CN108254650A

CN108254650A - A kind of quick distinguishing method of substation busbars singlephase earth fault

Info

Publication number: CN108254650A
Application number: CN201810336334.4A
Authority: CN
Inventors: 李政洋; 李景禄
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-04-16
Filing date: 2018-04-16
Publication date: 2018-07-06
Anticipated expiration: 2038-04-16
Also published as: CN108254650B

Abstract

The present invention is a kind of quick distinguishing method of substation busbars singlephase earth fault, and when singlephase earth fault occurs, I is measured by each feeder line zero sequence current mutual inductor₁₀、I₂₀…I_n0、I_j、I_N,The feeder line of zero-sequence current maximum is found out than width method by zero-sequence current, if meeting I_jmax0=I₁₀+I₂₀+…+I_n0+I_m0‑I_nj0, i.e., the value of maximum zero sequence current is the sum of remaining feeder line zero-sequence current and busbar zero-sequence current in addition to itself in feeder line, then is judged as that singlephase earth fault occurs for the feeder line of zero-sequence current maximum；If I_jmax0≠I₁₀+I₂₀+…+I_n0+I_m0‑I_nj0I.e. the zero-sequence current of the feeder line is less than the circuit zero-sequence current value maximum in metallic earthing, then judges that singlephase earth fault occurs for substation busbars.

Description

A kind of quick distinguishing method of substation busbars singlephase earth fault

Technical field

The present invention is one-phase earthing failure in electric distribution network process field, is mainly used for substation busbars and singlephase earth fault occurs When failure quickly judge.

Background technology

When being handled using earth fault processing unit singlephase earth fault, since substation busbars can also be sent out sometimes Raw singlephase earth fault needs to judge that singlephase earth fault is happened at the single-phase of the feeder line generation that is connect on busbar either busbar Earth fault need to judge that singlephase earth fault is happened at substation bus bar or feeder line, could carry out accurately carrying out failure Isolation processing.Because when singlephase earth fault occurs, the busbar being linked together is with feeder line in fault signature neutral-point displacement The variation of voltage is all identical, it is difficult to the quick judgement of fault zone is carried out according to Fault feature of single phase earthing, it such as cannot be accurate True judges fault zone, cannot carry out Fault Isolation processing, thus quickly judges when singlephase earth fault occurs It is out of order and region and timely troubleshooting is taken to be very important.

Invention content

A kind of quick distinguishing method of substation busbars singlephase earth fault has been invented in view of the above problems, when detecting power transformation Institute neutral point voltage U_NWhen abnormal, each feeder line zero-sequence current I is measured by each feeder line zero sequence current mutual inductor first₁₀、I₂₀…I_n0、 I_j、I_N,The feeder line of zero-sequence current maximum is found out than width method by zero-sequence current, if meeting I_jmax0=I₁₀+I₂₀+…+I_n0+I_m0- I_nj0, i.e., the value of maximum zero sequence current is the sum of remaining feeder line zero-sequence current and busbar zero-sequence current in addition to itself in feeder line, then sentences Break and singlephase earth fault occurs for the feeder line of zero-sequence current maximum；If I_jmax0≠I₁₀+I₂₀+…+I_n0+I_m0-I_nj0, and I_jmax0≤ I_jzmax0, I_jmax0≤I_max0, i.e. small or maximum in metallic earthing equal to the circuit zero-sequence current of the zero-sequence current of the feeder line Value, at the same it is small or equal to zero-sequence current value of the capacitance current maximum feeder line in metallic earthing in all feeder lines of the busbar, then Judge that singlephase earth fault occurs for substation busbars.

I_m0For substation busbars zero-sequence current over the ground, field measurement can be passed through or the method for calculating obtains；I_jzmax0For feeder line The zero-sequence current that circuit maximum during metallic earthing occurs for j can be obtained by field measurement or the method for calculating；I_max0For institute There is zero-sequence current value of the capacitance current maximum feeder line in metallic earthing in feeder line, field measurement or the method for calculating can be passed through It obtains.

Present invention tool has the advantage that：

1st, the invention solves the judgment technology problem of busbar singlephase earth fault and feeder line single-phase earthing, convenient for accurately carrying out Isolated fault prevents from accidentally cutting feeder line in busbar singlephase earth fault.

2nd, the invention by comparing zero-sequence current correlation, method is simple, it is quick, convenient for judging the property speed of failure Processing.

Specific embodiment

Calculating or measured data substation busbars capacitive earth current and the capacitive earth current of each feeder line are stored in The computer control of earth fault processing unit.

When voltage transformer detects electric substation residual voltage U_NWhen abnormal, when detecting electric substation neutral point voltage U_NIt is different Chang Shi measures each feeder line zero-sequence current I by each feeder line zero sequence current mutual inductor first₁₀、I₂₀…I_n0、I_j、I_N,Pass through zero-sequence current Than the feeder line that width method finds out zero-sequence current maximum, if meeting I_jmax0=I₁₀+I₂₀+…+I_n0+I_m0-I_nj0, i.e., maximum zero sequence in feeder line The value of electric current is the sum of remaining feeder line zero-sequence current and busbar zero-sequence current in addition to itself, then is judged as the feedback of zero-sequence current maximum Singlephase earth fault occurs for line, can carry out processing to feeder line earth fault at this time and further nature of trouble is judged, If being judged as, permanent earth fault can cut off faulty line and failure is isolated.

If I_jmax0≠I₁₀+I₂₀+…+I_n0+I_m0-I_nj0, and I_jmax0≤I_jzmax0, I_jmax0≤I_max0, i.e. the zero sequence of the feeder line Small or maximum in metallic earthing equal to the circuit zero-sequence current value of electric current, at the same it is small or equal in all feeder lines of the busbar Zero-sequence current value of the capacitance current maximum feeder line in metallic earthing then judges that singlephase earth fault occurs for substation busbars, Failure can be handled and nature of trouble is judged, be alarmed if permanent earth fault is judged as failure.

The above is only the preferred embodiment of the present invention, and protection scope of the present invention is not limited merely to above-mentioned implementation Example, all technical solutions belonged under thinking of the present invention all belong to the scope of protection of the present invention.It should be pointed out that for the art Those of ordinary skill for, several improvements and modifications without departing from the principles of the present invention also should be regarded as the guarantor of the present invention Protect range.

Claims

1. a kind of quick distinguishing method of substation busbars singlephase earth fault, it is characterised in that：When detecting electric substation's neutral point Voltage U_NWhen abnormal, each feeder line zero-sequence current I is measured by each feeder line zero sequence current mutual inductor first₁₀、I₂₀…I_n0、I_j、I_N,Pass through Zero-sequence current finds out the feeder line of zero-sequence current maximum than width method, if meeting I_jmax0=I₁₀+I₂₀+…+I_n0+I_m0-I_nj0, i.e., in feeder line The value of maximum zero sequence current is the sum of remaining feeder line zero-sequence current and busbar zero-sequence current in addition to itself, then is judged as zero-sequence current Singlephase earth fault occurs for maximum feeder line；If I_jmax0≠I₁₀+I₂₀+…+I_n0+I_m0-I_nj0, and I_jmax0≤I_jzmax0, I_jmax0≤ I_max0, i.e. small or maximum in metallic earthing equal to the circuit zero-sequence current value of the zero-sequence current of the feeder line, at the same it is small or Equal to zero-sequence current value of the capacitance current maximum feeder line in metallic earthing in all feeder lines of the busbar, then electric substation mother is judged Singlephase earth fault occurs for line.

2. a kind of quick distinguishing method of substation busbars singlephase earth fault according to claim 1, it is characterised in that：I_m0 For substation busbars zero-sequence current over the ground, field measurement can be passed through or the method for calculating obtains；I_jzmax0Metal occurs for feeder line j Property ground connection when the circuit maximum zero-sequence current can pass through field measurement or the method for calculating acquisition；I_max0It is electric in all feeder lines Zero-sequence current value of the capacitance current maximum feeder line in metallic earthing can be obtained by field measurement or the method for calculating.