CN105703349A

CN105703349A - Low excitation impedance transformer single-phase grounding protection device and protection method

Info

Publication number: CN105703349A
Application number: CN201410701149.2A
Authority: CN
Inventors: 杨云龙; 黄钢
Original assignee: LIAONING TUOXIN POWER ELECTRONIC Co Ltd
Current assignee: LIAONING TUOXIN POWER ELECTRONIC Co Ltd
Priority date: 2014-11-28
Filing date: 2014-11-28
Publication date: 2016-06-22

Abstract

The invention relates to a low excitation impedance transformer single-phase grounding protection device and a protection method. Through bypass grounding current shunting, grounding arcs are eliminated, the grounding protection effect is improved, grounding and line selection can be realized, and line selection and fault positioning are accurate. The device comprises three single-phase breakers, a low excitation impedance transformer, a signal generator, a zero sequence current transformer and a control detection device, wherein wire incoming sides of the three single-phase breakers are respectively connected with a corresponding bus through an isolation switch or a separation breaker, wire outgoing sides are connected with an original edge winding of the low excitation impedance transformer, the low excitation impedance transformer is a single-phase three winding dry core transformer having the original edge winding, a secondary edge main winding and a secondary edge secondary winding, one end of the original edge winding is connected with a ground network or a ground row through the zero sequence current transformer, the secondary edge main winding is connected with the signal generator, the secondary edge secondary winding is connected with the control detection device, the secondary edge main winding is for signal injection, and the secondary edge secondary winding is for signal measurement.

Description

Low excitation impedance transformator one-phase ground protection device and guard method

Technical field

The present invention relates to a kind of small electric current grounding system of distribution network one-phase ground protection device and guard method, particularly relate to low excitation impedance transformator single-phase ground protection method and guard method。

Background technology

Most faults that small electric current grounding system of distribution network occurs are singlephase earth fault, allow band single-phase earthing to run 1～2 hour according to code regulation, for avoiding ground arc expansion accident, are generally adopted neutral by arc extinction coil grounding mode and extinguish ground arc。But being affected by arc suppression coil over compensation operation mode, there is blow-out thorough, route selection and fault location are difficult。Using voltage transformer to carry out signal method for implanting and carry out route selection and fault location, it is possible to solve route selection and orientation problem, but by voltage transformer capacity limit, the particularly route selection in high resistance ground situation, locating accuracy are not high。

Summary of the invention

For the weak point that prior art exists; the technical problem to be solved is to provide a kind of low excitation impedance transformator one-phase ground protection device suitable in small electric current grounding system of distribution network and guard method; by by-pass shunt earth current; eliminate ground arc; improve ground protection effect, it may be achieved ground connection and route selection and route selection and fault location are accurate。

For solving above-mentioned technical problem, we are bright be the technical scheme is that

This low excitation impedance transformator one-phase ground protection device, by three single-phase circuit breakers, one low excitation impedance transformator, signal generator, zero sequence current mutual inductor and control detecting device composition, three single-phase circuit breaker inlet wire sides connect with corresponding phase bus respectively by isolating switch or interval chopper, outgoing line side is connected with low excitation impedance transformer primary side winding, described low excitation impedance transformator is single-phase three winding dry type appendiron core transformer, described three winding is primary side winding, secondary main winding and secondary time winding, primary side winding power frequency impedance is 1 ohm～3.5 ohm, the described primary side winding other end is connected with earth mat or ground row by described zero sequence current mutual inductor, low excitation impedance transformer secondary main winding is connected with described signal generator, secondary time winding is connected with described control detecting device, described secondary main winding injects for signal, secondary time winding is for signal measurement。

This low excitation impedance transformator single-phase ground protection method is:

1, when small electric current grounding system of distribution network generation singlephase earth fault, corresponding separate single-phase circuit breaker rapid closing, low excitation impedance transformer primary side winding is accessed between Earth Phase and earth mat, by Earth Phase and the earth multiple grounding, by-pass shunt earth current on the one hand, reduces and flows through earth point place electric current；Low excitation impedance transformer primary side winding accesses Earth Phase and earth mat on the other hand, be equivalent between Earth Phase and earth mat and connect the impedance less than 3.5 ohm of the resistance, clamp down on Earth Phase voltage, reduce ground arc and restrike probability, play the purpose extinguishing ground arc；

2, inject detection signal by signal generator to low excitation impedance transformer secondary main winding simultaneously; the detection signal injected flows in the loop being made up of Earth Phase, faulty line, earth point, the earth and low excitation impedance protection equipment for transformer; control detecting device detection Injection Signal; what have Injection Signal is ground path; on ground path, blackout position is earth point, thus being grounded route selection and location；

3, implementing in protection process at device, when there is out-phase ground connection such as All other routes, two Earth Phases are by low excitation impedance transformer short-circuit, owing to low excitation impedance transformator has certain impedance, it is possible to play the function of restriction two-phase grounding fault electric current。

The invention has the beneficial effects as follows: single-phase earthing extinguishing arc technology and signal injection technique are assembled integration apparatus；By by-pass shunt earth current, it is suppressed that intermittent grounding surge, elimination ground arc, improve ground protection effect；Injected by low excitation impedance transformator signal, increase injection intensity, improve route selection and positioning precision。

Accompanying drawing explanation

Fig. 1 is the structural representation of the low excitation impedance transformator one-phase ground protection device of the present invention。

Detailed description of the invention

As it can be seen, this low excitation impedance transformator one-phase ground protection device, it is made up of 3, low excitation impedance transformator 4 of three single-phase circuit breakers, signal generator 6, zero sequence current mutual inductor 7 and control detecting device 5。Described low excitation impedance transformator 4 is single-phase three winding dry type appendiron core transformer, described three winding is primary side winding 401, secondary main winding 402 and secondary time winding 403, the power frequency impedance of primary side winding 401 is 1 ohm～3.5 ohm, the present embodiment is 2 ohm, and three single-phase circuit breaker 4 inlet wire sides are by isolating switch (or interval chopper) 2(KA, KB, KC) respectively with corresponding phase bus 1(A,B, C)Connecting, outgoing line side is connected with low excitation impedance transformator 4 inlet wire side and primary side winding 401 one end, and low excitation impedance transformator 4 outgoing line side and primary side winding 401 other end are connected with grounded screen (or ground row) 8 by zero sequence current mutual inductor 7。Controlling detecting device 5 to be connected with low excitation impedance transformator 4 secondary time winding 403, signal generator 6 is connected with low excitation impedance transformator 4 secondary main winding 402。Control detecting device 5 real-time acquisition system bus 1 voltage Ua, Ub, Uc and residual voltage Uo, and the mutual relation according to the amplitude of system phase, line and residual voltage with phase place, it is judged that system is separate with or without single-phase earthing and ground connection。System generation singlephase earth fault is judged when controlling detecting device 5, control corresponding separate single-phase circuit breaker 3 to close a floodgate, low excitation impedance transformator 4 is accessed between Earth Phase and earth mat 8, injects detection signal by signal generator 6 to the secondary main winding 402 of low excitation impedance transformator simultaneously。

This low excitation impedance transformator single-phase ground protection method, step is as follows:

1, when small electric current grounding system of distribution network generation singlephase earth fault, corresponding separate single-phase circuit breaker rapid closing, low excitation impedance transformer primary side winding 401 is accessed between Earth Phase and earth mat 8, by Earth Phase and the earth multiple grounding, by-pass shunt earth current on the one hand, reduces and flows through earth point place electric current；Low excitation impedance transformer primary side winding 401 accesses Earth Phase and earth mat 8 on the other hand, be equivalent between Earth Phase and earth mat 8 and connect the impedance less than 3.5 ohm of the resistance, clamp down on Earth Phase voltage, reduce ground arc and restrike probability, play the purpose extinguishing ground arc；

2, inject detection signal by signal generator 6 to low excitation impedance transformer secondary main winding 402 simultaneously; the detection signal injected flows in the loop being made up of Earth Phase, faulty line, earth point, the earth and described low excitation impedance protection equipment for transformer; control detecting device 5 and detect Injection Signal; what have Injection Signal is ground path; on ground path, blackout position is earth point, thus being grounded route selection and location；

3, implementing in protection process at device, when there is out-phase ground connection such as All other routes, two Earth Phases are by the short circuit of low excitation impedance transformator 4, owing to low excitation impedance transformator 4 has certain impedance, it is possible to play the function of restriction two-phase grounding fault electric current。

The foregoing is only presently preferred embodiments of the present invention, not in order to limit the present invention, all any amendment, equivalent replacement and improvement etc. on technical scheme basis, the present embodiment made, should be included within protection scope of the present invention。

Claims

1. one kind low excitation impedance transformator one-phase ground protection device, it is characterized in that: by three single-phase circuit breakers, one low excitation impedance transformator, signal generator, zero sequence current mutual inductor and control detecting device composition, three single-phase circuit breaker inlet wire sides connect with corresponding phase bus respectively by isolating switch or interval chopper, outgoing line side is connected with low excitation impedance transformer primary side winding, described low excitation impedance transformator is single-phase three winding dry type appendiron core transformer, described three winding is primary side winding, secondary main winding and secondary time winding, primary side winding power frequency impedance is 1 ohm～3.5 ohm, the described primary side winding other end is connected with earth mat or ground row by described zero sequence current mutual inductor, low excitation impedance transformer secondary main winding is connected with described signal generator, secondary time winding is connected with described control detecting device, described secondary main winding injects for signal, secondary time winding is for signal measurement。

2. a low excitation impedance transformator single-phase ground protection method, is characterized in that:

1), when small electric current grounding system of distribution network generation singlephase earth fault, corresponding separate single-phase circuit breaker rapid closing, low excitation impedance transformer primary side winding is accessed between Earth Phase and earth mat, by Earth Phase and the earth multiple grounding, by-pass shunt earth current on the one hand, reduces and flows through earth point place electric current；Low excitation impedance transformer primary side winding accesses Earth Phase and earth mat on the other hand, be equivalent between Earth Phase and earth mat and connect the impedance less than 3.5 ohm of the resistance, clamp down on Earth Phase voltage, reduce ground arc and restrike probability, play the purpose extinguishing ground arc；

2), inject detection signal by signal generator to low excitation impedance transformer secondary main winding simultaneously; the detection signal injected flows in the loop being made up of Earth Phase, faulty line, earth point, the earth and low excitation impedance protection equipment for transformer; control detecting device detection Injection Signal; what have Injection Signal is ground path; on ground path, blackout position is earth point, thus being grounded route selection and location；

3), implementing in protection process at device, when there is out-phase ground connection such as All other routes, two Earth Phases are by low excitation impedance transformer short-circuit, owing to low excitation impedance transformator has certain impedance, it is possible to play the function of restriction two-phase grounding fault electric current。