CN112505430A - Passive high-voltage capacitor capacitance online monitoring system and method - Google Patents
Passive high-voltage capacitor capacitance online monitoring system and method Download PDFInfo
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Abstract
The invention relates to a passive high-voltage capacitor capacitance online monitoring system and a passive high-voltage capacitor capacitance online monitoring method, wherein the online monitoring system mainly comprises a current detection unit, a voltage detection unit, a power taking control unit, a temperature monitoring unit, a capacitance calculation and fault judgment unit, a receiving concentrator and upper computer communication unit and an upper computer data alarm display unit; by monitoring the running state of the capacitor in the using process, the fault symptom of the capacitor is predicted in advance, and the fault problem is accurately positioned and analyzed.
Description
Technical Field
The invention belongs to the technical field of on-line monitoring of capacitance of a high-voltage capacitor, and particularly relates to a passive on-line monitoring system and method for capacitance of the high-voltage capacitor.
Background
People are continuously strengthening the state control concept of the power equipment, and for a long time, the power equipment mostly adopts a post-repair mode, gradually develops into a preventive test and tries to detect the electrified state. The mature development after the condition maintenance is finished correspondingly promotes the development of the on-line monitoring device. China begins to research the problem of online monitoring of capacitor equipment in the 80 th century, and correspondingly increases the monitoring of capacitance, three-phase unbalanced current and internal partial discharge. On-line monitoring research of capacitive equipment tends to be mature, and power grid intellectualization develops to be the development trend of a power system. The substation power capacitors are mostly operated in the form of devices. The intelligent online monitoring device for the power capacitor equipment is researched and developed, faults existing in the operation of a power system can be predicted in advance, and countermeasures can be taken in time.
The method comprises the steps of researching and analyzing a capacitor equipment structure in the transformer substation, establishing a mathematical model, and carrying out simulation analysis on the damage fault of a capacitor element in the capacitor through operation software to obtain an applicability conclusion. Based on the development situation of the smart power grid, an intelligent online detection device is researched and developed, the fault symptom of the power capacitor is predicted in advance, and the fault problem is accurately positioned and analyzed. The intelligent online monitoring system for the power capacitor of the transformer substation researched and developed currently hopes to have referential value for related personnel.
Disclosure of Invention
The invention aims to provide a passive high-voltage capacitor capacitance online monitoring system and a passive high-voltage capacitor capacitance online monitoring method, which are used for monitoring the running state of a capacitor in the using process, predicting the fault symptoms of a power capacitor in advance and accurately positioning and analyzing the fault problems.
In order to achieve the above object, the present invention adopts the following technical solutions.
The invention firstly provides a passive high-voltage capacitor capacitance online monitoring system which comprises a current detection unit, a voltage detection unit, a power taking control unit, a temperature monitoring unit, a wireless transmission unit, a capacitance calculation and fault judgment unit, a receiving concentrator and upper computer communication unit and an upper computer data alarm display unit, wherein the current detection unit is connected with the voltage detection unit, the capacitance calculation and fault judgment unit is connected with the power taking control unit, the voltage detection unit, the temperature monitoring unit and the wireless transmission unit, and the wireless transmission unit is connected with the receiving concentrator, the upper computer communication unit and the upper computer data alarm display unit. The current detection unit and the power-taking control unit adopt the same CT ring to complete the functions of power taking and current detection, thereby effectively saving the cost and the volume.
In the technical scheme adopted by the invention, the current detection unit and the power taking control unit adopt the same CT ring to finish power taking and current detection, the power taking control module penetrates through the CT ring to charge equipment, the temperature monitoring unit measures the ambient temperature and the temperature of a capacitor box body, the capacitance calculation and fault judgment unit obtains the capacitance value of the capacitor through a Vout calculation formula, and the capacitor is judged whether to normally operate or not through an algorithm by combining the ambient temperature change and the temperature change of the capacitor box body. Under the condition of not influencing the capacitor and the field operation state, the power is supplied to the equipment by taking the power to measure all parameters of the capacitor, so that the problem of difficult field power supply is solved; by monitoring the running state of the capacitor in the using process, the fault symptom of the capacitor is predicted in advance, and the fault problem is accurately positioned and analyzed.
In any of the above-described embodiments, the current detection unit preferably defines parameters of a material, a wire diameter, a number of turns, and a winding method of the current transformer, and sets an induced current I on the CT loop to I1 (current flowing through the capacitor)/N (number of turns of the coil); the current detection unit does not damage the calculation unit when the transformer substation generates large current at the moment of switching on and switching off.
In any of the above technical solutions, preferably, the power-taking control unit is connected to the current detection unit, and includes a freewheeling device (D1), a voltage regulator (D2), and a capacitor (C) composed of a first capacitor (C1) and a seventeenth capacitor (C17), and charges the capacitor (C) by inducing a current flowing through the capacitor through a current transformer, via the freewheeling device (D1) and the voltage regulator (D2); the power taking control unit does not damage the capacitor (C) when the transformer substation generates large current at the moment of switching on and switching off; in the process of system operation, the voltage stabilizing device (D2) is used for controlling the power taking and consumed energy, preventing the capacitor (C) from being damaged due to overhigh charging voltage, and providing a stable voltage value for the capacitance calculation and fault judgment unit.
In any of the above technical solutions, preferably, the power-taking control unit further includes a voltage-reducing device (U1) and a charging control device (Q1), the capacitor (C) provides a stable working voltage for the capacitance calculation and fault determination unit through the voltage-reducing device (U1) during the discharging process, and the charging control device (Q1) prevents the capacitor (C) and the voltage stabilization device (D2) from being damaged due to excessive energy.
In any of the above technical solutions, preferably, the freewheeling device (D1) is connected to the charging control device (Q1), and the freewheeling device (D1) and the charging control device (Q1) have functions of maintaining their performance and functions without damage when a large current is generated at the moment of opening and closing the substation.
In any of the above technical solutions, preferably, the voltage detection unit employs a signal amplifier, amplifies the voltage signal converted from the current signal and raises the voltage signal to an appropriate voltage that can be sampled by the calculation unit:
vout is the output voltage value passing through the amplifier, Vref is the reference voltage, Vin is the voltage converted from current, R1 is the feedback resistor, and R2 is the current limiting resistor at the negative input end of the amplifier.
In any of the above technical solutions, preferably, the wireless transmitting unit adopts a 2.4G wireless signal transmission module, and has the performance of settable frequency band, settable communication address and strong anti-interference; the wireless transmitting unit and the receiving concentrator form master-slave data exchange, the signal acquisition end serves as a slave to wait for the receiving concentrator serving as a host to read data through a corresponding protocol, and the slave sends back the acquired data after verification passes; the wireless transmitting unit has the capability of stably transmitting wireless signals in an electric field generated by the transformer substation.
In any of the above technical solutions, it is preferable that the temperature monitoring unit has a temperature acquisition module, which acquires temperature by using a temperature sensor, and has a wide range temperature detection capability, a measurement accuracy of 0.25 ℃ or less, and a strong anti-interference capability.
In any of the above technical solutions, preferably, the capacitance calculation and fault determination unit includes an algorithm calculation module, which performs algorithm calculation on a signal of the collected current to obtain a capacitance value, a condition affecting the parameter is a structure inside the capacitor, the inside of the capacitor is composed of 36 capacitance elements, a parallel resistor of each string section has a capacitance of 6.6 μ F for each capacitance element, and a series resistor is 1.4M Ω; inductance of the reactor:
total impedance of the capacitor:
the total impedance of the branch circuit is that a reactor is connected with a capacitor in series:
according to the circuit law, vector analysis is carried out on the branch to obtain an equation (4):
in the formula (4), S represents capacitance, I represents current vector, U represents voltage, and UC represents capacitor terminal voltage; the capacitance calculation and fault judgment unit also comprises a data processing module which is connected with the temperature monitoring unit and has the functions of judging the state of the temperature sensor and accurately reading back corresponding data; and the capacitance calculation and fault judgment unit reads the ambient temperature and the temperature of the outer surface layer of the capacitor, and judges whether the capacitor has the problem of heating caused by the breakage of the inner resistance wire or not by combining the ambient temperature and the temperature of the outer surface layer of the capacitor.
In any of the above technical solutions, preferably, the receiving concentrator unit includes a polling control module, which polls the signal acquisition end and sets a wireless communication address and a frequency band of the wireless signal.
In any of the above technical solutions, preferably, the receiving concentrator and upper computer communication unit includes a communication module, which supports RS485 communication, optical fiber, ethernet, and GPRS transmission of data to the server.
In any of the above technical solutions, preferably, the upper computer data alarm display unit includes an alarm control module and a display interface, and exchanges data with the upper computer communication unit through the receiving concentrator, so as to display a current value, a capacitance value, a temperature value, and an alarm value of the acquisition terminal.
In any of the above technical solutions, preferably, the upper computer data alarm display unit further includes a data display module and a display interface, and has functions of viewing real-time data, viewing historical data curves, generating data reports, analyzing data, and displaying alarm states.
The invention also provides a passive high-voltage capacitor capacitance online monitoring method, which adopts the passive high-voltage capacitor capacitance online monitoring system. The capacitance online monitoring method of the passive high-voltage capacitor comprises the following steps: the current detection unit and the power taking control unit use the same CT ring, the power taking control module passes through the current CT ring through the current of the capacitor, the equipment is charged by using a power frequency material and an electromagnetic conversion induced current in the CT ring, and the temperature monitoring unit measures the ambient temperature and the temperature of the capacitor box body; the capacitance calculation and fault judgment unit sends the voltage value to the calculation unit through a Vout calculation formula, then calculates the capacitance value of the capacitor by using an algorithm, measures the temperature as an auxiliary judgment tool, and judges whether the capacitor normally operates or not through the algorithm according to the change of the environmental temperature and the temperature change of a capacitor box body; the wireless sending unit sends out the data that the collection and calculation reachd by wireless sending, receive concentrator unit and utilize wireless data to send and collect through the mode of polling and acquire every corresponding equipment data, arrange in order the storage to all data, the communication mode of receiving concentrator and host computer communication unit adopts RS485 communication, GPRS communication, optic fibre or ethernet transmission data to the server, host computer data warning display element receives the data of concentrator through the host computer, carry out the data unwrapping, show corresponding condenser equipment address, data and alarm state on the host computer interface. According to the passive high-voltage capacitor capacitance online monitoring method, a passive high-voltage capacitor capacitance online monitoring system is adopted, the structure of capacitor equipment in a transformer substation is analyzed and introduced, a mathematical model is established, damage faults of capacitor elements in the capacitor are analyzed in a simulation mode through operation software, and an applicability conclusion is obtained. Based on the development situation of the smart power grid, an intelligent online detection device is researched and developed, the fault symptom of the power capacitor is predicted in advance, and the fault problem is accurately positioned and analyzed. The passive high-voltage capacitor capacitance online monitoring system provided by the invention monitors the running state of the capacitor in the using process, predicts the fault symptoms of the power capacitor in advance, and accurately positions and analyzes the fault problem; the upper computer displays the parameters of each capacitor on the interface, provides historical data and historical data curve query, and displays the alarm state in the striking interface to achieve the purpose of warning; a plurality of communication means are provided, and the difficulties that data are difficult to communicate on site and the communication is unsuccessful are perfectly solved.
Compared with the prior art, the passive high-voltage capacitor capacitance online monitoring system and the passive high-voltage capacitor capacitance online monitoring method have the following beneficial effects: monitoring the running state of the capacitor in the using process, predicting the fault symptoms of the power capacitor in advance, and accurately positioning and analyzing the fault problem; the upper computer displays the relevant parameters of each capacitor on the interface one by one, provides historical data, conducts curve query on the historical data, and displays the alarm state in the striking interface to achieve the purpose of warning; a plurality of communication means are provided, and the difficulties that data are difficult to communicate on site and the communication is unsuccessful are perfectly solved. The invention adopts a power supply scheme of taking power, and measures various parameters of the capacitor by supplying power to the equipment through taking power under the condition of not influencing the running state of the capacitor and the site, thereby solving the problem of difficult site power supply.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic system diagram of a preferred embodiment of a passive on-line capacitance monitoring system for high-voltage capacitors in accordance with the present invention;
fig. 2 is a schematic diagram of the connection and function implementation of the current detection unit and the power-taking control unit in the embodiment of fig. 1 of the passive on-line capacitance monitoring system for the high-voltage capacitor according to the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order to research and develop an intelligent online monitoring device of power capacitor equipment and predict faults existing in the operation of a power system in advance so as to take countermeasures in time, the embodiment of the invention provides an online monitoring system and an online monitoring method for capacitance of a passive high-voltage capacitor.
As shown in fig. 1, the passive on-line capacitance monitoring system for the high-voltage capacitor in this embodiment mainly comprises a current detection unit, a voltage detection unit, a power-taking control unit, a temperature monitoring unit, a wireless transmission unit, a capacitance calculation and fault determination unit, a receiving concentrator, an upper computer communication unit and an upper computer data alarm display unit, wherein the current detection unit is connected with the voltage detection unit, the capacitance calculation and fault determination unit is connected with the power-taking control unit, the voltage detection unit, the temperature monitoring unit and the wireless transmission unit, and the wireless transmission unit is connected with the receiving concentrator, the upper computer communication unit and the upper computer data alarm display unit.
In this embodiment, the current detection unit and the power-taking control unit use the same CT ring to complete the power-taking and current detection functions.
In this embodiment, the current detection unit defines parameters of a material, a wire diameter, a number of turns, and a winding method of the current transformer, and sets an induced current I on the CT loop to I1 (current flowing through the capacitor)/N (number of turns of the coil); the current detection unit does not damage the calculation unit when the transformer substation generates large current at the moment of switching on and switching off.
In the embodiment, the power-taking control unit is connected with the current detection unit, and comprises a follow current component (D1), a voltage stabilizing component (D2) and a capacitor (C) consisting of a first capacitor (C1) and a seventeenth capacitor (C17), wherein the capacitor (C) is charged by the current flowing through the capacitor through the induction of a current transformer through the follow current component (D1) and the voltage stabilizing component (D2); the power taking control unit does not damage the capacitor (C) when the transformer substation generates large current at the moment of switching on and switching off; in the process of system operation, the voltage stabilizing device (D2) is used for controlling the power taking and consumed energy, preventing the capacitor (C) from being damaged due to overhigh charging voltage, and providing a stable voltage value for the capacitance calculation and fault judgment unit.
In this embodiment, the power-taking control unit further includes a voltage-reducing device (U1) and a charging control device (Q1), the capacitor (C) provides a stable working voltage for the capacitance calculating and fault judging unit through the voltage-reducing device (U1) during discharging, and the capacitor (C) and the voltage-stabilizing device (D2) are prevented from being damaged by excessive energy through the charging control device (Q1).
In the embodiment, the freewheeling device (D1) is connected with the charging control device (Q1), and the freewheeling device (D1) and the charging control device (Q1) have the functions of maintaining the performance and the function without damage when large current is generated at the moment of opening and closing of a transformer substation.
In this embodiment, the voltage detection unit employs a signal amplifier to amplify the voltage signal converted from the current signal and raise the voltage signal to an appropriate voltage that can be sampled by the calculation unit:
vout is the output voltage value passing through the amplifier, Vref is the reference voltage, Vin is the voltage converted from current, R1 is the feedback resistor, and R2 is the current limiting resistor at the negative input end of the amplifier.
In this embodiment, the wireless transmitting unit adopts a 2.4G wireless signal transmission module, and has the performance of settable frequency band, settable communication address and strong anti-interference. The wireless transmitting unit and the receiving concentrator form master-slave data exchange, the signal acquisition end serves as a slave to wait for the receiving concentrator serving as a host to read data through a corresponding protocol, and the slave sends back the acquired data after verification passes; the wireless transmitting unit has the capability of stably transmitting wireless signals in an electric field generated by the transformer substation.
In this embodiment, the temperature monitoring unit has a temperature acquisition module, which utilizes a temperature sensor to acquire temperature, and has wide-range temperature detection capability, measurement accuracy of 0.25 ℃ or less, and strong anti-interference capability.
In this embodiment, the capacitance calculating and fault determining unit includes an algorithm calculating module, which performs algorithm calculation on the signal of the collected current to obtain a capacitance value, the condition affecting the parameter is a structure inside the capacitor, the inside of the capacitor is composed of 36 capacitance elements, the capacitance of each capacitance element of each parallel resistor of each series section part is 6.6 μ F, and the series resistance is 1.4M Ω; inductance of the reactor:
total impedance of the capacitor:
the total impedance of the branch circuit is a reactor and a capacitor stringCombining:
according to the circuit law, vector analysis is carried out on the branch to obtain an equation (4):
in the formula (4), S represents capacitance, I represents current vector, U represents voltage, and UC represents capacitor terminal voltage; the capacitance calculation and fault judgment unit also comprises a data processing module which is connected with the temperature monitoring unit and has the functions of judging the state of the temperature sensor and accurately reading back corresponding data; and the capacitance calculation and fault judgment unit reads the ambient temperature and the temperature of the outer surface layer of the capacitor, and judges whether the capacitor has the problem of heating caused by the breakage of the inner resistance wire or not by combining the ambient temperature and the temperature of the outer surface layer of the capacitor.
In this embodiment, the receiving concentrator unit includes a polling control module, which polls the signal acquisition end and sets a wireless communication address and a frequency band of the wireless signal.
In this embodiment, the receiving concentrator and upper computer communication unit includes a communication module supporting RS485 communication, optical fiber, ethernet, GPRS transmission data to the server.
In this embodiment, the upper computer data alarm display unit includes alarm control module and show interface, and it carries out data exchange through receiving concentrator and upper computer communication unit and receiving concentrator, shows current value, capacitance value, temperature value, the alarm value of gathering terminal.
In this embodiment, the upper computer data alarm display unit further includes a data display module and a display interface, and has functions of viewing real-time data, viewing historical data curves, generating data reports, analyzing data, and displaying alarm states.
This embodiment passive high-voltage capacitor capacitance on-line monitoring system mainly comprises current detection unit, voltage detection unit, get the electric control unit, the temperature monitoring unit, wireless transmitting unit, electric capacity calculation and fault determination unit, receive the concentrator unit, receive concentrator and host computer communication unit and host computer data warning show unit and constitute, wherein, current detection unit uses same CT ring with the electric control unit of getting, effective reduce cost like this and reduce the volume, it passes through diode D1 to get the electricity, D2 charges for condenser C, this diode and MOS control tube constitute full-bridge circuit, H bridge top is diode D1, D2, the below is MOS pipe Q1, Q2, condenser C fills certain voltage and opens below MOS pipe measuring current. The voltage is converted into a voltage value through a resistor, and the voltage is boosted and amplified to generate a voltage suitable for being sampled by the computing unit.
In this embodiment, the current detection unit and the power taking control unit adopt the same CT ring to complete power taking and current detection, as shown in fig. 2, the power taking control module passes through the CT ring to charge the device, the temperature monitoring unit measures the ambient temperature and the temperature of the capacitor box, the capacitance calculation and fault determination unit obtains the capacitance value of the capacitor through a Vout calculation formula, and the operation of the capacitor is determined to be normal or not through an algorithm in combination with the ambient temperature change and the temperature change of the capacitor box. The capacitor can be used for measuring various parameters of the capacitor by supplying power to equipment through power supply under the condition of not influencing the operation state of the capacitor and the field, so that the problem of difficult field power supply is solved; by monitoring the running state of the capacitor in the using process, the fault symptom of the capacitor is predicted in advance, and the fault problem is accurately positioned and analyzed.
In the embodiment, a passive high-voltage capacitor capacitance online monitoring system is adopted to analyze and introduce a capacitor equipment structure in a transformer substation, a mathematical model is established, and damage faults of a capacitor element in the capacitor are analyzed through operation software simulation to obtain an applicability conclusion. Based on the development situation of the smart power grid, an intelligent online detection device is researched and developed, the fault symptom of the power capacitor is predicted in advance, and the fault problem is accurately positioned and analyzed. The passive high-voltage capacitor capacitance online monitoring system monitors the running state of the capacitor in the using process, predicts the fault symptoms of the power capacitor in advance, and accurately positions and analyzes the fault problem; the upper computer displays the parameters of each capacitor on the interface, provides historical data and historical data curve query, and displays the alarm state in the striking interface to achieve the purpose of warning; a plurality of communication means are provided, and the difficulties that data are difficult to communicate on site and the communication is unsuccessful are perfectly solved.
The capacitance online monitoring system of the passive high-voltage capacitor is adopted to realize online monitoring of the capacitance of the passive high-voltage capacitor, and the online monitoring method mainly comprises the following steps: the current detection unit and the power taking control unit use the same CT ring, the power taking control module passes through the current CT ring through the current of the capacitor, the equipment is charged by using a power frequency material and an electromagnetic conversion induced current in the CT ring, and the temperature monitoring unit measures the ambient temperature and the temperature of the capacitor box body; the capacitance calculation and fault judgment unit sends the voltage value to the calculation unit through a Vout calculation formula, then calculates the capacitance value of the capacitor by using an algorithm, measures the temperature as an auxiliary judgment tool, and judges whether the capacitor normally operates or not through the algorithm according to the change of the environmental temperature and the temperature change of a capacitor box body; the wireless sending unit sends out the data that the collection and calculation reachd by wireless sending, receive concentrator unit and utilize wireless data to send and collect through the mode of polling and acquire every corresponding equipment data, arrange in order the storage to all data, the communication mode of receiving concentrator and host computer communication unit adopts RS485 communication, GPRS communication, optic fibre or ethernet transmission data to the server, host computer data warning display element receives the data of concentrator through the host computer, carry out the data unwrapping, show corresponding condenser equipment address, data and alarm state on the host computer interface.
By adopting the power supply scheme of taking power, various parameters of the capacitor are measured by taking power to supply power to the equipment under the condition of completely not influencing the running states of the capacitor and the site, and the problem of difficult site power supply is solved.
The foregoing is merely illustrative of the preferred embodiments of the present invention and is not to be construed as limiting the scope of the invention; the above description is only for the specific embodiment of the present invention, and is not intended to limit the scope of the present invention; any modification, equivalent replacement, improvement and the like of the technical solution of the present invention by a person of ordinary skill in the art without departing from the design spirit of the present invention shall fall within the protection scope determined by the claims of the present invention.
Claims (10)
1. The utility model provides a passive high voltage capacitor capacitance on-line monitoring system, includes current detection unit and voltage detection unit, its characterized in that: still including getting electric control unit, temperature monitoring unit, wireless transmitting unit, electric capacity calculation and fault judgement unit, receiving concentrator and host computer communication unit and host computer data warning display unit, current detection unit connects voltage detection unit, electric capacity calculation and fault judgement unit with get electric control unit, voltage detection unit, temperature monitoring unit, wireless transmitting unit and be connected, wireless transmitting unit connects and receives concentrator and host computer communication unit and host computer data warning display unit.
2. The passive on-line capacitance monitoring system for high-voltage capacitors as claimed in claim 1, wherein: the current detection unit and the power taking control unit adopt the same CT ring to complete the functions of power taking and current detection; the current detection unit is used for limiting the material, the wire diameter, the number of turns and the winding mode of the current transformer, and setting the induced current I on the CT ring as I1 (current flowing through the capacitor)/N (the number of turns of the coil); the current detection unit does not damage the calculation unit when the transformer substation generates large current at the moment of switching on and switching off.
3. The passive on-line capacitance monitoring system for high-voltage capacitors as claimed in claim 1, wherein: the power taking control unit is connected with the current detection unit and comprises a follow current component (D1), a voltage stabilizing component (D2) and a capacitor (C) consisting of a first capacitor (C1) and a seventeenth capacitor (C17), and the capacitor (C) is charged by the current flowing through the capacitor through the induction of a current transformer and through the follow current component (D1) and the voltage stabilizing component (D2); the power taking control unit does not damage the capacitor (C) when the transformer substation generates large current at the moment of switching on and switching off; in the process of system operation, a voltage stabilizing device (D2) is used for controlling the power taking and consumed energy, preventing the capacitor (C) from being damaged due to overhigh charging voltage, and providing a stable voltage value for a capacitance calculation and fault judgment unit; the power-taking control unit further comprises a voltage-reducing device (U1) and a charging control device (Q1), stable working voltage is provided for the capacitance calculation and fault judgment unit through the voltage-reducing device (U1) in the discharging process of the capacitor (C), and the capacitor (C) and the voltage-stabilizing device (D2) are prevented from being damaged due to excessive energy through the charging control device (Q1); the follow current device (D1) is connected with the charging control device (Q1), and the follow current device (D1) and the charging control device (Q1) have the functions of maintaining the performance and the action of the transformer substation without damage when large current is generated at the moment of opening and closing of the transformer substation.
4. The passive on-line capacitance monitoring system for high-voltage capacitors as claimed in claim 1, wherein: the voltage detection unit adopts a signal amplifier to amplify and lift a voltage signal converted from a current signal to a proper voltage which can be sampled by the calculation unit:
vout is the output voltage value passing through the amplifier, Vref is the reference voltage, Vin is the voltage converted from current, R1 is the feedback resistor, and R2 is the current limiting resistor at the negative input end of the amplifier.
5. The passive on-line capacitance monitoring system for high-voltage capacitors as claimed in claim 1, wherein: the wireless transmitting unit adopts a 2.4G wireless signal transmission module, the wireless transmitting unit and the receiving concentrator form master-slave data exchange, the signal acquisition end is used as a slave to wait for the receiving concentrator used as a host to read data through a corresponding protocol, and the slave sends back the acquired data after passing the verification; the wireless transmitting unit has the capability of stably transmitting wireless signals in an electric field generated by the transformer substation.
6. The passive on-line capacitance monitoring system for high-voltage capacitors as claimed in claim 1, wherein: the temperature monitoring unit is provided with a temperature acquisition module which acquires temperature by using a temperature sensor, and has wide-range temperature detection capability, measurement precision of less than or equal to 0.25 ℃ and strong anti-interference capability.
7. The passive on-line capacitance monitoring system for high-voltage capacitors as claimed in claim 1, wherein: the capacitance calculation and fault judgment unit comprises an algorithm calculation module, the algorithm calculation module is used for calculating the signal of the acquired current to obtain a capacitance value, the condition influencing the parameter is the structure in the capacitor, the capacitor is internally composed of 36 capacitance elements, each capacitance element of each parallel resistor of each series section part has a capacitance of 6.6 mu F, and the series resistance is 1.4M omega; inductance of the reactor:
total impedance of the capacitor:
the total impedance of the branch circuit is that a reactor is connected with a capacitor in series:
according to the circuit law, vector analysis is carried out on the branch to obtain an equation (4):
in the formula (4), S represents capacitance, I represents current vector, U represents voltage, and UC represents capacitor terminal voltage; the capacitance calculation and fault judgment unit also comprises a data processing module which is connected with the temperature monitoring unit and has the functions of judging the state of the temperature sensor and accurately reading back corresponding data; and the capacitance calculation and fault judgment unit reads the ambient temperature and the temperature of the outer surface layer of the capacitor, and judges whether the capacitor has the problem of heating caused by the breakage of the inner resistance wire or not by combining the ambient temperature and the temperature of the outer surface layer of the capacitor.
8. The passive on-line capacitance monitoring system for high-voltage capacitors as claimed in claim 1, wherein: the receiving concentrator unit comprises a polling control module which polls the signal acquisition end and sets a wireless communication address and a frequency band of a wireless signal; the receiving concentrator and upper computer communication unit comprises a communication module which supports RS485 communication, optical fibers, Ethernet and GPRS data transmission to the server.
9. The passive on-line capacitance monitoring system for high-voltage capacitors as claimed in claim 1, wherein: the upper computer data alarm display unit comprises an alarm control module and a display interface, exchanges data with the upper computer communication unit through the receiving concentrator, and displays a current value, a capacitance value, a temperature value and an alarm value of the acquisition terminal; the upper computer data alarm display unit further comprises a data display module and a display interface, and the upper computer data alarm display unit has the functions of checking real-time data, historical data curves, data report generation, data analysis and alarm state display.
10. An on-line capacitance monitoring method for a passive high-voltage capacitor, which adopts the on-line capacitance monitoring system for the passive high-voltage capacitor as claimed in any one of claims 1 to 9, and is characterized in that the on-line capacitance monitoring method comprises the following steps: the current detection unit and the power taking control unit use the same CT ring, the power taking control module passes through the current CT ring through the current of the capacitor, the equipment is charged by using a power frequency material and an electromagnetic conversion induced current in the CT ring, and the temperature monitoring unit measures the ambient temperature and the temperature of the capacitor box body; the capacitance calculation and fault judgment unit sends the voltage value to the calculation unit through a Vout calculation formula, then calculates the capacitance value of the capacitor by using an algorithm, measures the temperature as an auxiliary judgment tool, and judges whether the capacitor normally operates or not through the algorithm according to the change of the environmental temperature and the temperature change of a capacitor box body; the wireless sending unit sends out the data that the collection and calculation reachd by wireless sending, receive concentrator unit and utilize wireless data to send and collect through the mode of polling and acquire every corresponding equipment data, arrange in order the storage to all data, the communication mode of receiving concentrator and host computer communication unit adopts RS485 communication, GPRS communication, optic fibre or ethernet transmission data to the server, host computer data warning display element receives the data of concentrator through the host computer, carry out the data unwrapping, show corresponding condenser equipment address, data and alarm state on the host computer interface.
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| CN202011487114.5A CN112505430A (en) | 2020-12-16 | 2020-12-16 | Passive high-voltage capacitor capacitance online monitoring system and method |
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| CN113295931A (en) * | 2021-06-18 | 2021-08-24 | 广东电网有限责任公司 | Capacitance detection system and method |
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| CN113295931A (en) * | 2021-06-18 | 2021-08-24 | 广东电网有限责任公司 | Capacitance detection system and method |
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