CN110297123B - Unbalanced current test system of series compensation device - Google Patents
Unbalanced current test system of series compensation device Download PDFInfo
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- CN110297123B CN110297123B CN201910667230.6A CN201910667230A CN110297123B CN 110297123 B CN110297123 B CN 110297123B CN 201910667230 A CN201910667230 A CN 201910667230A CN 110297123 B CN110297123 B CN 110297123B
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- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
Abstract
The invention discloses an unbalanced current test system of a series compensation device, which comprises an unbalanced current acquisition module, a capacitor bank total current acquisition module, a capacitor bank two-end voltage acquisition module, a signal output module and a digital control board, wherein the unbalanced current acquisition module is connected with a signal input end of the digital control board and is used for acquiring an unbalanced current of the series compensation device; the signal output end of the capacitor bank total current acquisition module is connected with the signal input end of the digital control board and is used for acquiring the total load input current of the capacitor bank in the series compensation device; the signal input ends of the voltage acquisition modules at the two ends of the capacitor bank are connected with the signal input end of the digital control board and are used for acquiring input voltages at the two ends of the capacitor bank of the series compensation device; the signal output module is connected with the signal output end of the digital control panel and used for outputting a control signal. The system has the advantage of high accuracy of the function diversity test.
Description
Technical Field
The invention relates to the technical field of current testing devices, in particular to an unbalanced current testing system of a series compensation device.
Background
The compensation of line reactance is realized by using a capacitor series compensation technology, the transmission power limit can be improved, and the alternating current transmission capacity is effectively improved. In a series compensation device, a defect or failure of a single or multiple capacitive elements may cause the voltage of other capacitive elements to rise, thereby causing large-area damage and endangering the safe and stable operation of the series compensation capacitor bank. At present, the online detection of internal defects or faults of a capacitor bank is generally realized by measuring capacitance values and variable quantities thereof between different branches of a series compensation capacitor bank. Because the capacitance value is easy to be affected by interference when being measured, the actual capacity of the capacitor is difficult to be measured, and when the internal unit of the capacitor is aged and failed and needs to be replaced, the test and the control of the unbalanced current become a complicated problem.
As shown in fig. 1, a series capacitance compensation device widely used in an electric power system at present generally includes a series compensation capacitor bank, a series compensation capacitor bank protection device, and other devices. The series compensation capacitor bank is composed of capacitor elements in series-parallel connection. The series compensation capacitor bank protection device generally comprises a metal oxide variable resistor, a discharge gap, a bypass switch and the like. The capacitor element is defective or failed, and there are two situations, namely, the fuse inside the capacitor element is blown out, and the capacitor element is broken down. A defect or malfunction of the capacitive element will directly result in a change of the capacitance of the series capacitance compensation device.
Referring to fig. 1, in order to realize online detection of capacitance variation of the series capacitance compensation device, the series compensation capacitor bank is designed in a bridge form. The series compensation capacitor bank is generally divided into four parts, namely C1-C4, and the four parts are respectively arranged on four bridge arms of a bridge, and a high-precision current transformer CT is arranged at a galvanometer position of a bridge circuit. Under an ideal normal operation state, the capacitances of the four bridge arms are equal, the bridge is in a balanced working condition, and the current value output by the current transformer CT is zero. When the capacitor element has a defect or a fault, the capacitances of the four bridge arms are not symmetrical any more, and the current transformer CT outputs a certain current value. It should be noted that, in an actual working environment, the current transformer CT has a smaller output even if the capacitors of the series capacitance compensation device are all working normally. This is because the capacitance elements cannot be strictly consistent in the production process, and the situation that the bridge arms of the bridge have asymmetric capacitance is inevitable. Therefore, the unbalanced current test platform of the series compensation device needs to set a reasonable threshold value, and false alarm of unbalanced current detection is avoided.
Disclosure of Invention
The invention aims to solve the technical problem of providing an unbalanced current test system of a series compensation device, which is accurate in measurement.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the utility model provides a series compensation device unbalance current test system which characterized in that: the device comprises an unbalanced current acquisition module, a capacitor bank total current acquisition module, a capacitor bank two-terminal voltage acquisition module, a signal output module and a digital control board, wherein the unbalanced current acquisition module is connected with a signal input end of the digital control board and is used for acquiring an unbalanced current of a series compensation device; the signal output end of the capacitor bank total current acquisition module is connected with the signal input end of the digital control board and is used for acquiring the total load input current of the capacitor bank in the series compensation device; the signal input ends of the voltage acquisition modules at the two ends of the capacitor bank are connected with the signal input end of the digital control board and are used for acquiring input voltages at the two ends of the capacitor bank of the series compensation device; the signal output module is connected with the signal output end of the digital control board and used for outputting a control signal; the digital control board is used for sending out a control command according to the acquired information.
The further technical scheme is as follows: the unbalanced current acquisition module comprises a first current-voltage conversion module, the signal output end of the first current-voltage conversion module is connected with the signal input end of a first signal conditioning and amplifying filter module, the output end of the first signal conditioning and amplifying filter module is connected with the signal input end of a first A/D high-speed acquisition module, the first A/D high-speed acquisition module is in two-way connection with a first signal isolation module, and the first signal isolation module is in two-way connection with the digital control panel.
The further technical scheme is as follows: the capacitor bank total current acquisition module comprises a second current-voltage conversion module, the signal output end of the second current-voltage conversion module is connected with the signal input end of the signal conditioning band-pass filter module, the output end of the signal conditioning band-pass filter module is connected with the signal input end of the second A/D high-speed acquisition module, the second A/D high-speed acquisition module is in two-way connection with the second signal isolation module, and the second signal isolation module is in two-way connection with the digital control panel.
The further technical scheme is as follows: the voltage acquisition modules at two ends of the capacitor bank comprise a second signal conditioning and amplifying filtering module, and the output end of the second signal conditioning and amplifying filtering module is connected with the signal input end of a third A/D high-speed acquisition module; the third A/D high-speed acquisition module is bidirectionally connected with the third signal isolation module, and the third signal isolation module is bidirectionally connected with the digital control board.
The further technical scheme is as follows: the signal output module comprises a digital-to-analog conversion module, a low-pass filtering module and a switching power supply power amplification module, the digital-to-analog conversion module is connected with the digital control board in a two-way mode, the output end of the digital-to-analog conversion module is connected with the signal input end of the low-pass filtering module, the output end of the low-pass filtering module is connected with the input end of the switching power supply power amplification module, and the output end of the switching power supply power amplification module is the control signal output end of the signal output module.
Preferably: the digital control board uses a DSP as a microprocessor.
The further technical scheme is as follows: the signal conditioning band-pass filter module includes electric capacity C47, the one end of electric capacity C47 is divided into two the tunnel, and first way does the input of filter module, another way divide into two the tunnel behind resistance R25, and first way is through electric capacity C48 ground connection, and the second way is connected with resistance R27's one end, electric capacity C47's other end ground connection, resistance R27's the other end does the signal output part of filter module.
Preferably: the A/D high-speed acquisition module uses an AD73360L type high-speed acquisition chip.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: the system has three conditioning and acquisition channels of unbalanced current, total current of the capacitor bank and voltage signals of the series compensation capacitor bank, and also has an output channel which is used for testing, the output current of the output channel is greater than 2A, and the maximum amplitude of the output channel is 60V, so that the system is convenient to use and high in testing accuracy.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
FIG. 1 is a schematic diagram of a series compensation capacitor bank and unbalanced current test in the prior art;
FIG. 2 is a functional block diagram of a system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a signal conditioning bandpass filtering module in the system according to an embodiment of the invention;
FIG. 4 is a schematic diagram of a high speed synchronous data acquisition module in the system according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a test of the system according to an embodiment of the invention.
Detailed Description
The technical solutions in the embodiments of the present invention are 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 the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.
In order to realize the online accurate measurement of the unbalanced current, a series compensation device unbalanced current test platform capable of collecting and analyzing the unbalanced current, the total current of the capacitor bank and the voltage of the series compensation capacitor bank is designed, and a hardware frame is shown in fig. 2.
The unbalanced current test platform of the series compensation device adopts a Digital Signal Processor (DSP) to collect and process signals, can receive control signals provided by an upper computer through a network port, and uploads the collected signals to the upper computer for display after calculation processing.
The signal acquisition of the unbalanced current test platform of the series compensation device mainly comprises 3 channels, and the conditioning and acquisition of the unbalanced current, the total current of the capacitor bank and the voltage signal of the series compensation capacitor bank are finished respectively. The unbalanced current (50 uA-5 mA) and the total current (50 mA-5A) of the capacitor bank are current acquisition channels, and a current-voltage conversion module is configured to convert a current signal into a voltage signal. Signals of the three signal acquisition channels are subjected to band-pass filtering amplification and then sent into a 16-bit A/D high-speed acquisition module, and after discretization sampling, the signals are transmitted to a signal processing unit DSP through a signal isolation unit.
The signal output channel of the unbalanced current test platform of the series compensation device consists of a digital part and a power part. The digital part adopts D/A to output small signals, and the small signals are sent to the power part after passing through the low-pass filtering module. The power part is powered by a switching power supply, so that the weight of equipment is reduced, a capacitive load can be carried, the output current is greater than 2A, and the maximum amplitude of output is 60V.
As shown in fig. 2, a system for testing an unbalanced current of a series compensation device includes an unbalanced current collection module, a total current collection module of a capacitor bank, a voltage collection module at two ends of the capacitor bank, a signal output module, and a digital control board, where the unbalanced current collection module is connected to a signal input end of the digital control board and is used for collecting an unbalanced current of the series compensation device; the signal output end of the capacitor bank total current acquisition module is connected with the signal input end of the digital control board and is used for acquiring the total load input current of the capacitor bank in the series compensation device; the signal input ends of the voltage acquisition modules at the two ends of the capacitor bank are connected with the signal input end of the digital control board and are used for acquiring input voltages at the two ends of the capacitor bank of the series compensation device; the signal output module is connected with the signal output end of the digital control board and used for outputting a control signal; the digital control board is used for sending out a control command according to the acquired information.
Further as shown in fig. 2: the unbalanced current acquisition module comprises a first current-voltage conversion module, the signal output end of the first current-voltage conversion module is connected with the signal input end of a first signal conditioning and amplifying filter module, the output end of the first signal conditioning and amplifying filter module is connected with the signal input end of a first A/D high-speed acquisition module, the first A/D high-speed acquisition module is in two-way connection with a first signal isolation module, and the first signal isolation module is in two-way connection with the digital control panel.
Further as shown in fig. 2: the capacitor bank total current acquisition module comprises a second current-voltage conversion module, the signal output end of the second current-voltage conversion module is connected with the signal input end of the signal conditioning band-pass filter module, the output end of the signal conditioning band-pass filter module is connected with the signal input end of the second A/D high-speed acquisition module, the second A/D high-speed acquisition module is in two-way connection with the second signal isolation module, and the second signal isolation module is in two-way connection with the digital control panel.
Further as shown in fig. 2: the voltage acquisition modules at two ends of the capacitor bank comprise a second signal conditioning and amplifying filtering module, and the output end of the second signal conditioning and amplifying filtering module is connected with the signal input end of a third A/D high-speed acquisition module; the third A/D high-speed acquisition module is bidirectionally connected with the third signal isolation module, and the third signal isolation module is bidirectionally connected with the digital control board.
Further as shown in fig. 2: the signal output module comprises a digital-to-analog conversion module, a low-pass filtering module and a switching power supply power amplification module, the digital-to-analog conversion module is connected with the digital control board in a two-way mode, the output end of the digital-to-analog conversion module is connected with the signal input end of the low-pass filtering module, the output end of the low-pass filtering module is connected with the input end of the switching power supply power amplification module, and the output end of the switching power supply power amplification module is the control signal output end of the signal output module.
Referring to fig. 3, the filter of the acquisition channel of the unbalanced current test platform of the series compensation device adopts an anti-aliasing filter circuit, which is composed of a parallel capacitor (C47) and a low-pass anti-aliasing filter (R25, C48), wherein the parallel capacitor filters out extremely high frequency interference, and the filter forms an RC passive filter circuit, filters out high frequency interference, and then transmits the filter to an a/D high-speed acquisition chip. Further, signal conditioning band-pass filter module includes electric capacity C47, the one end of electric capacity C47 is divided into two the tunnel, and first way does the input of filter module, another way divide into two the tunnel behind resistance R25, and first way is through electric capacity C48 ground connection, and the second way is connected with resistance R27's one end, electric capacity C47's other end ground connection, resistance R27's the other end does the signal output part of filter module.
Referring to fig. 4, the a/D high-speed acquisition chip adopted by the system design is a low-power consumption 16-bit chip AD73360L designed for high-speed synchronous data acquisition system by ADI corporation, and the sampling frequency thereof can be set by programming, and can provide sampling frequencies of 8kHz, 16kHz, 32kHz and up to 64 kHz. The AD73360L converts the voltage signals conditioned by the three channels into digital signals, and sends the sampling data of each channel to the DSP through the SPI serial port and the photoelectric isolation module. The unbalanced current test platform of the series compensation device selects a 16-bit fixed-point operation chip TMS320VC5502 of TI company as a signal processing unit, and the main frequency of the signal processing unit is set to 300 MHz. Compared with a C54x series digital signal processing chip with the main frequency of 120MHz, the TMS320VC5502 performance is improved by about 5 times, and the power consumption is reduced to 1/6.
Referring to fig. 5, the test platform designed by the system can receive the control signal of the control acquisition module through the wireless WiFi or the optical fiber ethernet, output a sinusoidal voltage signal and a square wave signal, and transmit the sinusoidal voltage signal and the square wave signal to the control acquisition module through the wireless WiFi or the optical fiber ethernet. The platform designed by the method is used for testing the unbalanced current of a certain line series compensation device, and the unbalanced currents of the series before and after the capacitor is adjusted in the running state are respectively tested, and the results are shown in table 1.
TABLE 1 series unbalance current before and after capacitor regulation in operating state
| Date | Condition | Phase sequence | Unbalanced current/mA |
| 2018-4-25 | Before adjustment | A | 59.45 |
| B | 71.25 | ||
| C | 334.48 | ||
| 2018-4-25 | After adjustment | A | -48.51 |
| B | -34.49 | ||
| C | -39.89 | ||
| 2018-5-17 | Before adjustment | A | 65.76 |
| B | 54.80 | ||
| C | 416.54 | ||
| 2018-5-17 | After adjustment | A | -66.91 |
| B | -57.49 | ||
| C | -49.38 |
The system has three conditioning and acquisition channels of unbalanced current, total current of the capacitor bank and voltage signals of the series compensation capacitor bank, and also has an output channel which is used for testing, the output current of the output channel is greater than 2A, and the maximum amplitude of the output channel is 60V, so that the system is convenient to use and high in testing accuracy.
Claims (4)
1. The utility model provides a series compensation device unbalance current test system which characterized in that: the device comprises an unbalanced current acquisition module, a capacitor bank total current acquisition module, a capacitor bank two-terminal voltage acquisition module, a signal output module and a digital control board, wherein the unbalanced current acquisition module is connected with a signal input end of the digital control board and is used for acquiring an unbalanced current of a series compensation device; the signal output end of the capacitor bank total current acquisition module is connected with the signal input end of the digital control board and is used for acquiring the total load input current of the capacitor bank in the series compensation device; the signal input ends of the voltage acquisition modules at the two ends of the capacitor bank are connected with the signal input end of the digital control board and are used for acquiring input voltages at the two ends of the capacitor bank of the series compensation device; the signal output module is connected with the signal output end of the digital control board and used for outputting a control signal; the digital control board is used for sending out a control command according to the acquired information;
the unbalanced current acquisition module comprises a first current-voltage conversion module, the signal output end of the first current-voltage conversion module is connected with the signal input end of a first signal conditioning and amplifying filter module, the output end of the first signal conditioning and amplifying filter module is connected with the signal input end of a first A/D high-speed acquisition module, the first A/D high-speed acquisition module is bidirectionally connected with a first signal isolation module, and the first signal isolation module is bidirectionally connected with the digital control board;
the capacitor bank total current acquisition module comprises a second current-voltage conversion module, the signal output end of the second current-voltage conversion module is connected with the signal input end of the signal conditioning band-pass filter module, the output end of the signal conditioning band-pass filter module is connected with the signal input end of a second A/D high-speed acquisition module, the second A/D high-speed acquisition module is bidirectionally connected with a second signal isolation module, and the second signal isolation module is bidirectionally connected with the digital control panel;
the voltage acquisition modules at two ends of the capacitor bank comprise a second signal conditioning and amplifying filtering module, and the output end of the second signal conditioning and amplifying filtering module is connected with the signal input end of a third A/D high-speed acquisition module; the third A/D high-speed acquisition module is bidirectionally connected with a third signal isolation module, and the third signal isolation module is bidirectionally connected with the digital control board;
the signal output module comprises a digital-to-analog conversion module, a low-pass filtering module and a switching power supply power amplification module, the digital-to-analog conversion module is connected with the digital control board in a two-way mode, the output end of the digital-to-analog conversion module is connected with the signal input end of the low-pass filtering module, the output end of the low-pass filtering module is connected with the input end of the switching power supply power amplification module, and the output end of the switching power supply power amplification module is the control signal output end of the signal output module.
2. The series compensation apparatus unbalanced current test system of claim 1, wherein: the digital control board uses a DSP as a microprocessor.
3. The series compensation apparatus unbalanced current test system of claim 1, wherein: the signal conditioning band-pass filter module includes electric capacity C47, the one end of electric capacity C47 is divided into two the tunnel, and first way does the input of filter module, another way divide into two the tunnel behind resistance R25, and first way is through electric capacity C48 ground connection, and the second way is connected with resistance R27's one end, electric capacity C47's other end ground connection, resistance R27's the other end does the signal output part of filter module.
4. The series compensation apparatus unbalanced current test system of claim 1, wherein: the A/D high-speed acquisition module uses an AD73360L type high-speed acquisition chip.
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| CN100583586C (en) * | 2007-09-21 | 2010-01-20 | 四川电力试验研究院 | Unbalanced protection method and device for high-voltage serial connection compensation capacitor group |
| CN202351302U (en) * | 2011-11-25 | 2012-07-25 | 华北电网有限公司张家口供电公司 | Testing instrument for simulating unbalance current of serial compensating device |
| CN103344843B (en) * | 2013-07-29 | 2015-10-14 | 国家电网公司 | A kind of measuring system of series capacitor compensation group |
| CN104076197A (en) * | 2014-07-14 | 2014-10-01 | 国家电网公司 | Unbalanced current testing device and method for capacitor bank |
| CN105262062A (en) * | 2015-09-25 | 2016-01-20 | 陈薇 | Power switch cabinet protection system |
| CN107144737A (en) * | 2017-06-09 | 2017-09-08 | 华北电力科学研究院有限责任公司 | A kind of series capacitor compensation element fault monitoring method and device |
| CN207336630U (en) * | 2017-09-11 | 2018-05-08 | 辽宁荣信兴业电力技术有限公司 | A kind of detection device of each branch current of High voltage series capacitor device compensation device |
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