JP2008161012A - Overcurrent relay device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an overcurrent relay device for power supply end and opposite end, capable of remarkably shortening a fault eliminating time. <P>SOLUTION: The overcurrent relay device 10<SB>1</SB>disposed on a power supply end of an own line 1L of a parallel dual power transmission line includes a trip signal generating circuit 20 for generating a first trip signal S<SB>1</SB>for interrupting a first breaker 4<SB>1</SB>provided on the power supply end side of the own line 1L when detecting a short circuit fault in the own line 1L. The trip signal generating circuit 20 includes an own line fault determining circuit 25 for obtaining a value calculated by dividing the difference between a first short circuit current I<SB>1</SB>and a second short circuit current I<SB>2</SB>by the sum of the first short circuit current I<SB>1</SB>and the second short circuit current I<SB>2</SB>, and outputting an output signal when the obtained value is not less than a determined value; and a AND circuit 23 for ANDing between an output signal of the own line fault determining circuit 25 and a second contact point signals S<SB>C2</SB>to be inputted from a second breaker 4<SB>2</SB>provided on the power supply end side of the other line 2L. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an overcurrent relay device, and more particularly to an overcurrent relay device suitable for installation on the power supply end side of a balanced two-line power transmission line.

In general, an overcurrent relay (OC) used for protection in the event of a short circuit in a power system is the magnitude of the amount of electricity (phase current) of its own line (the transmission line on which the overcurrent relay is installed). In order to determine the occurrence of a short-circuit accident based on the above, in order to determine the accident section, other overcurrent relay devices installed on the transmission line behind the opposite end (non-power supply) and time-coordinated (0.4 s ~ 0.5s).
Therefore, in the overcurrent relay device installed on the power supply end side of the own line, the accident elimination time becomes longer as will be described below, so the overcurrent relay device is used as a back-up protection in the balanced two-line transmission line. The accident removal time is shortened by installing a separate main protection relay device that is used and operates instantaneously due to a short circuit accident in the protection section.

As shown in FIG. 4, a first power transmission line 1L (hereinafter referred to as “own line 1L”) and a second power transmission line 2L (hereinafter referred to as “others”) branched from a bus line supplied with power from a power source 1. Overcurrent relay devices (hereinafter referred to as “first and second power supply end overcurrent relay devices 110 ₁ and 110 ₂ ”) are respectively provided on the power supply end side (bus side) of the line 2L ”. A short-circuit direction relay device (hereinafter referred to as “first and second opposite-end short-circuit direction relay device (DS) 120” is provided on the opposite end side (opposite side of the bus) of the own line 1L and the other line 2L. ₁ , 120 ₂ ”) are installed.

The first power supply overcurrent relay device 110 ₁ has a phase current (hereinafter referred to as “first short-circuit current”) input from the _first current transformer 3 ₁ installed on the power supply side of the own line 1L. ₁ ), the first trip signal S for breaking the _first circuit breaker 41 installed on the power supply end side of the own line 1L is detected. Generate ₁
The second power supply overcurrent relay device 110 ₂ is connected to a phase current (hereinafter referred to as “second short-circuit current I ₂ ”) input from a _second current transformer 3 ₂ installed in the other line 2L. 2), the second trip signal S ₂ for breaking the second circuit breaker 4 ₂ installed on the power supply end side of the other line 2L is generated. .

The first opposite-end short-circuit direction relay device 120 ₁ is connected to the line voltage V input from the instrument transformer 2 provided on the opposite-end bus (hereinafter referred to as “opposite-end bus”). Based on the phase current (hereinafter referred to as “third short-circuit current I ₃ ”) input from a _third current transformer 3 ₃ installed on the opposite end side of the line 1L, the current line 1L When the occurrence of a short circuit accident is detected, a third trip signal S ₃ for breaking the third circuit breaker 4 ₃ installed on the opposite end side of the own line 1L is generated.
The second opposite-end short-circuit direction relay device 120 ₂ includes a line voltage V input from the instrument transformer 2 and a fourth instrument current transformer 3 ₄ installed on the opposite end side of the other line 2L. When the occurrence of a short-circuit fault in the other line 2L is detected based on the input phase current (hereinafter referred to as “fourth short-circuit current I ₄ ”), a fourth installed on the opposite end side of the other line 2L. A fourth trip signal S ₄ for breaking the circuit breaker 4 ₄ is generated.

The first power supply overcurrent relay device 110 ₁ includes a trip signal generation circuit 130 as shown in FIG. 5 in order to generate the _first trip signal S ₁ .
Here, the trip signal generation circuit 130 includes a relay determination circuit 131 and a delay circuit (timer) 132.

The relay determination circuit 131 outputs a high-level first instantaneous element trip signal ST _a1 when it detects a short-circuit accident that has occurred within the instantaneous element operating range of its own line 1L based on the magnitude of the first short-circuit current I _1. At the same time, when a short-circuit fault occurring within the time-limit element operation range of the own line 1L is detected based on the magnitude of the first short-circuit current I ₁ , a high-level time-limit cutoff output signal is output to the delay circuit 132.
The delay circuit 132 generates a first time-limit elements trip signal ST _b1 by delaying the time-limit cutoff output signal of the relay determining circuit 131 only timed coordination time T1 _1. Here, timed coordination time T1 ₁ is set for the timed coordination with other overcurrent relay device installed in the transmission line opposite ends behind the own line 1L (not shown).
The first instantaneous element trip signal ST _a1 and the first time limit element trip signal ST _b1 are output to the _first circuit breaker 41 as the first trip signal S ₁ .

The second power supply terminal overcurrent relay device 110 ₂ includes a trip signal generation circuit (not shown) having the same configuration as the trip signal generation circuit 130 described above.

The first opposite-end short-circuit direction relay device 120 ₁ includes a trip signal generation circuit 140 as shown in FIG. 6 in order to generate a _third trip signal S ₃ .
Here, the trip signal generation circuit 140 includes a relay determination circuit 141 and a delay circuit (timer) 142.

Relay determining circuit 141 detects a short circuit accident occurs in the own line 1L based on the phase relation of the third magnitude of the short-circuit current I ₃ and the line voltage V and the third short-circuit current I _3, a high level Output the output signal.
The delay circuit 142 delays the output signal of the relay determining circuit 141 only timed coordination time T1 _3. Here, the time cooperation time T1 ₁ (for example, 400 ms) set in the delay circuit 132 shown in FIG. 5 is set to be longer than the time cooperation time T1 _{3 for} time cooperation (T1 ₁ > T1 ₃ ).
Note that the time-coordinated time T1 ₃ is set to 0 ms when there is no branch in the own line 1L. Therefore, the time-coordinated time T1 ₃ = 0 will be described below.

The second opposite-end short-circuit direction relay device 120 ₂ includes a trip signal generation circuit (not shown) having the same configuration as the trip signal generation circuit 140 described above.

If a short circuit accident occurs at time t ₀ shown in FIG. 7 within the time limit element operation range of the own line 1L that is the protection section of the first power supply overcurrent relay device 110 ₁ , the accident current (short circuit current) is Since the current flows toward the accident point as indicated by the broken arrow in FIG. 4, the _first to _fourth short-circuit currents I _{1 to} I ₄ flowing through the first to _fourth instrument current transformers 3 _{1 to} 3 ₄ respectively. The direction of is the direction indicated by the arrow in FIG. As a result, the first and second power source overcurrent relay devices 110 ₁ and 110 ₂ operate, and the direction of the third short-circuit current I ₃ is the same as the operation direction (internal direction). The end short-circuit direction relay device 120 ₁ operates.

Since the first opposing end short direction relay device 120 ₁ timed coordination time T1 ₃ as described above is set to 0ms, firstly, the first opposing end short direction relay device 120 ₁ is operated, blocking the third breaker 4 ₃ placed on the opposite end of its own line 1L. At this time, the third circuit breakers 4 _3, as shown in FIG. 7, a first time t ₁ the first opposing end short direction relay device 120 _first relay determination time T _RY (50 ms) has elapsed The circuit breaker is interrupted by the _third trip signal S ₃ output from the opposite-end short-circuit direction relay device 120 _1, but the third circuit breaker 4 ₃ is completely interrupted from time t ₂ The time t ₂ when T _CB (50 ms) has elapsed is reached.

When the third circuit breaker 4 ₃ is completely cut off at time t ₂ , the fault current (short-circuit current) flows only from the power supply end of the own line 1L toward the fault point (that is, as shown in FIG. 7). Since only the first short-circuit current I ₁ flows), only the first power supply end overcurrent relay device 110 ₁ continues to operate, and the first circuit breaker 4 ₁ installed on the power supply end side of the own line 1L. Shut off. At this time, the first circuit breaker 4 ₁ has passed the relay determination time T _RY (50 ms) and the time limit coordination time T1 ₁ (400 ms) of the first power supply overcurrent relay device 110 ₁ from the accident occurrence time t ₀ . The first circuit breaker is cut off by the first trip signal S ₁ (first time element trip signal ST _b1 ) output from the first power supply overcurrent relay device 110 ₁ at time t ₃ . 4 ₁ is completely cut off at time t ₄ when the circuit breaker breaking time T _CB (50 ms) has elapsed from time t ₃ .

In Patent Document 1 below, in order to easily realize protection coordination in the short-circuit region in multi-stage time difference settling, each of the instantaneous element determination unit and the time limit element determination unit operates on the current value of the current input unit. An overcurrent relay is disclosed in which the operation time characteristic is controlled by the operation determination unit in combination with the state of the operation characteristic switching means based on the signal from the determination unit.
The following Patent Document 2 includes an overcurrent relay that operates when a differential current flowing in a balanced two-line transmission line of a power system is equal to or greater than a predetermined value, and a short-circuit selection relay that inputs the differential current and the bus voltage, In the line selection relay device that selectively cuts off the accident line of the two-line transmission line, in order to prevent the circuit breaker trip signal from being erroneously output in the case of a rear failure in which circulating current flows through the balanced two-line transmission line due to a short circuit on the bus, First and second current direction relays for detecting the direction of current flowing in each line of the two-line power transmission line are provided, and when an AND condition is established for each output of the overcurrent relay, the short-circuit selection relay, and the first and second current direction relays A line selection relay device for tripping a circuit breaker is disclosed.
JP-A-8-205382 JP-A-6-022442

However, in the first power supply overcurrent relay device 110 ₁ described above, when a short circuit accident occurs within the time limit element operation range of the own line 1L, the first circuit breaker 4 ₁ starts from the accident occurrence time t _0. relay determination time T _RY, timed coordination time T1 ₁ and circuit breaker interrupting the total time of the time _{T CB (= 50ms + 400ms +} 50ms = 500ms) to be cut off at time t ₄ when has elapsed (see FIG. 7), to remove the short circuit However, there is a problem that it takes time and adversely affects the equipment.

  An object of the present invention is to provide an overcurrent relay device for a power supply terminal that can greatly reduce the accident removal time.

The first overcurrent relay device of the present invention is a balanced two-line transmission comprising a local line (1L) and another line (2L) laid between a power source end side bus and an opposing end side opposing end bus. An overcurrent relay device (10 ₁ ) installed on the power supply end side of the own line of the electric wire, and detecting a short-circuit accident in the own line, the own line provided on the power supply end side of the own line A trip signal generation circuit (20) for generating a trip signal (S ₁ ) for breaking the circuit breaker (4 ₁ ) is provided, and the trip signal generation circuit is directed from the power supply terminal of the own line toward the accident point. The difference between the flowing own line short-circuit current (I ₁ ) and the other line short-circuit current (I ₂ ) flowing from the power supply terminal of the other line toward the fault point, and the sum of the own line short-circuit current and the other line short-circuit current When a short circuit accident is detected based on the ratio, the trip signal is instantly generated. Characterized in that it comprises a trip signal generating means for.
Here, the trip signal generating means, the other line of the next line breaker installed in the power source terminal side (4 ₂₎ provided that the is not interrupted, short circuit in the self-line on the basis of the ratio When occurrence is detected, the trip signal may be generated instantaneously.
The trip signal generating means obtains a value obtained by dividing the difference between the own line short circuit current and the other line short circuit current by the sum of the own line short circuit current and the other line short circuit current, and the obtained value is a determination value. The logical product of the own line fault judgment circuit (25) that outputs an output signal as described above and the output signal of the own line fault judgment circuit and the contact signal (S _C2 ) input from the adjacent circuit breaker is calculated. And an AND circuit (23).
The determination value may be set to “1-X / 100” when an X% section from the power supply end to the opposite end of the own line is set as a time-reduced protection section.
The time-limited shortening protection section may be a section of 80 to 85% from the power supply end to the opposite end of the own line.
The other overcurrent relay device (10 ₂ ) installed on the power supply end side of the other line may have the same configuration as that of the overcurrent relay device and may be configured integrally.

The overcurrent relay device of the present invention has the following effects.
(1) The overcurrent relay device installed on the power supply end side of the balanced two-line transmission line has its own line short-circuit current flowing from the power supply end of the own line toward the fault point and from the power supply end of the other line to the fault point. When a short-circuit fault is detected based on the ratio of the difference between the short-circuit current of the other line that flows and the sum of the short-circuit current of the own line and the short-circuit current of the other line, a trip signal is instantly generated. Can be greatly shortened.
(2) Since the accident continuation time is also greatly shortened, adverse effects on the equipment at the time of the accident can be reduced.
(3) Since it is possible to omit the main protection relay device, the investment cost to the facility can be reduced.
(4) The difference between the short-circuit current of the own line and the short-circuit current of the other line alone is affected by the change in the power supply capacity behind the power supply terminal (the value of the short-circuit capacity expressed in% Z _at10MVABASE ). By using the ratio of the difference between the current and the sum of the short circuit current of the own line and the short circuit current of the other line, it is possible to determine the own line fault without being affected by the change in the power supply capacity behind the power supply end.

  Based on the ratio of the difference between the short-circuit current of the own line and the short-circuit current of the other line and the sum of the short-circuit current of the self-line and the short-circuit current of the other line. This was realized by generating a trip signal instantaneously when a short circuit accident was detected.

Embodiments of the overcurrent relay device of the present invention will be described below with reference to the drawings.
The overcurrent relay device of the present invention is an overcurrent relay device installed on the power supply end side of a balanced two-line transmission line, and when a short-circuit accident occurs, the fault current of the accident line at the power supply end of the balanced two-line transmission line Focusing on the fact that the ratio of (first short-circuit current I ₁ ) is larger than the ratio of fault current (second short-circuit current I ₂ ) of the healthy line, When a short-circuit fault is detected based on the ratio of the difference between the fault current and the fault current on the healthy line and the sum of the fault current on the fault line and the sum of the fault current on the healthy line (the former divided by the latter), the trip signal is instantaneously It is characterized by occurring.

Therefore, the first power supply terminal overcurrent relay device 10 ₁ (overcurrent relay device according to one embodiment of the present invention) shown in FIG. 1 is installed on the power supply terminal side of the other line 2L, which is a healthy line. 2 of the circuit breaker 4 ₂ is not interrupted, and (1) when it detects a short circuit occurs in its own line 1L with accident circuits based on the own line accident determination condition shown in the expression first trip signals S ₁ Is different from the conventional first power supply overcurrent relay device 110 _{1 shown} in FIG.
(I ₁ −I ₂ ) / (I ₁ + I ₂ ) ≧ 0.2 (1)
Here, the determination value on the right side of the equation (1) is determined by the time-reduced protection section (that is, the range of the own line 1L that instantaneously generates the _first trip signal S1 with respect to the short circuit accident), and the own line 1L When the section of X% from the power supply end to the opposite end is set as the time-reduced protection section, the judgment value = 1−X / 100. Therefore, the determination value = 0.2 in the expression (1) is used when the 80% section from the power supply end to the opposite end of the own line 1L is set as the time-reduced protection section. Note that the time reduction protection section requires a margin of about 15 to 20% in consideration of errors such as current transformer errors (CT errors), relay errors, and line constant errors. The section is 80 to 85% up to the opposite end.

That is, the first power supply terminal overcurrent relay device 10 _1, the second contact signal S _C2 is at a high level (blocked second breaker 4 ₂ inputted from the second circuit breaker 4 ₂ indicates that no.), and the second short inputted from the first short-circuit current I ₁ and the second current transformer 3 ₂ inputted from the first current transformer 3 ₁ the difference (= I ₁ -I ₂₎ the first short-circuit current I ₁ and the second sum of the short-circuit current I ₂ of (I ₁ + I ₂₎ divided by the value determined value of the current I ₂ (= 0. 2) The first trip signal S ₁ is instantaneously generated on the condition that it is greater than or equal to the above.
To achieve this, the first power supply terminal overcurrent relay device 10 _1, instead of the trip signal generating circuit 120 shown in FIG. 5, comprises a trip signal generating circuit 20 shown in FIG.

  As shown in FIG. 2, the trip signal generation circuit 20 includes a relay determination circuit 21, a delay circuit (timer) 22, a logical product circuit 23, and an own line fault determination circuit 25.

Relay determining circuit 21, similarly to the relay determining circuit 131 shown in FIG. 5, the first high level when it detects a short circuit accident occurs in the instantaneous element operating range based on the magnitude of the first short-circuit current I ₁ Output the instantaneous element trip signal ST _a1 and detect a short-circuit fault occurring within the time limit element operating range of the own line 1L based on the magnitude of the first short-circuit current I _1. Output to the delay circuit 22 and the logical product circuit 23.
Delay circuit 22, like the delay circuit 132 shown in FIG. 5, to generate a first time-limit elements trip signal ST _b1 by delaying the time-limit cutoff output signal of the relay determining circuit 21 only timed coordination time T1 _1.
Own line accident judging circuit 25, the difference between the first short-circuit current I ₁ and the second short-circuit current I ₂ (= I ₁ -I ₂₎ the first short-circuit current I ₁ and the second short-circuit current I ₂ A value obtained by dividing the sum by (I ₁ + I ₂ ) is obtained, and if the obtained value is equal to or greater than the determination value (= 0.2), a high-level output signal is output.
The logical product circuit 23 generates a first instantaneous trip signal ST _c1 by taking the logical product of the time-shut-off output signal of the relay determination circuit 21, the output signal of the own line fault determination circuit 25, and the second contact signal S _C2. To do. Here, the time cut-off output signal of the relay determination circuit 21 is input to the logical product circuit 23 when the relay determination circuit 21 does not detect a short-circuit accident (the first power supply overcurrent relay device 10). _This is to prevent the first instantaneous trip signal ST _{c1 from} being erroneously output when ₁ is not operating.
The first instantaneous element trip signal ST _a1 , the first time limit element trip signal ST _b1, and the first instantaneous trip signal ST _c1 are output to the _first circuit breaker 41 as the first trip signal S ₁ .

  Next, the operation of the trip signal generation circuit 20 when a short circuit accident occurs within the time limit element operation range of the own line 1L shown in FIG. 1 will be described with reference to FIG.

If a short circuit accident occurs at time t ₀ within the time limit element operation range of the own line 1L, the _first to _fourth current transformers 3 _{1 to} 3 ₄ flowing through the first to _fourth instrument current transformers 3 _{1 to} 3 ₄ as described with reference to FIG. The direction of the short circuit currents I _{1 to} I ₄ of FIG. _{4 is} the direction indicated by the arrows in FIG. As a result, the first and second power supply end overcurrent relay devices 10 ₁ and 10 ₂ operate, and the direction of the third short-circuit current I ₃ is the same as the operation direction (internal direction). The end short-circuit direction relay device 120 ₁ operates.

The relay determination circuit 21 of the trip signal generation circuit 20 included in the first power supply overcurrent relay device 10 ₁ causes a short circuit accident within the time limit element operation range of the own line 1L based on the _first short circuit current I _1. It is determined that it has occurred, and a high-level time cut-off output signal is output.
Further, the sum of the short-circuit current I ₂ difference (= I ₁ -I ₂₎ the first short-circuit current I ₁ and the second first short-circuit current I ₁ and the second short-circuit current I ₂ (I ₁ If the value divided by + I ₂ ) is equal to or greater than “0.2”, the own line fault determination circuit 25 determines that a short circuit fault has occurred in the own line 1L and outputs a high-level output signal.
As a result, the second contact signal S _C2 input from the second circuit breaker 4 ₂ When it is high level, the first instantaneous trip signal ST _c1 of a high level from the AND circuit 23 is output.

As a result, the first instantaneous trip signal ST _c1 of a high level at time t ₁ that has elapsed since the accident occurrence time t ₀ by a first power supply terminal overcurrent relay device 10 ₁ of the relay determination time T _RY (50 ms) The trip signal generation circuit 20 outputs the first trip signal S ₁ to the first circuit breaker 4 ₁ .

At this time, also in the first opposing end short-circuit direction relay device 120 ₁ , as described with reference to FIGS. 6 and 7, the second opposing end short-circuit direction relay device 120 ₂ from the accident occurrence time t ₀ . The high-level third trip signal S ₃ is output to the _third circuit breaker 4 ₃ at time t ₁ when the relay determination time T _RY (50 ms) elapses.

Accordingly, the first and third circuit breakers 4 ₁ and 4 ₃ are completely disconnected at time t ₂ when the circuit breaker breaking time T _CB (50 ms) has elapsed from time t ₁ . As a result, the first circuit breaker 4 ₁ is t ₄ −t ₂ = T1 as compared with the case of the conventional first power source overcurrent relay device 110 ₁ shown by the broken line in FIG. 3 (see FIG. 7). ₁ (first power supply overcurrent relay devices 10 ₁ , 110 ₁ time cooperation time = 400 ms) can be cut off as early as possible.

By also the second power supply terminal overcurrent relay device 10 ₂ configured similarly to the first power supply terminal overcurrent relay device 10 _1, when a short circuit accident occurs in timed shorter guard interval of other lines 2L, blocking the second circuit breaker 4 ₂ a second power supply terminal overcurrent relay device 10 _2, 110 by _two timed coordination time T1 ₂ faster than the ₂ second conventional power supply terminal overcurrent relay device 110 be able to.

In the above description, the first and second power supply end overcurrent relay devices 10 ₁ and 10 ₂ are individually configured, but may be configured integrally.
Further, the delay circuit such as the delay circuit 22 shown in FIG. 2 may be configured by a circuit that delays an input signal by a predetermined time, and when an input signal is input, it is output after counting a predetermined number of times. You may comprise with the timer which outputs a signal.

It is a diagram for explaining an embodiment the first power supply terminal overcurrent relay device is a overcurrent relay device according to 10 of the present _invention. First power supply terminal overcurrent relay device 10 ₁ shown in FIG. 1 is a block diagram showing the configuration of a trip signal generation circuit 20 that comprises. FIG. 3 is a diagram for explaining the operation of the trip signal generation circuit 20 shown in FIG. 2 when a short circuit accident occurs within the time limit element operation range of the own line 1L shown in FIG. It is a figure for demonstrating that the overcurrent relay apparatus is used as a backup protection in a balanced two-line transmission line. FIG. 5 is a block diagram showing a configuration of a trip signal generation circuit 130 included in the first power supply overcurrent relay device 110 ₁ shown in FIG. 4. FIG. 5 is a block diagram illustrating a configuration of a trip signal generation circuit 140 included in the first opposite-end short-circuit direction relay device 120 ₁ illustrated in FIG. 4. Operation of the first power supply end overcurrent relay device 110 ₁ and the first opposite-end short-circuit direction relay device 120 ₁ shown in FIG. 4 when a short circuit accident occurs within the time limit element operation range of the own line 1L It is a figure for demonstrating.

Explanation of symbols

1 power supply 2 potential transformer 3 ₁ to 3 ₄ first through current transformer for the fourth instrument 41 _{to 4} first to fourth breaker 10 _1, 10 _2, 110 _1, 110 ₂ first and Second power supply overcurrent relay device 20, 130, 140 Trip signal generation circuit 21, 131, 141 Relay determination circuit 22, 132, 142 Delay circuit 23 AND circuit 25 Own line fault determination circuit 120 ₁ , 120 ₂ 1 and second opposing-end short-circuit direction relay device 1L own line 2L other line V line voltage I _{1 to} I ₄ first to fourth short-circuit currents S _{1 to} S ₄ first to fourth trip signals ST _a1 , ST _a2 first and second instantaneous element trip signals ST _b1 , ST _b2 first and second time limit element trip signals ST _c1 , ST _c2 first and second instantaneous trip signals S _C1 , S _C2 first and Second contact signal T1 _{1 to} T1 ₄ time cooperation time T _RY Lay processing time T _CB breaker breaking time t _{0 to} t ₄ time

Claims (6)

Installed on the power supply end side of the own line of the balanced two-line power transmission line composed of the own line (1L) and the other line (2L) laid between the power supply end side bus line and the opposite end side opposite end bus line An overcurrent relay device (10 ₁ ),
When the occurrence of a short circuit accident in the own line is detected, a trip signal generating circuit (20) for generating a trip signal (S ₁ ) for breaking the own line breaker (4 ₁ ) provided on the power supply end side of the own line )
The trip signal generation circuit has its own line short-circuit current (I ₁ ) flowing from the power supply end of the own line toward the fault point and the other line short-circuit current (I ₂₎ flowing from the power supply end of the other line toward the fault point. ) And a trip signal generating means for instantaneously generating the trip signal when a short-circuit fault is detected based on the ratio of the difference between the short circuit current and the sum of the short circuit current of the other line and the short circuit current of the other line.
An overcurrent relay device. It said trip signal generating means, the other line of the next line breaker installed in the power supply end (4 ₂₎ provided that the is not interrupted, detect the short circuit occurs in the self-line on the basis of the ratio The overcurrent relay device according to claim 1, wherein the trip signal is generated instantaneously. The trip signal generating means is
A value obtained by dividing the difference between the short circuit current of the own line and the short circuit current of the other line by the sum of the short circuit current of the own line and the short circuit current of the other line is obtained. Own line accident judgment circuit (25) to output;
A logical product circuit (23) for taking a logical product of the output signal of the own line fault determination circuit and the contact signal (S _C2 ) input from the adjacent circuit breaker;
The overcurrent relay device according to claim 2, further comprising:   The determination value is set to "1-X / 100" when a section of X% from the power supply end of the own line to the opposite end is set as a time-reduced protection section. The overcurrent relay device described.   The overcurrent relay device according to claim 4, wherein the time-limited shortening protection section is a section of 80 to 85% from the power supply end to the opposite end of the own line. The other overcurrent relay device (10 ₂ ) installed on the power supply end side of the other line has the same configuration as that of the overcurrent relay device and is integrally formed. Item 6. The overcurrent relay device according to any one of Items 1 to 5.

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