CN101510680A - Zero-phase current differential relay - Google Patents

Zero-phase current differential relay Download PDF

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Publication number
CN101510680A
CN101510680A CNA2008100991776A CN200810099177A CN101510680A CN 101510680 A CN101510680 A CN 101510680A CN A2008100991776 A CNA2008100991776 A CN A2008100991776A CN 200810099177 A CN200810099177 A CN 200810099177A CN 101510680 A CN101510680 A CN 101510680A
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phase
current
zero
mutually
fault
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CN101510680B (en
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尾田重远
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Abstract

In the zero-phase currency differential relay detecting the malfunctions, even the end side malfunction currency is little, the invention can reliably processes the malfunction division and judgment for the electric lines without processing the voltage judgment whether 1 the grounding malfunction id generated. The malfunction judging portion (15) obtains the synthesized zero-phase currency data (IOS) according to the zero-phase currency (IOL) obtained from the end side 3 phase and the zero-phase currency (IOR) obtained from the 3-phase currency; the invention solutes the direct currency data (I 1SA-I 1SC) having the benchmark of the phases according to the synthesized currency data (IAS-ICS) from the end side 3-phase currency and the end side 3-phase currency; and the reverse phase currency data (I 2SA-I 2SC) of the benchmark is obtained according to the synthesized currency data (I AS-I CS) to process the malfunction division and the judgment whether 1 the grounding malfunction is generated.

Description

Zero-phase current differential relay
Technical field
The present invention relates to use the Zero-phase current differential relay of the Zero-phase current at power transmission line two ends.
Background technology
The part of existing current differential relay comprises and each corresponding 3 phase current differential relay unit and the Zero-phase current differential relay unit that can go out 1 phase fault with high-sensitivity detection.Existing current differential relay is in 1 phase fault of the inside of power transmission line, circulation is during more than or equal to the electric current of the phase current differential relay unit detection sensitivity of each phase, because of with the action of the corresponding phase current differential relay of this fault unit to fault circuit breaker output control signal (relay output) mutually.Utilize this point, cut off the only power transmission line of fault phase, eliminate the fault of power transmission line.
Yet existing current differential relay can not detect the electric current of fault current less than the action sensitivity of current differential relay.In the case, can detect fault, but can not determine the fault phase in the Zero-phase current differential relay unit by using the higher Zero-phase current differential relay unit of sensitivity.Therefore, the small connect ground fault current that exists the phase current differential relay unit to be failure to actuate carries out 3 actions mutually, cuts off the problem of 3 phases of whole power transmission lines.In order to reduce such problem, existing current differential relay lags the output of Zero-phase current differential relay unit and exports in the output ground of phase current differential relay unit.
Again, prior art as failure judgement phase in the 1 phase earth fault, patent documentation 1 discloses a kind of technology, and wherein the benchmark of this distolateral Zero-phase current and negative-phase sequence curent when consistent with minimum false voltage in 3 phase voltages, is judged as 1 phase earth fault of this phase for synchronous in fact mutually.
Patent documentation 1: the spy of Japan opens communique 2004-No. 364376
Yet, in the prior art of above-mentioned patent documentation 1 record, under some system condition, even thereby exist this distolateral little Zero-phase current differential relay of fault current unit action can not correctly judge the situation of 1 phase earth fault, often become with the judgement of home terminal current Zero-phase current differential relay is moved unwanted restriction.
Again, during the fault of above-mentioned patent documentation 1 record is judged mutually, no matter Zero-phase current differential relay itself does not need input voltage, in order to judge whether 1 phase earth fault, all need in 3 phase voltages, judge the voltage judgement that minimum voltage equates, so there is the problem of necessary input voltage information.
The present invention In view of the foregoing finishes, even its purpose is to obtain also to carry out reliably under the little situation of a kind of this distolateral fault current the earth fault that takes place on the power transmission line whether division of 1 phase earth fault and the Zero-phase current differential relay of its fault judgement mutually.
Summary of the invention
In order to solve above-mentioned problem and to arrive above-mentioned purpose, Zero-phase current differential relay of the present invention, be equipped with: judge the whether judging part of earth fault of power transmission line according to the Zero-phase current of distolateral 3 phase currents of the basis that obtains based on current transformer with from the calculus of differences result that the current transformer of opposite end obtains to the Zero-phase current of distolateral 3 phase currents from local terminal, wherein, described judging part is equipped with: whenever be combined to electric current according to what obtain after described distolateral 3 phase currents and described in-phase current to distolateral 3 phase currents are synthesized, obtaining with each is the portion that just is combined to of the positive phase current of benchmark phase mutually; Whenever be combined to electric current according to what obtain after described distolateral 3 phase currents and described in-phase current to distolateral 3 phase currents are synthesized, obtaining with each is the anti-phase synthetic portion of the negative-phase sequence curent of benchmark phase mutually; And the Zero-phase current of described distolateral 3 phase currents and described Zero-phase current to distolateral 3 phase currents synthesized, and the synthetic portion of the two ends Zero-phase current of obtaining synthetic Zero-phase current, and according to described positive phase current, described negative-phase sequence curent and described synthetic Zero-phase current, carry out the earth fault that takes place on the power transmission line whether 1 phase earth fault division and judge its fault phase.
According to the present invention, according to the Zero-phase current of distolateral 3 phase currents of the basis that obtains based on current transformer and the calculus of differences result that obtains from the current transformer of opposite end to the Zero-phase current of distolateral 3 phase currents from local terminal, when detecting the earth fault of power transmission line, according to based on to this distolateral 3 phase currents with obtain after in-phase current to distolateral 3 phase currents synthesizes what whenever be combined to electric current is the positive phase current of benchmark phase mutually with each; Based on to this distolateral 3 phase currents with obtain after in-phase current to distolateral 3 phase currents synthesizes what whenever be combined to electric current is the negative-phase sequence curent of benchmark phase mutually with each; And the synthetic Zero-phase current that obtains after synthesizing to the Zero-phase current of this distolateral 3 phase currents with to the Zero-phase current of distolateral 3 phase currents, carry out the whether division of 1 phase fault of the earth fault that takes place on the power transmission line, and carry out fault and judge mutually, therefore the effect that obtains can obtain a kind of Zero-phase current differential relay, even wherein under the situation that this distolateral fault current is little, the earth fault that takes place on the power transmission line also can be judged together with fault reliably mutually, carry out the whether division of 1 phase earth fault, judge and do not carry out voltage.
Description of drawings
Fig. 1 illustrates the figure that the electric power of using Zero-phase current differential relay of the present invention is used the composition of system.
Fig. 2 is the block diagram of composition that the Zero-phase current differential relay of execution mode 1 is shown.
Fig. 3 is the flow chart of action usefulness of fault phase judging part of the Zero-phase current differential relay of explanation execution mode 1.
Fig. 4 is the equivalent electric circuit of the method for symmetrical coordinates when A phase earth fault is shown.
Fig. 5 is the equivalent electric circuit of the method for symmetrical coordinates when BC phase earth fault is shown.
Fig. 6 is the block diagram of composition that the Zero-phase current differential relay of execution mode 2 is shown.
Fig. 7 is the flow chart of action usefulness of fault phase judging part of the Zero-phase current differential relay of explanation execution mode 2.
Fig. 8 is the equivalent electric circuit of the method for symmetrical coordinates when A phase earth fault is shown.
Fig. 9 is the equivalent electric circuit of the method for symmetrical coordinates when BC phase earth fault is shown.
Figure 10 is the block diagram of composition that the Zero-phase current differential relay of execution mode 3 is shown.
Figure 11 is the flow chart of action usefulness of fault phase judging part of the Zero-phase current differential relay of explanation execution mode 3.
Figure 12 is the block diagram of composition that the Zero-phase current differential relay of execution mode 4 is shown.
Figure 13 is the flow chart of action usefulness of fault phase judging part of the Zero-phase current differential relay of explanation execution mode 4.
Label declaration
The 1st, power transmission line, 2-1,2-2 is current transformers, 3,3a, 3b, 3c are Zero-phase current differential relays, and 4A, 4B, 4C are the input current transformation components, the 5th, and acceptance division, 6A, 6B, 6C are the input current transformation components, the 5th, acceptance division, 6A, 6B, 6C are the received current transformation components, the 7th, and the synchronous portion of current time, 8A, 8B, 8C are synthetic portions, the 9th, and local terminal zero is combined to portion.The 10th, opposite end zero is combined to portion, the 11st, just be combined to portion, the 12nd, anti-phase synthetic portion, the 13rd, two ends zero are combined to portion, and the 14th, Zero-phase current differential relay unit portion, 15,15a, 15b, 15c be fault phase judging part, 16A, 16B, 16C, 16BC, 16CA, 16AB, the 163rd, "AND" circuit, the 17th, sending part, the 18th, α current operator portion, the 19th, β current operator portion.
Embodiment
Below, describe Zero-phase current differential relay execution mode of the present invention with reference to the accompanying drawings in detail.Moreover the present invention is not limited by this execution mode.
Execution mode 1
With Fig. 1～Fig. 5 embodiment of the present invention 1 is described.Fig. 1 illustrates the figure that the electric power of using Zero-phase current differential relay of the present invention is used the composition of system.Among Fig. 1; electric power connects power supply E1 and power supply E2 with system by power transmission line 1; at the two ends of power transmission line 1 configuration current transformer 2 (illustrating 2-1,2-2), thereby and be equipped with the secondary current that is taken into current transformer 2 detect whether break down on the power transmission line 1 and according to the testing result control setting at the circuit breaker (not shown) at the two ends of power transmission line 1 Zero-phase current differential relay 3 (illustrating 3-1,3-2) with protection power transmission line 1.Among Fig. 1, the composition that forms is at power supply E1 side configuration current transformer 2-1, at power supply E2 side configuration current transformer 2-2, Zero-phase current differential relay 3-1 is taken into the secondary current of current transformer 2-1, and Zero-phase current differential relay 3-2 is taken into the secondary current of current transformer 2-2.
Zero-phase current differential relay 3 is equipped with communication function: being taken into from local terminal side converter 2 (is current transformer 2-1 under the situation of Zero-phase current differential relay 3-1, be current transformer 2-2 under the situation of Zero-phase current differential relay 3-2) electric current, the current value of the electric current that is taken into is sent to distolateral Zero-phase current differential relay 3 (being Zero-phase current differential relay 3-2 under the situation of Zero-phase current differential relay 3-1, is Zero-phase current differential relay 3-1 under the situation of Zero-phase current differential relay 3-2) as current information.Zero-phase current differential relay 3 carries out basis and detects the ratio calculus of differences that whether breaks down on the power transmission line 1 from the electric current of this distolateral current transformer 2 with from the current information that distolateral Zero-phase current differential relay 3 is received, and the control signal of circuit breaker is controlled in output according to ratio calculus of differences result.
Fig. 2 is the block diagram that the composition of Zero-phase current differential relay 3 shown in Figure 1 is shown.Moreover Zero-phase current differential relay is the component units that detects the power transmission line protection relay unit of the fault on the power transmission line 1 as a kind of, but only Zero-phase current differential relay unit and the single-phase action thereof that relates to as original intention of the present invention is described.
Among Fig. 2, Zero-phase current differential relay 3 is equipped with: input current transformation component 4 (4A, 4B, 4C are shown), sending part 17, acceptance division 5, received current transformation component 6 (6A, 6B, 6C are shown), the synchronous portion 7 of current time, synthetic portion 8 (8A, 8B, 8C are shown), just be combined to portion 11, anti-phase synthetic portion 12, local terminal zero and be combined to that portion 9, opposite end zero are combined to portion 10, two ends zero are combined to portion 13, Zero-phase current differential relay unit portion 14, fault phase judging part 15 and "AND" circuit 16 (16A, 16B, 16C, 16BC, 16CA, 16AB).
Input current transformation component 4A will to from these distolateral current transformer 2 inputs 3 mutually the input home terminal current IA of A phase implement the A phase home terminal current data I1A that obtains after the conversion process, output to the synchronous portion 7 of sending part 17 and current time.Input current transformation component 4B will to from these distolateral current transformer 2 inputs 3 mutually the input home terminal current IB of B phase implement the B phase home terminal current data I1B that obtains after the conversion process, output to the synchronous portion 7 of sending part 17 and current time.Input current transformation component 4C will to from these distolateral current transformer 2 inputs 3 mutually the input home terminal current IC of C phase implement the C phase home terminal current data I1C that obtains after the conversion process, output to the synchronous portion 7 of sending part 17 and current time.Conversion process is that the distolateral electric current of basis (expression IA, IB, IC) from the relevant phase of the current transformer 2 of local terminal side is taken in the Zero-phase current differential relay 3, and is transformed into the processing of the current data that Zero-phase current differential relay 3 handles.Particularly, be taken into this electric current I, isolate, remove the high order harmonic component of the electric current that is taken into, and will remove the home terminal current data I1 (representing I1A, I1B, I1C) that home terminal current I after the high order harmonic component is transformed into digital signal with the secondary end of current transformer 2.
Sending part 17 have with to the communication interface of distolateral Zero-phase current differential relay 3, will send to opposite end Zero-phase current differential relay 3 as current information from the current data I1 of input current transformation component 4 inputs.For example (Pulse Code Modulation: pulse-code modulation) transmission is as communication interface with PCM.
Acceptance division 5 have with to the communication interface of distolateral Zero-phase current differential relay 3, receive from current information the sending part 17 of distolateral Zero-phase current differential relay 3.Acceptance division 5 outputs to received current transformation component 6 with the current information that receives, and will receive the synchronous portion 7 of current information notice current time.
Received current transformation component 6A extracts the A phase home terminal current data I1A of the Zero-phase current differential relay 3 of opposite end from the current information of acceptance division 5 input, outputs to the synthetic 8A of portion and opposite end zero is combined to portion 10 as the opposite end current data IR1A of A phase.Received current transformation component 6B extracts the B phase home terminal current data I1B of the Zero-phase current differential relay 3 of opposite end from the current information of acceptance division 5 input, outputs to the synthetic 8B of portion and opposite end zero is combined to portion 10 as the opposite end current data IR1B of B phase.Received current transformation component 6C extracts the C phase home terminal current data I1C of the Zero-phase current differential relay 3 of opposite end from the current information of acceptance division 5 input, outputs to the synthetic 8C of portion and opposite end zero is combined to portion 10 as the opposite end current data IR1C of C phase.
The synchronous portion 7 of current time is according to the notice of receiving current information from acceptance division 5, proofread and correct the current spread time of delay of the Zero-phase current differential relay 3 of opposite end, make the time relationship of the opposite end current data IR1 (expression IR1A, IR1B, IR1C) of received current transformation component 6 outputs and the home terminal current data I1 that input current transformation component 4 is exported synchronous, and the home terminal current data I2 (expression I2A, I2B, I2C) is synchronously outputed to portion 8 and the zero portion 9 that is combined to of local terminal of synthesizing.
Synthetic portion 8 ask from every phase home terminal current I2 of the synchronous portion of current time 7 inputs with from the vector of every opposite end current data IR1 of received current transformation component 6 inputs and, with the vector obtained and resultant current data I S (expression IAS, IBS, ICS), output to and just be combined to portion 11 and anti-phase synthetic portion 12 as relevant phase.The synthetic 8A of portion outputs to and just is combined to portion 11 and anti-phase synthetic portion 12 with the vector of the home terminal current data I2A of A phase and A opposite end current data IR1A mutually with as the resultant current IAS of A phase.The synthetic 8B of portion outputs to and just is combined to portion 11 and anti-phase synthetic portion 12 with the vector of the home terminal current data I2B of B phase and B opposite end current data IR1B mutually with as the resultant current IBS of B phase.The synthetic 8C of portion outputs to and just is combined to portion 11 and anti-phase synthetic portion 12 with the vector of the home terminal current data I2C of C phase and C opposite end current data IR1C mutually with as the resultant current ICS of C phase.
Just be combined to portion 11 according to the resultant current data I S from every phase of synthetic portion 8 inputs, be the benchmark phase mutually with each, asks with positive phase current the positive current data I1S (representing I1SA, I1SB, I1SC) of each phase after synthetic.Here, if the resultant current data of A phase are IAS, the resultant current data of B phase are IBS, the resultant current data of C phase are ICS, then are the positive current data I1SA of the resultant current of benchmark phase mutually, are that the positive current data I1SB of the resultant current of benchmark phase can represent with formula 1, formula 2 and formula 3 respectively with the positive current data I1SC that is the resultant current of benchmark phase mutually mutually with B with C with A.
I1SA=(240 ° of 120 °+ICS of IAS+IBS ∠ ∠)/3 ... (formula 1)
I1SB=(120 ° of 240 °+IBS+ICS of IAS ∠ ∠)/3 ... (formula 2)
I1SC=(240 ° of 120 °+IBS of IAS ∠ ∠+ICS)/3 ... (formula 3)
Just being combined to that the above-mentioned formula 1～formula 3 of portion's 11 usefulness asks with each is the positive current data I1S of benchmark phase mutually, and the positive current data I1S that obtains is outputed to fault phase judging part 15.
Anti-phase synthetic portion 12 be the benchmark phase mutually according to the resultant current data I S from every phase of synthetic portion 8 inputs with each, asks with negative-phase sequence curent the negative-phase sequence curent data I 2S (representing I2SA, I2SB, I2SC) of each phase after synthetic.Here, if the resultant current data of A phase are IAS, the resultant current data of B phase are IBS, the resultant current data of C phase are ICS, then are the negative-phase sequence curent data I 2SA of the resultant current of benchmark phase mutually, are that the negative-phase sequence curent data I 2SB of the resultant current of benchmark phase can represent with formula 4, formula 5 and formula 6 respectively with the negative-phase sequence curent data I 2SC that is the resultant current of benchmark phase mutually mutually with B with C with A.
I2SA=(120 ° of 240 °+ICS of IAS+IBS ∠ ∠)/3 ... (formula 4)
I1SB=(240 ° of 120 °+IBS+ICS of IAS ∠ ∠)/3 ... (formula 5)
I1SC=(120 ° of 240 °+IBS of IAS ∠ ∠+ICS)/3 ... (formula 6)
It is the negative-phase sequence curent data I 2S of benchmark phase mutually that the anti-phase synthetic portion above-mentioned formula 4～formula 6 of 12 usefulness is asked with each, and the negative-phase sequence curent data I 2S that obtains is outputed to fault phase judging part 15.
Local terminal zero is combined to 9 pairs of Zero-phase currents from the synchronous home terminal current data I2 of the synchronous portion of current time 7 inputs of portion and synthesizes.Local terminal zero is combined to portion 9 synthetic electric current is outputed to zero portion 13 and the Zero-phase current differential relay unit portion 14 of being combined in two ends as the synthetic Zero-phase current IOL of local terminal.
Two ends zero are combined to 13 pairs in portion and are combined to the synthetic Zero-phase current data I L of local terminal of portion's 9 inputs and the zero synthetic Zero-phase current data I R in opposite end that is combined to portion's 10 inputs synthesizes from the opposite end from local terminal zero.Two ends zero are combined to portion 13 synthetic current data are outputed to fault phase judging part 15 as synthetic Zero-phase current data I S.
The zero synthetic Zero-phase current data I R in opposite end that is combined to portion's 10 inputs carries out calculus of differences according to the synthetic Zero-phase current data I L of local terminal that is combined to portion's 9 inputs from local terminal zero with from the opposite end in Zero-phase current differential relay unit portion 14, the calculus of differences result is outputed to "AND" circuit 16, and, output to the outside as the output of Zero-phase current differential relay unit.
Fault phase judging part 15 according to from the positive current data I1S of every phase of just being combined to portion's 11 inputs, from the negative-phase sequence curent data I 2S of every phase of anti-phase synthetic portion input and from two ends the zero synthetic Zero-phase current data I S that is combined to portion's 13 inputs, judge that the fault that whether breaks down on the power transmission line 1 when breaking down is mutually.When fault phase judging part 15 is judged as 1 phase earth fault of A phase, effectively (" effectively " carries out the implication of the signal of control action and uses by output to make judgement output OA, hereinafter also identical), and make other judge output OB, OC, OBC, OCA, OAB invalid (engineering noise uses by the implication of not exporting the signal that carries out control action, and is hereinafter also identical).When fault phase judging part 15 is judged as 1 phase earth fault of B phase, makes and judge that output OB is effective, and make other judge that output OA, OC, OBC, OCA, OAB are invalid.When fault phase judging part 15 is judged as 1 phase earth fault of C phase, makes and judge that output OC is effective, and make other judge that output OA, OB, OBC, OCA, OAB are invalid.
When fault phase judging part 15 is judged as 2 phase earth faults of BC phase, makes and judge that output OBC is effective, and make other judge that output OA, OB, OC, OCA, OAB are invalid.When fault phase judging part 15 is judged as 2 phase earth faults of CA phase, makes and judge that output OCA is effective, and make other judge that output OA, OB, OC, OBC, OAB are invalid.When fault phase judging part 15 is judged as 2 phase earth faults of AB phase, makes and judge that output OAB is effective, and make other judge that output OA, OB, OC, OCA, OCA are invalid.
"AND" circuit 16 will be represented to export as each action judged result A Φ T, B Φ T, C Φ T, BC Φ T, CA Φ T, AB Φ T mutually with the logic product of exporting from the Zero-phase current unit of Zero-phase current differential relay unit portion 14 inputs from the judgement output O (expression OA, OB, OC, OBC, OCA, OAB) of each phase judged result of fault phase judging part 15 inputs.Moreover described fault phase judging part 15 and "AND" circuit 16 provide the function of judging part of the present invention.
The action of the Zero-phase current differential relay 3 of present embodiment 1 then, is described.The electric current I of 4 pairs of relevant phases from 3 of these distolateral current transformer 2 inputs are imported mutually of input current transformation component is implemented conversion process.
The home terminal current data I1 that the electric current of relevant phase is implemented to obtain after the conversion process is outputed to sending part 17 and the synchronous portion 7 of current time.Sending part 17 will send to distolateral Zero-phase current differential relay 3 as current information from the home terminal current data I1 of input current transformation component 4 inputs.
On the other hand, acceptance division 5 receives the current information to sending part 17 transmissions of distolateral Zero-phase current differential relay 3, and the current information of receiving is outputed to received current transformation component 6, and the synchronous portion of current time 7 notices are received current information.Received current transformation component 6 outputs to the opposite end current data of extracting about the zero portion 10 that is combined to of mutually pairing synthetic portion 8 and opposite end as opposite end current data IR1 from the opposite end current data of current information extraction to the relevant phase of distolateral Zero-phase current differential relay 3.
The synchronous portion 7 of current time is according to the notice of receiving current information from acceptance division 5, proofread and correct the current spread time of delay of the Zero-phase current differential relay 3 of opposite end, make the time relationship of opposite end current data IR1 and home terminal current data I1 synchronous, and synchronous home terminal current data I2 is outputed to and relevant corresponding synthetic portion 8 and the zero portion 9 that is combined to of local terminal.
The home terminal current data I2 that synthetic portion 8 asks relevant phase and the vector of the opposite end current data IR1 of relevant phase with, vector of obtaining and resultant current data I S, output to and just be combined to IS of portion and anti-phase synthetic portion 12 as relevant phase.
Just be combined to the resultant current data I S that portion 11 uses every phase, being obtained with each by above-mentioned formula 1～formula 3 is the positive current data I1S of the resultant current of benchmark phase mutually, outputs to fault phase judging part 15.Anti-phase synthetic portion 12 uses the resultant current data I S of every phase, and being obtained with each by above-mentioned formula 4～formula 6 is the negative-phase sequence curent data I 2S of the resultant current of benchmark phase mutually, outputs to fault phase judging part 15.
Local terminal zero is combined to the synthetic Zero-phase current data 10L of local terminal that will obtain after portion 9 will synthesize the Zero-phase current from the home terminal current data I2 of each phase of the synchronous portion of current time 7 inputs, outputs to zero portion 13 and the Zero-phase current differential relay unit 14 of being combined to, two ends.Opposite end zero is combined to the synthetic Zero-phase current data I R in opposite end that will obtain after portion 10 will synthesize the Zero-phase current from the opposite end current data IR1 of each phase of received current transformation component 6 inputs, outputs to zero portion 13 and the Zero-phase current differential relay unit 14 of being combined to, two ends.
Two ends zero are combined to the synthetic Zero-phase current data I S that will obtain after portion 13 will synthesize the synthetic Zero-phase current data I L of local terminal and synthetic Zero-phase current data I R, output to fault phase judging part 15.Zero-phase current differential relay unit 14 carries out calculus of differences according to synthetic Zero-phase current data I L of local terminal and the synthetic Zero-phase current data I R in opposite end, the calculus of differences result is outputed to "AND" circuit 16, and, output to the outside as the output of Zero-phase current differential relay unit.
Fault phase judging part 15 is according to the negative-phase sequence curent data I 2S and the synthetic Zero-phase current data I S of the positive current data I1S of every phase, every phase, judges that the fault that whether breaks down on the power transmission line 1 when breaking down mutually.
Describe the judgment processing action of fault phase judging part 15 in detail with reference to the flow chart of Fig. 3.Fault phase judging part 15 judges that whether synthetic Zero-phase current data I S is greater than predetermined threshold value ε 1 (step S100).Here, threshold epsilon 1 being taken as expression sensitivity is equal to zero of Zero-phase current differential relay unit portion 14 and differs the value of current relay element sensitivity or differ the current relay element sensitivity greater than zero of Zero-phase current differential relay unit portion 14.
Synthetic Zero-phase current data I S is during greater than threshold epsilon 1 (be "Yes" among the step S100), fault phase judging part 15 judge synthesize Zero-phase current data I S with to being whether the phase difference of negative-phase sequence curent data I 2SA of resultant current of benchmark phase in the active region scope mutually with A.Be judged as synthetic Zero-phase current data I S with to A be the phase difference of negative-phase sequence curent data I 2SA of resultant current of benchmark phase not in the active region scope time (being "No" among the step S101) mutually, 15 judgements of fault phase judging part synthesize Zero-phase current data I S with to being whether the phase difference of negative-phase sequence curent data I 2SB of resultant current of benchmark phase in the active region scope (step S102) mutually with B.
Be judged as synthetic Zero-phase current data I S with to B be the phase difference of negative-phase sequence curent data I 2SB of resultant current of benchmark phase not in the active region scope time (being "No" among the step S102) mutually, 15 judgements of fault phase judging part synthesize Zero-phase current data I S with to being whether the phase difference of negative-phase sequence curent data I 2SC of resultant current of benchmark phase in the active region scope (step S103) mutually with C.
Be judged as synthetic Zero-phase current data I S with to C being the phase difference of negative-phase sequence curent data I 2SC of resultant current of benchmark phase in the active region scope time (being "Yes" among the step S103) mutually, 15 judgements of fault phase judging part to C be mutually the benchmark phase resultant current negative-phase sequence curent data I 2SC with to being whether the phase difference of positive current data I1SC of resultant current of benchmark phase in the active region scope (step S104) mutually with C.
Be judged as to C be mutually the benchmark phase resultant current negative-phase sequence curent data I 2SC with to being that the phase difference of positive current data I1SC of resultant current of benchmark phase is in the active region scope time (being "Yes" among the step S104) mutually with C, the judgement output OC that fault phase judging part 15 only makes 1 phase earth fault of expression C phase judge is effective, makes other judge output OA, OB, OBC, OCA, OAB invalid (step S105).
Be judged as to C be mutually the benchmark phase resultant current negative-phase sequence curent data I 2SC with to being that the phase difference of positive current data I1SC of resultant current of benchmark phase is not in the active region scope time (being "No" among the step S104) mutually with C, the judgement output OAB that fault phase judging part 15 only makes 2 phase earth faults of expression AB phase judge is effective, makes other judge output OA, OB, OC, OBC, OCA invalid (step S106).
On the other hand, synthetic Zero-phase current data I S during less than threshold epsilon 1 (being "No" among the step S100) or synthetic Zero-phase current data I S with to being that the phase difference of negative-phase sequence curent data I 2SC of combiner circuit of benchmark phase is not in active region the time (being "No" among the step S103) mutually with C, fault phase judging part 15 is judged as earth fault does not take place on the power transmission line 1, makes whole judgement output OA, OB, OC, OBC, OCA, OAB invalid (step S107).
On the other hand, be judged as synthetic Zero-phase current data I S with to B being the phase difference of negative-phase sequence curent data I 2SB of resultant current of benchmark phase in the active region scope time (being "Yes" among the step S102) mutually, 15 judgements of fault phase judging part to B be mutually the benchmark phase resultant current negative-phase sequence curent data I 2SB with to being whether the phase difference of positive current data I1SB of resultant current of benchmark phase in the active region scope (step S108) mutually with B.
Be judged as to B be mutually the benchmark phase resultant current negative-phase sequence curent data I 2SB be that the phase difference of negative-phase sequence curent data I 2SB of resultant current of benchmark phase is in the active region scope time (being "Yes" among the step S108) mutually with B, the judgement output OC that fault phase judging part 15 only makes 1 phase earth fault of expression B phase judge is effective, makes other judge output OA, OC, OBC, OCA, OAB invalid (step S109).
Be judged as to B be mutually the benchmark phase resultant current negative-phase sequence curent data I 2SB with to being that the phase difference of positive current data I1SB of resultant current of benchmark phase is not in the active region scope time (being "No" among the step S108) mutually with B, the judgement output OCA that fault phase judging part 15 only makes 2 phase earth faults of expression CA phase judge is effective, makes other judge output OA, OB, OC, OBC, OAB invalid (step S110).
On the other hand, be judged as synthetic Zero-phase current data I S with to A being the phase difference of negative-phase sequence curent data I 2SA of resultant current of benchmark phase in the active region scope time (being "Yes" among the step S101) mutually, 15 judgements of fault phase judging part to A be mutually the benchmark phase resultant current negative-phase sequence curent data I 2SA with to being whether the phase difference of positive current data I1SA of resultant current of benchmark phase in the active region scope (step S111) mutually with A.
Be judged as to A be mutually the benchmark phase resultant current negative-phase sequence curent data I 2SA be that the phase difference of negative-phase sequence curent data I 2SA of resultant current of benchmark phase is in the active region scope time (being "Yes" among the step S111) mutually with A, the judgement output OA that fault phase judging part 15 only makes 1 phase earth fault of expression A phase judge is effective, makes other judge output OB, OC, OBC, OCA, OAB invalid (step S112).
Be judged as to A be mutually the benchmark phase resultant current negative-phase sequence curent data I 2SA with to being that the phase difference of positive current data I1SA of resultant current of benchmark phase is not in the active region scope time (being "No" among the step S111) mutually with A, the judgement output OBC that fault phase judging part 15 only makes 2 phase earth faults of expression BC phase judge is effective, makes other judge output OA, OB, OC, OCA, OAB invalid (step S113).
Like this, fault phase judging part 15 is under the situation of synthetic Zero-phase current data I S more than or equal to threshold epsilon 1, synthetic Zero-phase current data I S is judged with A to be the negative-phase sequence curent data I 2SA of the resultant current of benchmark phase mutually, with B is the negative-phase sequence curent data I 2SB of the resultant current of benchmark phase mutually, and be that the negative-phase sequence curent data I 2S with which benchmark phase computing enters active region among the negative-phase sequence curent data I 2SC of resultant current of benchmark phase mutually with C, and judge whether the negative-phase sequence curent data I 2S that enters active region enters active region with the phase difference of the positive current data I1S of relevant phase.In this comparison about the I1S of phase benchmark and I2S, fault phase judging part 15 will be judged as effectively less than the situations of ± 90 degree (promptly existing with comparing anti-phase approaching relation) the positive current data I1S of the relevant phase of negative-phase sequence curent data I 2S of relevant phase.So when this judged result was effectively output, fault phase judging part 15 was also exported the relevant fault that is judged as mutually mutually as 1 phase earth fault.Otherwise this judged result is not when effectively exporting, and relevantly is equivalent to perfect phase mutually, so as 2 phase earth faults, relevant 2 beyond mutually is judged as fault mutually also exported mutually.Moreover the benchmark that active region is set A phase, B phase or C phase is the interior value of scope of active region mutually.
"AND" circuit 16A with Zero-phase current differential relay unit output and fault mutually the logic product of the judgement output OA of judging part 15 export as exporting A Φ T, "AND" circuit 16B with Zero-phase current differential relay unit output and fault mutually the logic product of the judgement output OB of judging part 15 export as exporting B Φ T, "AND" circuit 16C with Zero-phase current differential relay unit output and fault mutually the logic product of the judgement output OC of judging part 15 export as exporting C Φ T, "AND" circuit 16BC with Zero-phase current differential relay unit output and fault mutually the logic product of the judgement output OBC of judging part 15 export as exporting BC Φ T, "AND" circuit 16CA with Zero-phase current differential relay unit output and fault mutually the logic product of the judgement output OCA of judging part 15 export as output CA Φ T, "AND" circuit 16AB with the output of Zero-phase current differential relay unit and fault mutually the judgement of judging part 15 logic product of exporting OAB export as exporting AB Φ T.
Then, with reference to Fig. 4 and Fig. 5, the legitimacy of the action of above-mentioned Zero-phase current differential relay 3 is described.The equivalent electric circuit of the method for symmetrical coordinates when Fig. 4 illustrates the 1 phase earth fault (A phase earth fault) of A phase.The equivalent electric circuit of the method for symmetrical coordinates when Fig. 5 illustrates the 2 phase earth faults (BC phase earth fault) of BC phase.As shown in Figure 4, under the situation of A phase earth fault, electric current I 1, I2, the I0 electric current of homophase in fact that circulates.On the other hand, as shown in Figure 5, under the situation of BC phase earth fault, electric current I 2 and electric current I 0 homophase, but the anti-phase electric current of circulating current I2 and electric current I 1.And when break down in power transmission line inside, under the situation that the two ends power phase equates in fact, the polarity at two ends with CT connects into reversed polarity, so the phase place of electric current I 1, I2, I0 is equal in fact respectively.Therefore, even resultant current for two ends, under the situation of A phase earth fault, the current flowing that the electric current that the electric current that positive current data I1SA represents, reverse current data I 2SA represent, synthetic Zero-phase current data I S represent this condition of electric current of homophase is in fact also set up.On the other hand, under the situation of BC phase earth fault, the electric current homophase that electric current that negative-phase sequence curent data I 2SA represents and synthetic Zero-phase current data I S represent and anti-phase this condition of electric current of current flowing that electric current that negative-phase sequence curent data I 2S represents and positive current data I1S represent is set up.
Illustrated as mentioned, in this execution mode 1, according to the Zero-phase current of distolateral 3 phase currents of the basis that obtains based on current transformer and the calculus of differences result that obtains from the current transformer of opposite end to the Zero-phase current of distolateral 3 phase currents from local terminal, when detecting the earth fault of power transmission line, according to based on to this distolateral 3 phase currents with obtain after in-phase current to distolateral 3 phase currents synthesizes what whenever be combined to the electric current same phasor1 and the electric current of opposite end (local terminal with) is the positive phase current of benchmark phase mutually with each; Based on to this distolateral 3 phase currents with obtain after in-phase current to distolateral 3 phase currents synthesizes what whenever be combined to electric current is the negative-phase sequence curent of benchmark phase mutually with each; And the synthetic Zero-phase current that obtains after synthesizing to the Zero-phase current of this distolateral 3 phase currents with to the Zero-phase current of distolateral 3 phase currents, carry out the whether division of 1 phase fault of the earth fault that takes place on the power transmission line, and carry out fault and judge mutually, even therefore under the situation that this distolateral fault current is little, the earth fault that takes place on the power transmission line also can be judged together with fault reliably mutually, carry out the whether division of 1 phase earth fault, but not fault was judged such input voltage that uses mutually in the past.Again, in this execution mode 1, with the benchmark of the consistent in fact negative-phase sequence curent of the phase place of Zero-phase current mutually and under the situation of phase difference in the scope of active region of the forward current of this benchmark phase, be judged as 1 phase earth fault of relevant phase, even so under the situation that distolateral fault current is minimum, also can detect the fault phase on the power transmission line reliably, but not fault was judged such input voltage that uses mutually in the past.
Moreover, in the judgment processing action of preamble with reference to the fault judgement handling part of the flowchart text of Fig. 3, synthetic Zero-phase current data I S and predetermined threshold value ε 1 are compared, but also can be synthetic Zero-phase current data I S and predetermined threshold value ε 1 be compared, and judge effective or invalid as the Zero-phase current differential relay unit output of the output of Zero-phase current differential relay unit portion 14.At this moment, the situation of " output of Zero-phase current differential relay unit effectively " is equivalent to the situation of " synthetic Zero-phase current data I S is greater than threshold epsilon 1 ", and the situation of " output of Zero-phase current differential relay unit is invalid " is equivalent to the situation of " synthetic Zero-phase current data I S is less than threshold epsilon 1 ".
Execution mode 2
With Fig. 6～Fig. 9 embodiment of the present invention 2 is described.In the execution mode 1 of front, judge according to carrying out phase place, but present embodiment 2 carries out judging based on the phase place of the α electric current that utilizes the Clarke coordinate method, β electric current and Zero-phase current based on the positive of the method for symmetrical coordinates, anti-phase and zero computing mutually.
The electric power composition of system of using the Zero-phase current differential relay of present embodiment 2, identical with the electric power of preamble illustrated embodiment 1 with system, but use Zero-phase current differential relay 3a-1,3a-2, to replace Zero-phase current differential relay 3-1,3-2.
Fig. 6 is the block diagram of the composition of Zero-phase current differential relay 3a that present embodiment 2 is shown (expression 3a-1,3a-2).The Zero-phase current differential relay 3a of present embodiment 2 shown in Figure 6 is equipped with α current operator portion 18, β current operator portion 19 and fault judging part 15a mutually, with the portion that just is combined to 11, anti-phase synthetic portion 12 and the fault of the Zero-phase current differential relay 3 that replaces preamble execution mode 1 shown in Figure 2 judging part 15 mutually.The part that has with Zero-phase current differential relay 3 identical functions of preamble execution mode 1 shown in Figure 2 is marked same label, and the repetitive description thereof will be omitted.
α current operator portion 18 asks the α current data of every phase according to the resultant current data I S of every phase of importing from synthetic portion 8.If the resultant current data of A phase are IAS, the resultant current data of B phase are IBS, the resultant current data of C phase are ICS, then can represent to be the α current data I α SA of benchmark phase mutually, to be the α current data I α SB and the α current data I α SC that is the benchmark phase mutually of benchmark phase mutually with B with C with A with formula 7, formula 8 and formula 9 respectively.Formula 7～formula 9 below α current operator portion 18 uses is obtained the α current data I α S (expression I α SA, I α SB, I α SC) of every phase.α current operator portion outputs to fault phase judging part 15a with the α current data I α S of every phase.
I α SA=(2 * IAS-IBS-ICS)/3 ... (formula 7)
I α SB=(IAS+2 * IBS-ICS)/3 ... (formula 8)
I α SC=(IAS-IBS+2 * ICS)/3 ... (formula 9)
β current operator portion 19 asks the β current data of every phase according to the resultant current data I S of every phase of importing from synthetic portion 8.If the resultant current data of A phase are IAS, the resultant current data of B phase are IBS, the resultant current data of C phase are ICS, then can represent to be the β current data I β SA of benchmark phase mutually, to be the β current data I β SB and the α current data I β SC that is the benchmark phase mutually of benchmark phase mutually with B with C with A with formula 10, formula 11 and formula 12 respectively.Formula 10～formula 12 below β current operator portion 19 uses is obtained the β current data I β S (expression I β SA, I β SB, I β SC) of every phase.β current operator portion outputs to fault phase judging part 15a with the β current data I β S of every phase.
I β SA=(IBS-ICS) * (√ 3/3) ... (formula 10)
I β SB=(ICS-IAS) * (√ 3/3) ... (formula 11)
I β SC=(IAS-IBS) * (√ 3/3) ... (formula 12)
Fault phase judging part 15a according to from the α current data I α S of every phase of α current operator portion 18 input, from the β current data I β S of every phase of β current operator portion 19 inputs and from two ends the zero synthetic Zero-phase current data I S that is combined to portion's 13 inputs, the fault when judging 1 phase earth fault that whether the A phase takes place on the power transmission line 1 and breaking down is mutually.
When fault phase judging part 15a is judged as 1 phase earth fault of A phase, makes and judge that output OA is effective, and make other judge that output OB, OC, OBC, OCA, OAB are invalid.When fault phase judging part 15a is judged as 1 phase earth fault of B phase, makes and judge that output OB is effective, and make other judge that output OA, OC, OBC, OCA, OAB are invalid.When fault phase judging part 15a is judged as 1 phase earth fault of C phase, makes and judge that output OC is effective, and make other judge that output OA, OB, OBC, OCA, OAB are invalid.
When fault phase judging part 15a is judged as 2 phase earth faults of BC phase, makes and judge that output OBC is effective, and make other judge that output OA, OB, OC, OCA, OAB are invalid.When fault phase judging part 15a is judged as 2 phase earth faults of CA phase, makes and judge that output OCA is effective, and make other judge that output OA, OB, OC, OBC, OAB are invalid.When fault phase judging part 15a is judged as 2 phase earth faults of AB phase, makes and judge that output OAB is effective, and make other judge that output OA, OB, OC, OCA, OCA are invalid.
The action of the Zero-phase current differential relay 3a of present embodiment 2 then, is described.The difference of the Zero-phase current differential relay 3a of present embodiment 2 and the Zero-phase current differential relay 3 of preamble execution mode 1 is: in the Zero-phase current differential relay 3 of preamble execution mode 1, judge according to carrying out phase place, and the Zero-phase current differential relay 3a of present embodiment 2 utilizes the phase place of α electric current, β electric current and the Zero-phase current of Clarke coordinate method to judge based on the positive of the method for symmetrical coordinates, anti-phase and zero computing mutually.Other action is identical with the Zero-phase current differential relay 3 of preamble execution mode 1, and therefore difference only is described here.
α current operator portion 18 uses from the resultant current data I S of every phase of synthetic portion 8 inputs, obtains the α current data I α S of every phase by above-mentioned formula 7～formula 9, outputs to fault phase judging part 15a.β current operator portion 19 uses from the resultant current data I S of every phase of synthetic portion 8 inputs, obtains the β current data I β S of every phase by above-mentioned formula 10～formula 12, outputs to fault phase judging part 15a.Two ends zero are combined to the synthetic Zero-phase current data I S that will obtain after portion 13 will synthesize the synthetic Zero-phase current data I L of local terminal and synthetic Zero-phase current data I R, output to fault phase judging part 15a.Fault phase judging part 15a is according to the β current data I β S and the synthetic Zero-phase current data I S of the α current data I α S of every phase, every phase, judge in when, whether earth fault taking place on the power transmission line 1 and earth fault taking place fault mutually.
Describe the judgment processing action of fault phase judging part 15a in detail with reference to the flow chart of Fig. 7.Fault phase judging part 15a judges that whether synthetic Zero-phase current data I S is greater than predetermined threshold value ε 1 (step S200).Here, threshold epsilon 1 being taken as expression sensitivity is equal to zero of Zero-phase current differential relay unit portion 14 and differs the value of current relay element sensitivity or differ the current relay element sensitivity greater than zero of Zero-phase current differential relay unit portion 14.
Synthetic Zero-phase current data I S is during greater than threshold epsilon 1 (be "Yes" among the step S200), and fault phase judging part 15a judgement is whether the β current data I β SA of benchmark phase is less than predetermined threshold value ε 2 (step S201) with A mutually.Being judged as with A is the β current data I β SA of benchmark phase during less than threshold epsilon 2 (being "Yes" among the step S201) mutually, and fault phase judging part 15a judges synthetic Zero-phase current data I S and is whether the phase difference of α current data I α SA of benchmark phase is in the scope of active region (step S202) mutually with A.That is, the current phase of synthetic Zero-phase current data I S is judged by being whether the α electric current of benchmark phase computing of α electric current of benchmark phase is in the scope of active region mutually with A.
Be judged as synthetic Zero-phase current data I S and be that the phase difference of α current data I α SA of benchmark phase is in the active region scope time (being "Yes" among the step S202) mutually with A, the judgement output OA that fault phase judging part 15a only makes 1 phase earth fault of expression A phase judge is effective, makes other judge output OB, OC, OBC, OCA, OAB invalid (step S203).
Otherwise, being judged as with A is the β current data I β SA of benchmark phase during more than or equal to threshold epsilon 2 (being "No" among the step S201) mutually, the negative-phase sequence curent data that fault phase judging part 15a judges synthetic Zero-phase current data I S be whether the phase difference of α current data I α SA of benchmark phase in the scope of active region (step S204) mutually with A.That is, the negative-phase sequence curent of synthetic Zero-phase current data I S is judged with A to be that the α current data I α SA of benchmark phase computing is whether in the scope of active region mutually.
The negative-phase sequence curent data that are judged as synthetic Zero-phase current data I S be that the phase difference of α current data I α SA of benchmark phase is in the active region scope time (being "Yes" among the step S204) mutually with A, the judgement output OBC that fault phase judging part 15a only makes 2 phase earth faults of expression BC phase judge is effective, makes other judge output OA, OB, OC, OCA, OAB invalid (step S205).
The negative-phase sequence curent data that are judged as synthetic Zero-phase current data I S with A be the phase difference of α current data I α SA of benchmark phase (being "No" among the step S204) or synthetic Zero-phase current data I S and be the phase difference of α current data I α SA of benchmark phase not in the active region scope time (being "No" among the step S202) mutually with A not in the active region scope time mutually, fault phase judging part 15a judgement is whether the β current data I β SB of benchmark phase less than predetermined threshold value ε 2 (step S206) with B mutually.Being judged as with B is the β current data I β SB of benchmark phase during less than threshold epsilon 2 (among the step S206 for " whether ") mutually, and fault phase judging part 15a judges synthetic Zero-phase current data I S and is whether the phase difference of α current data I α SB of benchmark phase is in the scope of active region (step S207) mutually with B.That is,, judge by being whether the α electric current of benchmark phase computing of α electric current of benchmark phase is in the scope of active region mutually with B the current phase of synthetic Zero-phase current data I S.
Be judged as synthetic Zero-phase current data I S and be that the phase difference of α current data I α SB of benchmark phase is in the active region scope time (being "Yes" among the step S207) mutually with B, the judgement output OB that fault phase judging part 15a only makes 1 phase earth fault of expression B phase judge is effective, makes other judge output OA, OC, OBC, OCA, OAB invalid (step S208).
On the other hand, being judged as with B is the β current data I β SB of benchmark phase during greater than threshold epsilon 2 (being "No" among the step S206) mutually, the negative-phase sequence curent data that fault phase judging part 15a judges synthetic Zero-phase current data I S be whether the phase difference of α current data I α SB of benchmark phase in the scope of active region (step S209) mutually with B.That is, the negative-phase sequence curent of synthetic Zero-phase current data I S is judged with B to be that the α current data I α SB of benchmark phase computing is whether in the scope of active region mutually.
The negative-phase sequence curent data that are judged as synthetic Zero-phase current data I S be that the phase difference of α current data I α SB of benchmark phase is in the active region scope time (being "Yes" among the step S209) mutually with B, the judgement output OCA that fault phase judging part 15a only makes 2 phase earth faults of expression CA phase judge is effective, makes other judge output OA, OB, OC, OBC, OAB invalid (step S210).
The negative-phase sequence curent data that are judged as synthetic Zero-phase current data I S with B be the phase difference of α current data I α SB of benchmark phase (being "No" among the step S209) or synthetic Zero-phase current data I S and be the phase difference of α current data I α SB of benchmark phase not in the active region scope time (being "No" among the step S207) mutually with B not in the active region scope time mutually, fault phase judging part 15a judgement is whether the β current data I β SC of benchmark phase less than predetermined threshold value ε 2 (step S211) with C mutually.Being judged as with C is the β current data I β SC of benchmark phase during less than predetermined threshold value ε 2 (being "Yes" among the step S211) mutually, and fault phase judging part 15a judges synthetic Zero-phase current data I S and is whether the phase difference of α current data I α SC of benchmark phase is in the scope of active region (step S212) mutually with C.That is, the current phase of synthetic Zero-phase current data I S is judged by being whether the α electric current of benchmark phase computing of α electric current of benchmark phase is in the scope of active region mutually with C.
Be judged as synthetic Zero-phase current data I S and be that the phase difference of α current data I α SC of benchmark phase is in the active region scope time (being "Yes" among the step S212) mutually with C, the judgement output OC that fault phase judging part 15a only makes 1 phase earth fault of expression C phase judge is effective, makes other judge output OA, OB, OBC, OCA, OAB invalid (step S213).
On the other hand, being judged as with C is the β current data I β SC of benchmark phase during more than or equal to predetermined threshold value ε 2 (being "No" among the step S211) mutually, the negative-phase sequence curent data that fault phase judging part 15a judges synthetic Zero-phase current data I S be whether the phase difference of α current data I α SC of benchmark phase in the scope of active region (step S214) mutually with C.That is, the negative-phase sequence curent of synthetic Zero-phase current data I S is judged by being whether the α current data I α SC of benchmark phase phase computing is in the scope of active region mutually with C.
The negative-phase sequence curent data that are judged as synthetic Zero-phase current data I S be that the phase difference of α current data I α SC of benchmark phase is in the active region scope time (being "Yes" among the step S214) mutually with C, the judgement output OAB that fault phase judging part 15a only makes 2 phase earth faults of expression AB phase judge is effective, makes other judge output OA, OB, OC, OBC, OCA invalid (step S215).
On the other hand, the negative-phase sequence curent data that are judged as synthetic Zero-phase current data I S be that the phase difference of α current data I α SC of benchmark phase is not in the active region scope time (being "No" among the step S214) mutually with C, be judged as synthetic Zero-phase current data I S and be that the phase difference of α current data I α SC of benchmark phase is not in the active region scope time (being "No" among the step S212) mutually with C, or synthetic Zero-phase current data I S is during less than threshold epsilon 1 (being "No" among the step S200), fault phase judging part 15a is judged as on the power transmission line 1 and does not break down, and makes whole judgement output OA, OB, OC, OBC, OCA, OAB invalid (step S216).
Like this, fault phase judging part 15a is at synthetic Zero-phase current data I S during more than or equal to threshold epsilon 1, with the A phase, B mutually or C be mutually the benchmark phase β current data I β S smaller or equal to threshold epsilon 2 and with about be mutually under the situation of phase difference in the active region scope of α current data I α S and synthetic Zero-phase current data I S of benchmark phase (with relevant be under the situation of α current data I α S near homophase of benchmark phase mutually), being judged as relevant is the fault phase of 1 phase earth fault mutually, and with the A phase, B mutually or C be mutually the benchmark phase β current data I β S greater than threshold epsilon 2 and with about be mutually under the situation of anti-phase phase difference in the active region scope of α current data I α S and synthetic Zero-phase current data I S of benchmark phase (with relevant be under the approaching anti-phase situation of α current data I α S of benchmark phase mutually), be judged as about being the phase that perfects in the 2 phase earth faults mutually, 2 beyond the sound phase is the fault phase mutually.Moreover active region setting A phase, B phase, C the arbitrary of these benchmark phases mutually are the interior value of active region scope mutually.
Then, with reference to Fig. 8 and Fig. 9, the legitimacy of the action of above-mentioned Zero-phase current differential relay 3a is described.The equivalent electric circuit of the Clarke coordinate method when Fig. 8 illustrates the 1 phase earth fault (A phase earth fault) of A phase.The equivalent electric circuit of the Clarke coordinate method when Fig. 9 illustrates the 2 phase earth faults (BC phase earth fault) of BC phase.As shown in Figure 8, under the situation of A phase earth fault, β electric current I β is circulating current not, α electric current I α and the current data IO electric current of homophase in fact that circulates.On the other hand, as shown in Figure 9, under the situation of BC phase earth fault, β electric current I β circulating current, α electric current I α and the anti-phase in fact electric current of current data IO circulation.And when break down in power transmission line inside, under the situation that the power phase at two ends equates in fact, α electric current I α, the β electric current I β at two ends and the phase place of current data IO are equal in fact respectively.Therefore, even for the resultant current at two ends, also under the situation of A phase earth fault, β electric current I β is circulating current not, α electric current I α and the current data IO electric current of homophase in fact that circulates.On the other hand, under the situation of BC phase earth fault, the condition of the electric current that β electric current I β circulating current and α electric current I α and current data IO circulation are anti-phase is in fact set up.
Illustrated as mentioned, in this execution mode 2, according to the Zero-phase current of distolateral 3 phase currents of the basis that obtains based on current transformer and the calculus of differences result that obtains from the current transformer of opposite end to the Zero-phase current of distolateral 3 phase currents from local terminal, when detecting the earth fault of power transmission line, according to the synthetic Zero-phase current that obtains after synthesizing to the Zero-phase current of this distolateral 3 phase currents with to the Zero-phase current of distolateral 3 phase currents, based on to this distolateral 3 phase currents with obtain after in-phase current to distolateral 3 phase currents synthesizes whenever be combined to the electric current same phasor1 and the electric current of opposite end (local terminal with) every mutually the α electric current and based on the β electric current of every phase of this resultant current, carry out the whether division of 1 phase fault of the earth fault that takes place on the power transmission line, and carry out fault and judge mutually, even therefore under the situation that this distolateral fault current is little, also can carry out the whether division of 1 phase earth fault of the earth fault that takes place on the power transmission line reliably, and carry out fault and judge mutually, but not fault was judged such input voltage that uses mutually in the past.Again, in this execution mode 2, with the β electric current near zero and be judged as the fault phase of 1 phase earth fault mutually with the benchmark of the consistent in fact α electric current of the phase place of Zero-phase current, even so under the situation that distolateral fault current is minimum, also can detect the fault phase on the power transmission line reliably, but not fault was judged such input voltage that uses mutually in the past.
Moreover, in the judgment processing action of preamble with reference to the fault judgement handling part of the flowchart text of Fig. 7, synthetic Zero-phase current data I S and predetermined threshold value ε 1 are compared, but also can be synthetic Zero-phase current data I S and predetermined threshold value ε 1 be compared, and judge effective or invalid as the Zero-phase current differential relay unit output of the output of Zero-phase current differential relay unit portion 14.At this moment, the situation of " output of Zero-phase current differential relay unit effectively " is equivalent to the situation of " synthetic Zero-phase current data I S is greater than threshold epsilon 1 ", and the situation of " output of Zero-phase current differential relay unit is invalid " is equivalent to the situation of " synthetic Zero-phase current data I S is less than threshold epsilon 1 ".
Execution mode 3
With Figure 10 and Figure 11 embodiments of the present invention 3 are described.In the execution mode 2 of front, use with each mutually to the α current data I α S of benchmark phase, determine whether to take place on the power transmission line 1 earth fault and fault thereof mutually as the β current data I β S of benchmark phase and synthetic Zero-phase current IOS mutually with each.Present embodiment 3 is not the α current data I α S of benchmark phase mutually in order to each, and determines whether to take place on the power transmission line 1 earth fault and fault thereof mutually for the β current data I β S of benchmark phase and synthetic Zero-phase current IOS mutually in order to each.
Using the electric power of the Zero-phase current differential relay of present embodiment 3 uses system identical with the composition of system with the electric power of preamble illustrated embodiment 1, but use Zero-phase current differential relay 3b-1,3b-2, to replace Zero-phase current differential relay 3-1,3-2.
Figure 10 is the block diagram of the composition of Zero-phase current differential relay 3b that present embodiment 3 is shown (expression 3b-1,3b-2).The Zero-phase current differential relay 3b of present embodiment 3 shown in Figure 10 is the Zero-phase current differential relay 3a deletion α current operator portion 18 of texts and pictures 6 illustrated embodiment 2 in the past, and is equipped with fault phase judging part 15b, to replace fault phase judging part 15a.The part that has with the Zero-phase current differential relay 3a identical functions of preamble execution mode 2 shown in Figure 6 is marked same label, and the repetitive description thereof will be omitted.
Fault phase judging part 15b according to from the β current data I β S of every phase of β current operator portion 19 input and from two ends the zero synthetic Zero-phase current data I S that is combined to portion's 13 inputs, judge on the power transmission line 1 and whether break down.Fault phase judging part 15b makes and judges that output OA is effective when being judged as 1 phase earth fault of A phase, makes other judge that output OB, OC, OBC, OAC, OAB are invalid.Fault phase judging part 15b makes and judges that output OB is effective when being judged as 1 phase earth fault of B phase, makes other judge that output OA, OC, OBC, OAC, OAB are invalid.Fault phase judging part 15b makes and judges that output OC is effective when being judged as 1 phase earth fault of C phase, makes other judge that output OA, OB, OBC, OAC, OAB are invalid.
Fault phase judging part 15b makes and judges that output OBC is effective when being judged as 2 phase earth faults of BC phase, makes other judge that output OA, OB, OC, OCA, OAB are invalid.Fault phase judging part 15b makes and judges that output OCA is effective when being judged as 2 phase earth faults of CA phase, makes other judge that output OA, OB, OC, OBC, OAB are invalid.Fault phase judging part 15b makes and judges that output OAB is effective when being judged as 1 phase earth fault of AB phase, makes other judge that output OA, OB, OC, OBC, OCA are invalid.
The action of the Zero-phase current differential relay 3b of present embodiment 3 then, is described.The difference of the Zero-phase current differential relay 3a of the Zero-phase current differential relay 3b of present embodiment 3 and the execution mode 2 of front is: among the Zero-phase current differential relay 3a of the execution mode 2 of front, use with each and be the α current data I α S of benchmark phase mutually, with each be mutually the β current data I β S of benchmark phase determine whether to break down on the power transmission line 1 with synthetic Zero-phase current IOS and fault mutually, 3 of present embodiments are not the α current data I α S of benchmark phase mutually in order to each, and in order to each determine whether to break down on the power transmission line 1 with synthetic Zero-phase current IOS for the β current data I β S of benchmark phase mutually and fault mutually.Other action is identical with the Zero-phase current differential relay 3a of the execution mode 2 of front, so difference only is described, promptly carries out the action of the fault phase judging part 15b of fault phase judgment processing here.
With reference to the flow chart of Figure 11, the action of fault phase judging part 15b of the Zero-phase current differential relay 3b of present embodiment is described.Fault phase judging part 15b judges that whether synthetic Zero-phase current data I S is greater than predetermined threshold value ε 1 (step S300).Here, threshold epsilon 1 being taken as expression sensitivity is equal to zero of Zero-phase current differential relay unit portion 14 and differs the value of current relay element sensitivity or differ the current relay element sensitivity greater than zero of Zero-phase current differential relay unit portion 14.
When synthesizing Zero-phase current data I S smaller or equal to threshold epsilon 1 (being "No" among the step S300), fault phase judging part 15b is judged as on the power transmission line 1 and does not break down, and makes whole judgements output OA, OB, OC, OBC, OCA, OAB invalid (step S301).When synthesizing Zero-phase current data I S (being "Yes" among the step S300) greater than threshold epsilon 1, judge whether A mutually 1 phase earth fault takes place, promptly judge whether with A be mutually the β current data I β SA of benchmark phase less than predetermined threshold value ε 2 and with B be mutually the benchmark phase β current data I β SB be that the β current data I β SC of benchmark phase is greater than predetermined threshold value ε 3 (step S302) mutually with C.Moreover, hereinafter set forth threshold epsilon 2, ε 3.
The β current data I β SA that with A is the benchmark phase mutually less than threshold epsilon 2 and with B be mutually the benchmark phase β current data I β SB be that the β current data I β SC of benchmark phase is during greater than threshold epsilon 3 (being "Yes" among the step S302) mutually with C, fault phase judging part 15b is judged as A 1 phase earth fault takes place mutually, and the judgement output OA that the 1 phase earth fault that only makes expression A phase is judged is effective, makes other judge output OB, OC, OBC, OCA, OAB invalid (step S303).
With A is that the β current data I β SA of benchmark phase is during more than or equal to predetermined threshold value ε 2 mutually, or with B be mutually the benchmark phase β current data I β SB be that at least 1 of the β current data I β SC of benchmark phase is during smaller or equal to threshold epsilon 3 (being "No" among the step S302) mutually with C, fault phase judging part 15b judges whether B mutually 1 phase earth fault takes place, promptly judge whether with B be mutually the β current data I β SB of benchmark phase less than threshold epsilon 2 and with A be mutually the benchmark phase β current data I β SA be that the β current data I β SC of benchmark phase is greater than threshold epsilon 3 (step S304) mutually with C.
The β current data I β SB that with B is the benchmark phase mutually less than threshold epsilon 2 and with A be mutually the benchmark phase β current data I β SA be that the β current data I β SC of benchmark phase is during greater than threshold epsilon 3 (being "Yes" among the step S304) mutually with C, fault phase judging part 15b is judged as B 1 phase earth fault takes place mutually, and the judgement output OB that the 1 phase earth fault that only makes expression B phase is judged is effective, makes other judge output OA, OC, OBC, OCA, OAB invalid (step S305).
With B is that the β current data I β SB of benchmark phase is during more than or equal to predetermined threshold value ε 2 mutually, or with A be mutually the benchmark phase β current data I β SA be that at least 1 of the β current data I β SC of benchmark phase is during smaller or equal to threshold epsilon 3 (being "No" among the step S304) mutually with C, fault phase judging part 15b judges whether C mutually 1 phase earth fault takes place, promptly judge whether with C be mutually the β current data I β SC of benchmark phase less than threshold epsilon 2 and with A be mutually the benchmark phase β current data I β SA be that the β current data I β SB of benchmark phase is greater than threshold epsilon 3 (step S306) mutually with B.
The β current data I β SC that with C is the benchmark phase mutually less than threshold epsilon 2 and with A be mutually the benchmark phase β current data I β SA be that the β current data I β SB of benchmark phase is during greater than threshold epsilon 3 (being "Yes" among the step S306) mutually with B, fault phase judging part 15b is judged as C 1 phase earth fault takes place mutually, and the judgement output OC that the 1 phase earth fault that only makes expression C phase is judged is effective, makes other judge output OA, OB, OBC, OCA, OAB invalid (step S307).
The β current data I β SC that with C is the benchmark phase mutually more than or equal to threshold epsilon 2 and with A be mutually the benchmark phase β current data I β SA with B be at least 1 of the β current data I β SB of benchmark phase during smaller or equal to threshold epsilon 3 (being "No" among the step S306) mutually, fault phase judging part 15b judge with A be the β current data I β SA of benchmark phase mutually, with B be mutually the benchmark phase β current data I β SB be whether maximum among the β current data I β SC of benchmark phase is the β current data I β SA (step S308) of benchmark phase with A mutually mutually with C.
Be judged as with A be the β current data I β SA of benchmark phase mutually, with B be mutually the benchmark phase β current data I β SB be that maximum among the β current data I β SC of benchmark phase is (being "Yes" among the step S308) when being the β current data I β SA of benchmark phase mutually with A mutually with C, fault phase judging part 15b is judged as A and perfects phase, 2 phase earth faults take place in BC mutually, and the judgement output OBC that the 2 phase earth faults that only make expression BC phase are judged is effective, makes other judge output OA, OB, OC, OCA, OAB invalid (step S309).
Be judged as with A be the β current data I β SA of benchmark phase mutually, with B be mutually the benchmark phase β current data I β SB be that maximum among the β current data I β SC of benchmark phase is not (being "No" among the step S308) when being the β current data I β SA of benchmark phase mutually with A mutually with C, fault phase judging part 15b judge with A be the β current data I β SA of benchmark phase mutually, with B be mutually the benchmark phase β current data I β SB be whether maximum among the β current data I β SC of benchmark phase is the β current data I β SB (step S310) of benchmark phase with B mutually mutually with C.
Be judged as with A be the β current data I β SA of benchmark phase mutually, with B be mutually the benchmark phase β current data I β SB be that maximum among the β current data I β SC of benchmark phase is (being "Yes" among the step S310) when being the β current data I β SB of benchmark phase mutually with B mutually with C, fault phase judging part 15b is judged as B and perfects phase, 2 phase earth faults take place in CA mutually, and the judgement output OCA that the 2 phase earth faults that only make expression CA phase are judged is effective, makes other judge output OA, OB, OC, OBC, OAB invalid (step S311).
Be judged as with A is the β current data I β SA of benchmark phase mutually, with B be mutually the benchmark phase β current data I β SB be that maximum among the β current data I β SC of benchmark phase is not (being "No" among the step S310) when being the β current data I β SB of benchmark phase mutually with B mutually with C, promptly be judged as with A is the β current data I β SA of benchmark phase mutually, with B be mutually the benchmark phase β current data I β SB be that maximum among the β current data I β SC of benchmark phase is when being the β current data I β SC of benchmark phase mutually with C mutually with C, fault phase judging part 15b is judged as C and perfects phase, 2 phase earth faults take place in AB mutually, and the judgement output OAB that the 2 phase earth faults that only make expression AB phase are judged is effective, makes other judge output OA, OB, OC, OBC, OCA invalid (step S312).
The legitimacy of the fault judgement processing of described fault phase judging part 15b then, is described.The situation of the 1 phase earth fault (A phase earth fault) of A phase at first, is described.Under the situation of A phase earth fault, enter the home terminal current IA circulation fault current of the A phase of Zero-phase current differential relay 3b, B is communicated with load current with C home terminal current IB, IC mutually mutually.Owing to get the resultant current at two ends, the resultant current when load current connects at two ends like that only leaves fault current, and following formula 13 and formula 14 are set up.
IAS=If ... (formula 13)
IBS=ICS=0 ... (formula 14)
Moreover IAS is the resultant current data of A phase, and IBS is the resultant current data of B phase, and ICS is the resultant current data of C phase, and If is the fault current at two ends.
Promptly, by formula 10～formula 12, formula 13, formula 14, be the β current data I β SA of benchmark phase mutually, be that the β current data I β SB of benchmark phase becomes 3 following formula respectively with the β current data I β SC that is the benchmark phase mutually mutually with B with C with A, with fault is that the β current data I β S of benchmark phase becomes " 0 " mutually, the sound fault current that circulates mutually of β electric current.Thereby, " I β SA＜ε 2 ", " I β SB〉ε 3 " and " I β SC〉ε 3 " these 3 conditions establishments.Here, threshold epsilon 3 is to use because of the output of the internal fault Zero-phase current differential relay unit of power transmission line 1 to move the detected value of electric current energy of (effectively).And threshold epsilon 2 is values that the false retrieval that the current transformer error causes does not take place, and is taken as the value that can clearly distinguish less than ε 3.
IβSA＝(IBS-ICS)×(√3/3)＝0
IβSB＝(ICS-IAS)×(√3/3)＝-If(√3/3)
IβSC＝(IAS-IBS)×(√3/3)＝If(√3/3)
Again, when all being false, form 2 phase earth faults as 3 conditions of 3 conditions of 3 conditions of " the I β SA＜ε 2 " of 1 phase earth-fault conditions, " I β SB〉ε 3 " and " I β SC〉ε 3 ", " I β SC＜ε 2 ", " I β SA〉ε 3 " and " I β SC〉ε 3 " and " I β SC＜ε 2 ", " I β SA〉ε 3 " and " I β SB〉ε 3 ".For example, under the situation of the 2 phase earth faults (BC earth fault) of BC phase, the home terminal current IA carrying load current of A phase, B phase and C home terminal current circulation fault current mutually.Owing to get the resultant current at two ends, the resultant current when load current connects at two ends like that only leaves fault current, and following formula 15 is set up.
IAS＝0……(15)
Moreover IAS is the resultant current data of A phase.By above-mentioned formula 10～formula 12, formula 15, if B and C mutually between the current data of electric current of circulation be IBCS, then be the β current data I β SA of benchmark phase mutually, be that the β current data I β SB of benchmark phase becomes 3 following formula respectively with the β current data I β SC that is the benchmark phase mutually mutually with B with C with A.Here, the relation of " effective value of IBCS〉IBS the effective value of effective value=ICS " is set up, so to being the β current data I β SA of benchmark phase mutually with A, being the phase that perfects that β current data I β SB and the benchmark that these 3 current data of β current data I β SC that are the benchmark phase mutually present the maximum current data of benchmark phase becomes 2 phase earth faults mutually mutually with B with C.Like this, can judge with the effective value of the β current data I β S of every phase and carry out fault phase judgment processing.
IβSA＝(IBS-ICS)×(√3/3)＝IBCS(√3/3)
IβSB＝(ICS-IAS)×(√3/3)＝ICS(√3/3)
IβSC＝(IAS-IBS)×(√3/3)＝-IBS(√3/3)
Illustrated as mentioned, in this execution mode 3, according to the Zero-phase current of distolateral 3 phase currents of the basis that obtains based on current transformer and the calculus of differences result that obtains from the current transformer of opposite end to the Zero-phase current of distolateral 3 phase currents from local terminal, when detecting the earth fault of power transmission line, according to the synthetic Zero-phase current that obtains after synthesizing to the Zero-phase current of this distolateral 3 phase currents with to the Zero-phase current of distolateral 3 phase currents, and based on to this distolateral 3 phase currents and the every β electric current mutually that whenever is combined to the electric current same phasor1 and the electric current of opposite end (local terminal with) that obtains after in-phase current to distolateral 3 phase currents synthesizes, carry out the earth fault that takes place on the power transmission line whether the division of 1 phase fault judge mutually with fault, even therefore under the situation that this distolateral fault current is little, also carry out reliably the earth fault that takes place on the power transmission line whether the division of 1 phase earth fault judge mutually that with fault but not fault was judged such input voltage that uses mutually in the past.Again, in this execution mode 3, judge the fault phase of 2 phase earth faults, even therefore under the minimum situation of this distolateral fault current according to the size of the β current effective value of every phase, also can detect the fault phase on the power transmission line reliably, but not fault was judged such input voltage that uses mutually in the past.And, by using the Clarke coordinate method, do not need the positive phase current of symmetrical coordinates, the required phase shift computing of computing of negative-phase sequence curent, can make to handle and simplify.
Moreover, in the judgment processing action of preamble with reference to the fault judgement handling part of the flowchart text of Figure 11, synthetic Zero-phase current data I S and predetermined threshold value ε 1 are compared, but also can be synthetic Zero-phase current data I S and predetermined threshold value ε 1 be compared, and judge effective or invalid as the Zero-phase current differential relay unit output of the output of Zero-phase current differential relay unit portion 14.At this moment, the situation of " output of Zero-phase current differential relay unit effectively " is equivalent to the situation of " synthetic Zero-phase current data I S is greater than threshold epsilon 1 ", and the situation of " output of Zero-phase current differential relay unit is invalid " is equivalent to the situation of " synthetic Zero-phase current data I S is less than threshold epsilon 1 ".
Execution mode 4
With Figure 12 and Figure 13, embodiments of the present invention 4 are described.In the execution mode 1～3 of front, determine whether to take place on the power transmission line 11 phase earth fault or 2 phase earth faults and break down mutually, but present embodiment 4 only determines whether to take place on the power transmission line 11 phase earth fault or 2 phase earth faults and generation 1 phase of earth fault mutually.
Using the electric power of the Zero-phase current differential relay of present embodiment 4 uses system identical with the composition of system with the electric power of preamble illustrated embodiment 1, but use Zero-phase current differential relay 3c-1,3c-2, to replace Zero-phase current differential relay 3-1,3-2.
Figure 12 is the block diagram of the composition of Zero-phase current differential relay 3c that present embodiment 4 is shown (expression 3c-1,3c-2).The Zero-phase current differential relay 3c of present embodiment 4 shown in Figure 12 is Zero-phase current differential relay 3b deletion "AND" circuit 16BC, 16CA, the 16AB of texts and pictures 10 illustrated embodiment 3 in the past, add "AND" circuit 163, and be equipped with fault phase judging part 15c, to replace fault phase judging part 15b.The part that has with the Zero-phase current differential relay 3b identical functions of preamble execution mode 3 shown in Figure 10 is marked same label, and the repetitive description thereof will be omitted.
Fault phase judging part 15c according to from the β current data I β S of every phase of β current operator portion 19 input and from two ends the zero synthetic Zero-phase current data I S that is combined to portion's 13 inputs, judge on the power transmission line 1 and whether break down.Fault phase judging part 15c makes and judges that output OA is effective when being judged as 1 phase earth fault of A phase, makes other judge that output OB, OC, O3 Φ are invalid.Fault phase judging part 15c makes and judges that output OB is effective when being judged as 1 phase earth fault of B phase, makes other judge that output OA, OC, O3 Φ are invalid.Fault phase judging part 15c makes and judges that output OC is effective when being judged as 1 phase earth fault of C phase, makes other judge that output OA, OB, O3 Φ are invalid.And fault phase judging part 15c makes and judges that output O3 Φ is effective when being judged as the fault that takes place beyond the 1 phase earth fault, makes other judge that output OA, OB, OC are invalid.
The logic product that the judgement output O3 Φ that "AND" circuit 163 will move mutually from the expression 3 of the 15c of fault judgement portion input and the Zero-phase current unit of 14 inputs from the Zero-phase current differential relay unit are exported is moved judged result 3 Φ T mutually as 3 and is exported.
Then, the Zero-phase current differential relay 3c of embodiment of the present invention 4 with the difference of the Zero-phase current differential relay 3b of the execution mode 3 of front is: the Zero-phase current relay 3b of the execution mode 3 of front determines the 2 fault phases of earth fault mutually, and among the Zero-phase current relay 3c of present embodiment 4, the fault phase of uncertain 2 phase earth faults, and whether 3 judgements of action mutually of output.Other action is identical with the Zero-phase current relay 3b of the execution mode 3 of front, so difference only is described, promptly carries out the action of the fault phase judging part 15c of fault phase judgment processing here.
With reference to the flow chart of Figure 13, the action of fault phase judging part 15c of the Zero-phase current differential relay 3c of present embodiment 4 is described.Fault phase judging part 15c judges that whether synthetic Zero-phase current data I S is greater than predetermined threshold value ε 1 (step S400).When synthesizing Zero-phase current data I S less than threshold epsilon 1 (being "No" among the step S400), fault phase judging part 15c is judged as on the power transmission line 1 and does not break down, and makes whole judgements output OA, OB, OC, O3 Φ invalid (step S401).
Synthetic Zero-phase current data I S is during greater than threshold epsilon 1 (being "Yes" among the step S400), fault phase judging part 15c judge whether with A be mutually the β current data I β SA of benchmark phase less than predetermined threshold value ε 2 and with B be mutually the benchmark phase β current data I β SB be that the β current data I β SC of benchmark phase is greater than predetermined threshold value ε 3 (step S402) mutually with C.The β current data I β SA that with A is the benchmark phase mutually less than threshold epsilon 2 and with B be mutually the benchmark phase β current data I β SB be that the β current data I β SC of benchmark phase is during greater than threshold epsilon 3 (being "Yes" among the step S402) mutually with C, fault phase judging part 15c is judged as A 1 phase earth fault takes place mutually, and the judgement output OA that the 1 phase earth fault that only makes expression A phase is judged is effective, makes other judge output OB, OC, O3 Φ invalid (step S403).
With A is that the β current data I β SA of benchmark phase is during more than or equal to predetermined threshold value ε 2 mutually, or with B be mutually the benchmark phase β current data I β SB with C be at least 1 of the β current data I β SC of benchmark phase during smaller or equal to threshold epsilon 3 (being "No" among the step S402) mutually, fault phase judging part 15b judge whether with B be mutually the β current data I β SB of benchmark phase less than threshold epsilon 2 and with A be mutually the benchmark phase β current data I β SA be that the β current data I β SC of benchmark phase is greater than threshold epsilon 3 (step S404) mutually with C.The β current data I β SB that with B is the benchmark phase mutually less than threshold epsilon 2 and with A be mutually the benchmark phase β current data I β SA be that the β current data I β SC of benchmark phase is during greater than threshold epsilon 3 (being "Yes" among the step S404) mutually with C, fault phase judging part 15b is judged as B 1 phase earth fault takes place mutually, and the judgement output OB that the 1 phase earth fault that only makes expression B phase is judged is effective, makes other judge output OA, OC, O3 Φ invalid (step S405).
With B is that the β current data I β SB of benchmark phase is during more than or equal to predetermined threshold value ε 2 mutually, or with A be mutually the benchmark phase β current data I β SA with C be at least 1 of the β current data I β SC of benchmark phase during smaller or equal to threshold epsilon 3 (being "No" among the step S404) mutually, fault phase judging part 15c judge whether with C be mutually the β current data I β SC of benchmark phase less than threshold epsilon 2 and with A be mutually the benchmark phase β current data I β SA be that the β current data I β SB of benchmark phase is greater than threshold epsilon 3 (step S406) mutually with B.The β current data I β SC that with C is the benchmark phase mutually less than threshold epsilon 2 and with A be mutually the benchmark phase β current data I β SA be that the β current data I β SB of benchmark phase is during greater than threshold epsilon 3 (being "Yes" among the step S406) mutually with B, fault phase judging part 15c is judged as C 1 phase earth fault takes place mutually, and the judgement output OC that the 1 phase earth fault that only makes expression C phase is judged is effective, makes other judge output OA, OB, O3 Φ invalid (step S407).
The β current data I β SC that with C is the benchmark phase mutually more than or equal to threshold epsilon 2 and with A be mutually the benchmark phase β current data I β SA be that at least 1 of the β current data I β SB of benchmark phase is during smaller or equal to threshold epsilon 3 (being "No" among the step S406) mutually with B, fault phase judging part 15c is judged as 1 phase earth fault fault in addition takes place, the judgement output O3 Φ that expression 3 is moved mutually is effective, makes other judge output OA, OB, OC invalid (step S408).
Like this, the judgment processing of the 2 phase earth faults of the fault phase judging part 15b of the execution mode 3 of fault phase judging part 15c omission front, being judged as power transmission line 1 at synthetic Zero-phase current IOS during greater than threshold epsilon 1 does not break down, and when the fault that takes place is not 1 phase earth fault of A phase, B phase, C phase indeterminate fault phase, the only information that breaks down of output.
Illustrated as mentioned, in this execution mode 4, according to the Zero-phase current of distolateral 3 phase currents of the basis that obtains based on current transformer and the calculus of differences result that obtains from the current transformer of opposite end to the Zero-phase current of distolateral 3 phase currents from local terminal, when detecting the earth fault of power transmission line, according to the synthetic Zero-phase current that obtains after synthesizing to the Zero-phase current of this distolateral 3 phase currents with to the Zero-phase current of distolateral 3 phase currents, and based on to this distolateral 3 phase currents and the every β electric current mutually that whenever is combined to the electric current same phasor1 and the electric current of opposite end (local terminal with) that obtains after in-phase current to distolateral 3 phase currents synthesizes, carry out the earth fault that takes place on the power transmission line whether the division of 1 phase fault judge mutually with fault, even therefore under the situation that this distolateral fault current is little, also can carry out reliably the earth fault that takes place on the power transmission line whether the division of 1 phase earth fault judge mutually that with fault but not fault was judged such input voltage that uses mutually in the past.Again, in this execution mode 4, judge the fault phase of 1 phase earth fault, even therefore under the minimum situation of this distolateral fault current according to the size of the β current effective value of every phase, also can detect the fault phase on the power transmission line reliably, but not fault was judged such input voltage that uses mutually in the past.
And each action mutually as determining the fault phase in the 1 phase earth fault is taken as 3 actions mutually, does not determine the fault phase when 2 phase earth faults, so only be the judgement of each phase effective value size of β electric current, can make to handle and simplify.
Moreover, in the judgment processing action of preamble with reference to the fault judgement handling part of the flowchart text of Figure 13, synthetic Zero-phase current data I S and predetermined threshold value ε 1 are compared, but also can be synthetic Zero-phase current data I S and predetermined threshold value ε 1 be compared, and judge effective or invalid as the Zero-phase current differential relay unit output of the output of Zero-phase current differential relay unit portion 14.At this moment, the situation of " output of Zero-phase current differential relay unit effectively " is equivalent to the situation of " synthetic Zero-phase current data I S is greater than threshold epsilon 1 ", and the situation of " output of Zero-phase current differential relay unit is invalid " is equivalent to the situation of " synthetic Zero-phase current data I S is less than threshold epsilon 1 ".
Industrial practicality
Only cut off event when in sum, Zero-phase current differential relay of the present invention breaks down as power transmission line The invention of barrier phase is useful.

Claims (5)

1, a kind of Zero-phase current differential relay, be equipped with: according to the Zero-phase current of distolateral 3 phase currents of the basis that obtains based on current transformer and the calculus of differences result that obtains from the current transformer of opposite end the Zero-phase current of distolateral 3 phase currents from local terminal, judge whether power transmission line has the judging part of earth fault, it is characterized in that
Described judging part is equipped with:
According to described distolateral 3 phase currents and the every resultant current mutually that obtains after described in-phase current to distolateral 3 phase currents synthesizes, obtaining with each is the portion that just is combined to of the positive phase current of benchmark phase mutually;
According to described distolateral 3 phase currents and the every resultant current mutually that obtains after described in-phase current to distolateral 3 phase currents synthesizes, obtaining with each is the anti-phase synthetic portion of the negative-phase sequence curent of benchmark phase mutually; And
The Zero-phase current of described distolateral 3 phase currents and described Zero-phase current to distolateral 3 phase currents are synthesized, and obtain the synthetic portion of two ends Zero-phase current of synthetic Zero-phase current,
Described Zero-phase current differential relay is according to described positive phase current, described negative-phase sequence curent and described synthetic Zero-phase current, and whether the earth fault of carrying out taking place on the power transmission line can be judged as the division of the fault phase of 1 phase earth fault.
2, the Zero-phase current differential relay described in claim 1 is characterized in that,
Described judging part judges according to described synthetic Zero-phase current and each described negative-phase sequence curent mutually whether described earth fault is 1 phase earth fault, and
When judging described earth fault and be not 1 phase earth fault, be judged as 2 beyond the phase that is judged as this earth fault not 2 phase earth faults take place mutually.
3, a kind of Zero-phase current differential relay, be equipped with: according to the Zero-phase current of distolateral 3 phase currents of the basis that obtains based on current transformer and the calculus of differences result that obtains from the current transformer of opposite end the Zero-phase current of distolateral 3 phase currents from local terminal, judge the whether judging part of earth fault of power transmission line, it is characterized in that
Described judging part is equipped with:
According to described distolateral 3 phase currents and the every resultant current mutually that obtains after described in-phase current to distolateral 3 phase currents synthesizes, obtain the β current operator portion of the β electric current of every phase; And
The Zero-phase current of described distolateral 3 phase currents and described Zero-phase current to distolateral 3 phase currents are synthesized, and obtain the synthetic portion of two ends Zero-phase current of synthetic Zero-phase current,
Described Zero-phase current differential relay is according to β electric current and described synthetic Zero-phase current, and whether the earth fault of carrying out taking place on the power transmission line can be judged as the division of the fault phase of 1 phase earth fault.
4, the Zero-phase current differential relay described in claim 3 is characterized in that,
Described judging part judges according to the size of described β electric current whether described earth fault is 1 phase earth fault, and
When judging described earth fault and be not 1 phase earth fault, be judged as 2 beyond the phase of maximum current in the β electric current with described each phase 2 phase earth faults take place mutually.
5, the Zero-phase current differential relay described in claim 3 or 4 is characterized in that,
Described judging part also is equipped with:
According to described distolateral 3 phase currents and the every resultant current mutually that obtains after described in-phase current to distolateral 3 phase currents synthesizes, obtain the α current operator portion of the α electric current of every phase,
Described judging part is carried out following each judgment processing mutually to every:
According to the size of described β electric current, judge whether described earth fault is the 1st judgment processing of the earth fault of this phase;
When described the 1st judgment processing is judged described earth fault the possibility of 1 phase earth fault is arranged, according to the in-phase component of described synthetic Zero-phase current and the phase difference of described α electric current, judge whether described earth fault can be judged as the 2nd judgment processing of the fault phase of 1 phase earth fault; And
When described the 1st judgment processing is judged described earth fault and is not had the possibility of 1 phase fault, according to the negative-phase sequence curent of described synthetic Zero-phase current and the phase difference of described α electric current, judge whether to being judged as the 3rd judgment processing of the phase 2 phase earth faults in addition that do not have described 1 phase earth fault.
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