CN203519775U - Circuit for testing series capacitor overload tolerance capacity - Google Patents
Circuit for testing series capacitor overload tolerance capacity Download PDFInfo
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- CN203519775U CN203519775U CN201320687312.5U CN201320687312U CN203519775U CN 203519775 U CN203519775 U CN 203519775U CN 201320687312 U CN201320687312 U CN 201320687312U CN 203519775 U CN203519775 U CN 203519775U
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- 238000012360 testing method Methods 0.000 title claims abstract description 107
- 238000004146 energy storage Methods 0.000 claims abstract description 75
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- SFZCNBIFKDRMGX-UHFFFAOYSA-N sulfur hexafluoride Chemical compound FS(F)(F)(F)(F)F SFZCNBIFKDRMGX-UHFFFAOYSA-N 0.000 claims description 4
- 229960000909 sulfur hexafluoride Drugs 0.000 claims description 4
- 238000007599 discharging Methods 0.000 abstract 2
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Abstract
The utility model provides a circuit for testing the series capacitor overload tolerance capacity. The circuit comprises a voltage regulator, a transformer, a current-limiting resistor, an energy storage capacitor, a first matching reactor, a second switch, a tested series capacitor, a second matching reactor, a discharging resistor, and a third switch. The first end of the transformer is connected with the third end of the voltage regulator, the second end of the transformer is connected with the fourth end of the voltage regulator, and the third end of the transformer is connected with the first end of the current-limiting resistor. The second end of the current-limiting resistor is connected with the first end of a first switch. The second end of the energy storage capacitor is connected with the second end of the first matching reactor and the fourth end of the transformer separately. The second end of the first matching reactor is connected with the fourth end of the transformer. The second end of the tested series capacitor is connected with the second end of the second matching reactor and the ground separately. The second end of the second matching reactor is connected with the ground. The second end of the discharging resistor is connected with the first end of the third switch. The second end of the third switch is connected with the fourth end of the transformer. According to the utility model, the purpose of effectively ensuring the series capacitor quality can be achieved.
Description
Technical field
The utility model relates to Circuit Measurement Technology field, particularly a kind of circuit of testing series capacitor tolerance capability of overload.
Background technology
Development along with power technology, power transmission and transformation capacity and transmission line length are also in continuous increase, the thing followed is the continuous increase of corresponding line impedance, the increase of impedance can make again the transport capacity on circuit be restricted, quality of voltage can not be guaranteed, and also makes the bad stability of system.Therefore, need to seal in the line series capacitor, to compensate a part of line impedance, to reduce the loss of voltage, improve the stability of electric system, thereby reach the object of optimizing the distributing electric power between shunt circuit, the stable operation of guaranteeing series capacitor in this process is the basic premise that guarantees series compensation stability.
So-called series capacitor is a kind of capacitor being used in series compensation device, it has reduced the phase angle difference at circuit two ends when reducing circuit inductive reactance, in long-distance transmission line, series capacitor can be used for improving the stability of voltage characteristic and system, also can increase the transmission capacity of power transmission line.
The overload of series capacitor refers to the superpotential in short-term that series capacitor tolerates during electric power system fault, and the overladen of series capacitor determines it is an important indicator that guarantees the stable operation of series capacitor.For typical M type (; nonlinear resistor with bypass clearance) overvoltage protection; series capacitor should be able to bear 2.0pu to the superpotential in short-term within the scope of 2.5pu; wherein; pu represents the perunit value of level of protection, the rated voltage of series capacitor is defined as to a pu herein.
At present, what the commissioning test of series capacitor was continued to use is the test standard of shnt capacitor, namely make series capacitor stand DC test, yet, series capacitor and shnt capacitor are very different in the method for operation, therefore, existing test standard is difficult to effectively guarantee the quality of series capacitor.
For the problems referred to above, effective solution is not yet proposed at present.
Utility model content
The utility model embodiment provides a kind of circuit of testing series capacitor tolerance capability of overload, to reach the object of the quality of effective assurance series capacitor.
The utility model embodiment provides a kind of circuit of testing series capacitor tolerance capability of overload, comprising:
Pressure regulator, first end is the input end of the circuit of described test series capacitor tolerance capability of overload, the second end is the output terminal of the circuit of described test series capacitor tolerance capability of overload;
Transformer, first end is connected with the 3rd end of pressure regulator, and the second end is connected with the 4th end of pressure regulator, and the 3rd end is connected with the first end of current-limiting resistance;
Current-limiting resistance, the second end is connected with the first end of the first switch;
The first switch, the second end respectively with the first end of energy-storage capacitor, the first end of second switch, first coupling reactance first end be connected;
Energy-storage capacitor, the second end be connected with the second end of the first coupling reactance, the 4th end of transformer respectively;
The first coupling reactance, the second end is connected with the 4th end of transformer;
Second switch, the second end is connected with first end, the second coupling first end of reactance, the first end of discharge resistance of tested series capacitor respectively;
Tested series capacitor, the second end is connected with ground with the second end of the second coupling reactance respectively;
The second coupling reactance, the second end is connected to the ground;
Discharge resistance, the second end is connected with the first end of the 3rd switch;
The 3rd switch, the second end is connected with the 4th end of transformer.
In an embodiment, described transformer comprises: a plurality of transformers of series connection.
In an embodiment, the number of the transformer of series connection is 2.
In an embodiment, the product of the transformation ratio of each transformer and the product of pressure regulator output voltage in described a plurality of transformers, the maximum voltage value that the tested series capacitor that equals to set should be able to bear.
In an embodiment, described the first switch is sulfur hexafluoride breaker; And/or described second switch is vacuum circuit breaker.
In an embodiment, the resistance value of discharge resistance meets following formula:
U
t=U
c* e
(t/RC), wherein, U
tfor the magnitude of voltage after described tested series capacitor electric discharge, U
cfor the magnitude of voltage before described tested series capacitor electric discharge, e is a natural constant infinitely not circulating, and t is electric discharge required time, the resistance value that R is described discharge resistance, the capacitance that C is described tested series capacitor.
In an embodiment, U
t=0.1U
c.
In an embodiment, the resistance of described current-limiting resistance is 2000 Ω, and/or the resistance of described discharge resistance is 300 Ω.
In an embodiment, the second coupling reactance comprises a plurality of reactors, and the coil of each reactor self inside adopts the mode of series connection to connect, and adopts mode in parallel to connect between each reactor.
In an embodiment, the capacitance of energy-storage capacitor is 3 times of described tested series capacitor capacitance.
In an embodiment, energy-storage capacitor comprises 4n platform capacitor, and wherein, n is more than or equal to 2 positive integer.
In an embodiment, the connected mode between 4n platform energy-storage capacitor is: 4 energy-storage capacitor series connection of identical parameters, as one group, form n group energy-storage capacitor, in parallel between n group energy-storage capacitor.
In the circuit of the test series capacitor tolerance capability of overload of the utility model embodiment, be provided with pressure regulator, transformer, current-limiting resistance, in the parallel connection of the two ends of tested series capacitor the second matched impedance, in circuit, be provided with the energy storage resonant tank being formed by energy-storage capacitor and the first matched impedance simultaneously, and by the cooperation of the switch that arranges in circuit, thereby make first by alternating voltage, to energy storage resonant tank, to charge, and then at short notice tested capacitor is carried out to rapid charge by the electric energy of the storage in energy storage resonant tank, with the tolerance overload to tested series capacitor, test, test the technical scheme of series capacitor tolerance capability of overload compares with the DC test of available technology adopting, the utility model embodiment can realize the object that adopts alternating voltage to test series capacitor tolerance capability of overload, thereby guarantee the quality of series capacitor.
Accompanying drawing explanation
Accompanying drawing described herein is used to provide further understanding of the present utility model, forms the application's a part, does not form restriction of the present utility model.In the accompanying drawings:
Fig. 1 is the schematic diagram that the test series capacitor of the utility model embodiment tolerates the circuit of capability of overload;
Fig. 2 is the concrete schematic diagram that the test series capacitor of the utility model embodiment tolerates the circuit of capability of overload;
Fig. 3 is the method for work process flow diagram that the series capacitor of the utility model embodiment tolerates the circuit of capability of overload;
Fig. 4 is the near region short trouble waveform schematic diagram of the series capacitor of the utility model embodiment;
Fig. 5 is the far field short trouble waveform schematic diagram of the series capacitor of the utility model embodiment;
Fig. 6 is the parallel resonance applied voltage test loop schematic diagram of the utility model embodiment;
Fig. 7 is the parallel resonance pressurization capacitor charge waveforms schematic diagram of the utility model embodiment;
Fig. 8 is another loop schematic diagram of parallel resonance applied voltage test of the utility model embodiment;
Fig. 9 is the schematic diagram of the different energy storage multiple of the utility model embodiment impact that voltage is fallen;
Figure 10 is the schematic diagram of the different energy storage multiple of the utility model embodiment impact that voltage is overcharged.
Embodiment
For making the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with embodiment and accompanying drawing, the utility model is described in further details.At this, exemplary embodiment of the present utility model and explanation thereof are used for explaining the utility model, but not as to restriction of the present utility model.
Inventor finds, to the voltage test of series capacitor, is generally to adopt DC voltage withstand test, and DC voltage withstand test is compared with AC voltage withstand test, although have advantages of that testing equipment is light, little and be easy to the local defect of discovering device to insulation harm.Yet, DC voltage withstand test is different because the voltage that insulate inner under interchange, direct current distributes, cause DC voltage withstand test to be not so good as the more approaching reality of ac test to the test of insulation, DC voltage withstand test is difficult to examine well the over-voltage condition of capacitor under actual condition, this also just causes part series capacitor not go wrong when commissioning test, once and hanging net operation will go wrong.
Consider that series capacitor has the characteristic that voltage can not suddenly change, therefore can utilize the mode of parallel resonance energy storage to carry out the test of series capacitor tolerance capability of overload.So-called parallel resonance energy storage is that institute's energy requirement is slowly stored in jumbo capacitor group, then by capacitor group moment to tested series capacitor Implantation Energy, in the utility model embodiment, just provide a kind of by shunt-resonant circuit energy storage, then take mode that resonant tank is power supply pressurization tests the circuit of series capacitor tolerance capability of overload, as shown in Figure 1, comprising:
Current-limiting resistance 103, the second ends are connected with the first end of the first switch 104;
The first switch 104, the second ends respectively with the first end of energy-storage capacitor 105, the first end of second switch 106, first coupling reactance 107 first end be connected;
Energy-storage capacitor 105, the second ends be connected with the second end of the first coupling reactance 107, the 4th end of transformer 102 respectively;
The first coupling reactance 107, the second ends are connected with the 4th end of transformer 102;
Tested series capacitor 108, the second ends are connected with ground with the second end of the second coupling reactance 110 respectively;
The second coupling reactance 110, the second ends are connected to the ground;
The 3rd switch 111, the second ends are connected with the 4th end of transformer 102.
In the above-described embodiments, in the circuit of test series capacitor tolerance capability of overload, be provided with pressure regulator, transformer, current-limiting resistance, in the parallel connection of the two ends of tested series capacitor the second matched impedance, in circuit, be provided with the energy storage resonant tank being formed by energy-storage capacitor and the first matched impedance simultaneously, and by the cooperation of the switch that arranges in circuit, thereby make first by alternating voltage, to energy storage resonant tank, to charge, and then at short notice tested capacitor is carried out to rapid charge by the electric energy of the storage in energy storage resonant tank, with the tolerance overload to tested series capacitor, test, test the technical scheme of series capacitor tolerance capability of overload compares with the DC test of available technology adopting, the utility model embodiment can realize the object that adopts alternating voltage to test series capacitor tolerance capability of overload, make the performance of definite series capacitor more accurate.While is very high because adopted energy storage resonant tank that supply voltage can not needed, and has reduced the cost of test circuit.
Pressure regulator provides the single phase alternating current power supply of 0V-400V for transformer primary side, consider if adopt a transformer to reach needed transformation ratio cost compare high, the mode that can connect by a plurality of transformers reaches required transformation ratio, thereby the voltage of pressure regulator output is increased to the required magnitude of voltage of test.In one embodiment, transformer 102 can comprise as shown in Figure 2: the first transformer 201 of series connection and the second transformer 202.The connected mode of the first transformer 201 and the second transformer 202 as shown in Figure 2, the first end of the first transformer 201 is as the first end of transformer 102, the second end of the first transformer 201 is as the second end of transformer 102, the 3rd end of the first transformer 201 is connected with the first end of the second transformer 202, the 4th end of the first transformer 201 is connected with the second end of the second transformer 202, the 3rd end of the second transformer 202 is as the 3rd end of transformer 102, and the 4th end of the second transformer 202 is as the 4th end of transformer 102.Above-mentioned is to take to be comprised of two transformers the explanation that the transformer 102 in the circuit of testing series capacitor tolerance capability of overload carries out as example, if the transformer 102 in the circuit that forms together test series capacitor tolerance capability of overload by 3 or more transformer, according to the mode of above-mentioned two transformers, expand connection, do not repeat them here.The transformer of selecting in transformer 102 need to meet: the product of the product of the transformation ratio of each transformer and pressure regulator output voltage in a plurality of transformers, the requirement of the maximum voltage value that the tested series capacitor that equals to set should be able to bear, could be increased to the required magnitude of voltage of test by the voltage of pressure regulator output like this.
In one embodiment, above-mentioned the first switch can be selected sulfur hexafluoride breaker, and above-mentioned second switch can be selected vacuum circuit breaker.
The effect of current-limiting resistance 103 is mainly the protective effect realizing circuit; because provide voltage by energy storage resonant tank for tested series capacitor in this circuit; therefore the resistance of current-limiting resistance is not strict with so, general value 2000 Ω left and right.
In order to make the value of discharge resistance 106 more reasonable, can according to following formula, choose the size of discharge resistance, that is, the resistance value of discharge resistance meets following formula:
U
t=U
c×e
(-t/RC)
Wherein, U
tfor the magnitude of voltage after described tested series capacitor electric discharge, U
cfor the magnitude of voltage before described tested series capacitor electric discharge, e is a natural constant infinitely not circulating, and t is electric discharge required time, the resistance value that R is discharge resistance, the capacitance that C is described tested series capacitor.
Yet, if by the magnitude of voltage U after electric discharge
tbe made as zero, resistance value will be an infinitesimal number, so can think that condenser voltage discharges into 90%, that is, get U
t=0.1U
c.
In the process of implementing in reality, according to the characteristic of circuit, can choose the resistance of 300 Ω left and right as current-limiting resistance.
For above-mentioned energy-storage capacitor 105, it is that the capacitor of 3 times of described tested series capacitor capacitance is as energy-storage capacitor that the result obtaining according to test can be chosen capacitance.
In order to meet the superpotential of the prearranged multiple that reaches capacitor rated voltage, if directly provide a reactor as the second coupling reactance, the cost of this reactor will be very high so, also be difficult to realize, therefore the second coupling reactance can be a Reactor banks, coil in each reactor in Reactor banks self adopts the mode of series connection to connect, between each reactor, adopt mode in parallel to connect, thereby the final reactance value of the second coupling reactance can be met the demands, in order to make the reactance value of reactor adjustable, to meet the demand of different situations, also can in Reactor banks, increase REgulatable reactor, by the adjusting of REgulatable reactor being reached to the tuning-points of full remuneration.
Consider that coupling energy-storage reactor (i.e. the first coupling reactance) is 0.1H, this energy storage load balancing reactor needs the energy-storage capacitor of 101uF so, in order to realize a kind of like this energy-storage capacitor, in an example, can adopt 4 series connection of capacitor of identical parameters, for example, to meet the requirement of predetermined overvoltage value (2.3pu), then with the parallel connection of 4 Tai Wei units to meet the requirement of storage capacitor amount.That is, capacitor comprises 4n platform capacitor, and wherein, n is more than or equal to 2 positive integer, and the connected mode between 4n platform energy-storage capacitor is: 4 energy-storage capacitor series connection of identical parameters, as one group, form n group energy-storage capacitor, in parallel between n group energy-storage capacitor.
The method of work of the circuit of the test series capacitor tolerance capability of overload shown in above-mentioned Fig. 1 to Fig. 2, as shown in Figure 3, comprises the following steps:
Step 301: the boost in voltage of the AC power that transformer provides pressure regulator is to predetermined magnitude of voltage;
Step 302: the first switch is closed, and parallel resonance tank circuit is charged, and wherein, described parallel resonance tank circuit comprises: the loop that energy-storage capacitor and the first coupling reactance form;
Step 303: when the electric weight in the energy-storage capacitor in parallel resonance tank circuit no longer changes, second switch is closed, and tested series capacitor is charged;
Step 304: after the schedule time, second switch disconnects, and the 3rd switch is closed simultaneously, and described tested series capacitor is discharged.
In one embodiment, before above-mentioned steps 301, also comprise: regulate the reactance value of coupling reactance, until the reactance value of described coupling reactance reaches full remuneration.After above-mentioned steps 302, finally can also comprise: after tested series capacitor electric discharge finishes, disconnect second switch, complete test process.
In order to realize rapid discharge, the above-mentioned schedule time can be 100ms, that is, at energy storage resonant tank, be full of after electricity, controls second switch and disconnects after closed 100ms, simultaneously closed the 3rd switch.It should be noted that; above-mentionedly to the disconnection of second switch and the 3rd switch and closed control, can control by writing computer program; also can be to adopt the modes such as single-chip microcomputer, FPGA to realize control, as long as can realize mode that switch make-and-break time is controlled accurately all in protection domain of the present utility model.
Below in conjunction with a specific embodiment, the circuit of above-mentioned test series capacitor tolerance capability of overload is specifically described, yet what deserves to be explained is, following embodiment is only for the utility model is better illustrated, does not form improper restriction of the present utility model.
Mostly series capacitor generation problem is in the operating time of protection of 0.1 second at present, is mainly, owing to being unable to bear the overload of 2.3pu, internal fault occurs, finally accidents caused.According to shnt capacitor standard, mainly carry out the problem that partial discharge test, Dielectric Loss Test, AC voltage withstand test can not effectively be found series capacitor, therefore in the urgent need to the commissioning test method of research series capacitor and the equipment of corresponding series capacitor commissioning test, with Validity Test series capacitor tolerance capability of overload, thus the safe operation of assurance series capacitor.
As shown in Figure 4, be the typical waveform of near region short trouble, the 15ms fault that is constantly short-circuited in Fig. 4, because short dot is positioned at serial supplementary line side, short-circuit current is very large, and therefore after fault, the 1st half-wave series capacitor compensation voltage reach 2.3pu.It shown in Fig. 5, is far field fault waveform, short circuit is all 15ms constantly, because trouble spot is far away, short-circuit current is not very large, therefore the voltage of series capacitor is not very large in the amplitude of first half-wave, MOV(metal oxide pressure-limiting device) also not action, until second half crest value just reaches 2.3pu, MOV conducting simultaneously.
Near region short trouble waveform based on to the series capacitor shown in above-mentioned Fig. 4 and Fig. 5 and far field short trouble waveform, and the level of protection of Insulation Coordination design and MOV, analyze and show that series capacitor should be able to bear the superpotential in short-term of 0.1s, 2.3pu.
Therefore, the circuit of the test series capacitor tolerance capability of overload of design, test loop is necessary can be in the situation that power supply capacity be certain, by the voltage on tested series capacitor below 1.1pu, in three cycle 60ms, be increased to suddenly 2.3pu, and excise after 0.1s, test voltage and duration are realized to accurate control simultaneously.
Based on above-mentioned requirements, the design of series capacitor short-circuit impact test loop is studied, by the electrical module in the Simulink of MATLAB simulation software, design proposal is carried out to emulation.Consider that capacitor has voltage this characteristic of can not suddenling change, can adopt the reactor that mates with the tested capacitor resonance object of boosting fast that reaches in parallel with it.Resonance is a kind of compensation completely, and power supply, without reactive power is provided, only provides resistance needed active power, and power supply electric energy is all resistance consumption, becomes pure resistor element circuit.The reactor that employing is mated with tested series capacitor resonance is the object of boosting fast that reaches in parallel with it.
Wherein, the inductance value of the second coupling reactance (being compensating inductance) can be according to formula
determine, wherein, f is work of electric power system frequency 50(Hz), L is load balancing reactor inductance value (H), the electric capacity that C is tested series capacitor (uF).
From the angle of energy, consider, make the voltage of tested series capacitor can rise to rapidly 2.3p.u. in the short time, just need to can inject large energy (being mainly quadergy) to capacitor in the short time, so just need to improve the capacity of power supply.This utility model people is found required energy to be slowly stored in jumbo capacitor group, and the capacitor group moment that stores large energy by this in the process of test is to test product Implantation Energy.In example, for the defect of direct weighting mode, proposed this shunt-resonant circuit energy storage of passing through, the mode that the resonant tank of then take pressurizes as power supply is tested the circuit of series capacitor tolerance capability of overload.
In conjunction with current conventional testing equipment, in the process of emulation, the parameter of selected element is:
Power supply: rated voltage 380V, rated current 600A, short-circuit current 10kA;
Single-phase voltage regulator: rated capacity 200kVA;
Transformer T1:0.4/10kV, rated capacity 400kVA, short-circuit impedance 10%;
Transformer T2:10/35kV, rated capacity 5000kVA, short-circuit impedance 10%;
Tested capacitor: rated voltage 5.79kV, electric capacity 54.98 μ F;
Coupling reactance: 0.1842H.
The parallel resonance energy pre-storage test loop of design as shown in Figure 6, wherein, K1, K2, K3, K4 represent switch, 601 represent the first voltage transformer (VT), and 602 represent that second voltage mutual inductor, 603 represents that voltage limiter, 604 represents bypass clearance, and Cx represents tested series capacitor, C1 represents energy-storage capacitor, L1 represents the reactance of energy storage coupling, and the represented device of other label is identical with Fig. 2, does not repeat them here.In process of the test, first, in the situation that K4 switch disconnects, K3 switch is closed, and the energy storage resonant tank of L1 and C1 composition is charged, and when charging reaches stable state, is incorporated into K4 switch tested series capacitor is charged when disconnecting K3 switch.
In tank circuit, capacitor, reactor capacity can represent with N with energy storage multiple, wherein, N represents the multiple relation of the electric capacity of energy-storage capacitor group electric capacity and tested capacitor, after preliminary emulation, obtaining N is 8 o'clock, and the waveform of emulation is illustrated in figure 7 the transient-wave of parallel resonance energy storage test loop.Transient-wave from Fig. 7 can find out, within the Closing Switch K4 short time, the voltage of tested series capacitor can reach rapidly expection level, and subsequently because original shunt-resonant circuit is destroyed, condenser voltage starts to decline; But in the front 100ms after K switch 4 closures, capacitor two point voltages maintain certain level substantially, decay slower.Because the rising of condenser voltage in this loop does not have beat frequency process, so its voltage peak controllability is stronger.
Also on analyzing for the impact of tank circuit capacity, after analyzing, find that tank circuit capacity in parallel is larger, after charging, voltage attenuation is slower simultaneously.
By above-mentioned test and analysis result, show, if need to reach comparatively desirable test findings, the stored energy capacitance needing is very large, probably to need to reach the more than 8 times of tested series capacitor capacity, if select the reactor of rated voltage 20kV grade, capacity is about 55MVar left and right, realizes difficulty larger, therefore need to further optimize test loop.
For this reason, on the basis of circuit as shown in Figure 6, tested series capacitor is increased to a resonance reactance L2, obtain test loop as shown in Figure 8.This measure can so that the loop resulting impedance of tested series capacitor after charging still close to parallel resonance state, can effectively reduce the rate of decay of voltage like this, after charging, the natural frequency of vibration of test loop is still power frequency simultaneously, can guarantee that electric voltage frequency meets the demands.
In the situation that test loop pattern is as shown in Figure 8 constant, study the impact of the parameter of each element on loop performance, and the Type Selection Principle of definite testing equipment.
The impact of voltage being fallen by the different energy storage multiple of simulation analysis, obtain as shown in Figure 9 the relatively rear voltage of closed rear the 5th peak value and first of tested condenser voltage of K switch 3 under different energy storage multiples and fall schematic diagram, wherein horizontal ordinate represents multiple, ordinate represents the number percent that voltage falls, as seen from Figure 9, along with reducing of energy storage multiple N, after charging, the voltage of tank circuit falls corresponding increase.Impact voltage being overcharged by the different energy storage multiple of simulation analysis, obtain as shown in figure 10 closed rear the first cycle crest value ratio schematic diagram of K switch 3 under different energy storage multiples, wherein, horizontal ordinate represents multiple, and ordinate represents crest value ratio, as seen from Figure 10, when energy storage multiple is larger, overshoot is all in 1%, and be down to 3 when following when energy storage multiple, overshoot multiple obviously increases, and can reach 9% left and right.
Therefore, if need to reduce energy storage multiple, need to be from the viewpoint of two: the pre-charge voltage that energy storage device can certain multiple on the one hand; Should guarantee that the overshoot voltage producing is within the scope of acceptable on the one hand on tested series capacitor in addition.By the analysis to emulated data, learn, select the testing requirements that 3 times of stored energy capacitances can be substantially satisfied.
By simulation analysis and preliminary verification experimental verification, as shown in Figure 8 this kind of loop form can reach the test effect of expection comparatively ideally, result according to above-mentioned test simulation, obtain testing the circuit theory design of series capacitor tolerance capability of overload as shown in Figure 2, mainly comprise power unit and test product part, by electrical equipment principle, can be divided into boost loop and discharge loop.
The course of work of foregoing circuit is mainly: pressure regulator, and for transformer primary side provides the single phase alternating current power supply of 0V to 400V.The step-up transformer that is respectively 0.4/10kV and 10/35kV by two-stage is elevated to the required magnitude of voltage of test.After mains side boosts and puts in place, gauge tap K2 is closed to charge for energy storage resonant tank.When charging reaches stable state, Closing Switch K3 charges to tested series capacitor.According to series capacitor, bear the superpotential requirement in short-term of 0.1s, 2.3pu, gauge tap K3 disconnects after closed 100ms, at K switch 4 closed pair test product resonant tanks, carry out rapid discharge simultaneously, discharge process is finished in one-period 20ms, to guarantee that test product accepts superpotential examination in 0.1 second.
In conjunction with current conventional device parameter, in the circuit of test series capacitor tolerance capability of overload as shown in Figure 2, the parameter of each element can be selected according to following parameter:
According to power regulator scope, two-stage step-up transformer no-load voltage ratio, can calculate the output test voltage of test loop, its value should equal 2.3pu.
That is, U
m=U
s* k
1* k
2
Wherein, U
mfor maximum output test voltage, U
sfor power regulator output voltage, k
1and k
2be respectively the no-load voltage ratio of the first transformer and the second transformer.
Current-limiting resistance, the selection range of resistance is 2000 Ω left and right.
Discharge resistance, the selection range of resistance can be chosen according to the electric discharge formula of capacitor:
U
t=U
c×e
(-t/RC)
Wherein, U
tfor the magnitude of voltage after tested series capacitor electric discharge, U
cfor the magnitude of voltage before described tested series capacitor electric discharge, e is natural constant, and its value is about 2.71828, is an infinitely period not, and t is electric discharge required time, the resistance value that R is discharge resistance, the capacitance that C is described tested series capacitor.
Yet, if by the magnitude of voltage U after the magnitude of voltage electric discharge after tested series capacitor electric discharge
tbe made as zero, resistance will be an infinitesimal number, therefore it has been generally acknowledged that condenser voltage electric discharge 90%, namely U
t=0.1U
c.
According to the result of above-mentioned simulation analysis, the large I of choosing of energy-storage capacitor arranges according to the size of about 3 times of tested series capacitor capacitance.
Below for a concrete example that carries out the test of series capacitor short-circuit impact:
In loop, the design parameter of equipment arranges as follows:
Capacitor parameters: rated voltage: 6.186kV, electric capacity: 65uF, corresponding compensation load balancing reactor need mate for 0.156H.
Experiment power supply: rated voltage 380V, rated current 600A, short-circuit current 10kA;
Single-phase voltage regulator rated capacity 200kVA, rated voltage 0-400v;
The first transformer: 0.4/10kV, rated capacity 400kVA, short-circuit impedance 10%;
The second transformer: 10/35kV, rated capacity 5000kVA, short-circuit impedance 10%;
Current-limiting resistance, can select the section resistance of impulse voltage generator, and its advantage is to be easy to dismountable, can change according to the size of tested series capacitor, and generally selecting resistance is the resistance of 2000 Ω left and right.
Discharge resistance, because needs flow through larger discharge current, can select water resistance by analysis, and it is simple and easy that water resistance has assembling, and resistance is easily adjusted and the larger advantage of capacity.According to capacitor size and electric discharge formula, to consider simultaneously and will within one to two cycle, residual voltage be bled off, the resistance that calculates water resistance is 300 Ω left and right.
Second switch, can be used sulfur hexafluoride breaker, and rated voltage 40.5kV can cut-off the short-circuit current of 2.5kA.
The 3rd switch, operable is vacuum circuit breaker.
Second switch and the 3rd switch can be unified to be controlled by programming controller, and its degree of accuracy unit can reach 1ms.
In order to meet the requirement of 2.3 times of pu superpotential 14.2kV of capacitor rated voltage, can select Reactor banks to realize the object of the second coupling reactance, after all reactors in Reactor banks can be selected series wiring mode, (coil that is each reactor inside adopts the mode of connecting in parallel connection, between reactor, adopt mode in parallel to connect, thereby reach required reactance value), regulate REgulatable reactor to reach the tuning-points of full remuneration.The parameter of the load balancing reactor that this example is used is as shown in table 1:
Table 1
Energy-storage reactor is 0.1H, mates so the energy-storage capacitor that energy-storage reactor needs 101uF.The capacitor of available 10 kinds of different parameters, 4 of the series connection of identical parameters, to meet 2.3pu magnitude of voltage, then can meet storage capacitor amount with the parallel connection of 4 Tai Wei units, and the parameter of the energy-storage capacitor that this example is used is as shown in table 2:
Table 2
| Every rated voltage (KV) | Every electric capacity (uF) | Four series electrical capacity (uF) |
| 11/√3 | 5.5 | 1.375 |
| 12/√3 | 21.9 | 5.475 |
| 6 | 31.3 | 7.825 |
| 6.168 | 65.4 | 16.35 |
| 6.168 | 66.0 | 16.5 |
| 6 | 67.2 | 16.8 |
| 6 | 67.2 | 16.8 |
| 12 | 13.1 | 3.275 |
| 5.5 | 53.08 | 13.27 |
| 5.4 | 70.06 | 17.515 |
Coding controller code, make it meet second switch closure in the rear 100ms of program operation, at capacitor, bear after the superpotential in short-term of 0.1s, 2.3pu, control second switch and when the postrun 200ms of program, disconnect (second switch disconnects after closed 100ms).Meanwhile, control the 3rd switch closed when second switch disconnects, so that tested series capacitor is carried out to rapid discharge.
The job step of foregoing circuit can be mainly: regulate mains side pressure regulator to make it boost to 14.2kV, closed the first Switching Power Supply is slowly charged to parallel resonance tank circuit.When charging reaches stable state, closed second switch, after 100ms, disconnects second switch, and simultaneously closed the 3rd switch, to complete complete test process.
In this example, a kind of circuit of new test series capacitor tolerance capability of overload has been proposed, it is commissioning test mode, series capacitor is simulated the overload trial of actual condition before linked network puts into operation, thereby can find in time the Insulation Problems of series capacitor, after effectively having avoided directly putting into operation, there is major accident, reach the object of the safe operation that guarantees series capacitor.
From above description, can find out, the utility model embodiment has realized following technique effect: in the circuit of test series capacitor tolerance capability of overload, be provided with pressure regulator, transformer, current-limiting resistance, in the parallel connection of the two ends of tested series capacitor the second matched impedance, in circuit, be provided with the energy storage resonant tank being formed by energy-storage capacitor and the first matched impedance simultaneously, and by the cooperation of the switch that arranges in circuit, thereby make first by alternating voltage, to energy storage resonant tank, to charge, and then at short notice tested capacitor is carried out to rapid charge by the electric energy of the storage in energy storage resonant tank, with the tolerance overload to tested series capacitor, test, test the technical scheme of series capacitor tolerance capability of overload compares with the DC test of available technology adopting, the utility model embodiment can realize the object that adopts alternating voltage to test series capacitor tolerance capability of overload, thereby guaranteed the quality of series capacitor.While is very high because adopted energy storage resonant tank that supply voltage can not needed, and has reduced the cost of test circuit.
The foregoing is only preferred embodiment of the present utility model, be not limited to the utility model, for a person skilled in the art, the utility model embodiment can have various modifications and variations.All within spirit of the present utility model and principle, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection domain of the present utility model.
Claims (12)
1. a circuit of testing series capacitor tolerance capability of overload, is characterized in that, comprising:
Pressure regulator, first end is the input end of the circuit of described test series capacitor tolerance capability of overload, the second end is the output terminal of the circuit of described test series capacitor tolerance capability of overload;
Transformer, first end is connected with the 3rd end of pressure regulator, and the second end is connected with the 4th end of pressure regulator, and the 3rd end is connected with the first end of current-limiting resistance;
Current-limiting resistance, the second end is connected with the first end of the first switch;
The first switch, the second end respectively with the first end of energy-storage capacitor, the first end of second switch, first coupling reactance first end be connected;
Energy-storage capacitor, the second end be connected with the second end of the first coupling reactance, the 4th end of transformer respectively;
The first coupling reactance, the second end is connected with the 4th end of transformer;
Second switch, the second end is connected with first end, the second coupling first end of reactance, the first end of discharge resistance of tested series capacitor respectively;
Tested series capacitor, the second end is connected with ground with the second end of the second coupling reactance respectively;
The second coupling reactance, the second end is connected to the ground;
Discharge resistance, the second end is connected with the first end of the 3rd switch;
The 3rd switch, the second end is connected with the 4th end of transformer.
2. the circuit of test series capacitor tolerance capability of overload as claimed in claim 1, is characterized in that, described transformer comprises: a plurality of transformers of series connection.
3. the circuit of test series capacitor tolerance capability of overload as claimed in claim 2, is characterized in that, the number of the transformer of series connection is 2.
4. test series capacitor as claimed in claim 2 tolerates the circuit of capability of overload, it is characterized in that, the product of the transformation ratio of each transformer and the product of pressure regulator output voltage in described a plurality of transformer, the maximum voltage value that the tested series capacitor that equals to set should be able to bear.
5. test series capacitor as claimed in claim 1 tolerates the circuit of capability of overload, it is characterized in that:
Described the first switch is sulfur hexafluoride breaker;
And/or described second switch is vacuum circuit breaker.
6. the circuit of test series capacitor tolerance capability of overload as claimed in claim 1, is characterized in that, the resistance value of described discharge resistance meets following formula:
U
t=U
c* e
(t/RC), wherein, U
tfor the magnitude of voltage after described tested series capacitor electric discharge, U
cfor the magnitude of voltage before described tested series capacitor electric discharge, e is a natural constant infinitely not circulating, and t is electric discharge required time, the resistance value that R is described discharge resistance, the capacitance that C is described tested series capacitor.
7. the circuit of test series capacitor tolerance capability of overload as claimed in claim 6, is characterized in that U
t=0.1U
c.
8. test series capacitor as claimed in claim 1 tolerates the circuit of capability of overload, it is characterized in that:
The resistance of described current-limiting resistance is 2000 Ω,
And/or the resistance of described discharge resistance is 300 Ω.
9. the test series capacitor as described in any one in claim 1 to 8 tolerates the circuit of capability of overload, it is characterized in that, described the second coupling reactance comprises a plurality of reactors, the coil of each reactor self inside adopts the mode of series connection to connect, and adopts mode in parallel to connect between each reactor.
10. the circuit of the tolerance of the test series capacitor as described in any one in claim 1 to 8 capability of overload, is characterized in that, the capacitance of described energy-storage capacitor is 3 times of described tested series capacitor capacitance.
The circuit of 11. test series capacitor as described in any one in claim 1 to 8 tolerance capability of overloads, is characterized in that, described energy-storage capacitor comprises 4n platform capacitor, and wherein, n is more than or equal to 2 positive integer.
The circuit of 12. test series capacitor tolerance capability of overloads as claimed in claim 11, it is characterized in that, connected mode between described 4n platform energy-storage capacitor is: 4 energy-storage capacitor series connection of identical parameters are as one group, form n group energy-storage capacitor, in parallel between n group energy-storage capacitor.
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| CN201320687312.5U CN203519775U (en) | 2013-11-01 | 2013-11-01 | Circuit for testing series capacitor overload tolerance capacity |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103558537A (en) * | 2013-11-01 | 2014-02-05 | 国家电网公司 | Circuit for testing overload tolerance capacity of series capacitor and working method of circuit |
| CN111781544A (en) * | 2020-06-12 | 2020-10-16 | 矽力杰半导体技术(杭州)有限公司 | Energy storage capacitor device and state monitoring circuit thereof |
-
2013
- 2013-11-01 CN CN201320687312.5U patent/CN203519775U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103558537A (en) * | 2013-11-01 | 2014-02-05 | 国家电网公司 | Circuit for testing overload tolerance capacity of series capacitor and working method of circuit |
| CN103558537B (en) * | 2013-11-01 | 2015-12-30 | 国家电网公司 | The circuit of test series capacitor tolerance capability of overload and method of work thereof |
| CN111781544A (en) * | 2020-06-12 | 2020-10-16 | 矽力杰半导体技术(杭州)有限公司 | Energy storage capacitor device and state monitoring circuit thereof |
| CN111781544B (en) * | 2020-06-12 | 2023-04-28 | 矽力杰半导体技术(杭州)有限公司 | Energy storage capacitor device and state monitoring circuit thereof |
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