CN115219791A - Harmonic impedance scanning method - Google Patents
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Abstract
The present application relates to a harmonic impedance scanning method, apparatus, computer device, storage medium and computer program product. The method comprises the following steps: obtaining harmonic frequency parameters; generating harmonic source signals with different scanning frequencies according to the harmonic frequency parameters; harmonic source signals with different scanning frequencies are simultaneously injected into the high-voltage direct-current power transmission system, and electric signal values of the high-voltage direct-current power transmission system are collected; and determining harmonic impedance values of the high-voltage direct-current power transmission system corresponding to the harmonic source signals according to the electric signal values. By adopting the method, the harmonic impedance scanning of the high-voltage direct-current power transmission system can be efficiently and conveniently carried out.
Description
Technical Field
The present application relates to the field of power system technologies, and in particular, to a harmonic impedance scanning method, apparatus, computer device, storage medium, and computer program product.
Background
In recent years, with the rapid development of power systems, the conventional dc technology is generally adopted in the current ultra-high voltage and extra-high voltage dc transmission, a converter thereof has a large amount of characteristic harmonics, and a certain number of filters are required to be configured for suppressing the harmonics, but the harmonic instability of the ac/dc system may be caused by improper filter design or operation mode of the dc system. Determining the harmonic impedance characteristics of a High Voltage Direct Current (HVDC) system is a key to research on the problem of alternating Current-Direct Current harmonic resonance. At present, methods for determining harmonic impedance characteristics of a high-voltage direct-current transmission system mainly utilize a test signal method (also called a small signal test method or a frequency scanning method); the test signal method is used for scanning to obtain the harmonic impedance value of the high-voltage direct-current transmission system by injecting harmonic sources with different frequencies into the high-voltage direct-current transmission system one by one and measuring the response mode of the high-voltage direct-current transmission system. However, the harmonic impedance scanning method is complicated in operation process and low in scanning efficiency.
Therefore, how to improve the scanning efficiency of the harmonic impedance scanning of the high-voltage direct-current power transmission system is a technical problem to be solved by those skilled in the art.
Disclosure of Invention
In view of the above, it is necessary to provide a harmonic impedance scanning method, an apparatus, a computer device, a computer readable storage medium and a computer program product, which can efficiently and conveniently perform harmonic impedance scanning on a high voltage direct current transmission system.
In a first aspect, the present application provides a method of harmonic impedance scanning, the method comprising:
obtaining harmonic frequency parameters;
generating harmonic source signals with different scanning frequencies according to the harmonic frequency parameters;
simultaneously injecting the harmonic source signals with different scanning frequencies into a high-voltage direct-current power transmission system, and collecting an electric signal value of the high-voltage direct-current power transmission system;
and determining harmonic impedance values of the high-voltage direct-current power transmission system corresponding to the harmonic source signals according to the electric signal values.
In one embodiment, the harmonic frequency parameters include an initial sweep frequency and a sweep frequency interval; the generating harmonic source signals of different scanning frequencies according to the harmonic frequency parameters comprises:
determining a preset number of scanning frequencies according to the initial scanning frequency and the scanning frequency interval;
acquiring an initial phase and a phase difference value of a harmonic source signal to be generated;
determining a target initial phase value corresponding to each scanning frequency according to the initial phase and the phase difference value;
and generating harmonic source signals of different scanning frequencies according to the scanning frequencies and the target initial phase values.
In one embodiment, the phase difference values comprise a plurality of different phase difference values;
generating the target initial phase values of the harmonic source signals of different scanning frequencies according to the scanning frequencies and the target initial phase values, wherein the generating comprises:
and generating target initial phase values of harmonic source signals of different scanning frequencies according to the scanning frequencies and the target initial phase values for each phase difference value.
In one embodiment, the method further comprises:
counting the harmonic source total amplitude of the harmonic source signals corresponding to the same phase difference value;
determining the minimum value of the harmonic total amplitude, and determining a target phase difference value according to the phase difference value corresponding to the minimum value of the harmonic source total amplitude;
determining a target initial phase value and a target initial phase value corresponding to each scanning frequency according to the initial phase and the phase difference value, including:
and determining a target initial phase value corresponding to each scanning frequency according to the initial phase and the target phase difference value.
In one embodiment, the method further comprises:
determining whether the total amplitude of the harmonic source is smaller than a preset amplitude threshold value;
if the total harmonic source amplitude is smaller than the preset amplitude threshold, entering the step of determining the minimum value of the total harmonic source amplitude, and determining a target phase difference value according to the phase difference value corresponding to the minimum value of the total harmonic source amplitude;
if not, generating prompt information; and the prompt information is used for prompting that the total amplitude of the harmonic source is abnormal.
In one embodiment, the harmonic source signals include a harmonic voltage source signal and a harmonic current source signal.
In a second aspect, the present application also provides a harmonic impedance scanning apparatus, the apparatus comprising:
the acquisition module is used for acquiring harmonic frequency parameters;
the first determining module is used for generating harmonic source signals with different scanning frequencies according to the harmonic frequency parameters;
the input module is used for simultaneously injecting the harmonic source signals with different scanning frequencies into the high-voltage direct-current power transmission system and acquiring the electric signal value of the high-voltage direct-current power transmission system;
and the second determining module is used for determining a harmonic impedance value of the high-voltage direct-current power transmission system corresponding to each harmonic source signal according to the electric signal value.
In a third aspect, the present application also provides a computer device. The computer device comprises a memory storing a computer program and a processor implementing the steps of the above method when executing the computer program.
In a fourth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method as above.
In a fifth aspect, the present application further provides a computer program product. The computer program product comprising a computer program which, when executed by a processor, carries out the steps of the method as above.
According to the harmonic impedance scanning method, the harmonic impedance scanning device, the computer equipment, the storage medium and the computer program product, after harmonic frequency parameters are obtained, harmonic source signals with different scanning frequencies are generated according to the harmonic frequency parameters, then the harmonic source signals with different scanning frequencies are simultaneously injected into a high-voltage direct-current power transmission system, and electric signal values of the high-voltage direct-current power transmission system are collected; determining harmonic impedance values respectively corresponding to the high-voltage direct-current power transmission system and each harmonic source signal according to the electric signal values; by acquiring electric signal values corresponding to harmonic source signals with different scanning frequencies injected into the high-voltage direct-current power transmission system at the same time, the need of respectively acquiring corresponding electric signal values for each harmonic source signal is avoided; and then, the harmonic impedance values corresponding to the harmonic source signals in the high-voltage direct-current transmission system are determined according to the acquired electric signal values, and the harmonic impedance values corresponding to different harmonic source signals can be determined in batches according to the electric signal values acquired at a single time, so that the scheme can efficiently and conveniently perform harmonic impedance scanning on the high-voltage direct-current transmission system.
Drawings
FIG. 1 is a schematic flow chart diagram of a harmonic impedance scanning method in one embodiment;
FIG. 2 is a flowchart illustrating the steps of generating harmonic source signals at different scanning frequencies according to harmonic frequency parameters in one embodiment;
FIG. 3 is a diagram of an AC/DC equivalent impedance structure of an embodiment of a DC-DC converter;
FIG. 4 is a schematic flow chart of a harmonic impedance scanning method in another embodiment;
FIG. 5 is a block diagram of an embodiment of a harmonic impedance scanning device;
FIG. 6 is a diagram illustrating an internal structure of a computer device according to an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
The harmonic impedance scanning method provided by the embodiment of the application can be applied to a terminal, and the terminal acquires harmonic frequency parameters; generating harmonic source signals with different scanning frequencies according to the harmonic frequency parameters; harmonic source signals with different scanning frequencies are simultaneously injected into the high-voltage direct-current power transmission system, and electric signal values of the high-voltage direct-current power transmission system are collected; and determining harmonic impedance values of the high-voltage direct-current power transmission system corresponding to the harmonic source signals according to the electric signal values. The terminal can be, but is not limited to, various personal computers, notebook computers, smart phones and tablet computers.
In an embodiment, as shown in fig. 1, a method for scanning harmonic impedance is provided, which is exemplified by applying the method to a terminal, and in this embodiment, the method includes the following steps:
s200: and acquiring harmonic frequency parameters.
Specifically, the harmonic frequency parameter may be a parameter for determining the scanning frequency; the harmonic frequency parameters may include a maximum value of the sweep frequency, a minimum value of the sweep frequency, and a sweep frequency interval; the harmonic frequency parameter may also be a sweep frequency.
In actual operation, the harmonic frequency parameter may be obtained through an input operation in response to a user, or the harmonic frequency parameter stored in advance may be read from a specified storage location.
S400: and generating harmonic source signals with different scanning frequencies according to the harmonic frequency parameters.
The harmonic source signal refers to a test signal injected into the high-voltage direct-current power transmission system when harmonic impedance scanning is performed on the high-voltage direct-current power transmission system based on a test signal method. In the embodiment, after the harmonic frequency parameters are obtained, different scanning frequencies of a preset number are determined; and generating corresponding harmonic source signals aiming at different scanning frequencies respectively.
S600: and simultaneously injecting harmonic source signals with different scanning frequencies into the high-voltage direct-current power transmission system, and collecting the electric signal value of the high-voltage direct-current power transmission system.
After a plurality of harmonic source signals with different scanning frequencies are generated, the harmonic source signals with different scanning frequencies are simultaneously injected into the high-voltage direct-current power transmission system. It should be noted that, when the high-voltage direct-current power transmission system is started to operate to a steady state, a harmonic source signal can be injected into the high-voltage direct-current power transmission system; after the high-voltage direct-current transmission system is transited to a steady state again, scanning equivalent impedance on an alternating current side or a direct current side of the high-voltage direct-current transmission system, and collecting a corresponding electric signal value; wherein the electrical signal values include a current value and a voltage value.
S800: and determining harmonic impedance values of the high-voltage direct-current power transmission system corresponding to the harmonic source signals according to the electric signal values.
In this embodiment, calculation is performed according to the collected current value and voltage value, and specifically, discrete Fourier Transform (DFT) and a sequential component phasor algorithm may be used to perform analysis processing, so as to separate harmonic impedance values corresponding to harmonic source signals of each scanning frequency; and obtaining harmonic impedance values respectively corresponding to the high-voltage direct-current power transmission system and each harmonic signal source.
In the harmonic impedance scanning method, after harmonic frequency parameters are obtained, harmonic source signals with different scanning frequencies are generated according to the harmonic frequency parameters, then the harmonic source signals with different scanning frequencies are simultaneously injected into the high-voltage direct-current power transmission system, and electric signal values of the high-voltage direct-current power transmission system are collected; determining harmonic impedance values respectively corresponding to the high-voltage direct-current power transmission system and each harmonic source signal according to the electric signal values; by acquiring electric signal values corresponding to harmonic source signals with different scanning frequencies simultaneously injected into the high-voltage direct-current power transmission system, the need of respectively acquiring corresponding electric signal values for each harmonic source signal is avoided; and then, the harmonic impedance values corresponding to the harmonic source signals in the high-voltage direct-current power transmission system are determined according to the acquired electric signal values, and the harmonic impedance values corresponding to different harmonic source signals can be determined in batches according to the electric signal values acquired at a single time, so that the scheme can efficiently and conveniently perform harmonic impedance scanning on the high-voltage direct-current power transmission system.
On the basis of the above embodiment, this embodiment further describes and optimizes the technical solution, and specifically, as shown in fig. 2, a flow diagram of a step of generating harmonic source signals of different scanning frequencies according to harmonic frequency parameters in an embodiment. In this embodiment, the harmonic frequency parameter includes an initial scanning frequency and a scanning frequency interval; generating harmonic source signals at different scanning frequencies according to the harmonic frequency parameters comprises:
s402: and determining a preset number of scanning frequencies according to the initial scanning frequency and the scanning frequency interval.
Wherein the initial scanning frequency comprises a minimum scanning frequency f min Maximum scanning frequency f max (ii) a According to the minimum scanning frequency f min Maximum scanning frequency f max And determining a preset number of scanning frequencies at a scanning frequency interval Δ f
In particular, at a minimum scanning frequency f min And then, taking the scanning frequency interval as a step length, and sequentially determining corresponding scanning frequencies to obtain a preset number of scanning frequencies, wherein each scanning frequency is as follows: f. of min 、f min +Δf、f min +2Δf…f max (f min +(N-1)Δf)。
S404: and acquiring an initial phase and a phase difference value of a harmonic source signal to be generated.
It is understood that the magnitude and direction of the harmonic source signal is time-varying, and the initial phase refers to the phase of the sinusoid of the harmonic source signal at t =0, also referred to as the initial phase angle or phase. Typically, the initial phase is set to 0 °.
The phase difference refers to the amount of change of the phase corresponding to the adjacent time point. In actual operation, 360 degrees can be divided into preset equal parts, and the value of each equal part is a phase difference value; for example, suppose that 360 ° is divided into 3 equal parts and the phase difference Δ α is
The specific value of the phase difference value is not limited in this embodiment, and may be set according to actual requirements.
S406: and determining a target initial phase value corresponding to each scanning frequency according to the initial phase and the phase difference value.
Specifically, assume that the initial phase is 0 °, and the phase difference is Δ α; that is, if the phase difference value of the harmonic source signals corresponding to different scanning frequencies is Δ α, the target initial phase values corresponding to the scanning frequencies are: 0.Δ α, 2 × Δ α … … (N-1) × Δ α.
S408: and generating harmonic source signals of different scanning frequencies according to the scanning frequencies and the target initial phase values.
Specifically, according to the amplitude A of the harmonic source signal m And generating harmonic source signals of different scanning frequencies by using each scanning frequency and each target initial phase value.
In one embodiment, the harmonic source signal includes a harmonic voltage source signal and a harmonic current source signal.
The harmonic voltage source signal can be generated through the harmonic voltage source, and the harmonic current source signal can be generated through the harmonic current source; the present implementation does not limit the specific type of harmonic source signal.
Specifically, assume the amplitude of the harmonic source signal is A m The phase difference is delta alpha;
when the scanning frequency is f min When the target initial phase value is 0 °, the harmonic voltage source signal is: v 0 ＝A m sin(2πf min t+0°)；
When the scanning frequency is f min + Δ f, when the target initial phase value is Δ α, the harmonic voltage source signal is: v 1 ＝A m sin[2π(f min +Δf)t+Δα]；
When the scanning frequency is f min +2 Δ f, when the target initial phase value is 2 × Δ α, the harmonic voltage source signal is: v 2 ＝A m sin[2π(f min +2Δf)t+2Δα]
By analogy, when the scanning frequency is f max (f min + (N-1) Δ f), target initial phaseThe value is (N-1). Times.DELTA.alpha 1 Then, the harmonic voltage source signal is:
V N-1 ＝A m sin{2π[f min +(N-1)Δf]t+(N-1)Δα 1 }。
therefore, harmonic source signals with different scanning frequencies are generated according to the scanning frequencies and the target initial phase values, the harmonic source signals are various, and comprehensive and accurate harmonic impedance scanning of the high-voltage direct-current power transmission system can be achieved.
On the basis of the foregoing embodiment, the present embodiment further describes and optimizes the technical solution, and specifically, in the present embodiment, the phase difference value includes a plurality of different phase difference values;
generating initial target phase values of the harmonic source signals at different scanning frequencies according to the scanning frequencies and the initial target phase values, wherein the method comprises the following steps:
and generating the target initial phase values of the harmonic source signals of different scanning frequencies according to the scanning frequencies and the target initial phase values for each phase difference value.
Specifically, on the basis that 360 degrees are divided into preset equal parts and the value of each equal part is the phase difference value, the preset multiple of each equal part is further determined as different phase difference values. For example, if the preset equal part is M, the specific values of the different phase difference values Δ α may include:
more specifically, it is assumed that the value of the phase difference value Δ α includes Δ α 1 、Δα 2 …Δα M (ii) a When the phase difference value delta alpha is delta alpha 1 When the current is in the normal state;
when the scanning frequency is f min The target initial phase value is 0 °, and the harmonic voltage source signal is: v 0 ＝sin(2πf min t+0°)；
When the scanning frequency is f min + Δ f, target initial phase value Δ α 1 The harmonic voltage source signal is: v 1 ＝sin[2π(f min +Δf)t+Δα 1 ]；
When the scanning frequency is f min +2 Δ f, target initial phase value of 2 × Δ α 1 The harmonic voltage source signal is: v 2 ＝sin[2π(f min +2Δf)t+2Δα 1 ]；
By analogy, when the scanning frequency is f max (f min + (N-1) Δ f), target initial phase value is (N-1). Times.Δ α 1 The harmonic voltage source signal is:
V N-1 ＝sin{2π[f min +(N-1)Δf]t+(N-1)Δα 1 }。
when the phase difference value delta alpha is delta alpha 2 The method comprises the following steps:
when the scanning frequency is f min The target initial phase value is 0 °, and the harmonic voltage source signal is: v 0 ＝sin(2πf min t+0°)；
When the scanning frequency is f min + Δ f, target initial phase value Δ α 2 The harmonic voltage source signal is: v 1 ＝sin[2π(f min +Δf)t+Δα 2 ]；
When the scanning frequency is f min +2 Δ f, target initial phase value of 2 × Δ α 2 The harmonic voltage source signal is: v 2 ＝sin[2π(f min +2Δf)t+2Δα 2 ]；
By analogy, when the scanning frequency is f max (f min + (N-1) Δ f), target initial phase value is (N-1). Times.Δ α 2 The harmonic voltage source signal is:
V N-1 ＝sin{2π[f min +(N-1)Δf]t+(N-1)Δα 2 }。
therefore, the harmonic source signals can be determined respectively according to different phase difference values, the harmonic source signals are various, and comprehensive and accurate harmonic impedance scanning of the high-voltage direct-current power transmission system can be achieved.
It should be noted that when the harmonic source signals are injected in batch, impact may be brought to the high-voltage direct-current transmission system, so that the operating point of the high-voltage direct-current transmission system is shifted, thereby reducing the reliability and accuracy of the harmonic impedance scanning result of the high-voltage direct-current transmission system. On the basis of the foregoing embodiment, the present embodiment further describes and optimizes the technical solution, and specifically, in the present embodiment, the method further includes:
the method comprises the following steps: and counting the harmonic source total amplitude of the harmonic source signals corresponding to the same phase difference value.
In this embodiment, after the corresponding harmonic source signal is determined for each phase difference value, the total harmonic source amplitude of the harmonic source signals corresponding to the same phase difference value is further counted. For each value of the phase difference value delta alpha, calculating the sum of the amplitudes of the harmonic source signals according to the harmonic source signals corresponding to the value, and obtaining the total amplitude of the harmonic source signals.
In actual operation, the manner of calculating the harmonic source total amplitude of the harmonic source signal includes:
∑|V|＝|V 0 +V 1 +V 2 +...+V N-1 |；
where, Σ | V | represents the total amplitude of the harmonic source, V 0 、V 1 、V 2 、...V N-1 Respectively representing harmonic source signals corresponding to the same phase difference values;
when the phase difference value delta alpha takes the value delta alpha 1 Then obtaining the total amplitude of the harmonic source as | V ¬ non-conducting phosphor 1 ；
When the phase difference value delta alpha takes the value delta alpha 2 Then obtaining the total amplitude of the harmonic source as | V ¬ non-conducting phosphor 2 ；
By analogy, when the phase difference value delta alpha takes 360 degrees, the total amplitude of the harmonic source is Σ | V ¬ Y M 。
Step two: determining the minimum value of the total amplitude of the harmonic wave, and determining a target phase difference value according to the phase difference value corresponding to the minimum value of the total amplitude of the harmonic wave source;
step three: determining a target initial phase value corresponding to each scanning frequency according to the initial phase and the phase difference value, wherein the step of determining the target initial phase value comprises the following steps: and determining a target initial phase value corresponding to each scanning frequency according to the difference value of the initial phase and the target phase.
Specifically, after the harmonic source total amplitudes of the harmonic source signals corresponding to the same phase difference value are counted, comparing the magnitude relation of the harmonic source total amplitudes, determining the minimum value of the harmonic source total amplitudes from the harmonic source total amplitudes, obtaining a phase difference value corresponding to the minimum value of the harmonic source total amplitudes, and determining the phase difference value as a target phase difference value; and the target phase difference value corresponding to the minimum value of the total amplitude of the harmonic source is the optimal phase difference value.
That is, the total amplitude Σ | V | of each calculated harmonic source is not branched 1 ～∑|V| M Determining the minimum value of the total amplitude of each harmonic source as | V ¬ non-conducting phosphor min ，∑|V| min The corresponding phase difference value delta alpha is the optimal phase difference value to be searched; and aiming at the current high-voltage direct-current power transmission system, a harmonic source signal corresponding to the target phase difference value is injected, so that the impact on the high-voltage direct-current power transmission system is minimum. That is to say, in this embodiment, by finding the optimal phase difference value of each harmonic source signal, when the harmonic source signal is injected into the high-voltage direct current transmission system, the impact on the high-voltage direct current transmission system is minimized, and the reliability and the accuracy of the harmonic impedance scanning result of the high-voltage direct current transmission system are improved.
In one embodiment, the harmonic impedance scanning method further includes:
determining whether the total amplitude of the harmonic source is smaller than a preset amplitude threshold value;
if the total amplitude of the harmonic source is smaller than the preset amplitude threshold, determining the minimum value of the total amplitude of the harmonic source, and determining a target phase difference value according to a phase difference value corresponding to the minimum value of the total amplitude of the harmonic source;
if not, generating prompt information; and the prompt information is used for prompting the abnormity of the total amplitude of the harmonic source.
Specifically, after the harmonic source total amplitude of the harmonic source signal corresponding to the same phase difference value is obtained, the harmonic source total amplitude is compared with a preset amplitude threshold value, and whether the harmonic source total amplitude is smaller than the preset amplitude threshold value is determined.
If the total amplitude of the harmonic source is smaller than the preset amplitude threshold, the total amplitude of the harmonic source is in a standard range, so that the minimum value of the total amplitude of the harmonic wave is determined, and a target phase difference value is determined according to a phase difference value corresponding to the minimum value of the total amplitude of the harmonic wave; if not, the total amplitude of the harmonic source exceeds the standard range, and therefore prompt information is generated and used for prompting that the corresponding total amplitude of the harmonic source is abnormal.
It should be noted that, in this embodiment, the specific type of the prompt message is not limited, and for example, the prompt message may be displayed in a manner of displaying corresponding characters or images on the terminal display.
In this embodiment, it is further determined whether the total amplitude of the harmonic source is smaller than the preset amplitude threshold, and when it is determined that the total amplitude of the harmonic source is not smaller than the preset amplitude threshold, prompt information is generated to prompt a user that the stability and reliability of the high-voltage direct-current power transmission system may be affected by the harmonic source signal injected in the batch.
In order to make those skilled in the art better understand the technical solutions in the present application, the following describes the technical solutions in the embodiments of the present application in detail with reference to practical application scenarios. In the embodiment of the present application, a schematic diagram of an ac/dc equivalent impedance structure of a dc converter shown in fig. 3 is described.
In this embodiment, U S Is an alternating voltage source, Z S Is the impedance of the AC system, Z f Is the impedance of an AC filter, Z AC The impedance of the alternating current system (the equivalent impedance seen from the converter transformer network side to the alternating current system comprises the impedance of an alternating current filter); the arrows in fig. 3 represent the reference direction of the current. The method for simulating and scanning the relevant parameters and meanings of the relevant equivalent impedance of the high-voltage direct-current transmission system by adopting a test signal method comprises the following steps:
AC equivalent impedance Z of converter HAC : the impedance value of the converter as seen from the converter valve side. In practical application, a converter transformer and a converter are often considered as a whole, and the AC equivalent impedance of a converter station is obtained as the AC equivalent impedance of the converter;
DC equivalent impedance Z of converter HDC : the impedance value of the converter viewed from the smoothing reactor valve side;
DC system impedance Z DC : looking at the equivalent impedance of the direct current network from the valve side of the smoothing reactor;
DC loop impedance Z D : series impedance of DC circuit, i.e. equal to Z HDC +Z DC 。
After a corresponding model is built on the basis of an electromagnetic simulation platform, in combination with a flow schematic diagram of a harmonic impedance scanning method shown in fig. 4, the harmonic impedance scanning method specifically comprises the following steps:
step 1: obtaining harmonic frequency parameters; the harmonic frequency parameters include an initial scanning frequency and a scanning frequency interval Δ f; the initial scanning frequency comprises a minimum scanning frequency f min Maximum scanning frequency f max ；
Step 2: determining a preset number of scanning frequencies according to the initial scanning frequency and the scanning frequency interval; determining a preset number
Each scanning frequency is: f. of min 、f min +Δf、f min +2Δf…f max (f min +(N-1)Δf)；
And step 3: acquiring an initial phase and a phase difference value of a harmonic source signal to be generated; the phase difference values comprise a plurality of different phase difference values;
and 4, step 4: determining a target initial phase value corresponding to each scanning frequency according to the initial phase and the phase difference value;
and 5: generating harmonic source signals of different scanning frequencies according to each scanning frequency and each target initial phase value aiming at each phase difference value;
step 6: counting the harmonic source total amplitude of the harmonic source signals corresponding to the same phase difference value;
and 7: determining the minimum value of the total amplitude of the harmonic wave, and determining a target phase difference value according to the phase difference value corresponding to the minimum value of the total amplitude of the harmonic wave source;
and 8: harmonic source signals with different scanning frequencies are simultaneously injected into the high-voltage direct-current power transmission system, and electric signal values of the high-voltage direct-current power transmission system are collected;
specifically, when the direct current transmission system is started to operate to a steady state, the harmonic voltage source is injected: if necessary, the AC equivalent positive sequence impedance Z of the converter is obtained as shown in FIG. 3 HAC Then three-phase positive sequence harmonic electricity is injectedPressure source U ACN (ii) a If necessary, the related equivalent impedance Z of the DC side of the converter is obtained HDC Then, a single-phase harmonic voltage source U is injected DCN (ii) a After the direct current power transmission system is transited to a stable state, scanning the equivalent impedance of the alternating current (or direct current) side, and collecting m points (or m points of the direct current side) of the alternating current side 1 Point sum m 2 Point) voltage current sample values.
And step 9: determining harmonic impedance values of the high-voltage direct-current power transmission system corresponding to the harmonic source signals according to the electric signal values;
and calculating the alternating current (or direct current) equivalent impedance of the converter under the corresponding harmonic source frequency by using a Discrete Fourier Transform (DFT) and a sequence component phasor algorithm, wherein the harmonic impedance values corresponding to different scanning frequencies are obtained by using the following calculation formula.
In the formula:
respectively m-point positive sequence harmonic voltage and current;
are each m 1 Point sum m 2 Point harmonic voltage;
is m 2 Direction of point flow m 1 Harmonic currents of the points.
In the harmonic impedance scanning method, after harmonic frequency parameters are obtained, harmonic source signals with different scanning frequencies are generated according to the harmonic frequency parameters, then the harmonic source signals with different scanning frequencies are simultaneously injected into the high-voltage direct-current power transmission system, and electric signal values of the high-voltage direct-current power transmission system are collected; determining harmonic impedance values respectively corresponding to the high-voltage direct-current power transmission system and each harmonic source signal according to the electric signal values; by acquiring electric signal values corresponding to harmonic source signals with different scanning frequencies simultaneously injected into the high-voltage direct-current power transmission system, the need of respectively acquiring corresponding electric signal values for each harmonic source signal is avoided; and then, the harmonic impedance values corresponding to the harmonic source signals in the high-voltage direct-current power transmission system are determined according to the acquired electric signal values, and the harmonic impedance values corresponding to different harmonic source signals can be determined in batches according to the electric signal values acquired at a single time, so that the scheme can efficiently and conveniently perform harmonic impedance scanning on the high-voltage direct-current power transmission system. In addition, the method has the advantages that the optimal phase difference value of each harmonic source signal is found, so that when the harmonic source signals are injected into the high-voltage direct-current transmission system, the impact on the high-voltage direct-current transmission system is minimum, and the reliability and the accuracy of the harmonic impedance scanning result of the high-voltage direct-current transmission system are improved.
It should be understood that, although the steps in the flowcharts related to the above embodiments are shown in sequence as indicated by the arrows, the steps are not necessarily performed in sequence as indicated by the arrows. The steps are not limited to being performed in the exact order illustrated and, unless explicitly stated herein, may be performed in other orders. Moreover, at least a part of the steps in the flowcharts related to the above embodiments may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of performing the steps or stages is not necessarily sequential, but may be performed alternately or alternately with other steps or at least a part of the steps or stages in other steps.
Based on the same inventive concept, the embodiment of the present application further provides a harmonic impedance scanning apparatus for implementing the above-mentioned harmonic impedance scanning method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more embodiments of the harmonic impedance scanning device provided below can be referred to the limitations of the harmonic impedance scanning method in the above, and are not described herein again.
In one embodiment, as shown in fig. 5, there is provided a harmonic impedance scanning apparatus including: an obtaining module 502, a first determining module 504, an input module 506, and a second determining module 508, wherein:
an obtaining module 502, configured to obtain a harmonic frequency parameter;
a first determining module 504, configured to generate harmonic source signals with different scanning frequencies according to the harmonic frequency parameter;
the input module 506 is configured to inject harmonic source signals with different scanning frequencies into the high-voltage direct-current power transmission system at the same time, and acquire an electrical signal value of the high-voltage direct-current power transmission system;
and a second determining module 508, configured to determine, according to the electric signal value, a harmonic impedance value of the high-voltage direct-current power transmission system corresponding to each harmonic source signal.
The harmonic impedance scanning device provided by the embodiment of the application has the same beneficial effects as the harmonic impedance scanning method.
In one embodiment, the harmonic frequency parameters include an initial sweep frequency and a sweep frequency interval; the first determining module includes:
the first determining submodule is used for determining a preset number of scanning frequencies according to the initial scanning frequency and the scanning frequency interval;
the acquisition submodule is used for acquiring an initial phase and a phase difference value of a harmonic source signal to be generated;
the second determining submodule is used for determining a target initial phase value corresponding to each scanning frequency according to the initial phase and the phase difference value;
and the generation submodule is used for generating harmonic source signals of different scanning frequencies according to the scanning frequencies and the target initial phase values.
In one embodiment, the phase difference values comprise a plurality of different phase difference values; the second determination submodule includes:
and the first determining unit is used for generating the target initial phase value of the harmonic source signal at different scanning frequencies according to each scanning frequency and each target initial phase value aiming at each phase difference value.
In one embodiment, a harmonic impedance scanning apparatus further comprises:
the statistical module is used for counting the harmonic source total amplitude of the harmonic source signals corresponding to the same phase difference value;
the target determining module is used for determining the minimum value of the total amplitude of the harmonic wave and determining a target phase difference value according to the phase difference value corresponding to the minimum value of the total amplitude of the harmonic wave source;
the second determination sub-module includes:
and the second determining unit is used for determining a target initial phase value corresponding to each scanning frequency according to the initial phase and the target phase difference value.
In one embodiment, a harmonic impedance scanning apparatus further comprises:
the prompting module is used for determining whether the total amplitude of the harmonic source is smaller than a preset amplitude threshold value; if the total amplitude of the harmonic source is smaller than a preset amplitude threshold, calling a target determining module; if not, generating prompt information; the prompt message is used for prompting the abnormality of the total amplitude of the harmonic source.
In one embodiment, the harmonic source signal includes a harmonic voltage source signal and a harmonic current source signal.
The various modules in the harmonic impedance scanning apparatus described above may be implemented in whole or in part by software, hardware, and combinations thereof. The modules can be embedded in a hardware form or independent of a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.
In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as shown in fig. 6. The computer device includes a processor, a memory, a communication interface, a display screen, and an input device connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The communication interface of the computer device is used for carrying out wired or wireless communication with an external terminal, and the wireless communication can be realized through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. The computer program is executed by a processor to implement a harmonic impedance scanning method. The display screen of the computer equipment can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer equipment can be a touch layer covered on the display screen, a key, a track ball or a touch pad arranged on the shell of the computer equipment, an external keyboard, a touch pad or a mouse and the like.
It will be appreciated by those skilled in the art that the configuration shown in fig. 6 is a block diagram of only a portion of the configuration associated with the present application, and is not intended to limit the computing device to which the present application may be applied, and that a particular computing device may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.
In one embodiment, a computer device is provided, comprising a memory in which a computer program is stored and a processor which, when executing the computer program, carries out the steps of the above-mentioned method.
The computer equipment provided by the embodiment of the application has the same beneficial effects as the harmonic impedance scanning method.
In an embodiment, a computer-readable storage medium is provided, on which a computer program is stored, which computer program, when being executed by a processor, carries out the steps of the above-mentioned method.
The computer-readable storage medium provided by the embodiment of the application has the same beneficial effects as the harmonic impedance scanning method.
In an embodiment, a computer program product is provided, comprising a computer program which, when executed by a processor, performs the steps of the above-described method.
The computer program product provided by the embodiment of the application has the same beneficial effects as the harmonic impedance scanning method.
It should be noted that, the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, presented data, etc.) referred to in the present application are information and data authorized by the user or sufficiently authorized by each party.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, database, or other medium used in the embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, high-density embedded nonvolatile Memory, resistive Random Access Memory (ReRAM), magnetic Random Access Memory (MRAM), ferroelectric Random Access Memory (FRAM), phase Change Memory (PCM), graphene Memory, and the like. Volatile Memory can include Random Access Memory (RAM), external cache Memory, and the like. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM), for example. The databases involved in the embodiments provided herein may include at least one of relational and non-relational databases. The non-relational database may include, but is not limited to, a block chain based distributed database, and the like. The processors referred to in the embodiments provided herein may be general purpose processors, central processing units, graphics processors, digital signal processors, programmable logic devices, quantum computing based data processing logic devices, etc., without limitation.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.
Claims (10)
1. A method of harmonic impedance scanning, the method comprising:
obtaining harmonic frequency parameters;
generating harmonic source signals with different scanning frequencies according to the harmonic frequency parameters;
simultaneously injecting the harmonic source signals with different scanning frequencies into a high-voltage direct-current power transmission system, and collecting an electric signal value of the high-voltage direct-current power transmission system;
and determining harmonic impedance values of the high-voltage direct-current power transmission system corresponding to the harmonic source signals according to the electric signal values.
2. The method of claim 1, wherein the harmonic frequency parameters include an initial sweep frequency and a sweep frequency interval; generating harmonic source signals of different scanning frequencies according to the harmonic frequency parameters comprises:
determining a preset number of scanning frequencies according to the initial scanning frequency and the scanning frequency interval;
acquiring an initial phase and a phase difference value of a harmonic source signal to be generated;
determining a target initial phase value corresponding to each scanning frequency according to the initial phase and the phase difference value;
and generating harmonic source signals of different scanning frequencies according to the scanning frequencies and the target initial phase values.
3. The method of claim 2, wherein the phase difference value comprises a plurality of different phase difference values;
generating target initial phase values of harmonic source signals of different scanning frequencies according to each scanning frequency and each target initial phase value, including:
and generating a target initial phase value of the harmonic source signal at different scanning frequencies according to the scanning frequencies and the target initial phase values for each phase difference value.
4. The method of claim 3, further comprising:
counting the harmonic source total amplitude of the harmonic source signals corresponding to the same phase difference value;
determining the minimum value of the harmonic total amplitude, and determining a target phase difference value according to the phase difference value corresponding to the minimum value of the harmonic source total amplitude;
determining a target initial phase value and a target initial phase value corresponding to each scanning frequency according to the initial phase and the phase difference value, including:
and determining a target initial phase value corresponding to each scanning frequency according to the initial phase and the target phase difference value.
5. The method of claim 4, further comprising:
determining whether the total amplitude of the harmonic source is smaller than a preset amplitude threshold value;
if yes, determining the minimum value of the total harmonic amplitude, and determining a target phase difference value according to the phase difference value corresponding to the minimum value of the total harmonic amplitude;
if not, generating prompt information; and the prompt information is used for prompting that the total amplitude of the harmonic source is abnormal.
6. The method of any of claims 1 to 5, wherein the harmonic source signals comprise harmonic voltage source signals and harmonic current source signals.
7. A harmonic impedance scanning apparatus, the apparatus comprising:
the acquisition module is used for acquiring harmonic frequency parameters;
the first determining module is used for generating harmonic source signals with different scanning frequencies according to the harmonic frequency parameters;
the input module is used for simultaneously injecting the harmonic source signals with different scanning frequencies into the high-voltage direct-current power transmission system and acquiring the electric signal value of the high-voltage direct-current power transmission system;
and the second determining module is used for determining a harmonic impedance value of the high-voltage direct-current power transmission system corresponding to each harmonic source signal according to the electric signal value.
8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor realizes the steps of the method of any one of claims 1 to 6 when executing the computer program.
9. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 6.
10. A computer program product comprising a computer program, characterized in that the computer program realizes the steps of the method of any one of claims 1 to 6 when executed by a processor.
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| CN112131816A (en) * | 2020-09-22 | 2020-12-25 | 清华四川能源互联网研究院 | Harmonic source amplitude determination method, device, medium and equipment for harmonic impedance scanning |
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