JP2002027663A - Distance relay - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent wrong judgment on an element other than the fault phase as being a fault phase. SOLUTION: When any one of ground fault relay elements 8-1 to 8-3 operates, this operation is stores as phase operation storage processes 9-4 to 9-6 during operation. When a ground fault zero-phase over-current relay element 10 operates, a selection process 16 or 17 of the fault phase is executed, depending on the number of operation phases in the steps 11, 12, 18 in order to judge the fault phase. If any one of the ground fault distance relay elements 7-1 to 7-3 operates, this operation is stored as the phase voltage storage processes 9-1 to 9-3 during operation. When the ground fault zero phase overcurrent relay element 10 does not operate and the three-phase operation is executed in the step 13, it is judged that a fault has been generated in all phases. When an operation is executed in the step 14, and the fault of the phase is judged by executing the selection process 15 for the fault phase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance relay device having a function of selecting a failed phase in a power system.

[0002]

2. Description of the Related Art FIG.
FIG. 5 is a block diagram showing a protection sequence in the case of protection for a direct grounding system of the conventional distance relay device shown in FIG. In the figure, reference numeral 1 denotes a short-circuit protection distance relay element, and its output indicates a relay output at the time of a short-circuit fault. Reference numeral 2 denotes a ground fault protection distance relay element, whose output is separated into one, two, and three distance relay elements. 3-1
Reference numeral 3-3 denotes an undervoltage relay element of A phase, B phase, and C phase, respectively. 4-1 to 4-5 are AND circuits and 5-1 respectively.
Is an OR circuit, and 6-1 is a NOT circuit.

Next, the operation will be described. The first output of the ground fault distance relay element one stage is input to the AND circuit 4-1 together with the condition during use of the carrier, and the output is the output of each phase of the undervoltage relay elements 3-1 to 3-3. The outputs are input to AND circuits 4-2 to 4-4, and these outputs become trip outputs of the respective phases.

The second output of the ground fault distance relay element is input to an AND circuit 4-5 together with a condition in which a carrier is being used, which is inverted by a NOT circuit 6-1.
The output of the ND circuit 4-5 is an OR circuit 5-5 together with the output of the short-circuit protection distance relay, the output of the ground fault distance relay element in two stages, and the output of the three stages.
1 and a three-phase trip by the output of the OR circuit 5-1.

[0005] Even if the accident is a short-circuit accident or a ground fault, when two or three elements of the ground fault distance relay element operate, or when one of the instantaneous elements of the ground fault distance relay element is operated, Even if it operates, when the carrier is not used and high-speed reclosing is not possible, a three-phase trip occurs, and the single reclosing is performed according to the operating phase of the undervoltage relay at the time of the one-stage ground fault element operation under the condition of using the carrier. .

As described above, conventionally, in each single-phase reclosing circuit, the number of phase trips is determined by each phase undervoltage relay element 3-1 to 3-3. As shown in this example, in a sequence in which a three-phase trip can be performed when two or more phases fail, and a single-phase trip can be performed only when a one-phase failure occurs, if the healthy phase voltage does not decrease at the time of failure, each phase undervoltage relay is performed in the phase determination. It is effective to use electricity, but the type of failure that actually occurred
In the case of the AB-phase short-circuit fault, the CA-phase and BC-phase short-circuit elements cannot accurately measure the fault distance, and are used for the ground fault element calculation even in the possibility of overreach and erroneous determination due to the fault distance and the A-phase ground fault. , B-phase and C-phase ground fault elements may also operate due to the zero-phase compensation calculation.

[0007]

The protection relay device of the conventional distance relay system is configured as described above.
There has been a problem that it is not possible to determine the failure type, and that elements other than the failure phase may be erroneously determined to be the failure phase. If the operation of a phase other than the failed phase is determined, the impedance calculation is not accurately reflected, which may cause an overreach in a distant forward failure and a malfunction in a rear failure.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a distance relay device which not only determines a failure type but also does not mistakenly determine an element other than the failure phase as a failure phase. The purpose is to provide.

[0009]

According to a first aspect of the present invention, in a distance relay device for protecting a three-phase AC power system, a ground fault distance relay element of each phase and a short circuit of each phase are provided. Distance relay element, zero-phase overcurrent relay element, deriving means for deriving each inter-phase voltage according to the operation of the ground fault distance relay element or the short-circuit distance relay element, and the ground fault distance relay element When one or two elements of the above-mentioned elements operate and the zero-phase overcurrent relay element operates, or one or two elements of the short-circuit distance relay element operate and the zero-phase When the overcurrent relay element does not operate, there is provided a discriminating means for discriminating a phase having the smallest voltage among the inter-phase voltages derived by the deriving means as a failure phase for a two-wire failure.

(2) A distance relay device for protecting a three-phase AC power system according to claim 2 of the present invention, wherein a ground fault distance relay element of each phase, a short-circuit distance relay element of each phase, Zero-phase overcurrent relay element, deriving means for deriving each phase voltage according to the operation of the ground fault distance relay element or the short-circuit distance relay element,
When one or two of the ground fault distance relay elements operate and the zero-phase overcurrent relay element operates, or one or two elements of the short circuit distance relay element operate. When the zero-phase overcurrent relay element does not operate, the phase having the largest voltage among the phase voltages derived by the deriving means is determined to be the healthy phase for the two-wire failure, and the phase other than the healthy phase is determined. And a determining means for setting the phase as a failure phase.

(3) A distance relay device for protecting a three-phase AC power system according to a third aspect of the present invention, wherein a ground fault distance relay element of each phase, a short-circuit distance relay element of each phase, Zero-phase overcurrent relay element, deriving means for deriving each phase voltage according to the operation of the ground fault distance relay element or the short-circuit distance relay element,
When one or two of the ground fault distance relay elements operate and the zero-phase overcurrent relay element operates, or one or two elements of the short circuit distance relay element operate. And when the zero-phase overcurrent relay element does not operate, determining means for determining the phase of the smallest voltage among the phase voltages derived by the deriving means as a failure phase for one-line failure. It is provided.

(4) A distance relay device for protecting a three-phase AC power system according to a third aspect of the present invention, wherein the ground fault distance relay element of each phase, the zero-phase overcurrent relay element, Deriving means for deriving the amount of impedance of each phase according to the operation of the ground fault distance relay element, one or two of the ground fault distance relay elements operate, and the zero-phase overcurrent relay element Is operated, the discriminating means is provided for discriminating the phase having the smallest impedance amount among the phase impedance amounts derived by the deriving means as the failure phase due to the one-line failure.

(5) A distance relay device for protecting a three-phase AC power system, wherein the short-circuit distance relay element of each phase, the zero-phase overcurrent relay element, and the short circuit Deriving means for deriving the short-circuit impedance amount between the phases according to the operation of the distance relay element, one or two elements of the short-circuit distance relay element operate, and the zero-phase overcurrent relay element When it does not operate, it is provided with a discriminating means for discriminating a phase having the smallest short-circuit impedance amount among the phase short-circuit impedance amounts derived by the deriving means as a failure phase for a two-wire failure.

(6) A distance relay device for protecting a three-phase AC power system according to claim 6 of the present invention, wherein a ground fault distance relay element of each phase, a short-circuit distance relay element of each phase, Zero-phase overcurrent relay element, deriving means for deriving a phase angle between a positive-phase voltage and a negative-phase voltage for each phase according to the operation of the ground fault distance relay element or the short-circuit distance relay element, When one or two elements of the ground fault distance relay element operate and the zero-phase overcurrent relay element operates, or one or two elements of the short circuit distance relay element operate. When the zero-phase overcurrent relay element does not operate, if the phase angle difference for each phase derived by the deriving means is near 180 degrees, the phase is determined to be the failure phase for one-line failure. And determination means for performing the determination.

(7) A seventh aspect of the present invention is the third aspect.
In the distance relay device according to any one of 4, 6 and 7, a forward direction element is provided, and when the forward direction element operates, a failure phase is determined by the determination means, so that a one-line failure occurs due to a forward failure. This is to determine the phase.

(8) Claim 8 of the present invention relates to claims 1 to
7. In the distance relay device according to any one of 7, the operation of the phases other than the failed phase is locked when the failed phase is determined by the determining means.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating the sequence processing of each element in the logic circuit of the distance relay device. In FIG. 1, 7-1 to 7-3 are short-distance relay elements, 8-1 to 8-3 are ground-fault relay elements, and 9-1 to 9-6 are short-distance relay elements 7-. 1-7-
3, a phase voltage storage process for storing each phase voltage including an operation phase when the ground fault distance relay elements 8-1 to 8-3 operate, 10 is a zero-phase overcurrent relay element for detecting a ground fault, 11 14 and 18 are operating phase checks, 15 to 17 are faulty phase selection processes, 19
21 to 21 indicate lock processing of a healthy phase other than the failed phase.

Next, the operation will be described. (1) In FIG. 1, each relay element 7-1 to 7-3, 8-1 to 8-
When the operation is performed in steps 3 and 10, the operation is branched in the Y direction. All operations of each relay element are executed in series. (2) The ground fault short-circuit distance relay elements 7-1 to 7-3 and the ground fault distance relay elements 8-1 to 8-3 convert the response of the short-circuit / ground short-circuit relay element into a predetermined arithmetic expression. Calculate accordingly.

(3) Phase voltage preservation processing 9-1 to 9 during operation
-6 is the phase voltage of the operated phase and the healthy phase when the short-circuit distance relay elements 7-1 to 7-3 and the ground-fault distance relay elements 8-1 to 8-3 operate and move in the Y direction. Perform save processing. (4) 51G of the zero-phase overcurrent relay element 10 for ground fault detection,
The relay element is calculated using the zero-sequence current, and proceeds in the Y direction when operating, and proceeds in the N direction when not operating.

(5) Zero-phase overcurrent relay element 10 for ground fault detection
Is not operating, the power system is sound or short circuit has occurred.
Proceeding to 3, the operation phase is checked based on the phase voltages of the phase voltage storage processes 9-1 to 9-3. (6) If all three phases are operating, it is determined that a three-phase short-circuit fault has occurred. (7) If all three phases are not operating, the process proceeds to step 14, and it is determined whether or not a two-phase operation is performed based on the phase voltages stored in the phase voltage storage processes 9-1 to 9-3. If a short-circuit failure is not established, it is determined to be sound.

(8) Zero-phase overcurrent relay element 10 for ground fault detection
Is a ground fault at the time of operation, it is checked at 11 whether or not one phase is operating based on the operating phase voltage storage information of the phase voltage storage processes 9-4 to 9-6. (9) If there is only one phase, it is determined that the fault is a one-phase ground fault. (10) If it is not one phase, the possibility of two-phase ground fault is high and 1
The process proceeds to step 2 to detect two phases based on the operating voltage storage information of the phase voltage storage processing to 9-6 and determine that the ground is a two-phase ground fault. (11) If it is not two-phase, proceed to 18 and if it is a three-phase operation, determine that it is a three-phase short circuit. (12) After classifying the fault types in this way,
If 12 and 14 are Y, a fault phase selection process is performed in 15 to 17.

The contents of the fault phase selection processes 15 to 17 are the same, and the process of the fault selection process 17 will be described as a specific example of the process with reference to the fault phase selection flowchart shown in FIG. In FIG. 2, reference numeral 22 denotes an arithmetic operation for calculating an inter-phase voltage from the voltages stored in the phase voltage storage processes 9-4 to 9-6 during operation; 23, a voltage comparison between VAB and VBC;
Is a voltage comparison between VAB and VCA, and 25 is a voltage comparison between VBC and VCA.

Next, the operation will be described. (1) The phase voltages VA, VB, and VC stored in the phase voltage storage processes 9-4 to 9-6 during the operation in FIG. 1 are input to 22, and the inter-phase voltages VAB, VBC, and VCA of each phase are calculated. And
It is input to a voltage comparison 23 between VAB and VBC. (In this case, at least one of the inter-phase voltages VAB, VBC, and VCA decreases, and the ground fault distance relay elements 8-1 to 8-1
At least one element of 8-3 operates, and each phase voltage at the time of element operation is stored in the phase voltage storage processing 9-1 to 9-6. However, in this case, the failure selection processing 17 is performed, so that
In the determination of the presence of the phase operation, two elements operate and their phase voltages are stored. )

(2) At 23, a voltage comparison judgment is made, and VA
If B <VBC, a voltage comparison determination is made in the voltage comparison 24 between VAB and VCA, and if VAB <VCA, VAB
Is determined to be the voltage with the lowest voltage, and is determined to be the failure phase (ie, AB phase failure) for the ground fault two-wire failure (2φG).

(3) Voltage comparison between VAB and VBC 23
If VAB> VBC, a voltage comparison judgment is made in the voltage comparison 25 between VBC and VCA, and if VBC <VCA, V
It is determined that BC is the voltage with the lowest voltage, and is determined to be the failure phase (ie, BC phase failure) for the ground fault 2-wire failure (2φG).

(4) In the voltage comparison judgment 25, VBC> VCA
, VCA is determined to be the voltage with the lowest voltage, and the fault phase (ie, C
A failure). In addition, when the voltage comparison
If B> VCA, it is determined that VCA is the voltage with the lowest voltage, and similarly, it is determined that the failure phase is a two-wire failure (2φG) (that is, a CA phase failure). (5) Further, the operation of phases other than the failed phase is locked by the lock processing 21 of FIG.

Similarly, for the short-circuit two-wire fault (2φS), the voltage at which the voltage is the lowest is determined, the fault phase is determined for the short-circuit two-wire fault, and the operation of the phases other than the fault phase is locked. be able to. As a result, it is possible to prevent an overreach due to the operation of the two-phase short-circuit element other than the failure phase in the two-wire failure and a malfunction due to the failure behind the two-phase failure element.

Embodiment 2 In the first embodiment, the means for comparing the inter-phase voltages VAB, VBC, and VCA of each phase to determine a failed phase has been described.
"Phase voltage" is used in place of "inter-phase voltage", the maximum voltage phase is determined to be a healthy phase based on the comparison of phase voltages, and the remaining phases are determined to be failure phases (two-wire failure).

Hereinafter, a second embodiment of the present invention will be described with reference to FIG. A diagram for performing the sequence processing of each element in the logic circuit of the distance relay device is the same as the sequence diagram of FIG.

Next, the operation will be described. After classifying the fault types, the fault phases are selected at 15 to 17 in FIG. 1
As an example of the specific processing contents of the failure phase selection of 5 to 17, the processing of the failure selection processing 17 (two-line failure) will be described with reference to the failure phase selection flowchart shown in FIG. In the figure, 2
6 is a voltage comparison between VA and VB, 27 is a voltage comparison between VB and VC, and 28 is a voltage comparison between VA and VC.

(1) Operation phase voltage preservation processing 9-4 in FIG.
The phase voltages VA, VB, and VC stored in ９9-6 are
A and VB are input to a voltage comparison 26. (In this case, at least one of the phase voltages VA, VB, and VC decreases, and at least one of the ground fault distance relay elements 8-1 to 8-3 operates, and the phase voltage saving process is performed. 9-1 to 9-6
Each phase voltage at the time of element operation is stored. However, in this case, since the failure selection processing 17 is performed, two elements operate in the determination of the presence of the two-phase operation, and the phase voltage is stored. )

(2) A voltage comparison judgment is made by a voltage comparison 26 between VA and VB. If VA <VB, a voltage comparison judgment is made by a voltage comparison 27 between VB and VC. If VB> VC, a voltage comparison judgment is made.
VB is determined to be the largest voltage, the two phases (2φG) are determined to be healthy phases, and the operations of the two phases A and C that do not include the healthy phase are determined to be failure phases (that is, CA phase failures).

(3) VA <VA <V
If it is VB, a voltage comparison judgment is made by the voltage comparison 28 between VA and VC. If VA> VC, it is judged that VC is the voltage that has increased most, and it is judged that the two phases (2φG) are in a healthy phase. The operations of the two phases A and B that do not include the healthy phase are determined as the failed phases.

(4) In the voltage comparison judgment 27 between VB and VC, V
If B <VC, it is determined that VA is the voltage that has increased the most, the two phases (2φG) are determined to be healthy phases, and the operations of the two phases B and C that do not include the healthy phase are determined to be failure phases. . If VA> VC in the voltage comparison 28 between VA and VC,
It is determined that VA is the voltage that has increased most, and two wires (2φG)
2 phase B that does not include the healthy phase
The operation of C is determined to be the failure phase. (5) Further, the operation of the phase not including the failed phase is locked by the lock processing 21 of FIG.

According to this method, in the first embodiment, for example, when a two-wire ground fault has an arc resistance at the fault point, the voltage vector phase is shifted when the arc resistance is unbalanced. When the phase is a two-phase ground fault, it is not always the failed phase, so that a more reliable determination result can be obtained.

Embodiment 3 In the first embodiment, the means for comparing the inter-phase voltages to determine the failed phase has been described.
In the third embodiment, “phase voltage” is used instead of “interphase voltage”, and the minimum voltage phase is determined to be the failure phase (one-line failure) based on the comparison of the phase voltages.

Hereinafter, a third embodiment of the present invention will be described with reference to FIG. A diagram for performing the sequence processing of each element in the logic circuit of the distance relay device is the same as the sequence diagram of FIG.

Next, the operation will be described. After classifying the fault types, the fault phases are selected at 15 to 17 in FIG. 1
As an example of specific processing contents of the failure phase selection of 5 to 17, the processing of the failure selection processing 16 will be described with reference to a failure phase selection flowchart shown in FIG. In the figure, 29 is VA and V
B is a voltage comparison, 30 is a voltage comparison between VA and VC, 31 is V
It is a voltage comparison between B and VC.

(1) Operating Voltage Storage Process 9-4 to 9 in FIG.
The phase voltages VA, VB, and VC stored at -6 are input to the voltage comparison 29 between VA and VB. (In this case, at least one of the phase voltages VA, VB, and VC decreases, and at least one of the ground fault distance relay elements 8-1 to 8-3 becomes lower.
One element operates, and each phase voltage at the time of element operation is stored in the phase voltage storage processing 9-1 to 9-6. However, in this case, since the failure selection processing 17 is performed, the determination that there are two two-phase operations is 2
Two elements are active and their phase voltages are preserved. )

(2) A voltage comparison judgment is performed by a voltage comparison 29 between VA and VB. If VA <VB, a voltage comparison judgment is performed by a voltage comparison 30 between VA and VC. If VA <VC, a voltage comparison judgment is made.
It is determined that VA is the lowest voltage, and one line (1φG)
Is determined to be an A-phase failure.

(3) VA> 29.
If it is VB, a voltage comparison determination is made in the voltage comparison 31 between VB and VC. If VB <VC, it is determined that VB is the lowest voltage, and it is determined that one line (1φG) is a B-phase failure. .

(4) VA> 29.
If it is VB, a voltage comparison judgment is made in the voltage comparison 31 between VB and VC. If VB> VC, it is judged that VC is the lowest voltage, and it is judged that one line (1φG) is a C-phase failure. . In addition, in the voltage comparison 30 between VA and VC, VA> VC
If so, it is determined that the voltage at which VC is the lowest is determined, and it is determined that a C-phase failure is detected for one line (1φG). (5) Further, in the lock processing 20 of FIG. 1, the operation of the phase not including the failed phase is locked.

In the third embodiment, it is possible to determine a failure phase due to a one-line failure, and to prevent a failure due to erroneous determination of another two-phase ground fault element.

Embodiment 4 FIG. In the third embodiment, the means for comparing the phase voltages to determine the failed phase has been described. In this embodiment, instead of the “phase voltage”, “phase impedance” ZA, ZB, ZC is used, and the impedance is determined. Is determined based on the comparison of the minimum impedance phase as the failure phase.

Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram illustrating a failure type determination circuit of the distance relay device. In the fourth embodiment, a one-line failure (1φG) in FIG. 5 will be described.
The line fault (2φS, 2φG) will be described in a fifth embodiment.

Next, the operation will be described. (1) Reference numeral 32 denotes a 1φG failure phase determination element, which outputs a failure phase determination result of a one-line failure according to the third embodiment. 37 is 2φ
The S, 2φG failure determination element outputs the failure phase determination result of the two-wire failure of the first embodiment.

(2) The A-phase impedance ZA34 is ZA
= VA / IA, B-phase impedance ZB35 is ZB = V
B / IB, C phase impedance ZC36 is ZC = VC
(3) The impedance signal of each phase is calculated by the AND circuit 38−
1, 38-2, and 38-3, and outputs the signal A
Obtain B, BC, CA. (4) These signals are input to the OR circuit 40, and the output signal and the zero-phase current I033 are input to the AND circuit 38-4.

(5) The output signal and the output signal from the one-wire (1φG) fault phase determination element 32, the signals of the A-phase impedance ZA34, the B-phase impedance ZB35, and the C-phase impedance ZC36 are respectively AND circuits 38-5. ,
Signals a, AN which are input to 38-6, 38-7 and indicate that the output 41 from the AND circuit 38-5 is an A-phase fault
An output 42 from the D circuit 38-6 becomes a signal b indicating a B-phase fault, and an output 43 from 38-7 becomes a signal c indicating a C-phase fault.

When considering the logic circuit for determining the type of fault shown in FIG. 5, all the signals may be determined to be faulty in the 1φG fault phase determination 32 depending on the fault case for various faults. Hard to do. Therefore, FIG.
As shown in FIG. In the figure, reference numeral 50 denotes a comparison between ZA and ZB, 51 denotes a comparison between ZA and ZC, and 52 denotes a comparison between ZB and ZC.

(1) Comparison of impedance between ZA and ZB 5
Perform impedance comparison judgment with 1. If ZA <ZB, an impedance comparison judgment is made in the impedance comparison 51 of ZA and ZC, and if ZA <ZC, it is determined that the impedance of ZA is the lowest and one line (1φG)
Is determined to be an A-phase failure.

(2) Comparison of impedance between ZA and ZB 5
If ZA> ZB at 0, an impedance comparison determination is made by ZB and ZC impedance comparison 52, and ZB <ZC
If so, it is determined that the impedance of ZB is the lowest, and it is determined that a B-phase failure has occurred for one line (1φG).

(3) Comparison of impedance between ZB and ZC 5
2, the impedance is compared and determined. If ZB> ZC, it is determined that the impedance of ZC is the lowest, and
It is determined that the failure is the phase C of the line (1φG). Also, Z
In the impedance comparison 51 between A and ZC, if ZA> ZC, it is determined that the impedance of ZC is the lowest,
It is determined that a C-phase fault has occurred for one line (1φG).

(4) It is also possible to lock the operation of the phase that does not include the failed phase based on the result.

The use of impedance has the advantage that the failure can be determined more accurately due to the difference in current even when the voltage drop is small.

Embodiment 5 In the fourth embodiment, the means for determining the failed phase by combining the impedances of the respective phases has been described. In this embodiment, instead of “impedance”, “short-circuit (line-to-line) impedance” ZA
B, ZBC, and ZCA are used, and the minimum short-circuit impedance phase is determined to be a failure phase. Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG. FIG.
Is the same as the block diagram showing the failure determination circuit of the distance relay device used in the fourth embodiment.

Next, the operation will be described. (1) 34 is the short-circuit impedance ZAB, ZAB
= VAB / IAB, 35 is calculated as a short-circuit impedance ZBC, ZBC = VBC / IBC, 36 is calculated as a short-circuit impedance ZCA, ZCA = VCA / ICA,
(2) Input to the AND circuits 38-1, 38-2, 38-3, and output as signals AB / BC, BC / CA, CA /
Get AB.

(3) These signals and the output signals from the 2φS and 2φG fault phase determining elements 37 are output to the AND circuit 38-1.
1, 38-12, 38-13, and (4) AND
The signal ab indicating that the output 47 from the circuit 38-11 is an AB-phase fault for two lines (2φG), and the output 48 from the AND circuit 38-12 is a BC-phase fault for two lines (2φG). Bc indicating AND circuit 3
The output 49 from 8-13 is the C for two wires (2φG).
The signal ca indicates the A-phase failure.

When considering the logic circuit for determining the type of a fault shown in FIG. 5, 2φS,
In some cases, all the signals are determined to be failures in the 2φG failure phase determination 37, and it is difficult to determine the number of phase failures. Therefore, as shown in FIG. 7, a failure phase selection flowchart is followed. In the figure, 53 indicates a short-circuit impedance comparison between ZAB and ZBC, 54 indicates a short-circuit impedance comparison between ZAB and ZCA, and 55 indicates a short-circuit impedance comparison between ZBC and ZCA.

(1) A short-circuit impedance comparison judgment is made in a short-circuit impedance comparison 53 between ZAB and ZBC, and ZA and ZBC are compared.
If B <ZBC, a short-circuit impedance comparison judgment is made in the short-circuit impedance comparison 54 of ZAB and ZCA,
If ZAB <ZCA, it is determined that ZAB is the shortest impedance in which ZAB is the lowest, and it is determined that the AB phase is faulty for two wires (2φG).

(2) If the comparison judgment in the short-circuit impedance comparison 53 between ZAB and ZBC is ZAB> ZBC,
A short-circuit impedance comparison determination is made in the short-circuit impedance comparison 55 between ZBC and ZCA. If ZBC <ZCA, it is determined that the impedance of ZBC is the lowest, and 2
It is determined that a BC phase failure has occurred for the line (2φG).

(3) If the comparison judgment in the short-circuit impedance comparison 55 between ZBC and ZCA indicates that ZBC> ZCA,
The ZCA is determined to be the shortest impedance with the lowest drop, and the CA phase failure is determined for two wires (2φG).
If the comparison determination in the short-circuit impedance comparison 54 between ZAB and ZCA is ZAB> ZCA, the short-circuit impedance is determined to be the lowest ZCA, and the two-wire (2φG)
Is determined to be a CA phase failure.

(4) It is possible to lock the operation of the phase that does not include the failed phase based on the result.

Further, the zero-phase current I033 is supplied to the NOT circuit 3
9, this output signal and two wires (2φS, 2φG)
An output signal from the failure phase determination element 37 is output to an AND circuit 38.
-8, 38-9, and 38-10, and the AND circuit 3
Outputs 44, 4 of 8-8, 38-9, 38-10 respectively
When the signals 5 and 46 become signals indicating the fault phase in the two lines (2φS), the fault phase can be similarly determined by comparing the short-circuit impedance.

In contrast to the first embodiment in which only voltage is used,
Since the impedance also uses the current information, more accurate failure phase determination is possible.

Embodiment 6 FIG. In the first embodiment, the means for comparing the inter-phase voltages to determine the failed phase has been described.
In this embodiment, the phase voltage “1φ · 2φ phase angle” is used in place of the “interphase voltage”, and the difference between the phase angles of 1φ and 2φ is within a range based on the comparison of the phase angle of each phase voltage. , The failure phase is determined. Hereinafter, a sixth embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a vector diagram of the phase angle of each phase voltage, and FIG. 9 shows a specific process of fault selection.

Next, the operation will be described. By the sequence processing of the distance relay device, the three-phase voltages VA, VB, and VC are input together with the operation of each relay element, and the negative-phase voltage V2
A, V2B, V2C and respective phase angles are calculated, and a vector diagram as shown in FIG. 8 is obtained based on the phase angles.

The specific processing content of the failure phase determination is shown in the failure phase selection flowchart shown in FIG. (1) In the figure, 56 is the difference between the phase angles of VA and V2A,
This is a calculation process for calculating the difference between the phase angles of VB and V2B and the difference between the phase angles of VC and V2C. According to the characteristics of the vector diagram of FIG. 8, when a failure phase occurs, only the failure phase has a characteristic in which the difference between the phase angles of Vφ and V2φ approaches 180 °. The difference between the phase angle between VA and V2A in FIG. 8 is 180 °, which indicates a failure phase, the difference between the phase angle between VB and V2B, and V
The difference between the phase angles of C and V2C is sufficiently smaller than 180 °, indicating a healthy phase.

(2) Using this characteristic, the difference in the phase angle of the A-phase voltage at 57 is close to 180 ° (for example, 180 ° ±
60 °), and if they are close, it is determined to be an A-phase failure for one line (1φG).

(3) If the phase angle difference is not close to 180 ° in 57, it is determined in 58 whether the phase angle difference of the B-phase voltage is close to 180 °, and if close, B for one line (1φG) is determined. Judge as phase failure.

(4) If the difference between the phase angles is not close to 180 ° at 58, it is determined at 59 whether the difference between the phase angles of the C-phase voltage is close to 180 °, and if close, the C value for one line (1φG) is determined. Judge as phase failure.

(5) According to the result, it is possible to lock the operation of the phase not including the failed phase.

As described above, the same failure phase can be determined by using the opposite phase voltage. Furthermore, in the above description, the determination is made based on the phase relationship between the voltage of a certain phase and the negative phase voltage based on that phase. However, instead of the certain phase voltage, -V0 (V0 is a zero-phase voltage) may be used. In the case of a one-line fault, -V0 is in phase with the phase voltage, and the V0 circuit and V2 circuit (negative-phase voltage circuit) are not affected by load current and system step-out phenomenon. There is an advantage that accurate judgment can be made.

Embodiment 7 In the third embodiment, the means for determining the failed phase by comparing the phase voltages has been described. In this embodiment, however, the “forward element” is used for determining the failed phase for one line (1φG) in the third embodiment. "
The failure phase is determined only for the forward failure.

Hereinafter, a seventh embodiment of the present invention will be described with reference to FIG. FIG. 10 is a block diagram showing a failure phase determination circuit of the distance relay device.

Next, the operation will be described. In this embodiment, for example, 67N which is a reverse-phase direction element to which a negative-phase voltage and a negative-phase current are input is used as the forward direction element. (1) A-phase 67N element 62-1, B-phase 67N element 62-
2. The signal of the C-phase 67N element 62-3 is
-1, 63-2, 63-3, and obtains signals AB, BC, CA as outputs. (2) These signals are input to the OR circuit 64, and the output signal and the zero-phase current I061 are input to the AND circuit 63-4.

(3) The output signal, the output signal from the 1-wire (1φG) failure phase determination element 60, and the A-phase 67N element 6
2-1, B phase 67N element 62-2, C phase 67N element 62
-3 is input to the AND circuits 63-5, 63-6, 63-7. (4) One of the outputs 65, 66, 67 is one line (1φ
It is determined to be a signal indicating a failure phase for the forward failure in G). (5) In response to this signal, it becomes possible to lock the operation of the phase not including the failed phase.

By adding the negative phase element determination, not only the failure phase but also the forward failure can be limited, so that a more reliable determination can be made.

[0078]

As described above, according to the present invention, a faulty phase can be reliably selected.

[Brief description of the drawings]

FIG. 1 is a flowchart of a distance relay device according to Embodiment 1 of the present invention.

FIG. 2 is a flowchart showing specific processing of fault phase selection of the distance relay device according to Embodiment 1 of the present invention.

FIG. 3 is a flowchart showing specific processing of fault phase selection of a distance relay device according to Embodiment 2 of the present invention.

FIG. 4 is a flowchart showing a specific process of fault phase selection of a distance relay device according to Embodiment 3 of the present invention.

FIG. 5 is a sequence diagram showing a process of selecting a failure phase of the distance relay device according to Embodiment 4 of the present invention.

FIG. 6 is a flowchart showing specific processing of fault phase selection of a distance relay device according to Embodiment 4 of the present invention.

FIG. 7 is a flowchart showing specific processing of fault phase selection of a distance relay device according to Embodiment 5 of the present invention.

FIG. 8 is a vector diagram illustrating characteristics of Vφ and V2φ of a distance relay device according to Embodiment 6 of the present invention.

FIG. 9 is a flowchart showing specific processing of fault phase selection of a distance relay device according to Embodiment 6 of the present invention.

FIG. 10 is a sequence diagram showing a fault phase selection process of the distance relay device according to the seventh embodiment of the present invention.

FIG. 11 is a block diagram of a conventional distance relay device.

[Explanation of symbols]

7-1 Phase A short-circuit undervoltage relay element, 7-2 Phase B short-circuit undervoltage relay element, 7-3 Phase C short-circuit undervoltage relay element, 8-1 A-phase ground fault undervoltage relay element Electric element, 8-2
B-phase ground-fault undervoltage relay element, 8-3 C-phase ground-fault undervoltage relay element, 9-1 to 9-6 operating phase voltage preservation processing, 10 ground-fault zero-phase overcurrent relay element, 11 ~ 1
4, 18 Checking process of operating phase, 15-17 Selecting process of faulty phase, 19-21 Locking process of healthy phases other than faulty phase, 22 Interphase voltage calculation process, 23
Comparison judgment of VAB and VBC, comparison judgment of 24 VAB and VCA, 25 comparison judgment of VBC and VCA, 2
6 Comparison judgment between VA and VB, 27 VB and V
C comparison judgment, 28 VA and VC comparison judgment,
29 Comparison judgment between VA and VB, 30 Comparison judgment between VA and VC, 31 Comparison judgment between VB and VC, 32
1φG failure phase judgment processing, 33 zero-phase current, 3
4 A phase impedance, 35 B phase impedance, 36 C phase impedance, 37
2φG, 2φS failure phase determination processing 38-1 to 38-13
AND circuit, 39 NOT circuit, 40 OR circuit,
41 1φG phase A fault phase signal,
42 1φG B-phase fault phase signal, 43 1φG C-phase fault phase signal, 44 2φS AB-phase fault phase signal, 45 2φS BC-phase fault phase signal, 46 2
φS CA phase failure phase signal, 47 2φG AB phase failure phase signal, 482 φG BC phase failure phase signal, 49
2φG CA phase failure phase signal, 50 ZA and ZB comparison decision, 51 ZA and ZC comparison decision, 52
ZB and ZB comparison judgment, 53 ZAB and ZB
C comparison judgment, 54 ZAB and ZCA comparison judgment,
55 Comparison between ZBC and ZCA, 56 Vφ and V
2φ phase angle difference calculation processing, 57 A phase angle difference comparison, 58 B phase angle difference comparison, 59 C
Phase phase angle difference comparison determination, 601 φG failure phase determination processing, 61 zero-phase current, 62-1 A-phase forward element signal, 62-2 B-phase forward element signal, 62-
3 C-phase forward direction element signal, 63-1 to 63-7A
ND circuit, 64 OR circuit, 65
A phase failure phase signal, 66 B phase failure phase signal,
67 C phase failure phase signal

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takashi Hattori 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation F-term (reference) 2G014 AA03 AA04 AA19 AB33 AC18 2G028 AA05 BF03 CG08 DH01 GL04 MS01 2G033 AA02 AB05 AC02 AC04 AC06 AD11 AD18 AE06 AF01 AF05 AG12 AG14 5G058 EE01 EF02 EF03 EG15 EH01 EH02

Claims (8)

[Claims] In a distance relay device for protecting a three-phase AC power system, a ground fault distance relay element of each phase, a short-circuit distance relay element of each phase, a zero-phase overcurrent relay element, Deriving means for deriving each phase voltage according to the operation of the ground fault distance relay element or the short-circuit distance relay element;
One or two elements operate and the zero-phase overcurrent relay element operates, or one or two of the short-circuit distance relay elements operate and the zero-phase overcurrent When the relay element does not operate, a determining means for determining a phase having the smallest voltage among the inter-phase voltages derived by the deriving means as a failure phase for a two-wire fault is provided. Electrical equipment. 2. A distance relay device for protecting a three-phase AC power system, wherein a ground fault distance relay element of each phase, a short-circuit distance relay element of each phase, a zero-phase overcurrent relay element, Deriving means for deriving each phase voltage according to the operation of the ground fault distance relay element or the short circuit distance relay element; one or two elements of the ground fault distance relay element operate; When the phase overcurrent relay element operates, or when one or two of the short-circuit distance relay elements operate and the zero-phase overcurrent relay element does not operate, the derivation means A distance relay device comprising: a determining unit that determines a phase of the largest voltage among the derived phase voltages as a healthy phase for a two-wire failure and determines a phase other than the healthy phase as a failed phase. . 3. A distance relay device for protecting a three-phase AC power system, wherein a ground fault distance relay element of each phase, a short-circuit distance relay element of each phase, a zero-phase overcurrent relay element, Deriving means for deriving each phase voltage according to the operation of the ground fault distance relay element or the short circuit distance relay element; one or two elements of the ground fault distance relay element operate; When the phase overcurrent relay element operates, or when one or two of the short-circuit distance relay elements operate and the zero-phase overcurrent relay element does not operate, the derivation means A distance relay device comprising: a determination unit configured to determine a phase having the smallest voltage among the derived phase voltages as a failure phase for a one-line failure. 4. A distance relay device for protecting a three-phase AC power system, wherein a ground fault distance relay element of each phase, a zero-phase overcurrent relay element, and an operation of the ground fault distance relay element. Deriving means for deriving the amount of impedance of each phase accordingly, and when one or two elements of the ground fault distance relay element operate and the zero-phase overcurrent relay element operates, A distance relay device comprising: a determination unit configured to determine a phase having the smallest impedance amount among the derived phase impedance amounts as a failure phase due to a one-line failure. 5. A distance relay device for protecting a three-phase AC power system, wherein a short-circuit distance relay element of each phase, a zero-phase overcurrent relay element, and an operation of the short-circuit distance relay element are performed. Deriving means for deriving the amount of short-circuit impedance between the phases, and when one or two of the short-circuit distance relay elements operate and the zero-phase overcurrent relay element does not operate, A distance relay device comprising: a determination unit configured to determine a phase having a smallest short-circuit impedance amount among the derived phase short-circuit impedance amounts as a failure phase for a two-wire failure. 6. A distance relay device for protecting a three-phase AC power system, wherein a ground fault distance relay element of each phase, a short-circuit distance relay element of each phase, a zero-phase overcurrent relay element, Deriving means for deriving the phase angle difference between the positive-phase voltage and the negative-phase voltage for each phase according to the operation of the ground fault distance relay element or the short-circuit distance relay element, and When one or two elements operate and the zero-phase overcurrent relay element operates, or one or two elements of the short-circuit distance relay element operate and the zero-phase overcurrent relay element operates; When the current relay element does not operate, a discriminating means is provided for discriminating the phase as a failure phase for a one-line fault if the phase angle difference for each phase derived by the deriving means is near 180 degrees. A distance relay device, characterized in that: 7. The distance relay device according to claim 3, wherein a forward direction element is provided, and when the forward direction element operates, a failure phase is determined by a determination unit. A distance relay device for determining a failure phase of a one-line failure based on a forward failure. 8. The distance relay device according to claim 1, wherein when a failure phase is determined by the determination means, an operation of a phase other than the failure phase is locked. Distance relay device.