to the grid. It can act as a reactive power compensation device to provide reactive power to the grid. The grid-connected power generation operation of the photovoltaic grid-connected system with reactive power compensation function can not only effectively provide the active energy of the grid, but also compensate the reactive power required in the grid, which is conducive to further improvement of the power supply capacity and quality of the grid.

当电网的电压、电流、相位或有功功率、无功功率等信息被传输到并网逆变器而被采集到并网逆变器根据数据进行计算其无功功率时，由于通信线路的延迟，此时线路的相位差有所变化，因此得到的无功功率需求并不能准确地作为当前检测周期的无功功率需求。因此并网逆变器通过这种方式获取的电网无功功率需求只适合于静态无功补偿，不适合于动态无功补偿。When the voltage, current, phase or active power, reactive power and other information of the grid are transmitted to the grid-connected inverter and collected to the grid-connected inverter to calculate its reactive power according to the data, due to the delay of the communication line, At this time, the phase difference of the line changes, so the obtained reactive power demand cannot be accurately used as the reactive power demand of the current detection period. Therefore, the grid reactive power demand obtained by the grid-connected inverter in this way is only suitable for static reactive power compensation, and is not suitable for dynamic reactive power compensation.

本发明实施例中，无功功率检测装置通过获取接入线路的阻抗以及逆变器在当前检测周期的电压、电流及相位差，并使之用于计算电网在当前检测周期的无功功率。本发明实施例将接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，而逆变器的当前检测周期的电压、电流及相位差获取并进行使用并不会造成通信上的延迟，因此无功功率检测装置通过这些数据计算得出的无功功率需求可以较为准确地作为电网当前检测周期的无功功率需求。In the embodiment of the present invention, the reactive power detecting device obtains the impedance of the access line and the voltage, current, and phase difference of the inverter during the current detection period, and uses it to calculate the reactive power of the power grid during the current detection period. In the embodiment of the present invention, the impedance of the current detection period of the access line is approximated to the impedance of the previous detection period, and the voltage, current, and phase difference of the current detection period of the inverter are acquired and used without causing a delay in communication. Therefore, the reactive power demand calculated by the reactive power detecting device through these data can be accurately used as the reactive power demand of the current detection period of the power grid.

本发明实施例的核心思想是，通过获取上一检测周期存储的数据计算得到接入线路的阻抗，作为当前检测周期的阻抗，而接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，通过阻抗以及获取逆变器在当前检测周期的信息来计算无功功率。The core idea of the embodiment of the present invention is that the impedance of the access line is calculated by acquiring the data stored in the previous detection period as the impedance of the current detection period, and the impedance of the current detection period of the access line is approximated by the previous detection period. The impedance, through the impedance and the information of the inverter in the current detection period to calculate the reactive power.

为便于理解，下面对本发明实施例中的具体流程进行描述，请参阅图2，本发明实施例中检测电网动态无功功率的方法一个实施例包括：For the sake of understanding, the specific process in the embodiment of the present invention is described below. Referring to FIG. 2, an embodiment of the method for detecting dynamic reactive power of a power grid in an embodiment of the present invention includes:

201、无功功率检测装置获取接入线路在上一检测周期的阻抗。201. The reactive power detecting device acquires an impedance of the access line during the last detection period.

无功功率检测装置可以是安装在逆变器上的元件，也可以是逆变器本身，也可以是与逆变器串联的一个检测装置，此处不作限定，然而在本实施例中以无功功率检测装置为逆变器本身为例进行说明。The reactive power detecting device may be an element mounted on the inverter, or may be the inverter itself, or may be a detecting device connected in series with the inverter, which is not limited herein, but in this embodiment, The power power detecting device is an example of the inverter itself.

获取接入线路在上一检测周期的阻抗，作为该接入线路在当前检测周期的阻抗是本发明实施例的核心点，由于接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，因此以接入线路在上一检测周期的阻抗可以看作是接入线路的当前检测周期的阻抗，并能够以此较为准确地、准时地计算得到的无功功率。根据不同的具体实施方式，上一检测周期指与当前检测周期相邻的前一个检测周期，或者当前检测周期前预置时间范围内的任一检测周期，或者当前检测周期前制定的某检测周期，不作限定。Obtaining the impedance of the access line in the last detection period, as the impedance of the access line in the current detection period is the core point of the embodiment of the present invention, since the impedance of the current detection period of the access line approximates the impedance of the previous detection period. Therefore, the impedance of the access line during the last detection period can be regarded as the access line. The impedance of the current detection period of the road, and can calculate the reactive power more accurately and on time. According to different specific implementation manners, the previous detection period refers to a previous detection period adjacent to the current detection period, or any detection period within a preset time range before the current detection period, or a certain detection period established before the current detection period. , no restrictions.

202、无功功率检测装置获取逆变器在当前检测周期的电压、电流及相位差。202. The reactive power detecting device acquires a voltage, a current, and a phase difference of the inverter during the current detection period.

当前检测周期为需要无功功率需求进行补偿的检测周期。The current detection period is a detection period that requires compensation for reactive power requirements.

由于在每个检测周期里，逆变器的电压、电流及相位差都有所不同，因此在每个检测需要使用到逆变器的电压或电流时，都需要重新获取当前检测周期的逆变器的电压、电流数据作为当前检测周期使用的电压、电流及相位差。Since the voltage, current and phase difference of the inverter are different in each detection cycle, it is necessary to reacquire the inverter of the current detection cycle when each inverter needs to use the voltage or current of the inverter. The voltage and current data of the device are used as the voltage, current and phase difference used in the current detection cycle.

需要说明的是，在本发明实施例中，相位差是指电压和电流的相位差。逆变器的电压、电流及相位差即为逆变器的电压、逆变器的电流以及逆变器的电压和电流的相位差。电网的电压、电流及相位差即为电网的电压、逆变器的电流以及逆变器的电压和电流的相位差。同样的，变压器的电压、电流及相位差即为变压器的电压、变压器的电流以及变压器的电压和电流的相位差。It should be noted that, in the embodiment of the present invention, the phase difference refers to the phase difference between the voltage and the current. The voltage, current and phase difference of the inverter are the voltage of the inverter, the current of the inverter, and the phase difference between the voltage and current of the inverter. The voltage, current and phase difference of the grid are the voltage of the grid, the current of the inverter and the phase difference between the voltage and current of the inverter. Similarly, the voltage, current, and phase difference of the transformer are the voltage of the transformer, the current of the transformer, and the phase difference between the voltage and current of the transformer.

无功功率检测装置获取逆变器在当前检测周期的电压、电流及相位差的具体方法为通过检测逆变器的电压、电流的幅值，以及电压和电流的相位差，通过电压、电流的幅值及其相位差，计算得到其电压、电流。至于检测电压、电流的幅值及其相位差的具体方法为公知常识，在此不再赘述。The specific method for the reactive power detecting device to obtain the voltage, current and phase difference of the inverter during the current detection period is to detect the voltage and current amplitude of the inverter, and the phase difference between the voltage and the current, and the voltage and current. The amplitude and its phase difference are calculated and its voltage and current are calculated. The specific method for detecting the magnitude of the voltage and current and the phase difference thereof is common knowledge and will not be described herein.

需要说明的话，步骤202与步骤201并没有时序上的关系，即步骤202可以发生在步骤201之前，也可以发生在步骤201之后，此处不作限定。It should be noted that there is no time-series relationship between step 202 and step 201, that is, step 202 may occur before step 201, or may occur after step 201, which is not limited herein.

由于逆变器的信息是可以视为被即时获取的，无功功率检测装置获得逆变器的数据并不会造成通信上的延迟，因此使用逆变器的数据作为参考计算不影响所计算的无功功率的准确性。Since the information of the inverter can be regarded as being acquired immediately, the data obtained by the reactive power detecting device from the inverter does not cause a delay in communication, so using the data of the inverter as a reference calculation does not affect the calculated The accuracy of reactive power.

203、无功功率检测装置在当前检测周期根据接入线路的阻抗以及逆变器在当前检测周期的电压、电流及相位差计算该电网在当前检测周期的电压、电流及相位差。203. The reactive power detecting device calculates the voltage, current, and phase difference of the power grid during the current detection period according to the impedance of the access line and the voltage, current, and phase difference of the current detection period of the inverter during the current detection period.

无功功率检测装置采用下述公式计算该电网的电压、电流：The reactive power detecting device calculates the voltage and current of the power grid by the following formula:

θ_grid＝θ_live+θ_inv，θ _grid =θ _live +θ _inv ,

其中，

为电网的电压，

为逆变器的电压，Z_line为接入线路的阻抗，

为电网的电流，

为逆变器的电流，θ_grid为电网的电压和电流的相位差，θ_inv为逆变器的电压和电流的相位差，θ_line为Z_line的阻抗角。among them,

For the voltage of the grid,

For the voltage of the inverter, Z _line is the impedance of the access line.

Current for the grid,

The phase difference current of the inverter, _grid phase difference, θ _inv grid voltage and current of the inverter voltage and current θ, θ _line impedance Z _line of the angle.

由于逆变器、各级变压器以及电网为串联的关系，因此逆变器的电流也可以看作是电网的电流，也可以看作是接入线路的电流。因此逆变器的电流与接入线路阻抗的乘积即为接入线路的电流与接入线路的阻抗的乘积，即得到接入线路的电压。Since the inverter, the transformers at all levels, and the grid are in series, the current of the inverter can also be regarded as the current of the grid, or it can be regarded as the current of the access line. Therefore, the product of the current of the inverter and the impedance of the access line is the product of the current of the access line and the impedance of the access line, that is, the voltage of the access line is obtained.

由于逆变器、各级变压器以及电网为串联的关系，逆变器的电压一路经过变压器会被各级变压器分压，因此将逆变器的电压减去接入线路的电压即得到电网的电压。Since the inverter, the transformers at all levels, and the power grid are in series, the voltage of the inverter will be divided by the transformers at all times through the transformer. Therefore, the voltage of the inverter is subtracted from the voltage of the access line. .

如上，即得到电网的电压、电流及相位差。As above, the voltage, current and phase difference of the grid are obtained.

204、无功功率检测装置根据计算得到的该电网的电压、电流及相位差计算当前检测周期电网的动态无功功率；204. The reactive power detecting device calculates dynamic reactive power of the current detecting period power grid according to the calculated voltage, current, and phase difference of the power grid;

本发明实施例中的无功功率检测装置使用不存在通信延迟的数据进行无功检测，因此能及时地为电网计算动态无功功率，进而使电网据此进行恰当的无功补偿。The reactive power detecting device in the embodiment of the present invention performs reactive power detection using data without communication delay, so that dynamic reactive power can be calculated for the power grid in time, thereby enabling the power grid to perform appropriate reactive power compensation accordingly.

无功功率检测装置采用下述公式计算当前检测周期电网的动态无功功率：The reactive power detecting device uses the following formula to calculate the dynamic reactive power of the grid during the current detection period:

其中，Q_grid为当前检测周期电网的动态无功功率，U_grid为电网的电压有效值，I_grid为电网的电流有效值，θ_grid为电网的电压和电流的相位差。Among them, Q _grid is the dynamic reactive power of the _grid in the current detection period, U _grid is the voltage effective value of the _grid , I _grid is the current RMS value of the _grid , and θ _grid is the phase difference between the voltage and current of the grid.

无功功率检测装置根据计算得到的当前检测周期电网的无功功率指示逆变器控制电信号中电压、电流，以使得电网得到该无功功率作为无功补偿。The reactive power detecting device instructs the inverter to control the voltage and current in the electrical signal according to the calculated reactive power of the current detection period, so that the grid obtains the reactive power as reactive power compensation.

本发明实施例将接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，并及时获取当前检测周期逆变器端的电压、电流，避免了通讯延迟对于数据获取的影响，因此无功功率检测装置通过这些数据计算得出的无功功率需求可以较为准确地作为电网当前检测周期的无功功率需求。In the embodiment of the present invention, the impedance of the current detection period of the access line is approximated to the impedance of the previous detection period, and the voltage and current of the inverter end of the current detection period are obtained in time, thereby avoiding the influence of the communication delay on the data acquisition, and thus the reactive power The power detection device calculates the reactive power required by these data. The request can be more accurately used as the reactive power demand of the current detection cycle of the power grid.

无功功率检测装置通过获取接入线路的信息以及获取逆变器在当前检测周期的电压、电流，并通过第一计算模块计算接入线路的阻抗，进而计算得到电网在当前检测周期的无功功率。接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，并及时获取当前检测周期逆变器端的电压、电流，避免了通讯延迟对于数据获取的影响，因此无功功率检测装置通过这些数据计算得出的无功功率需求可以较为准确地作为电网当前检测周期的无功功率需求。The reactive power detecting device obtains the information of the access line and acquires the voltage and current of the inverter during the current detection period, and calculates the impedance of the access line through the first calculation module, thereby calculating the reactive power of the power grid in the current detection period. power. The impedance of the current detection period of the access line approximates the impedance of the previous detection period, and timely acquires the voltage and current of the inverter end of the current detection period, thereby avoiding the influence of the communication delay on the data acquisition, so the reactive power detection device passes these The reactive power demand calculated by the data can be more accurately used as the reactive power demand of the current detection period of the grid.

本实施例中，获取接入线路在上一检测周期的阻抗可以根据该接入线路在上一检测周期的电压、电流及相位差计算该接入线路的阻抗，也可以根据该电网在上一检测周期的电压、电流以及该逆变器在上一检测周期的电压、电流，计算该接入线路的阻抗，具体请参阅图3，本发明实施例检测电网动态无功功率的方法另一实施例包括：In this embodiment, obtaining the impedance of the access line in the previous detection period may calculate the impedance of the access line according to the voltage, current, and phase difference of the access line in the previous detection period, or may be based on the power grid. The voltage and current of the detection period and the voltage and current of the inverter during the last detection period are calculated, and the impedance of the access line is calculated. Referring to FIG. 3, another embodiment of the method for detecting the dynamic reactive power of the power grid according to the embodiment of the present invention is shown. Examples include:

一、通过获取接入线路的数据计算得到接入线路在上一检测周期的阻抗，作为该接入线路在当前检测周期的阻抗：1. Calculate the impedance of the access line in the previous detection period by obtaining the data of the access line as the impedance of the access line in the current detection period:

301、无功功率检测装置获取接入线路中每一级变压器在上一检测周期的电压、电流；301. The reactive power detecting device obtains the voltage and current of the transformer in each stage of the access line during the previous detection period;

本发明实施例中，根据在接入线路在上一检测周期采集到的电压、电流及相位差计算该接入线路的阻抗。In the embodiment of the present invention, the impedance of the access line is calculated according to the voltage, current, and phase difference acquired during the last detection period of the access line.

上一检测周期是指无功功率检测装置获取到电网、变压器、逆变器的电压、电流、相位、有功功率、无功功率等信息的最新检测周期，可以为最紧靠当前检测周期的上一个检测周期，也可以为由于通信延迟而上一检测周期的相关信息还未到的时候的更早的检测周期，也可以为指定的更早的检测周期，此处不作限定。The last detection cycle refers to the latest detection cycle of the reactive power detection device to obtain the voltage, current, phase, active power, reactive power and other information of the grid, transformer, inverter, etc., which can be the closest to the current detection cycle. A detection period may be an earlier detection period when the relevant information of the previous detection period has not arrived due to the communication delay, and may be a designated earlier detection period, which is not limited herein.

需要说明的是，此处该的电压为电压向量，与后述的电压有效值有所区别；同理，此处该的电流为电流向量，与后述的电流有效值有所区别。而所称无功功率检测装置获取的电压、电流、相位、有功功率、无功功率等均为其信息数据，而非电压、电流、相位、有功功率、无功功率等本身。而电压有效值与电流有效值为公知常识，在此不再赘述。It should be noted that the voltage here is a voltage vector, which is different from the voltage effective value to be described later. Similarly, the current here is a current vector, which is different from the current effective value described later. The voltage, current, phase, active power, and reactive power acquired by the so-called reactive power detecting device are all information data, not voltage, current, phase, active power, reactive power, and the like. The effective value of the voltage and the effective value of the current are common knowledge, and will not be described here.

当逆变器工作时，会有电信号通过接入线路从逆变器通向电网，此时在接入线路中的每一级变压器、逆变器以及电网会产生相应的电压、电流的数据都会被无功功率检测装置采集，并被存储在无功功率检测装置的存储模块中，并作为更新的数据替换掉原来的数据，而该上一检测周期的数据是指最新更新的数据。当无功功率检测装置在任意一个检测周期需要用上存储的电流和电压的相关数据时，就会从存储模块中获取得到。When the inverter is working, there will be an electrical signal passing through the access line from the inverter to the grid. Each stage of the transformer, inverter and grid in the line will generate corresponding voltage and current data will be collected by the reactive power detection device, and stored in the storage module of the reactive power detection device, and as an update The data replaces the original data, and the data of the last detection cycle refers to the latest updated data. When the reactive power detecting device needs to use the data related to the stored current and voltage in any one of the detection cycles, it is obtained from the storage module.

302、无功功率检测装置根据每一级变压器在上一检测周期的电压、电流计算每一级变压器的阻抗；302. The reactive power detecting device calculates the impedance of each stage transformer according to the voltage and current of each stage of the transformer in the previous detecting period;

首先计算每一级变压器在上一检测周期的电压和电流的相位差θ，作为该级变压器的阻抗角，然后采用下述公式计算该级变压器的阻抗：First, calculate the phase difference θ of the voltage and current of each stage of the transformer in the previous detection period as the impedance angle of the transformer of the stage, and then calculate the impedance of the transformer of the stage by the following formula:

其中，Z为该级变压器的阻抗，U为该级变压器的电压有效值，I为该级变压器的电流有效值，θ为该级变压器的阻抗角。Where Z is the impedance of the transformer of the stage, U is the effective value of the voltage of the transformer of the stage, I is the current effective value of the transformer of the stage, and θ is the impedance angle of the transformer of the stage.

逆变器每次计算得到的每一级变压器的阻抗的数据都会被无功功率检测装置存储在无功功率检测装置的存储模块中，并作为更新的数据替换掉原来的数据。当无功功率检测装置在任意一个检测周期需要用上存储的某一级的变压器的阻抗时，就会从存储模块中获取得到。由于变压器的阻抗可以被看作在一定时间不变的数据，因此当以此作为之后的若干检测周期所使用的数据，可以被看作是准确的数据。The data of the impedance of each stage of the transformer calculated by the inverter is stored in the storage module of the reactive power detecting device by the reactive power detecting device, and the original data is replaced as the updated data. When the reactive power detecting device needs to use the impedance of a certain level of the stored transformer in any one of the detection cycles, it is obtained from the storage module. Since the impedance of the transformer can be regarded as data that is constant at a certain time, the data used as the subsequent detection periods can be regarded as accurate data.

在接入线路中可以仅存在串联的变压器，也可以存在其他与变压器串联的元件，这种情况下也可以将其他与变压串联的元件当作在接入线路的一个变压器看待，此处不作限定，然而在本实施例中以在接入线路中仅存在变压为例进行说明。而由于接入线路中的电线的阻抗太小，可以被忽略不计，因此在本发明实施例中不作考虑。In the access line, there may be only a series connected transformer, or there may be other components connected in series with the transformer. In this case, other components connected in series with the transformer can also be regarded as a transformer in the access line. It is defined, however, in the present embodiment, an example in which only a transformer is present in the access line will be described. However, since the impedance of the wires in the access line is too small, it can be ignored, and therefore is not considered in the embodiment of the present invention.

303、无功功率检测装置将该多级变压器的阻抗进行求和，得到接入线路在上一检测周期的阻抗，作为该接入线路在该当前检测周期的阻抗；303. The reactive power detecting device sums the impedances of the multi-stage transformers to obtain an impedance of the access line in the last detecting period, as the impedance of the access line in the current detecting period;

由于在本实施例中接入线路中的电线的阻抗忽略不计，则接入线路的阻抗可以看成是多级变压器的阻抗之和，因此将接入线路中的多级变压器的阻抗相加便得到该接入线路的阻抗，作为该接入线路在该当前检测周期的阻抗。Since the impedance of the wires in the access line is negligible in the present embodiment, the impedance of the access line can be regarded as the sum of the impedances of the multi-stage transformers, so that the impedances of the multi-stage transformers in the access line are added. The impedance of the access line is obtained as the impedance of the access line during the current detection period.

逆变器每次计算得到的阻抗都会被无功功率检测装置存储在无功功率检测装置的存储模块中，并作为更新的数据替换掉原来的数据。当无功功率检测装置在任意一个检测周期需要用上存储的阻抗时，就会从存储模块中获取得到。由于阻抗可以被看作在一定时间不变的数据，因此当以此作为之后的若干检测周期所使用的数据，可以被看作是准确的数据。The impedance calculated by the inverter each time is stored in the memory module of the reactive power detecting device by the reactive power detecting device, and the original data is replaced as updated data. Reactive power detection When the device needs to use the stored impedance in any one of the detection cycles, it will be obtained from the memory module. Since the impedance can be regarded as data that is constant at a certain time, the data used as the subsequent several detection periods can be regarded as accurate data.

304、无功功率检测装置获取逆变器在当前检测周期的电压、电流及相位差；304. The reactive power detecting device acquires a voltage, a current, and a phase difference of the inverter during the current detection period;

305、无功功率检测装置在当前检测周期根据接入线路的阻抗以及逆变器在当前检测周期的电压、电流及相位差计算该电网在当前检测周期的电压、电流及相位差；305. The reactive power detecting device calculates, according to the impedance of the access line and the voltage, current, and phase difference of the inverter during the current detection period, the voltage, current, and phase difference of the power grid during the current detection period;

306、无功功率检测装置根据计算得到的该电网的电压、电流及相位差计算当前检测周期电网的动态无功功率；306. The reactive power detecting device calculates dynamic reactive power of the current detecting period power grid according to the calculated voltage, current, and phase difference of the power grid;

本实施例中步骤304至步骤306与上述实施例的步骤202至步骤204相同，此处不赘述。 Steps 304 to 306 in this embodiment are the same as steps 202 to 204 of the foregoing embodiment, and are not described herein.

由于在发明实施例中，接入线路被看成是串联的变压器组成的，因此接入线路的阻抗可以看成为接入线路中所有串联的变压器的阻抗之和，所以直接通过计算串联的多级变压器在进行求和，可以直接得到准确的接入线路的阻抗数据。Since in the embodiment of the invention, the access line is formed as a transformer connected in series, the impedance of the access line can be regarded as the sum of the impedances of all the series connected transformers in the access line, so the multi-stage in series is directly calculated. When the transformer is summed, the impedance data of the access line can be directly obtained.

二、通过获取上一检测周期电网和逆变器的数据，计算得到接入线路在上一检测周期的阻抗，作为该接入线路在当前检测周期的阻抗：Second, by obtaining the data of the grid and the inverter of the previous detection cycle, the impedance of the access line in the previous detection period is calculated as the impedance of the access line in the current detection period:

401、无功功率检测装置获取电网在上一检测周期的电压、电流以及逆变器在上一检测周期的电压、电流；401. The reactive power detecting device obtains the voltage and current of the grid during the last detection period and the voltage and current of the inverter during the last detection period;

当逆变器工作时，会有电信号通过接入线路从逆变器通向电网，此时在逆变器和电网会产生相应的电压、电流。逆变器和电网每次产生的电流和电压的数据都会被无功功率检测装置采集，并被存储在无功功率检测装置的存储模块中，并作为更新的数据替换掉原来的数据。当无功功率检测装置在任意一个检测周期需要用上存储的电流和电压的相关数据时，就会从存储模块中获取得到。When the inverter is working, there will be an electrical signal passing through the access line from the inverter to the grid. At this time, the voltage and current will be generated in the inverter and the grid. The current and voltage data generated by the inverter and the grid are collected by the reactive power detecting device and stored in the memory module of the reactive power detecting device, and the original data is replaced as updated data. When the reactive power detecting device needs to use the data related to the stored current and voltage in any one of the detection cycles, it is obtained from the storage module.

402、根据该电网在上一检测周期的电压、电流和该逆变器在上一检测周期的电压、电流计算该接入线路在上一检测周期的阻抗，采用下述公式计算该接入线路在上一检测周期的阻抗：402. Calculate the impedance of the access line in the previous detection period according to the voltage and current of the power grid in the previous detection period and the voltage and current of the inverter in the previous detection period, and calculate the access line by using the following formula. Impedance during the last detection cycle:

其中，

为接入线路的电压，

为接入线路的电流，Z_line为接入线路的阻抗，

为电网的电流，

为逆变器的电压。among them,

To access the voltage of the line,

For the current to the _line , Z _line is the impedance of the access line.

Current for the grid,

The voltage for the inverter.

逆变器每次计算得到的每一级变压器的阻抗的数据都会被无功功率检测装置存储在无功功率检测装置的存储模块中，并作为更新的数据替换掉原来的数据。当无功功率检测装置在任意一个检测周期需要用上存储的某一级的变压器的阻抗时，就会从存储模块中获取得到。The data of the impedance of each stage of the transformer calculated by the inverter is stored in the storage module of the reactive power detecting device by the reactive power detecting device, and the original data is replaced as the updated data. When the reactive power detecting device needs to use the impedance of a certain level of the stored transformer in any one of the detection cycles, it is obtained from the storage module.

需要特别说明的是，无功功率检测装置还可以通过获取存储的上一检测周期的无功功率或有功功率、上一检测周期的逆变器的电压、电流计算获得阻抗的数据，只要能通过存储的上一检测周期的数据计算得到电网的阻抗的最新数据，在此不作限定。It should be specially noted that the reactive power detecting device can also obtain the impedance data by obtaining the stored reactive power or active power of the last detection cycle, the voltage of the inverter of the previous detection cycle, and the current, as long as it can pass The data of the last detection period of the storage is calculated to obtain the latest data of the impedance of the power grid, which is not limited herein.

403、无功功率检测装置获取逆变器在当前检测周期的电压、电流及相位差；403. The reactive power detecting device acquires a voltage, a current, and a phase difference of the inverter during the current detection period;

404、无功功率检测装置在当前检测周期根据接入线路的阻抗以及逆变器在当前检测周期的电压、电流及相位差计算该电网在当前检测周期的电压、电流及相位差；404. The reactive power detecting device calculates a voltage, a current, and a phase difference of the power grid during the current detection period according to the impedance of the access line and the voltage, current, and phase difference of the current detection period of the inverter during the current detection period;

405、无功功率检测装置根据计算得到的该电网的电压、电流及相位差计算当前检测周期电网的动态无功功率；405. The reactive power detecting device calculates the dynamic reactive power of the current detecting period power grid according to the calculated voltage, current, and phase difference of the power grid;

本实施例中步骤403至步骤405与上述实施例的步骤202至步骤204相同，此处不再赘述。 Steps 403 to 405 in this embodiment are the same as steps 202 to 204 of the foregoing embodiment, and details are not described herein again.

由于本实施例是根据电网和逆变器的数据计算得到的接入线路的阻抗的，而不是根据变压器的数据计算的，由于变压器的数量比较多，所使用到的数据比较多，而使用逆变器和电网的数据计算更加简便，使用的数据更少，减轻无功功率检测装置的处理的负担。Since the present embodiment is based on the impedance of the access line calculated from the data of the power grid and the inverter, rather than being calculated based on the data of the transformer, since the number of transformers is relatively large, more data is used, and the inverse is used. The data calculation of the transformer and the grid is simpler, the data used is less, and the burden of processing the reactive power detecting device is reduced.

然而本发明实施例中，不仅仅以上两种获取接入线路阻抗的方式，如还可以为由第三方设备获取，在此不作限定。However, in the embodiment of the present invention, not only the above two methods for obtaining the impedance of the access line, but also may be obtained by a third-party device, which is not limited herein.

上面对本发明实施例中检测电网动态无功功率的方法进行描述，下面对本发明实施例中的无功功率检测装置进行描述， The method for detecting the dynamic reactive power of the power grid in the embodiment of the present invention is described above. The reactive power detecting device in the embodiment of the present invention is described below.

请参考图5，本发明实施例还提供一种无功功率检测装置500，用于电网***，该电网***包括电网以及通过接入线路接入该电网的逆变器，该逆变器把直流电转变成交流电通过该接入线路并入该电网中；Referring to FIG. 5, an embodiment of the present invention further provides a reactive power detecting apparatus 500 for a power grid system, where the power grid system includes a power grid and an inverter that accesses the power grid through an access line, and the inverter turns the DC power Converted into alternating current into the grid through the access line;

该无功功率检测装置包括：The reactive power detecting device includes:

第一获取模块501，用于获取该接入线路在上一检测周期的阻抗；其中，根据不同的具体实施方式，上一检测周期指与当前检测周期相邻的前一个检测周期，或者当前检测周期前预置时间范围内的任一检测周期，或者当前检测周期前制定的某检测周期，不作限定；The first obtaining module 501 is configured to obtain an impedance of the access line in a previous detection period. According to different specific implementation manners, the previous detection period refers to a previous detection period adjacent to the current detection period, or current detection. Any detection period within the preset time range before the period, or a certain detection period established before the current detection period, is not limited;

第二获取模块502，用于获取该逆变器在当前检测周期的电压、电流及相位差；a second obtaining module 502, configured to acquire a voltage, a current, and a phase difference of the inverter during a current detection period;

第一计算模块503，用于在该当前检测周期根据该第一获取模块501获取的该接入线路在该当前检测周期的阻抗以及该第二模块502获取的该逆变器在该当前检测周期的电压、电流及相位差计算该电网的电压、电流及相位差；a first calculation module 503, configured to acquire, according to the current acquisition period, the impedance of the access line acquired by the first acquisition module 501 in the current detection period, and the inverter acquired by the second module 502 in the current detection period. Voltage, current and phase difference calculate the voltage, current and phase difference of the grid;

第二计算模块504，用于根据该第一计算模块503计算得到的该电网的电压、电流及相位差计算该当前检测周期该电网的动态无功功率。The second calculating module 504 is configured to calculate dynamic reactive power of the power grid according to the voltage, current, and phase difference of the power grid calculated by the first calculating module 503.

无功功率检测装置通过第一获取模块501获取接入线路的信息以及通过第二获取模块502获取逆变器在当前检测周期的电压、电流，并通过第一计算模块503计算接入线路的阻抗，进而通过第二计算模块504计算得到电网在当前检测周期的无功功率。本发明实施例将接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，并及时获取当前检测周期逆变器端的电压、电流，避免了通讯延迟对于数据获取的影响，因此无功功率检测装置通过这些数据计算得出的无功功率需求可以较为准确地作为电网当前检测周期的无功功率需求。The reactive power detecting device acquires the information of the access line through the first acquiring module 501, and acquires the voltage and current of the inverter in the current detecting period through the second acquiring module 502, and calculates the impedance of the access line through the first calculating module 503. Then, the second computing module 504 calculates the reactive power of the grid during the current detection period. In the embodiment of the present invention, the impedance of the current detection period of the access line is approximated to the impedance of the previous detection period, and the voltage and current of the inverter end of the current detection period are obtained in time, thereby avoiding the influence of the communication delay on the data acquisition, and thus the reactive power The reactive power demand calculated by the power detecting device through these data can be more accurately used as the reactive power demand of the current detection period of the power grid.

请参考图6，在一些实施例中，该第一获取模块501包括：Referring to FIG. 6, in some embodiments, the first obtaining module 501 includes:

第一获取单元5011，用于获取该接入线路在该上一检测周期的电压、电流及相位差；The first obtaining unit 5011 is configured to obtain a voltage, a current, and a phase difference of the access line during the last detection period;

第一计算单元5012，用于该第一获取单元获取的该接入线路在该上一检测周期的电压、电流及相位差计算该接入线路的阻抗。The first calculating unit 5012 is configured to calculate, according to the voltage, current, and phase difference of the access line acquired by the first acquiring unit, the impedance of the access line.

请参考图6，一些实施例中，该接入线路包括串联的多级变压器；Referring to FIG. 6, in some embodiments, the access line includes a multi-stage transformer connected in series;

该第一获取单元5011，具体用于获取该多级变压器中的每一级变压器在该上一检测周期的电压、电流及相位差； The first obtaining unit 5011 is specifically configured to acquire voltage, current, and phase difference of the transformer of each stage in the multi-stage transformer during the last detection period;

该第一计算单元5012，具体用于根据该第一获取单元获取的该每一级变压器在该上一检测周期的电压、电流及相位差，计算该每一级变压器的阻抗，并对该多级变压器的阻抗求和，得到该接入线路的阻抗。The first calculating unit 5012 is configured to calculate, according to the voltage, current, and phase difference of the transformer of each stage in the last detection period acquired by the first acquiring unit, the impedance of the transformer of each stage, and the multiple The impedance of the transformer is summed to obtain the impedance of the access line.

请参考图7，在一些实施例中，该第一计算单元5012具体用于根据该第一获取单元获取的该每一级变压器在该上一检测周期的相位差θ，作为该级变压器的阻抗角，并采用下述公式计算该级变压器的阻抗：Referring to FIG. 7 , in some embodiments, the first calculating unit 5012 is specifically configured to use the phase difference θ of the transformer of each stage in the last detection period acquired by the first acquiring unit as the impedance of the transformer of the stage. Angle, and calculate the impedance of the transformer of this class by the following formula:

其中，Z为该级变压器的阻抗，U为该级变压器的电压有效值，I为该级变压器的电流有效值，θ为该级变压器的阻抗角，并对该多级变压器的阻抗求和，得到该接入线路的阻抗，作为该接入线路在当前检测周期的阻抗。Where Z is the impedance of the transformer of the stage, U is the effective value of the voltage of the transformer of the stage, I is the current effective value of the transformer of the stage, θ is the impedance angle of the transformer of the stage, and the impedance of the multi-stage transformer is summed, The impedance of the access line is obtained as the impedance of the access line during the current detection period.

请参考图8，在一些实施例中，该第一获取模块501包括：Referring to FIG. 8, in some embodiments, the first obtaining module 501 includes:

第二获取单元5013，用于获取该电网在该上一检测周期的电压、电流以及该逆变器在该上一检测周期的电压、电流；a second obtaining unit 5013, configured to acquire voltages and currents of the power grid during the last detection period, and voltages and currents of the inverter during the last detection period;

第二计算单元5014，用于根据该第二获取单元获取的该电网在该上一检测周期的电压、电流以及该逆变器在该上一检测周期的电压、电流，计算该接入线路的阻抗。a second calculating unit 5014, configured to calculate, according to the voltage and current of the power grid of the last detection period acquired by the second acquiring unit, and the voltage and current of the inverter during the last detection period, calculate the access line impedance.

请参考图9，在一些实施例中，该第二计算单元5014具体用于采用下述公式计算该接入线路的阻抗：Referring to FIG. 9, in some embodiments, the second calculating unit 5014 is specifically configured to calculate the impedance of the access line by using the following formula:

其中，

为接入线路的电压，

为接入线路的电流，Z_line为接入线路的阻抗，

为电网的电流，

为逆变器的电压。among them,

To access the voltage of the line,

For the current to the _line , Z _line is the impedance of the access line.

Current for the grid,

The voltage for the inverter.

请参考图10，在一些实施例中，该第一计算模块503具体用于采用下述公式计算该电网的电压、电流及相位差；Referring to FIG. 10, in some embodiments, the first calculating module 503 is specifically configured to adopt the following The formula calculates the voltage, current and phase difference of the grid;

θ_grid＝θ_live+θ_inv，θ _grid =θ _live +θ _inv ,

其中，

为电网的电压，

为逆变器的电压，Z_line为接入线路的阻抗

为电网的电流，

For the voltage of the grid,

For the voltage of the inverter, Z _line is the impedance of the access line.

Current for the grid,

For the current of the inverter, θ _grid is the phase difference between the voltage and current of the grid, θ _inv is the phase difference between the voltage and current of the inverter, and θ _line is the impedance angle of Z _line .

由于根据电网和逆变器的数据计算得到的接入线路的阻抗，作为该接入线路在当前检测周期的阻抗，而不是根据变压器的数据计算的，变压器的数量比较多，所使用到的数据比较多，而使用逆变器和电网的数据计算更加简便，使用的数据更少，减轻无功功率检测装置的处理的负担。Since the impedance of the access line calculated from the data of the grid and the inverter is calculated as the impedance of the access line at the current detection period, rather than based on the data of the transformer, the number of transformers is relatively large, and the used data is used. There are many, and the data calculation using the inverter and the grid is simpler, the data used is less, and the burden of the processing of the reactive power detecting device is reduced.

请参考图10，在一些实施例中，该第二计算模块504具体用于采用下述公式计算当前检测周期该电网的动态无功功率：Referring to FIG. 10, in some embodiments, the second calculating module 504 is specifically configured to calculate the dynamic reactive power of the power grid in the current detection period by using the following formula:

上面从模块化功能实体的角度对本发明实施例中的网络设备进行描述，下面从硬件处理的角度对本发明实施例中的无功功率检测装置进行描述，请参阅图11，本发明实施例提供一种无功功率检测装置，用于电网***，该电网***包括电网以及通过接入线路接入该电网的逆变器，该逆变器把直流电转变成交流电通过该接入线路并入该电网中；The network device in the embodiment of the present invention is described above from the perspective of a modular functional entity. The reactive power detecting device in the embodiment of the present invention is described below from the perspective of hardware processing. Referring to FIG. 11, an embodiment of the present invention provides a a reactive power detecting device for a power grid system, the power grid system comprising a power grid and an inverter connected to the power grid through an access line, the inverter converting the direct current power into an alternating current power into the power grid through the access line ;

采集器601、处理单元602； Collector 601, processing unit 602;

采集器601、处理单元602通过线路连接；The collector 601 and the processing unit 602 are connected by a line;

采集器601用于获取所述逆变器在当前检测周期的电压、电流及相位差；The collector 601 is configured to acquire a voltage, a current, and a phase difference of the inverter during a current detection period;

处理单元602用于根据所述接入线路在上一检测周期的阻抗以及所述逆变器在所述当前检测周期的电压、电流及相位差，计算所述电网的电压、电流及相位差；且根据所述计算得到的所述电网的电压、电流及相位差计算所述电网的无功功率。The processing unit 602 is configured to calculate a voltage, a current, and a phase difference of the power grid according to an impedance of the access line in a previous detection period and a voltage, a current, and a phase difference of the inverter in the current detection period; And calculating reactive power of the power grid according to the calculated voltage, current, and phase difference of the power grid.

而接入线路在上一检测周期的阻抗的获取可以有多种方式，在一种具体的实施方式中，该采集器601，用于获取接入线路在上一检测周期的电压、电流及相位差；该处理单元602，用于根据接入线路在上一检测周期的电压、电流及相位差，计算接入线路在上一检测周期的阻抗；本具体实施例所对应的电路结构如图12所示，其中采集器601具体包括电流表603、电压表604等，用来获取电流、电压、相位差等电路参数数据。在另一种具体的实施方式中，该采集器601，用于获取电网在上一检测周期的电压、电流以及逆变器在上一检测周期的电压、电流；该处理单元602，用于根据电网在上一检测周期的电压、电流以及逆变器在上一检测周期的电压、电流，计算接入线路在上一检测周期的阻抗；本具体实施例所对应的电路结构如图13所示，其中采集器601具体包括电流表603、电压表604等，用来获取电流、电压、相位差等电路参数数据。The acquisition of the impedance of the access line in the previous detection period may be performed in various manners. In a specific implementation, the collector 601 is configured to obtain the voltage, current, and phase of the access line during the previous detection period. The processing unit 602 is configured to calculate the impedance of the access line in the previous detection period according to the voltage, current, and phase difference of the access line in the previous detection period; the circuit structure corresponding to the specific embodiment is shown in FIG. 12 . As shown, the collector 601 specifically includes an ammeter 603, a voltmeter 604, and the like for acquiring circuit parameter data such as current, voltage, and phase difference. In another specific implementation, the collector 601 is configured to acquire voltages and currents of the power grid during the last detection period and voltages and currents of the inverter during the last detection period; and the processing unit 602 is configured to The voltage and current of the power grid in the last detection period and the voltage and current of the inverter in the previous detection period calculate the impedance of the access line in the previous detection period; the circuit structure corresponding to the specific embodiment is as shown in FIG. The collector 601 specifically includes an ammeter 603, a voltmeter 604, and the like for acquiring circuit parameter data such as current, voltage, and phase difference.

应理解，采集器601可以包括电压表、电流表、阻抗计、电流电压感应模块等中的一种或多种的组合，本发明对用来测量电路的电压、电流、阻抗、相位差等电路参数的测量器或感应器，不作限定，可以为电子仪器或者机械仪器，不作限定。It should be understood that the collector 601 may include a combination of one or more of a voltmeter, an ammeter, an impedance meter, a current voltage sensing module, etc., and the present invention is used to measure circuit parameters such as voltage, current, impedance, and phase difference of the circuit. The measuring device or the sensor is not limited, and may be an electronic device or a mechanical device, which is not limited.

应理解，处理单元602可以包括处理器、计算器、存储器等各种用于处理采集器所采集的电路物理量参数数据的仪器或者芯片，不作限定。It should be understood that the processing unit 602 may include various instruments, such as a processor, a calculator, a memory, and the like, for processing the physical quantity parameter data collected by the collector, and is not limited.

无功功率检测装置通过获取接入线路的信息以及获取逆变器在当前检测周期的电压、电流，并通过第一计算模块计算接入线路的阻抗，作为该接入线路在当前检测周期的阻抗，进而计算得到电网在当前检测周期的无功功率。本发明实施例将接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，并及时获取当前检测周期逆变器端的电压、电流，避免了通讯延迟对于数据获取的影响，因此无功功率检测装置通过这些数据计算得出的无功功率需求可以较为准确地作为电网当前检测周期的无功功率需求。The reactive power detecting device obtains the information of the access line and acquires the voltage and current of the inverter during the current detection period, and calculates the impedance of the access line through the first calculating module as the impedance of the access line in the current detection period. And then calculate the reactive power of the grid during the current detection period. In the embodiment of the present invention, the impedance of the current detection period of the access line is approximated to the impedance of the previous detection period, and the voltage and current of the inverter end of the current detection period are obtained in time, thereby avoiding the influence of the communication delay on the data acquisition, and thus the reactive power The power detection device can calculate the reactive power demand through these data. To accurately calculate the reactive power demand for the current detection cycle of the grid.

本发明实施例提供一种逆变器，用于电网***，该电网***包括电网以及通过接入线路接入该电网的逆变器，该逆变器把直流电转变成交流电通过该接入线路并入该电网中；该逆变器包括：无功功率检测模块和电流转换模块；该电流转换模块用于把输入的直流电转换为交流电输出；该无功功率检测模块采用与图11所示的无功功率检测装置相同的结构，执行相同的功能。An embodiment of the present invention provides an inverter for a power grid system, where the power grid system includes a power grid and an inverter that accesses the power grid through an access line, and the inverter converts direct current power into alternating current power through the access line. Entering the power grid; the inverter includes: a reactive power detecting module and a current converting module; the current converting module is configured to convert the input direct current into an alternating current output; the reactive power detecting module adopts the none shown in FIG. The power power detecting device has the same structure and performs the same function.

结合上述本发明实施例在一种具体实现方式中，该逆变器的无功功率检测模块还包括通讯单元，用于接收远程采集的电路参数的数据，供给无功功率检测模块中的处理单元使用。In combination with the foregoing embodiment of the present invention, in a specific implementation manner, the reactive power detecting module of the inverter further includes a communication unit, configured to receive data of the remotely collected circuit parameters, and supply the processing unit in the reactive power detecting module. use.

本发明实施例将接入线路的当前检测周期的阻抗近似于上一检测周期的阻抗，并及时获取当前检测周期逆变器端的电压、电流，避免了通讯延迟对于数据获取的影响，因此无功功率检测装置通过这些数据计算得出的无功功率需求可以较为准确地作为电网当前检测周期的无功功率需求。同时，将无功功率检测模块集成于传统的逆变器内，简化了***的结构。进一步的，通过接收远程采集的电路参数数据，更方便操作。In the embodiment of the present invention, the impedance of the current detection period of the access line is approximated to the impedance of the previous detection period, and the voltage and current of the inverter end of the current detection period are obtained in time, thereby avoiding the influence of the communication delay on the data acquisition, and thus the reactive power The reactive power demand calculated by the power detecting device through these data can be more accurately used as the reactive power demand of the current detection period of the power grid. At the same time, the reactive power detection module is integrated into the traditional inverter, which simplifies the structure of the system. Further, it is more convenient to operate by receiving circuit parameter data collected remotely.

所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的***，装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。A person skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the system, the device and the unit described above can refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.

在本申请所提供的几个实施例中，应该理解到，所揭露的***，装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，该单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个***，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。In the several embodiments provided by the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or may be Integrate into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

该作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

另外，在本发明各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。In addition, each functional unit in various embodiments of the present invention may be integrated in one processing unit. It is also possible that each unit physically exists alone, or two or more units may be integrated in one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

该集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本发明的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本发明各个实施例该方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(ROM，Read-Only Memory)、随机存取存储器(RAM，Random Access Memory)、磁碟或者光盘等各种可以存储程序代码的介质。The integrated unit, if implemented in the form of a software functional unit and sold or used as a standalone product, can be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product stored in a storage medium. A number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method of various embodiments of the present invention. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like. .

以上所述，以上实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的精神和范围。 The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the embodiments are modified, or the equivalents of the technical features are replaced by the equivalents of the technical solutions of the embodiments of the present invention.

Claims

一种检测电网动态无功功率的方法，其特征在于，所述方法用于电网***，所述电网***包括电网以及通过接入线路接入所述电网的逆变器，所述逆变器把直流电转变成交流电通过所述接入线路并入所述电网中；A method for detecting dynamic reactive power of a power grid, characterized in that the method is applied to a power grid system, the power grid system comprising a power grid and an inverter that accesses the power grid through an access line, the inverter Converting direct current into alternating current into the power grid through the access line;

所述方法包括：The method includes:

获取所述接入线路在上一检测周期的阻抗，所述上一检测周期是指所述当前检测周期以前的一个检测周期；Obtaining an impedance of the access line in a previous detection period, where the last detection period refers to a detection period before the current detection period;

获取所述逆变器在当前检测周期的电压、电流及相位差；根据所述接入线路在所述上一检测周期的阻抗以及所述逆变器在所述当前检测周期的电压、电流及相位差，计算所述电网的电压、电流及相位差；且Obtaining a voltage, a current, and a phase difference of the inverter during a current detection period; according to an impedance of the access line in the last detection period, and a voltage and current of the inverter in the current detection period a phase difference, calculating a voltage, a current, and a phase difference of the power grid;

根据所述计算得到的所述电网的电压、电流及相位差计算所述电网的无功功率。Calculating reactive power of the power grid according to the calculated voltage, current, and phase difference of the power grid.
根据权利要求1所述的检测电网动态无功功率的方法，其特征在于，所述上一检测周期是指与所述当前检测周期相邻的前一个检测周期。The method for detecting dynamic reactive power of a power grid according to claim 1, wherein the previous detection period refers to a previous detection period adjacent to the current detection period.
根据权利要求1所述的检测电网动态无功功率的方法，其特征在于，所述上一检测周期是指所述当前检测周期前预置时间范围内的任一检测周期。The method for detecting dynamic reactive power of a power grid according to claim 1, wherein the previous detection period refers to any detection period within a preset time range before the current detection period.
根据权利要求1-3任一项所述检测电网动态无功功率的方法，其特征在于，所述获取所述接入线路在上一检测周期的阻抗，包括：The method for detecting dynamic reactive power of a power grid according to any one of claims 1 to 3, wherein the acquiring the impedance of the access line in the previous detection period comprises:

获取所述接入线路在所述上一检测周期的电压、电流及相位差；Obtaining a voltage, a current, and a phase difference of the access line during the last detection period;

根据所述接入线路在所述上一检测周期的电压、电流及相位差，计算所述接入线路的阻抗。Calculating an impedance of the access line according to a voltage, a current, and a phase difference of the access line during the last detection period.
根据权利要求4所述检测电网动态无功功率的方法，其特征在于，所述接入线路包括串联的多级变压器；The method for detecting dynamic reactive power of a power grid according to claim 4, wherein said access line comprises a multi-stage transformer connected in series;

所述获取所述接入线路在所述上一检测周期的电压、电流及相位差，包括：And obtaining the voltage, current, and phase difference of the access line in the last detection period, including:

获取所述多级变压器中的每一级变压器在所述上一检测周期的电压、电流及相位差；Obtaining a voltage, a current, and a phase difference of each of the multi-stage transformers in the last detection period;

所述根据所述接入线路在所述上一检测周期的电压、电流及相位差，计算所述接入线路的阻抗，包括：Calculating the impedance of the access line according to the voltage, current, and phase difference of the access line in the last detection period, including:

根据所述每一级变压器在所述上一检测周期的电压、电流及相位差，计算所述每一级变压器的阻抗，并对所述每一级变压器的阻抗求和，得到所述接入线路的阻抗。Calculating an impedance of each of the transformers according to a voltage, a current, and a phase difference of each of the transformers in the previous detection period, and summing the impedances of the transformers of each of the transformers to obtain the access The impedance of the line.
根据权利要求5所述检测电网动态无功功率的方法，其特征在于，所述根据所述每一级变压器在所述上一检测周期的电压、电流及相位差，计算所述每一级变压器的阻抗，并对所述每一级变压器的阻抗求和，得到所述接入线路的阻抗，包括：The method for detecting dynamic reactive power of a power grid according to claim 5, wherein said calculating each of said transformers according to voltage, current and phase difference of said each stage of said transformer during said last detection period And the impedance of each of the transformers is summed to obtain the impedance of the access line, including:

根据所述每一级变压器在所述上一检测周期的相位差θ，作为该级变压器的阻抗角，并采用下述公式计算该级变压器的阻抗：According to the phase difference θ of the transformer of each stage in the previous detection period, as the impedance angle of the transformer of the stage, the impedance of the transformer of the stage is calculated by the following formula:

其中，Z为该级变压器的阻抗，U为该级变压器的电压有效值，I为该级变压器的电流有效值，并对所述每一级变压器的阻抗求和，得到所述接入线路的阻抗。Where Z is the impedance of the transformer of the stage, U is the voltage effective value of the transformer of the stage, I is the current effective value of the transformer of the stage, and the impedance of each transformer is summed to obtain the access line impedance.
根据权利要求1-3任一项所述检测电网动态无功功率的方法，其特征在于，所述获取所述接入线路在上一检测周期的阻抗，包括：The method for detecting dynamic reactive power of a power grid according to any one of claims 1 to 3, wherein the acquiring the impedance of the access line in the previous detection period comprises:

获取所述电网在所述上一检测周期的电压、电流以及所述逆变器在所述上一检测周期的电压、电流；Obtaining a voltage and a current of the power grid during the last detection period and voltages and currents of the inverter during the last detection period;

根据所述电网在所述上一检测周期的电压、电流以及所述逆变器在所述上一检测周期的电压、电流，计算所述接入线路的阻抗。Calculating the impedance of the access line according to the voltage and current of the power grid during the last detection period and the voltage and current of the inverter during the last detection period.
根据权利要求7所述检测电网动态无功功率的方法，其特征在于，所述根据所述电网在所述上一检测周期的电压、电流以及所述逆变器在所述上一检测周期的电压、电流，计算所述接入线路的阻抗，包括：The method for detecting dynamic reactive power of a power grid according to claim 7, wherein said voltage and current according to said power grid during said last detection period and said inverter are in said last detection period Voltage and current, calculating the impedance of the access line, including:

采用下述公式计算所述接入线路的阻抗：The impedance of the access line is calculated using the following formula:

其中，
为所述接入线路的电压，
为所述接入线路的电流，Z_line为所述接入线路的阻抗，
为所述电网的电流，
为所述逆变器的电压。among them,
For the voltage of the access line,
For the current of the access line, Z _line is the impedance of the access line,
For the current of the grid,
Is the voltage of the inverter.
根据权利要求1-8任一项所述检测电网动态无功功率的方法，其特征在于，所述根据所述接入线路在所述上一检测周期的阻抗以及所述逆变器在所述当前检测周期的电压、电流及相位差，计算所述电网的电压、电流及相位差，包括：The method for detecting dynamic reactive power of a power grid according to any one of claims 1-8, wherein said impedance according to said access line in said last detection period and said inverter are in said Calculating the voltage, current, and phase difference of the current detection period, and calculating the voltage, current, and phase difference of the power grid, including:

采用下述公式计算所述电网的电压、电流及相位差；Calculating the voltage, current and phase difference of the power grid using the following formula;

θ_grid＝θ_line+θ_inv，θ _grid =θ _line +θ _inv ,

其中，
为所述电网的电压，
为所述逆变器的电压，Z_line为所述接入线路的阻抗，
为所述电网的电流，
为所述逆变器的电流，θ_grid为所述电网的电压和电流的相位差，θ_inv为所述逆变器电压和电流的相位差，θ_line为Z_line的阻抗角。among them,
For the voltage of the grid,
For the voltage of the inverter, Z _line is the impedance of the access line,
For the current of the grid,
For the current of the inverter, θ _grid is the phase difference between the voltage and current of the grid, θ _inv is the phase difference of the inverter voltage and current, and θ _line is the impedance angle of Z _line .
根据权利要求1-9任一项所述检测电网动态无功功率的方法，其特征在于，所述根据所述计算得到的所述电网的电压、电流及相位差，计算所述电网的无功功率，包括：The method for detecting dynamic reactive power of a power grid according to any one of claims 1 to 9, wherein said calculating a reactive power of said power grid based on said calculated voltage, current and phase difference of said power grid Power, including:

根据所述电网的电压计算所述电网的电压有效值，根据所述电网的电流计算所述电网的电流有效值，并采用下述公式计算所述电网的无功功率：Calculating a voltage effective value of the power grid according to a voltage of the power grid, calculating a current effective value of the power grid according to the current of the power grid, and calculating a reactive power of the power grid by using the following formula:

Q_grid＝U_grid×I_grid×sinθ_grid，Q _grid =U _grid ×I _grid ×sinθ _grid ,

其中，Q_grid为所述电网的动态无功功率，U_grid为所述电网的电压有效值，I_grid为所述电网的电流有效值，θ_grid为电网的电压和电流的相位差。Where Q _grid is the dynamic reactive power of the power _grid , U _grid is the voltage effective value of the power grid, I _grid is the current effective value of the power grid, and θ _grid is the phase difference between the voltage and current of the power grid.
一种无功功率检测装置，其特征在于，用于电网***，所述电网***包括电网以及通过接入线路接入所述电网的逆变器，所述逆变器把直流电转变成交流电通过所述接入线路并入所述电网中；A reactive power detecting device, characterized in that it is used in a power grid system, the power grid system comprising a power grid and an inverter that accesses the power grid through an access line, and the inverter converts direct current into an alternating current The access line is incorporated into the power grid;

所述无功功率检测装置包括：The reactive power detecting device includes:

第一获取模块，用于获取所述接入线路在上一检测周期的阻抗，所述上一检测周期是指所述当前检测周期以前的一个检测周期；a first acquiring module, configured to acquire an impedance of the access line in a previous detection period, where the last detection period refers to a detection period before the current detection period;

第二获取模块，用于获取所述逆变器在当前检测周期的电压、电流及相位差；a second acquiring module, configured to acquire a voltage, a current, and a phase difference of the inverter during a current detection period;

第一计算模块，用于根据所述第一获取模块获取的所述接入线路在所述上一检测周期的阻抗以及所述第二获取模块获取的所述逆变器在所述当前检测周期的电压、电流及相位差，计算所述电网的电压、电流及相位差；a first calculating module, configured to: according to the access line acquired by the first acquiring module, Calculating a voltage, a current, and a phase difference of the power grid according to an impedance of a detection period and a voltage, a current, and a phase difference of the inverter acquired by the second acquisition module during the current detection period;

第二计算模块，用于根据所述计算模块计算得到的所述电网的电压、电流及相位差计算所述电网的无功功率。And a second calculating module, configured to calculate reactive power of the power grid according to the voltage, current, and phase difference of the power grid calculated by the computing module.
根据权利要求11所述无功功率检测装置，其特征在于，所述上一检测周期是指与所述当前检测周期相邻的前一个检测周期。The reactive power detecting apparatus according to claim 11, wherein said last detection period refers to a previous detection period adjacent to said current detection period.
根据权利要求11所述无功功率检测装置，其特征在于，所述上一检测周期是指所述当前检测周期前预置时间范围内的任一检测周期。The reactive power detecting apparatus according to claim 11, wherein said last detecting period is any one of detecting periods within a preset time range before said current detecting period.
根据权利要求11-13任一项所述无功功率检测装置，其特征在于，所述第一获取模块包括：The reactive power detecting device according to any one of claims 11 to 13, wherein the first acquiring module comprises:

第一获取单元，用于获取所述接入线路在所述上一检测周期的电压、电流及相位差；a first acquiring unit, configured to acquire a voltage, a current, and a phase difference of the access line during the last detection period;

第一计算单元，用于根据所述第一获取单元获取的所述接入线路在所述上一检测周期的电压、电流及相位差计算所述接入线路的阻抗。a first calculating unit, configured to calculate an impedance of the access line according to a voltage, a current, and a phase difference of the access line acquired by the first acquiring unit in the last detection period.
根据权利要求14所述无功功率检测装置，其特征在于，所述接入线路包括串联的多级变压器；The reactive power detecting apparatus according to claim 14, wherein said access line comprises a multi-stage transformer connected in series;

所述第一获取单元，具体用于获取所述多级变压器中的每一级变压器在所述上一检测周期的电压、电流及相位差；The first obtaining unit is specifically configured to acquire a voltage, a current, and a phase difference of each stage of the multi-stage transformer during the last detection period;

所述第一计算单元，具体用于根据所述第一获取单元获取的所述每一级变压器在所述上一检测周期的电压、电流及相位差，计算所述每一级变压器的阻抗，并对所述每一级变压器的阻抗求和，得到所述接入线路的阻抗。The first calculating unit is configured to calculate, according to the voltage, current, and phase difference of the last detection period of the transformer of each stage acquired by the first acquiring unit, calculate an impedance of the transformer of each stage, And summing the impedances of the transformers of each stage to obtain the impedance of the access line.
根据权利要求15无功功率检测装置，其特征在于，所述第一计算单元具体用于根据所述第一获取单元获取的所述每一级变压器在所述上一检测周期的相位差θ，作为该级变压器的阻抗角，并采用下述公式计算该级变压器的阻抗：The reactive power detecting apparatus according to claim 15, wherein said first calculating unit is specifically configured to: according to said phase difference θ of said each stage transformer obtained by said first obtaining unit in said last detecting period, As the impedance angle of the transformer of this stage, the impedance of the transformer of this stage is calculated by the following formula:

其中，Z为该级变压器的阻抗，U为该级变压器的电压有效值，I为该级变压器的电流有效值，并对所述每一级变压器的阻抗求和，得到所述接入线路的阻抗，作为所述接入线路在所述当前检测周期的阻抗。Where Z is the impedance of the transformer of the stage, U is the voltage effective value of the transformer of the stage, I is the current effective value of the transformer of the stage, and the impedance of each transformer is summed to obtain the access line Impedance as the impedance of the access line during the current detection period.
根据权利要求11-13任一项所述无功功率检测装置，其特征在于，所述第一获取模块包括：A reactive power detecting device according to any one of claims 11-13, characterized in that The first obtaining module includes:

第二获取单元，用于获取所述电网在所述上一检测周期的电压、电流以及所述逆变器在所述上一检测周期的电压、电流；a second acquiring unit, configured to acquire voltages and currents of the power grid during the last detection period, and voltages and currents of the inverter during the last detection period;

第二计算单元，用于根据所述第二获取单元获取的所述电网在所述上一检测周期的电压、电流以及所述逆变器在所述上一检测周期的电压、电流，计算所述接入线路的阻抗。a second calculating unit, configured to calculate, according to the voltage and current of the power grid in the last detection period and the voltage and current of the inverter in the last detection period, according to the second acquiring unit The impedance of the access line.
根据权利要求17所述无功功率检测装置，其特征在于，所述第二计算单元具体用于采用下述公式计算所述接入线路的阻抗：The reactive power detecting apparatus according to claim 17, wherein the second calculating unit is specifically configured to calculate an impedance of the access line by using the following formula:

其中，
为所述接入线路的电压，
为所述接入线路的电流，Z_line为所述接入线路的阻抗，
为所述电网的电流，
为所述逆变器的电压。among them,
For the voltage of the access line,
For the current of the access line, Z _line is the impedance of the access line,
For the current of the grid,
Is the voltage of the inverter.
根据权利要求11-18任一项所述无功功率检测装置，其特征在于，所述第一计算模块具体用于采用下述公式计算所述电网的电压、电流及相位差；The reactive power detecting device according to any one of claims 11 to 18, wherein the first calculating module is specifically configured to calculate a voltage, a current, and a phase difference of the power grid by using the following formula;

θ_grid＝θ_line+θ_ive，θ _grid =θ _line +θ _ive ,

其中，
为所述电网的电压，
为所述逆变器的电压，Z_line为所述接入线路的阻抗，
为所述电网的电流，
为所述逆变器的电流，θ_grid为电网的电压和电流的相位差，θ_inv为逆变器的电压和电流的相位差，θ_line为Z_line的阻抗角。among them,
For the voltage of the grid,
For the voltage of the inverter, Z _line is the impedance of the access line,
For the current of the grid,
For the current of the inverter, θ _grid is the phase difference between the voltage and current of the grid, θ _inv is the phase difference between the voltage and current of the inverter, and θ _line is the impedance angle of Z _line .
根据权利要求11-19任一项所述无功功率检测装置，其特征在于，所述第二计算模块具体用于根据所述电网的电压计算所述电网的电压有效值，根据所述电网的电流计算所述电网的电流有效值，并采用下述公式计算所述电网的无功功率：The reactive power detecting device according to any one of claims 11 to 19, wherein the second calculating module is specifically configured to calculate a voltage effective value of the power grid according to a voltage of the power grid, according to the power grid The current calculates the current rms value of the grid and calculates the reactive power of the grid using the following formula:

Q_grid＝U_grid×I_grid×sinθ_grid， _{_{_{Q grid = U grid × I grid}}} × sinθ grid,

其中，Q_grid为所述电网的动态无功功率，U_grid为所述电网的电压有效值，I_grid为所述电网的电流有效值，θ_grid为电网的电压和电流的相位差。Where Q _grid is the dynamic reactive power of the power _grid , U _grid is the voltage effective value of the power grid, I _grid is the current effective value of the power grid, and θ _grid is the phase difference between the voltage and current of the power grid.
一种无功功率检测装置，其特征在于，用于电网***，所述电网***包括电网以及通过接入线路接入所述电网的逆变器，所述逆变器把直流电转变成交流电通过所述接入线路并入所述电网中；A reactive power detecting device, characterized in that it is used in a power grid system, the power grid system comprising a power grid and an inverter that accesses the power grid through an access line, and the inverter converts direct current into an alternating current The access line is incorporated into the power grid;

所述无功功率检测装置包括：The reactive power detecting device includes:

处理单元和采集器；Processing unit and collector;

所述采集器，用于获取所述逆变器在当前检测周期的电压、电流及相位差；The collector is configured to acquire a voltage, a current, and a phase difference of the inverter during a current detection period;

所述处理单元，用于根据所述接入线路在上一检测周期的阻抗以及所述逆变器在所述当前检测周期的电压、电流及相位差，计算所述电网的电压、电流及相位差；且根据所述计算得到的所述电网的电压、电流及相位差计算所述电网的无功功率。The processing unit is configured to calculate a voltage, a current, and a phase of the power grid according to an impedance of the access line in a previous detection period and a voltage, a current, and a phase difference of the inverter in the current detection period. Poor; and calculating the reactive power of the power grid based on the calculated voltage, current, and phase difference of the power grid.
根据权利要求21所述无功功率检测装置，其特征在于，The reactive power detecting device according to claim 21, wherein

所述采集器还用于获取所述接入线路在所述上一检测周期的电压、电流及相位差；The collector is further configured to acquire a voltage, a current, and a phase difference of the access line during the last detection period;

所述处理单元还用于根据所述接入线路在所述上一检测周期的电压、电流及相位差，计算所述接入线路在上一检测周期的阻抗。The processing unit is further configured to calculate an impedance of the access line in a previous detection period according to a voltage, a current, and a phase difference of the access line in the last detection period.
根据权利要求21所述无功功率检测装置，其特征在于，The reactive power detecting device according to claim 21, wherein

所述采集器还用于获取所述电网在所述上一检测周期的电压、电流以及所述逆变器在所述上一检测周期的电压、电流；The collector is further configured to acquire voltages and currents of the power grid during the last detection period, and voltages and currents of the inverter during the last detection period;

所述处理单元还用于根据所述电网在所述上一检测周期的电压、电流以及所述逆变器在所述上一检测周期的电压、电流，计算所述接入线路在上一检测周期的阻抗。 The processing unit is further configured to calculate, according to the voltage and current of the power grid during the last detection period, and the voltage and current of the inverter in the last detection period, calculate the access line in the previous detection. The impedance of the cycle.