JPH06303720A - Fault point locating apparatus - Google Patents

Abstract

PURPOSE:To accurately determine the distance of a fault point by deciding and executing whether a channel branching load compensation is executed or not by an identifying means, and then determining the distance to the point by a fault point locating means by a Z0 system. CONSTITUTION:When a ground-fault accident occurs, a ground-fault direction relay 11 is operated by a channel current/voltage of an FL installation terminal to drive auxiliary timers 12, 12', and a one-shot multivibrator 13 outputs to AND gates 14, 14' when the relay 11 is reset by a grip of a circuit breaker. In the case of a serial trip, an inhibiting means 15 is operated to inhibit a branch load compensating means 16 by a serial trip identification signal X from the gate 14, while in the case of a trip by a ground-fault direction relay DG, a branch load compensating means 16 is operated by a trip identification signal Y from the gate 14' to convert a current flowing to a fault channel only to a fault current. Then, a fault point locating means of a Z0 system is operated to obtain an impedance to a fault point F, thereby calculating to obtain the distance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fault point evaluation device having a high resistance grounding system multi-terminal parallel two-line system countermeasure.

[0002]

2. Description of the Related Art In general, a failure point rating device (hereinafter simply referred to as "fault point rating device (FL)") having a high resistance grounding system multi-terminal parallel two-line system countermeasure has a multi-terminal parallel two-line system. When a one-line ground fault occurs, (1). The impedance to the fault point is measured using the line voltage and line current of its own terminal, and the distance to the fault point is calculated from the known impedance per unit length. Zg method ".) (2). Failure of parallel 2 lines and healthy line (zero phase)
A zero-phase-difference current calculation method (hereinafter simply referred to as “Io method”) for calculating the distance from the current ratio to the failure point is applied.

FIG. 1 shows a rating system of a conventional fault point rating device (FL) adapted to a three-terminal parallel two-line system of a high resistance grounding system. The fault point rating device (FL) (3) It shows a case of a one-line ground fault at a point F farther from the branch point (5) when viewed from the A terminal (s / s) which is the installation end of the.

In FIG. 1, 1 is an AC power source,
It is grounded through the high resistor (2) and constitutes a three-terminal power system having A, B, C terminals (s / s). In addition, each terminal A, B,
A circuit breaker (CB) (6) is installed at each of the C terminals (s / s). And this electric power system is A terminal (s /
s) -branch point (5) consists of parallel two-line power transmission line consisting of impedance Z1, and impedance between the partner terminal combined bus (4) and branch point (5) -C terminal (s / s). It consists of a single-line transmission line consisting of Z2.

Now, as seen from the A terminal (s / s), which is the installation end of the failure point rating device (FL) (3), the F far from the branch point (5)
When a one-line ground fault occurs at a point, the fault point rating device (FL) (3) uses the Zg method to divide the fault (electric phase) current If into each line (1L, 2L). Since the current flows by 1 / 2.If, the impedance value to the fault point F calculated from the line voltage / current of the A terminal (s / s) is approximately doubled, resulting in double distance evaluation. Further, in the Io method, since the failure (zero phase) currents of both lines (1L, 2L) are equal, it is considered as a failure of the partner terminal combined bus (4), which causes a problem that distance evaluation becomes impossible. .

Therefore, conventionally, a fault point evaluation device (FL) has been used.
When viewed from the A terminal (s / s) which is the installation end of (3), there is a failure far from the branch point 5 and a failure before the branch point (5) at the installation end of the failure point rating device (FL) (3). Paying attention to the difference in trip time of the circuit breaker (6a) at a certain A terminal (s / s), the data immediately before the FL built-in relay (ground fault direction relay (DG)) is reset and the built-in relay (DG) ), The auxiliary timer (DGT) is used to drive the Io system and the Zg system.

[0007]

However, in the Io method, since the distance to the failure point is obtained from the ratio of the failure (zero-phase) currents of the parallel two failed circuits and the sound circuit, a highly accurate evaluation can be performed in principle. However, it has a drawback that it cannot be used when operating one line of two parallel lines, and the Zo method has a drawback that the following rating error occurs.

In the system shown in FIG. 1, the A terminal (s / s)
When a one-line ground fault occurs at point F beyond the branch point (5), the line (1L, 2L) is already branched to the B terminal (s / s) via the partner terminal combined bus (4). Load current i
Therefore, in the Zg method in such a system, the current flowing from the A terminal (s / s) to each line (1L, 2L) is the fault current (If / 2) and the branch load current (i / 2). ) Is added, the impedance obtained by the voltage and current of each line (1L, 2L) is smaller than the impedance up to the actual failure point F, so that an error occurs in the distance evaluation. Therefore, as a countermeasure, a means (hereinafter, referred to as "branch load compensation") for setting a branch load capacity in advance and subtracting the branch load current (i) from the fault current of each line phase of the A terminal (s / s) is used. Although it is used, the fault point evaluation device (FL) applied to the 3-terminal 2-line system shown in FIG. 1 has the FL installation terminal (A s / s) in the case of a fault beyond the branch point (5).
Since the trip of the circuit breaker (6a) of 6 may be the last of the series trips that sequentially trip from the line breakers (6b, 6c) of the terminals (B, Cs / s) close to the ground fault point F,
The data just before this series trip (immediately before the recovery of the FL built-in relay DG) shows that the branch load current i at the branch point (5) is zero (i / 2
= 0), an error will occur if the branch load current compensation is performed as it is. On the other hand, it is necessary to perform branch load compensation in the case of single line operation that does not result in series trip.

Therefore, in the present situation, whether or not to perform branch load compensation must be determined only by the presence or absence of input of a set value of the branch load current, and must be divisible by either operation. The rating device (FL) has a drawback that it is not possible to accurately assess the distance of a failure point, and therefore, there is a problem that quick failure recovery of the system cannot be performed. The present invention has been made to solve the above problems.

[0010]

[Means and Actions for Solving the Problems] First and second auxiliary timers (DGT) driven by the operation of a ground fault direction relay (DG) with a built-in fault point evaluation device (FL) are installed, and first The auxiliary timer (DGT1) of the above is set to the series trip time limit by the existing line selection relay (SG), and the second auxiliary timer (DGT2) is set to the ground fault direction relay (DG).
A trip means for performing a trip time limit according to the above, and a discriminating means for discriminating which of the first and second auxiliary timers (DGT) the trip of the circuit breaker (SG) at the FL installation end has been performed, After determining and executing whether or not the line branch load compensation is performed by the determination means, the distance to the failure point is evaluated by the failure point evaluation means by the Zo method.

[0011]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 2 shows a fault point evaluation device (FL) of the present invention.
Is a multi-terminal parallel two-line system of a high resistance grounding system for evaluating the ground fault point by applying the above.

This multi-terminal parallel two-line system is a high resistor
AC power source grounded via (2) (1) Supply terminal A terminal (s / s) and B terminal, which are the installation ends of the failure point rating device (3)
(s / s), C terminal (s / s), D terminal (s / s) and E terminal (s / s).

Each terminal (s / s) has a circuit breaker (C
B) A load (L) is connected via (6).

The setting of the line selection relay (SG, not shown) recognizes the branch load of the parallel two lines (1L, 2L) protected by the line selection relay (SG), that is, a failure (accident). It is set by adding the branch load current to the current.

Table 1 shows the order of trips due to the ground fault section and the fault elimination time at the A terminal (s / s) in the multi-terminal parallel two-line system of the high resistance grounding system shown in FIG.
It indicates the trip time.

In the high resistance grounding multi-terminal parallel two-line system shown in FIG. 2, the F1 of the section (a) near the A terminal (s / s) is now.
When a one-line ground fault occurs at a point, an excessive fault current flows in the fault line 2L of the A terminal (s / s), and the existing line selection relay (SG, not shown) is set to the breaking current value. , And the malfunction prevention timer (SGT, for example, settling for 60 ms, not shown) operate, and as shown in Table 1, after “60 ms second + α” elapses, the circuit breaker (6a) trips and the fault point F1 Is disconnected from the AC power source (1). When the fault point F1 is disconnected, the sneak fault current flows from the AC power supply (1) through the sound line (1L) and is superimposed on the branch load current of each terminal (s / s), so that each terminal (s / s) ) Current rapidly increases, and the line breaker (6b) at the B terminal (s / s) and the line breaker (6c) at the C terminal (s / s) near the fault point F1 sequentially trip.

After that, if the line current rises and the branch line current at the lower terminals D and E (s / s) reaches the set breaking current value, the circuit of the D and E terminals (s / s). Circuit breaker (6
d, 6e) are also tripped in sequence.

Next, if a one-line ground fault occurs at point F2 in the intermediate section (b) between the A terminal (s / s) and the B terminal (s / s), A
Since a fault current flows in the branch line of the terminal (s / s) and B terminal (s / s), the line selection relay (SG, not shown) and malfunction prevention timer (SGT, not shown) already installed on both terminals. Is activated, and as shown in Table 1, “(60ms + α)” and “(60ms +
β) ”, the circuit breakers (6a, 6b) trip almost at the same time and disconnect the fault point F2. After that, C terminal (s /
The branch line current of s) rises due to the sneak fault current from the healthy line (1L) and the line breaker (6c) already installed at the terminal trips, and the other terminals D (s / s), E (s / Similarly, the line breakers (6d, 6e) in (s) also trip due to the magnitude of the fault-current healthy line sneak current.

Next, F3 in the section (c) near the B terminal (s / s)
If a one-line ground fault occurs at a point, a fault current will flow in the branch line of the B terminal (s / s).
s) As shown in Table 1, after the existing line selection relay (SG, not shown) and malfunction prevention timer (SGT, not shown) are activated, the line breaker (6b) )
Will trip. After the circuit breaker (6b) of the B terminal (s / s) trips, all the fault current flowing to the fault point F3 flows through the fault circuit (2L) of the A terminal (s / s). / s) The line current rises and the line selection relay (SG, not shown) and the malfunction prevention timer (SG) already installed at the terminal.
(T, not shown) operates and the line breaker (6a) trips in series after "60 ms + α", that is, after "120 ms + α + β" has passed since the occurrence of the ground fault. Almost at the same time, C terminal
The branch line current at the (s / s) terminal is also a sneak fault current from the healthy line (1L), and after "60ms + γ" has passed,
That is, the circuit breaker (6e) trips in series after “120 ms + β + γ” has elapsed since the occurrence of the ground fault accident.

Next, if a one-line ground fault occurs at point F4 in the intermediate section (d) between the B terminal (s / s) and the C terminal (s / s), B
The line breakers (6b, 6c) of the terminal (s / s) and C terminal (s / s) trip almost simultaneously after "60ms + β" and "60ms + γ", respectively. If those line breakers (6b, 6c) trip, the fault current will flow through the fault line (2L) at the A (s / s) end, so the line current of the A terminal (s / s) will rise. Then, after the circuit breaker (6a) of the terminal has passed "60ms + α", that is, "120ms + α + β" after the occurrence of the ground fault.
Series trips after a lapse of time.

Furthermore, a section far from the A terminal (s / s) (e)
If a one-line ground fault occurs at F5 point of the, the line breaker (6c, 6) of C terminal (s / s) and D terminal (s / s) near the fault point F5
d) trips first. After that, the branch line current of the B terminal (s / s) increases and the line breaker (6b) of the B terminal (s / s)
Connected in series, and then the A terminal (s / s) circuit breaker
(6a) trips in series.

As shown in Table 1, the trip of the circuit breaker 6a of the A terminal (s / s) is as follows: When the fault section is (c) or (d), the fault elimination time is "(60ms + β) + (60ms + α). ) = 120 + α
In the case of (e) section, the trip is the second with "+ β", and the fault elimination time is "(60ms + γ) + (60ms + β) + (60ms + α) = 1
The trip is the third with "80 + α + β + γ", and both are so-called "series trips".

The fault point evaluation device (FL) (3) installed at the A terminal (s / s) has a fault (zero phase) that flows when a ground fault occurs.
The current is measured by the current transformer for instrument (7a), and the distance of the fault point F is evaluated by the above-mentioned Zg method. Distance evaluation by this Zg method calculates the line impedance up to the fault point F based on the line voltage / current of the A terminal (s / s) at the time of a ground fault and compares it with the known line impedance per unit. It is to evaluate. Therefore, the line current measurement in the Zg method is
As described above, an error will occur in the distance evaluation unless the failure current alone is used.

The failure point rating device (FL) of the present invention which does not cause a rating error will be described below with reference to Table 1.

When a ground fault occurs in the sections (a) and (b), the current flowing through the failure line (2L) of the A terminal (s / s), which is the installation end of the failure point evaluation device (3), fails. Since it is only the current If, the size of the line current (only the fault current) flowing within the time (60ms + α) until the line breaker (6a) of this fault line (2L) trips is measured and the distance is evaluated. If you do, there will be no distance evaluation error.

Next, when the ground fault accident occurs in the section (C), the B terminal (s / s) is connected to the failure line (2L) of the A terminal (s / s) which is the installation end of the failure point evaluation device 3. s) branch load current (i)
Therefore, in order to measure only the fault current If and perform the distance evaluation without causing the evaluation error, the above “branch load compensation” must be executed, but the line breaker (6a)
The current flowing in the fault line (2L) immediately before the trip is the fault current I at the time of series trip by the line selection relay (SG).
It is not possible to determine whether it is only f or a fault current including a branch load current at the time of a trip by the ground fault direction relay (DG). If branch load compensation is performed unnecessarily, a distance evaluation error will occur.

This is the same when the ground fault accident occurs in the sections (d) and (e), and the installation end A of the distance rating device 3
B (s / s), C (s / s), D are connected to the faulty line (2L) of the terminal (s / s).
Since the branch load current (i) to (s / s) and the E terminal (s / s) flows, if branch load compensation is performed unnecessarily, a distance evaluation error will occur.

Therefore, the failure point rating device (FL) of the present invention.
Indicates whether the trip of the circuit breaker (6a) at the terminal (s / s) that is the FL installation end is a series trip due to the line selective relay (SG) or a trip due to the ground fault direction relay (DG) with built-in FL. It is determined that the branch load is compensated for the current flowing through the fault circuit immediately before the trip only in the latter case, that is, only when the trip is caused by the ground fault direction relay (DG).

FIG. 3 shows a fault point evaluation device (F) of the present invention.
It is a block diagram which shows the Example of L).

In the figure, reference numeral 11 is a built-in ground fault relay (DG) which is built in the FL, which is activated by a one-line ground fault in the system and is restored by a fault current interruption due to a trip of a circuit breaker (CB, not shown), 12 is set time T1 ((120ms + α
+ Β) ∧T1∧ (180ms + α + β + γ)) and is driven by the operation of the ground fault direction relay (DG), an auxiliary timer (67GT1), 12 'is set time T2 (T2> (180ms +
α + β + γ)), and an auxiliary timer (DGT2) driven by the operation of the ground fault direction relay (DG), 13 is a one-shot multi that operates when the ground fault direction relay (DG) returns, 14 is a line disconnection AND circuit which outputs the discrimination signal X for discriminating that the trip of the circuit breaker (CB) is a series trip by the line selective relay (SG), and 14 'is the trip of the circuit breaker CB is the ground fault direction relay (with the FL built-in). DG)
AND circuit for outputting a discrimination signal Y for discriminating that the trip is caused by the above, 15 is prohibiting means for prohibiting branch load compensation by parallel 2 line branch, 16 is compensating means for performing branch load compensation by parallel 2 line branch, 17 Is a failure point evaluation means for calculating the distance to the failure point by the Zo method.

Now, when a one-line ground fault occurs in the multi-terminal two-line system shown in FIG. 2, the FL installation terminal A terminal (s /
The ground current direction relay (11) which is a FL built-in relay is activated by the line current and voltage of (s). The operation of the ground fault direction relay (11) drives the auxiliary timers (12, 12 ') set to the set times T1 and T2, respectively. Due to the trip of the circuit breaker (6a) of the A terminal (s / s), an output is generated from the one-shot multi (13) when the ground fault direction relay (11) is restored, and the AND circuit (14, 14 ' ). AND circuit
At (14, 14 '), the trip of the circuit breaker (6a) is set at the set time T1 by taking the logical product of the output of the auxiliary timer (12, 12') and the output of the one-shot multi (13). Alternatively, it is possible to determine whether the operation is performed within T2, and the logical product circuit (1
The serial trip determination signal X or the normal trip determination signal Y is output from 4) or (14 '). That is,
In the multi-terminal parallel two-line system shown in Fig. 2, if the trip of the circuit breaker (6a) of the A terminal (s / s), which is the FL installation terminal, may be a series trip, the above consideration is required. As is clear from Table 1, the fault elimination time (T1, trip time) in the case of the one-line ground fault in the sections (C), (D), and (E) is as shown in Table 1. (120m
s + α + β) <T1 (180 ms + α + β + γ) ”, it can be determined that the line breaker (6a) of the A terminal (s / s) trips within the time T1 is a“ series trip ”. Also, the trip of the circuit breaker (6a) of the A terminal (s / s) is similar to the section (C), (D),
(E) The trip time (fault removal time) due to the one-line ground fault accident is the time T2 (“T2> (180 ms + α + β +
.gamma.) "), it can be determined that the trip is not the" series trip "but the relay having the FL built-in relay (11, DG).

A circuit breaker (6) for A terminal (s / s) installed on the FL
When a) is a series trip by a line selection relay (SG, not shown), the prohibiting means (15) operates and the branch load compensating means (16) is generated by the series trip determination signal X from the AND circuit (14). In addition, the failure point evaluation means of the Zo system is operated, the impedance to the failure point (F) is obtained, and the distance from the impedance to the failure point (F) is calculated.

Further, when the line breaker (6a) of the A terminal (s / s) installed in the FL is tripped by the ground fault direction relay (11, DG) built in the FL, the AND circuit (14 ') The branch load compensation means (16) is operated by the trip determination signal Y to perform branch load compensation by branching in two parallel lines, and FL
Convert the current flowing in the faulty line of the installation terminal (A (s / s)) into only the "faulty current" and activate the fault point evaluation means by the Zo method to obtain the impedance to the fault point (F). The distance from the impedance to the failure point (F) is calculated and obtained.

[0035]

As described above, according to the present invention, the auxiliary timer of the ground fault direction relay (DG) which is the FL built-in relay.
By properly setting (DGT), it is possible to determine whether the trip at the FL installation end is a series trip by the existing line selection relay (SG) or a trip by the ground fault direction relay (DG) from another device. Since it can be accurately recognized without taking in the condition of, the branch load compensation can be properly performed, the distance of the failure point can be evaluated with high accuracy, and it can be useful for prompt failure recovery. it can.

By setting the auxiliary timer (DGT) to be variable, it is possible to flexibly cope with various multi-terminal two-line systems.

[Brief description of drawings]

FIG. 1 Conventional high resistance grounding system fault point rating device (FL)
3-terminal 2-line system diagram to explain the rating system

FIG. 2 is a high resistance grounding system fault point evaluation device (F of the present invention).
Multi-terminal two-line system diagram to explain L) rating method

FIG. 3 is a high resistance grounding system fault point rating device (FL) of the present invention.
Block diagram showing an embodiment of

[Explanation of symbols]

 1 AC power source 2 High resistor 3 Fault point rating device (FL) 4 Bus line with other terminal 5 Branch point 6 Circuit breaker (CB) 7 Current transformer for line current measurement 8 Branch load 11 FL built-in relay (ground fault direction) Relay DG) 12 Auxiliary timer of ground fault direction relay-13 One shot multi 14 Logical product (AND) means 15 Branch load compensation prohibition means 16 Branch load compensation means 17 Zo method Failure point evaluation means

[Procedure amendment]

[Submission date] August 19, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

[Title of Invention] Fault Locator

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fault point locating device having a high resistance grounding system multi-terminal parallel two-line system countermeasure.

[0002]

2. Description of the Related Art In general, a fault point locating device (hereinafter simply referred to as "fault point locating device (FL)") having a high resistance grounding system multi-terminal parallel two-line system countermeasure is provided in a multi-terminal parallel two-line system. When a one-line ground fault occurs, (1). The impedance to the fault point is measured using the line voltage and line current of its own terminal, and the distance to the fault point is calculated from the known impedance per unit length. Zg method ".) (2). Failure of parallel 2 lines and healthy line (zero phase)
A zero-phase-difference current calculation method (hereinafter simply referred to as “Io method”) for calculating the distance from the current ratio to the failure point is applied.

FIG. 1 shows a conventional fault point locating device (FL) locating system adapted to a high resistance grounding three-terminal parallel two-line system. The fault locating device (FL) (3) is shown in FIG. It shows a case of a one-line ground fault at a point F farther from the branch point (5) when viewed from the A terminal (s / s) which is the installation end of the.

In FIG. 1, 1 is an AC power source,
It is grounded through the high resistor (2) and constitutes a three-terminal power system having A, B, C terminals (s / s). In addition, each terminal A, B,
A circuit breaker (CB) (6) is installed at each of the C terminals (s / s). And this electric power system is A terminal (s /
s) -branch point (5) consists of parallel two-line power transmission line consisting of impedance Z1, and impedance between the partner terminal combined bus (4) and branch point (5) -C terminal (s / s). It consists of a single-line transmission line consisting of Z2.

Now, as seen from the A terminal (s / s) which is the installation end of the fault point locator (FL) (3), the F far from the branch point (5)
When a one-line ground fault occurs at a point, the fault point locator (FL) (3) is the orientation method, and in the Zg method, the fault (zero phase) current If is shunted to each line (1L, 2L). Since the current flows by 1/2 ・ If, the impedance value to the fault point F calculated from the line voltage / current of the A terminal (s / s) is approximately doubled, resulting in double distance localization. Also, in the Io method, since the failure (zero phase) currents of both lines (1L, 2L) are equal, it is considered as a failure of the partner terminal combined bus (4), and there is a problem that distance localization becomes impossible. .

Therefore, conventionally, a fault point locating device (FL) has been used.
When viewed from the A terminal (s / s), which is the installation end of (3), there is a failure far from the branch point 5 and a failure before the branch point (5) at the installation end of the fault location device (FL) (3). Paying attention to the difference in trip time of the circuit breaker (6a) at a certain A terminal (s / s), the data immediately before the FL built-in relay (ground fault direction relay (DG)) is reset and the built-in relay (DG) ), The auxiliary timer (DGT) is used to drive the Io system and the Zg system.

[0007]

However, in the Io method, since the distance to the failure point is obtained from the ratio of the failure (zero-phase) currents of the parallel two failed circuits and the sound circuit, a highly accurate orientation can be performed in principle. However, it has a drawback that it cannot be used when operating one line of two parallel lines, and the Zo method has a drawback that the following orientation error occurs.

In the system shown in FIG. 1, the A terminal (s / s)
When a one-line ground fault occurs at point F beyond the branch point (5), the line (1L, 2L) is already branched to the B terminal (s / s) via the partner terminal combined bus (4). Load current i
Therefore, in the Zg method in such a system, the current flowing from the A terminal (s / s) to each line (1L, 2L) is the fault current (If / 2) and the branch load current (i / 2). ) Is added, the impedance obtained by the voltage and current of each line (1L, 2L) is smaller than the impedance up to the actual failure point F, so an error occurs in the distance localization. Therefore, as a countermeasure, a means (hereinafter, referred to as "branch load compensation") for setting a branch load capacity in advance and subtracting the branch load current (i) from the fault current of each line phase of the A terminal (s / s) is used. The fault location device (FL) applied to the 3-terminal 2-line system shown in FIG. 1 is used for the FL installation terminal (A s / s) in the case of a fault beyond the branch point (5).
Since the trip of the circuit breaker (6a) of 6 may be the last of the series trips that sequentially trip from the line breakers (6b, 6c) of the terminals (B, Cs / s) close to the ground fault point F,
The data just before this series trip (immediately before the recovery of the FL built-in relay DG) shows that the branch load current i at the branch point (5) is zero (i / 2
= 0), an error will occur if the branch load current compensation is performed as it is. On the other hand, it is necessary to perform branch load compensation in the case of single line operation that does not result in series trip.

Therefore, in the present situation, whether or not to perform branch load compensation must be determined only by the presence or absence of input of a set value of the branch load current, and must be divisible by either operation. The locating device (FL) has a drawback that it is not possible to accurately locate the distance of the failure point, and therefore, there is a problem that the failure of the system cannot be quickly restored. The present invention has been made to solve the above problems.

[0010]

First and second auxiliary timers (DGT) driven by the operation of a ground fault direction relay (DG) with a built-in fault location device (FL) are installed. The auxiliary timer (DGT1) of the above is set to the series trip time limit by the existing line selection relay (SG), and the second auxiliary timer (DGT2) is set to the ground fault direction relay (DG).
A trip means for performing a trip time limit according to the above, and a discriminating means for discriminating which of the first and second auxiliary timers (DGT) the trip of the circuit breaker (SG) at the FL installation end has been performed, After determining and executing whether or not the line branch load compensation is performed by the determining means, the distance to the fault point is determined by the fault point locating means by the Zo method.

[0011]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 2 shows a fault location device (FL) of the present invention.
Is a multi-terminal parallel two-line system of a high resistance grounding system for locating a ground fault point by applying.

This multi-terminal parallel two-line system is a high resistor
AC power source (1) grounded via (2) A terminal (s / s) and B terminal that are the installation terminals of the fault locator (1) supply terminal
(s / s), C terminal (s / s), D terminal (s / s) and E terminal (s / s).

Each terminal (s / s) has a circuit breaker (C
B) A load (L) is connected via (6).

The setting of the line selection relay (SG, not shown) recognizes the branch load of the parallel two lines (1L, 2L) protected by the line selection relay (SG), that is, a failure (accident). It is set by adding the branch load current to the current.

Table 1 shows the order of trips due to the ground fault section and the fault elimination time at the A terminal (s / s) in the multi-terminal parallel two-line system of the high resistance grounding system shown in FIG.
It indicates the trip time.

In the high resistance grounding multi-terminal parallel two-line system shown in FIG. 2, the F1 of the section (a) near the A terminal (s / s) is now.
When a one-line ground fault occurs at a point, an excessive fault current flows in the fault line 2L of the A terminal (s / s), and the existing line selection relay (SG, not shown) is set to the breaking current value. , And the malfunction prevention timer (SGT, for example, 60 ms settling, not shown) is activated, and as shown in Table 1, after “60 ms + α” elapses, the circuit breaker (6a) trips and the accident point F1 is switched to AC power. Disconnect from source (1). When the fault point F1 is disconnected, the sneak fault current flows from the AC power supply (1) through the sound line (1L) and is superimposed on the branch load current of each terminal (s / s), so that each terminal (s / s) ) Current rapidly increases, and the line breaker (6b) at the B terminal (s / s) and the line breaker (6c) at the C terminal (s / s) near the fault point F1 sequentially trip.

After that, if the line current rises and the branch line current at the lower terminals D, E terminals (s / s) reaches the set breaking current value, the circuit breaks at the D, E terminals (s / s). Bowl (6d,
6e) is also tripped in sequence.

Next, if a one-line ground fault occurs at point F2 in the intermediate section (b) between the A terminal (s / s) and the B terminal (s / s), A
Since a fault current flows in the branch line of the terminal (s / s) and B terminal (s / s), the line selection relay (SG, not shown) and malfunction prevention timer (SGT, not shown) already installed on both terminals. Is activated, and as shown in Table 1, “(60ms + α)” and “(60ms +
β) ”, the circuit breakers (6a, 6b) trip almost at the same time and disconnect the fault point F2. After that, C terminal (s /
The branch line current of s) rises due to the sneak fault current from the healthy line (1L) and the line breaker (6c) already installed at the terminal trips, and the other terminals D (s / s), E (s / Similarly, the line breakers (6d, 6e) in (s) also trip due to the magnitude of the fault-current healthy line sneak current.

Next, F3 in the section (c) near the B terminal (s / s)
If a one-line ground fault occurs at a point, a fault current will flow in the branch line of the B terminal (s / s).
s) As shown in Table 1, after the existing line selection relay (SG, not shown) and malfunction prevention timer (SGT, not shown) are activated, the line breaker (6b) )
Will trip. After the circuit breaker (6b) of the B terminal (s / s) trips, all the fault current flowing to the fault point F3 flows through the fault circuit (2L) of the A terminal (s / s). / s) The line current rises and the line selection relay (SG, not shown) and the malfunction prevention timer (SG) already installed at the terminal.
(T, not shown) operates and the line breaker (6a) trips in series after "60 ms + α", that is, after "120 ms + α + β" has passed since the occurrence of the ground fault. Almost at the same time, C terminal
The branch line current at the (s / s) terminal is also a sneak fault current from the healthy line (1L), and after "60ms + γ" has passed,
That is, the circuit breaker (6e) trips in series after “120 ms + β + γ” has elapsed since the occurrence of the ground fault accident.

Next, if a one-line ground fault occurs at point F4 in the intermediate section (d) between the B terminal (s / s) and the C terminal (s / s), B
The line breakers (6b, 6c) of the terminal (s / s) and C terminal (s / s) trip almost simultaneously after "60ms + β" and "60ms + γ", respectively. If those line breakers (6b, 6c) trip, the fault current will flow through the fault line (2L) at the A (s / s) end, so the line current of the A terminal (s / s) will rise. Then, after the circuit breaker (6a) of the terminal has passed "60ms + α", that is, "120ms + α + β" after the occurrence of the ground fault.
Series trips after a lapse of time.

Furthermore, a section far from the A terminal (s / s) (e)
If a one-line ground fault occurs at F5 point of the, the line breaker (6c, 6) of C terminal (s / s) and D terminal (s / s) near the fault point F5
d) trips first. After that, the branch line current of the B terminal (s / s) increases and the line breaker (6b) of the B terminal (s / s)
Connected in series, and then the A terminal (s / s) circuit breaker
(6a) trips in series.

As shown in Table 1, the trip of the circuit breaker 6a of the A terminal (s / s) is as follows: When the fault section is (c) or (d), the fault elimination time is "(60ms + β) + (60ms + α). ) = 120ms +
In the case of the (e) section, the trip is the second with "α + β", and the fault clearance time is "(60ms + γ) + (60ms + β) + (60ms + α)
= 180ms + α + β + γ ”trips third and both are so-called“ series trips ”.

The fault locator (FL) (3) installed at the A terminal (s / s) has a fault (zero phase) that flows when a ground fault occurs.
The current is measured by the current transformer (7a) for measuring instrument and the distance of the fault point F is determined by the above-mentioned Zg method. This Zg method locates the line impedance up to the fault point F based on the line voltage / current of the A terminal (s / s) at the time of a ground fault, and compares it with the known line impedance per unit. Orientation is performed. Therefore, the line current measurement in the Zg method is
As described above, if the fault current alone is not used, an error will occur in the distance localization.

The fault point locating device (FL) of the present invention in which no orientation error occurs will be described below with reference to Table 1.

When a ground fault occurs in the sections (a) and (b), the current flowing through the failure line (2L) of the A terminal (s / s), which is the installation end of the failure point locator (3), fails. Since only the current If is measured, the size of the line current (only the fault current) flowing within the time (60ms + α) until the line breaker (6a) of this fault line (2L) trips is measured and the distance is determined. If you do, no distance localization error will occur.

Next, when a ground fault occurs in the section (c), the B terminal (s / s) is connected to the failure line (2L) of the A terminal (s / s) which is the installation end of the failure point locating device 3. s) branch load current (i)
Therefore, in order to measure only the fault current If and to perform the distance orientation without causing the orientation error, the above-mentioned "branch load compensation" must be implemented, but the circuit breaker (6a)
The current flowing in the fault line (2L) immediately before the trip is the fault current I at the time of series trip by the line selection relay (SG).
It is not possible to determine whether only f or the fault current including the branch load current at the time of trip by the ground fault direction relay (DG) can be discriminated, and if the branch load compensation is performed unnecessarily, a distance localization error will occur.

This is the same when the ground fault accident occurs in the sections (d) and (e), and the installation end A of the distance locator 3 is
B (s / s), C (s / s), D are connected to the faulty line (2L) of the terminal (s / s).
Since the branch load current (i) to (s / s) and the E terminal (s / s) flows, if the branch load compensation is performed unnecessarily, a distance localization error will occur.

Therefore, the fault point locator (FL) of the present invention
Determines whether the trip of the circuit breaker (6a) at the terminal (s / s) that is the FL installation end is a series trip due to the line selective relay (SG) or a trip due to the ground fault direction relay (DG). In the latter case, that is, only when a trip occurs due to the ground fault direction relay (DG), branch load compensation is performed for the current flowing in the faulty circuit immediately before the trip.

FIG. 3 shows a fault point locating device (F
It is a block diagram which shows the Example of L).

In the figure, reference numeral 11 is a built-in ground fault relay (DG) which is built in the FL, which is activated by a one-line ground fault in the system and is restored by a fault current interruption due to a trip of a circuit breaker (CB, not shown), 12 is set time T1 ((120ms + α
+ Β) <T1 <(180ms + α + β + γ)), and the auxiliary timer (67GT1) driven by the operation of the ground fault direction relay (DG), 12 ′ is set time T2 (T2> (180ms +
α + β + γ)), and an auxiliary timer (DGT2) driven by the operation of the ground fault direction relay (DG), 13 is a one-shot multi that operates when the ground fault direction relay (DG) returns, 14 is a line disconnection AND circuit which outputs the discrimination signal X for discriminating that the trip of the circuit breaker (CB) is a series trip by the line selective relay (SG), and 14 'is the trip of the circuit breaker CB is the ground fault direction relay (with the FL built-in). DG)
AND circuit for outputting a discrimination signal Y for discriminating that the trip is caused by the above, 15 is prohibiting means for prohibiting branch load compensation by parallel 2 line branch, 16 is compensating means for performing branch load compensation by parallel 2 line branch, 17 Is a fault point locating means for calculating the distance to the fault point by the Zo method.

Now, when a one-line ground fault occurs in the multi-terminal two-line system shown in FIG. 2, the FL installation terminal A terminal (s /
The ground current direction relay (11) which is a FL built-in relay is activated by the line current and voltage of (s). The operation of the ground fault direction relay (11) drives the auxiliary timers (12, 12 ') set to the set times T1 and T2, respectively. Due to the trip of the circuit breaker (6a) of the A terminal (s / s), an output is generated from the one-shot multi (13) when the ground fault direction relay (11) is restored, and the AND circuit (14, 14 ' ). AND circuit
At (14, 14 '), the trip of the circuit breaker (6a) is set at the set time T1 by taking the logical product of the output of the auxiliary timer (12, 12') and the output of the one-shot multi (13). Alternatively, it is possible to determine whether the operation is performed within T2, and the logical product circuit (1
The serial trip determination signal X or the normal trip determination signal Y is output from 4) or (14 '). That is,
In the multi-terminal parallel two-line system shown in Fig. 2, if the trip of the circuit breaker (6a) of the A terminal (s / s), which is the FL installation terminal, may be a series trip, the above consideration is required. As is clear from Table 1, the fault elimination time (T1, trip time) in the case of the one-line ground fault in the sections (C), (D), and (E) is as shown in Table 1. (120m
s + α + β) <T1 <(180ms + α + β + γ) ”, it can be determined that the trip of the line breaker (6a) of the A terminal (s / s) within the time T1 is a“ series trip ”. In addition, the trip of the circuit breaker (6a) of the A terminal (s / s) also occurs in the sections (C), (D),
(E) The trip time (fault removal time) due to the one-line ground fault accident is the time T2 (“T2> (180 ms + α + β +
.gamma.) "), it can be determined that the trip is not the" series trip "but the relay having the FL built-in relay (11, DG).

A circuit breaker (6) for A terminal (s / s) installed on the FL
When a) is a series trip by a line selection relay (SG, not shown), the prohibiting means (15) operates and the branch load compensating means (16) is generated by the series trip determination signal X from the AND circuit (14). In addition, the fault point locating means by the Zo method is operated, the impedance to the fault point (F) is obtained, and the distance from the impedance to the fault point (F) is calculated and obtained.

When the line breaker (6a) of the A terminal (s / s) installed in the FL is tripped by the ground fault direction relay (DG), the trip judgment signal Y from the AND circuit (14 ') The branch load compensation means (16) is activated to perform branch load compensation by branching the two parallel lines, and the FL installation terminal (A (s /
s)) Converting the current flowing through the faulty circuit into "faulty current" only and activating the fault point locating means by the Zo method
The impedance to (F) is obtained, and the distance to the failure point (F) is calculated from the impedance.

[0035]

As described above, according to the present invention, the auxiliary timer of the ground fault direction relay (DG) which is the FL built-in relay.
By properly setting (DGT), it is possible to determine whether the trip at the FL installation end is a series trip by the existing line selection relay (SG) or a trip by the existing ground fault direction relay (DG). Since it can be accurately recognized without taking in the conditions from the above, branch load compensation can be carried out appropriately, distances of fault points can be located with high accuracy, and it is useful for prompt fault recovery. You can

By setting the auxiliary timer (DGT) to be variable, it is possible to flexibly cope with various multi-terminal two-line systems.

[Brief description of drawings]

FIG. 1 Conventional high resistance grounding system fault point locator (FL)
3-terminal 2-line system diagram to explain the orientation system

FIG. 2 is a high-resistance grounding system fault location device (F
Multi-terminal two-line system diagram to explain L) rating method

FIG. 3 is a high resistance grounding system fault point locator (FL) of the present invention.
Block diagram showing an embodiment of

[Explanation of symbols] 1 AC power source 2 High resistance 3 Fault point locator (FL) 4 Bus line with other terminal 5 Branch point 6 Circuit breaker (CB) 7 Current transformer for line current measurement 8 Branch load 11 FL built-in Relay (ground fault direction relay DG) 12 Auxiliary timer for ground fault direction relay-13 One-shot multi 14 Logical product (AND) means 15 Branch load compensation prohibition means 16 Branch load compensation means 17 Zo system fault point locating means

Claims (2)

[Claims] 1. A fault point evaluation device having a multi-terminal parallel two-line system countermeasure for a high resistance grounding system, which is a ground fault direction relay operated by a ground fault fault current, and is driven by the operation of the ground fault direction relay. A series trip time limit by a line selection relay at the fault point rating device installation end, and first and second auxiliary timers set at a trip time limit by the ground fault direction relay; and a return signal for the ground fault direction relay, A fault line current for which parallel two-line branch load compensation has been performed, or an impedance to a fault point is obtained based on the fault line current based on the result of the logical product of the settling time signals of the first and second auxiliary timers, A failure point evaluation device comprising: an evaluation unit that calculates a distance to a failure point; 2. A fault point evaluation device having a multi-terminal parallel two-line system countermeasure for a high resistance grounding system, comprising a ground fault direction relay operated by a ground fault fault current and driven by the operation of the ground fault direction relay. , A series trip time limit by a line selection relay at the fault point rating device installation end, and first and second auxiliary timers set at a trip time limit by the ground fault direction relay, and at the time of a return operation of the ground fault direction relay A one-shot multivibrator that obtains an output pulse; and a logical product means that obtains a first and a second output by performing a logical product of the output pulse of the one-shot multivibrator and each settling time output of the first and second auxiliary timers. The second output of the logical product means performs branch load compensation by the parallel two-line branch for the fault line current at the fault point rating device installation end. A branch load compensating means for performing the distance calculation to the fault point by a ground fault impedance computing method based on the fault line current at the terminal for installing the fault point rating device by the first output of the AND means; And a rating means for calculating a distance to a fault point by a ground fault impedance calculation method based on the fault line current in which the branch load compensation means has performed the branch load compensation by the second output of Failure point evaluation device.