JP2010115080A - Ground fault protection relay system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground fault protection relay system preventing dual line interruption when a main protection (ground fault line selecting relay device) is not used and prolonging of a fault continuation time, and eliminating the necessity of the main protection. <P>SOLUTION: A first power transmission terminal ground fault direction relay device 11<SB>1</SB>is provided with: a first trip signal instantaneously generating means for instantaneously generating a first trip signal T<SB>DG1</SB>for interrupting a first breaker 4<SB>1</SB>on conditions that a first ground fault detecting overvoltage relay device installed on a power transmission terminal bus line operates, that it is determined that "a ground fault occurs in an own line direction", that a second power transmission terminal ground fault direction relay device 11<SB>2</SB>does not determine that "a ground fault occurs in the own line direction", and that first and second breakers 4<SB>1</SB>, 4<SB>2</SB>are both in an input state. The same is applied for a second power transmission terminal ground fault direction relay device 11<SB>2</SB>, and first and second power reception terminal ground fault relay devices 12<SB>1</SB>, 12<SB>2</SB>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a ground fault protection relay system, and more particularly, to a ground fault protection relay system suitable for protecting a balanced two-line transmission line of a single-ended power source from a ground fault.

  Conventionally, a ground fault protection relay system for a balanced two-line transmission line with a single-ended power source uses a ground fault line selection relay device (SG) as a main protection and a ground fault direction relay device (DG) as a back-up protection. (See Patent Document 1 below).

For example, as shown in FIG. 9, a power transmission end ground fault line selection relay device 111 (main protection) is connected to the power transmission end side (power supply side) of the first and second transmission lines 1L and 2L constituting the balanced two-line transmission line. ) And the first and second power transmission terminal ground fault direction relay devices 121 ₁ , 121 ₂ (rear protection) and the power receiving end side of the first and second power transmission lines 1L, 2L (opposite to the power source) By installing the receiving end ground fault line selection relay device 112 (main protection) and the first and second receiving end ground fault direction relay devices 122 ₁ , 122 ₂ (rear protection), Line transmission lines are protected from ground faults.

Here, the first power transmission terminal ground fault direction relay device 121 ₁ is the first zero input from the first zero-phase current transformer 3 ₁ installed on the power transmission terminal side of the first power transmission line 1L. phase current I ₀₁ and the power transmission end of the bus (hereinafter, "the sending end bus" and referred.) in the installed first earth type potential transformer (EVT) 5 ₁ sending end zero-phase voltage is inputted from the V _When the fault line determination is performed based on _0S and a ground fault occurred in the direction of the own line (first transmission line 1L) is detected, the first interruption provided on the transmission end side of the first transmission line 1L generating a first trip signal T _DG1 for blocking vessels 4 _1.

The second power transmission terminal ground fault direction relay device 121 ₂ has a second zero-phase current I input from a second zero-phase current transformer 3 ₂ installed on the power transmission terminal side of the second power transmission line 2L. ₀₂ and performs an accident line determination based on the first sending end zero-phase voltage V _0S inputted from earth type potential transformer 5 _1, the self line ground fault has occurred (second transmission line 2L) direction When the accident is detected, a second trip signal T _DG2 for breaking the _second circuit breaker ₄₂ provided on the power transmission end side of the second power transmission line 2L is generated.

The first receiving end earth fault direction relay device 122 _1, the third zero-phase current I is input from the first transmission line 1L third zero-phase current transformer 3 ₃ installed on the receiving end side of the ₀₃ and the power receiving end of the bus (hereinafter, "receiving end bus" and referred.) based on the on installed a second receiving end zero-phase voltage V _0R inputted from earth type potential transformer 5 ₂ accident performs line determination, blocking detects its own line ground fault that occurred (first transmission line 1L) direction, the third breaker 4 ₃ provided on the receiving end side of the first transmission line 1L generating a third trip signal T _DG3 for.

The second power receiving end ground fault direction relay device 122 ₂ has a fourth zero-phase current I input from a fourth zero-phase current transformer 3 ₄ installed on the power receiving end side of the second power transmission line 2L. ₀₄ and performs an accident line determination based on the second receiving end zero-phase voltage V _0R inputted from earth type potential transformer 5 _2, self line ground fault has occurred (second transmission line 2L) direction When an accident is detected, a fourth trip signal T _DG4 for breaking the _fourth circuit breaker ₄₄ provided on the power receiving end side of the second power transmission line 2L is generated.

Therefore, the first power transmission ground fault direction relay device 121 ₁ includes a relay determination circuit 131, first to third delay circuits (timers) 132 _{1 to} 132 ₃ , an AND circuit 133, as shown in FIG. A first power transmission ground fault direction relay device trip signal generation circuit 130 having an OR circuit 134 is provided.
Relay determining circuit 131, a ground fault in the first zero-phase current measurement and sending end zero-phase voltage V _0S and a first "self-line direction based on the phase relation of the zero-phase current I ₀₁ of I ₀₁ is generated If it is determined that the first fault line determination result signal S ₁ at a high level is output.
The first delay circuit 132 _1, first OVG output signal S _OVG1 the first timed coordination time GT1 ₁ delayed input from the first ground detection site fault over-voltage relay device not shown (OVG) To do. Here, the first ground fault overvoltage relay device for ground fault detection outputs a high-level first OVG output signal S _OVG1 when the magnitude of the power transmission end zero-phase voltage V _0S becomes a set value or more. The first timed coordination time GT1 ₁ is set for the timed coordination with the first transmission line 1L other ground direction relay device installed in the receiving end behind the transmission line (not shown) (For example, set to 800 ms).
The AND circuit 133 outputs the first OVG output delayed by the first time-spanning coordination time GT1 ₁ by the first fault circuit determination result signal S ₁ input from the relay determination circuit 131 and the first delay circuit 132 ₁ . The logical product with the signal S _OVG1 is obtained.
The second delay circuit 132 ₂ delays the output signal of the AND circuit 133 by the first zero-phase free vibration malfunction prevention time GT2 ₁ . Here, the first zero-phase free vibration lockout time GT2 ₁ is the zero-phase free vibration is set to prevent malfunction due to (after the accident point disconnecting also the zero-phase voltage only remains phenomenon predetermined time) (typically 100ms To be set).
The third delay circuit 132 ₃ delays the first OVG output signal S _OVG1 only first OVG breaking time GT3 _1. Here, the first OVG cutoff time GT3 ₁ is set in order to shut off the first circuit breaker 4 ₁ only by the operation of the first ground fault detection ground fault overvoltage relay device.
The logical sum circuit 134 takes a logical sum of the output signal of the _second delay circuit 132 _{2 and} the output signal of the third delay circuit 132 ₃ . The OR circuit 134 outputs a first trip signal T _DG1 .

The second power transmission terminal ground fault direction relay device 121 ₂ is a _second power transmission terminal ground fault direction relay device configured in the same manner as the first power transmission terminal ground fault direction relay device trip signal generation circuit 130 described above. A trip signal generation circuit (not shown) is provided.

The first receiving end earth fault direction relay device 122 ₁ includes a relay determining circuit 141 as shown in FIG. 11 first to third delay circuit (timer) 142 _{1 to 142 3} and the AND circuit 143 and the logical OR A first power receiving end ground fault direction relay device trip signal generating circuit 140 having a circuit 144;
Relay determining circuit 141, a third zero-phase current I ₀₃ of the size and receiving end zero-phase voltage V _0R and third earth fault in the "own line direction based on the phase relation of the zero-phase current I ₀₃ of occurrence If it is determined that the "outputs the third accident line determination result signal S ₃ of the high level.
The first delay circuit 142 ₁ delays the second OVG output signal S _OVG2 input from a second ground fault detection ground fault overvoltage relay device (not shown ₎ by the third time cooperation time GT1 ₃ . Here, the second ground fault overvoltage relay device for ground fault detection outputs the second OVG output signal S _OVG2 at a high level when the magnitude of the power receiving end zero-phase voltage V _0R becomes a set value or more. Further, the third time cooperation time GT1 ₃ is set to a value (for example, 400 ms) smaller than the _first time cooperation time GT1 ₁ (for example, 800 ms) described above.
The AND circuit 143 outputs the second OVG output delayed by the third time limit coordination time GT1 ₃ by the third fault line determination result signal S ₃ input from the relay determination circuit 141 and the first delay circuit 142 ₁ . The logical product with the signal S _OVG2 is obtained.
The second delay circuit 142 ₂ delays the output signal of the AND circuit 143 by the third zero-phase free vibration malfunction prevention time GT2 ₃ . The third zero-phase free vibration lockout time GT2 ₃ is set in order to prevent malfunction due to zero-phase free vibration (normally set to 100 ms).
The third delay circuit 142 ₃ delays the second OVG output signal S _OVG2 by the third OVG cutoff time GT3 ₃ . Here, the third OVG cutoff time GT3 ₃ is set in order to shut off the third circuit breaker 4 ₃ only by the operation of the second ground fault detection ground fault overvoltage relay device.
OR circuit 144 takes the logical sum of the second delay circuit 142 and _second output signal and the third delay circuit 142 ₃ of the output signal. The OR circuit 144 outputs a third trip signal T _DG3 .

The second power receiving end ground fault direction relay device 122 ₂ is the _second power receiving end ground fault direction relay device configured in the same manner as the first power receiving end ground fault direction relay device trip signal generation circuit 140 described above. A trip signal generation circuit (not shown) is provided.

In Patent Document 2 below, it is determined whether the ratio between the line zero-phase current and the neutral point zero-phase current is greater than 1 / W (number of lines). When the ratio of the zero-phase current is larger than 1 / W, it is determined that a ground fault has occurred, and the interruption signal is supplied to the circuit breaker, so that the ratio of the line zero-phase current and the neutral zero-phase current is Since the fault point resistance value is not included, a ground fault line selective protection relay device that reliably detects a ground fault without being affected by the fault point resistance value is disclosed.
Japanese Patent Laid-Open No. 11-69608 JP-A-5-328588

However, in the ground fault protection relay system shown in FIG. 9, referring to FIGS. 12 (a) to (c), FIGS. 13 (a) to (c) and FIGS. 14 (a) and (b), As will be described, there is a problem that two lines are cut off and the accident duration is prolonged when the power transmission terminal ground fault line selection relay device 111 and the power reception terminal ground fault line selection relay device 112, which are the main protection, are not used.
In FIGS. 12A to 12C and FIGS. 13A to 13C, the first power transmission terminal ground fault direction relay device 121 ₁ is “DG _S1 ” and the second power transmission terminal ground fault. The direction relay device 121 ₂ is “DG _S2 ”, the first power receiving end ground fault direction relay device 122 ₁ is “DG _R1 ”, and the second power receiving end ground fault direction relay device 122 ₂ is “DG _R2 ”. ".

(1) the earth at the time t ₀ shown in FIG. 14 (a) at sending end close to the first transmission line 1L as shown in 12 (a) 2-line blocking view when sending end ground fault at close occurs When fault accident occurs, the sending end bus to set point over the sending end zero-phase voltage V _0S occurs, first OVG output signal S _OVG1 the first ground detection site fault over-voltage relay device for high level Are output to the first and second power transmission terminal ground fault direction relay devices 121 ₁ , 121 _2, and the power receiving terminal zero-phase voltage V _0R greater than the set value is generated on the power receiving terminal bus. The second OVG output signal S _OVG2 is output from the second ground fault detection ground fault overvoltage relay device to the first and second power receiving end ground fault direction relay devices 122 ₁ and 122 ₂ .

In addition, the first zero-phase current I ₀₁ larger than the set value flows through the first transmission line 1L in the inner direction, and the second zero-phase current I ₀₂ smaller than the set value passes through the second transmission line 2L. The third zero-phase current I ₀₃ smaller than the set value flows in the first transmission line 1L, and the fourth zero-phase current I ₀₄ smaller than the set value becomes the second transmission line 2L. Flows outward.

Therefore, only the first power transmission end ground fault direction relay device 121 ₁ operates as shown by the shaded area in FIG. 12B, and the first power transmission end ground fault direction relay device trip signal generation circuit 130 operates. The relay determination circuit 131 (see FIG. 10) determines that “a ground fault has occurred in the direction of the own line” based on the first zero-phase current I ₀₁ and the transmission-end zero-phase voltage V _OS , The first fault line determination result signal S ₁ is output to the AND circuit 133. Further, the high-level first OVG output signal S _OVG1 is delayed by the first time cooperation time GT1 ₁ by the first delay circuit 132 ₁ and input to the AND circuit 133. For this reason, the output signal of the AND circuit 133 changes from the low level to the high level at time t ₁ shown in FIG. 14A when the first time cooperation time GT1 ₁ (= 800 ms) has elapsed since the occurrence of the ground fault.
As a result, a total time (= GT1 ₁ + GT2 ₁ = 800 ms + 100 ms = 900 ms) elapses from the occurrence of the ground fault accident by the first time cooperation time GT1 ₁ and the first zero-phase free vibration malfunction prevention time GT2 ₁ (= 100 ms). At time t ₂ shown in FIG. 14A, the first trip signal T _DG1 is output from the first power transmission terminal ground fault direction relay device 121 ₁ to the first circuit breaker 4 ₁ .
Thereby, as shown by x in FIG. 12B, the first circuit breaker 4 ₁ has the first time cooperation time GT1 ₁ and the first zero-phase free vibration malfunction prevention time GT2 from the occurrence of the ground fault. ₁ and the time t ₃ shown in FIG. 14A when the total time (= GT1 ₁ + GT2 ₁ + T _CB = 900 ms + 30 ms = 930 ms) of the circuit breaker breaking time T _CB (= 30 ms) of the first circuit breaker 4 ₁ has elapsed. Is completely blocked.

In this manner, when the first breaker 4 ₁ is completely cut off, the first zero-phase current I ₀₁ does not flow, the bypass current, the second zero-phase current I ₀₂ is greater than setting value is the The third zero-phase current I ₀₃ flowing in the inner direction through one transmission line 1L and flowing in the inner direction through the second transmission line 2L larger than the set value, and the fourth zero-phase current I ₀₄ larger than the set value. Flows in the external direction through the second power transmission line 2L. Therefore, the second transmission terminal and the ground fault direction relay device 121 ₂ first and receiving end earth fault direction relay device 122 ₁ begins to operate as shown by hatching in FIG. 12 (c).

That is, in the second sending end ground fault direction relay device trip signal generation circuit, at the time of the first breaker 4 ₁ blocked delayed by the first delay circuit by a second timed coordination time GT1 ₂ (= 800 ms) since the first OVG output signal S _OVG1 of high level is input to the aND circuit, an accident line determination result signal S ₂ second of a high level is input to the aND circuit from the relay determining circuit, logic The output signal of the product circuit changes from low level to high level (see FIG. 10).
As a result, the total time (= T _RY ) of the relay determination time T _RY (= 20 ms) of the relay determination circuit and the second zero-phase free vibration malfunction prevention time GT _{2 2} (= 100 ms) after the _first circuit breaker 41 is turned off. + GT2 ₂ = 20 ms + 100 ms = 120 ms) at time t ₄ shown in FIG. 14A, the second trip signal T _DG2 is transferred from the second power transmission ground fault relay device 121 ₂ to the second circuit breaker 4. Output to ₂ .
Thus, the second circuit breakers 4 _2, 12 as indicated by × mark (c), the relay determination time T _RY and second zero-phase free vibration lockout time from the first breaker 4 ₁ blocked The time t shown in FIG. 14 (a) when the total time (= T _RY + GT2 ₂ + T _CB = 120 ms + 30 ms = 150 ms) of GT2 ₂ and the breaker breaking time T _CB (= 30 ms) of the second breaker 4 ₂ has elapsed. ₅ , completely blocked.

Similarly, in the first power receiving end ground fault direction relay device trip signal generation circuit 140 (see FIG. 11), the first delay circuit 142 ₁ causes the third time limit coordination time GT1 when the _first circuit breaker 41 is shut off. ₃ since (= 400 ms) delayed by the second OVG output signal S _OVG2 high level was is inputted to the aND circuit 143, third accident line determination result signal S ₃ of the high-level relay determining circuit 141 Is input to the AND circuit 143, the output signal of the AND circuit 143 changes from the low level to the high level.
As a result, the total time (= 100 ms) of the relay determination time T _RY (= 20 ms) of the relay determination circuit 141 and the third zero-phase free vibration malfunction prevention time GT2 ₃ (= 100 ms) from when the _first circuit breaker 41 is cut off. the _{T RY + GT2 3 = 20ms +} 100ms = 120ms) time t ₄ when shown in FIG. 14 (a) which has elapsed, a third shut-off from the third trip signal T _DG3 the first receiving end earth fault direction relay device 122 ₁ It is output to the vessel 4 _3.
As a result, the third circuit breaker 4 ₃ prevents the relay determination time T _RY and the third zero-phase free vibration malfunction from the time when the _first circuit breaker ₄₁ is interrupted, as indicated by a cross in FIG. The time shown in FIG. 14A when the total time (= T _RY + GT2 ₃ + T _CB = 120 ms + 30 ms = 150 ms) of the time GT2 ₃ and the circuit breaker breaking time T _CB (= 30 ms) of the third circuit breaker 4 ₃ has elapsed. to t _5, it is completely blocked.

When a ground fault occurs near the power transmission end of the first power transmission line 1L when the power transmission terminal ground fault line selection relay device 111 and the power reception terminal ground fault line selection relay device 112, which are main protections, are not used as described above. In this case, not only the first and third circuit breakers 4 ₁ and 4 ₃ installed in the first power transmission line 1L but also the second circuit breaker 4 ₂ installed in the second power transmission line 2L is blocked. Therefore, two lines are cut off.

Conventionally, in order to avoid the interruption of the two lines, the first and second when the power transmission terminal ground fault line selection relay device 111 and the power reception terminal ground fault line selection relay apparatus 112, which are the main protection, are not used. The power transmission terminal ground fault direction relay devices 121 ₁ and 121 ₂ are set and changed so as to reduce the first and second time cooperation times GT1 ₁ and GT1 ₂ (for example, from 800 ms to 400 ms), and the first and second The settling change is made so that the zero-phase free vibration malfunction prevention times GT2 ₁ and GT2 ₂ are increased (for example, from 100 ms to 500 ms).

(2) Prolonging the accident duration when a ground fault occurs near the power receiving end As shown in FIG. 13A, the time t shown in FIG. 14B near the power receiving end of the first transmission line 1L. ₀ to the ground fault occurs, the sending end bus to set point over the sending end zero-phase voltage V _0S occurs, first OVG output signal S _OVG1 the first ground detection site fault over voltage of a high level Since it is output from the relay device to the first and second power transmission terminal ground fault direction relay devices 121 ₁ and 121 _2, and the receiving end zero-phase voltage V _0R greater than the set value is generated at the receiving end bus, The second OVG output signal S _OVG2 at the level is output from the second ground fault detection ground fault overvoltage relay device to the first and second power receiving end ground fault direction relay devices 122 ₁ and 122 ₂ .

Also, the first zero-phase current I ₀₁ larger than the set value flows through the first transmission line 1L in the inner direction, and the second zero-phase current I ₀₂ greater than the set value passes through the second transmission line 2L. The third zero-phase current I ₀₃ larger than the set value flows in the first transmission line 1L, and the fourth zero-phase current I ₀₄ greater than the set value becomes the second transmission line 2L. Flows outward.
Therefore, the first and second power transmission terminal ground fault direction relay devices 121 ₁ and 121 ₂ and the first power receiving terminal ground fault direction relay device 122 ₁ operate as shown by the hatching in FIG. However, the second power receiving end ground fault direction relay device 122 ₂ does not operate.

Accordingly, the first receiving end earth fault direction relay device 122 _1, the relay determining circuit 141 of the first receiving end earth fault direction relay device trip signal generating circuit 140 (see FIG. 11), a third zero-phase Based on the current I ₀₃ and the receiving end zero-phase voltage V _OR , it is determined that “a ground fault has occurred in the direction of the own line”, and the high-level third fault line determination result signal S ₃ is sent to the AND circuit 143. Output. Further, the second OVG output signal S _OVG2 at the high level is delayed by the third time cooperation time GT1 ₃ by the _first delay circuit ₁₄₂₁ , and input to the AND circuit 143. Therefore, the output signal of the AND circuit 143 changes from the low level to the high level at time t ₁ shown in FIG. 14B when the third time cooperation time GT1 ₃ (= 400 ms) has elapsed since the occurrence of the ground fault.
As a result, a total time (= GT1 ₃ + GT2 ₃ = 400 ms + 100 ms = 500 ms) elapses from the occurrence of the ground fault accident by the third time cooperation time GT1 ₃ and the third zero-phase free vibration malfunction prevention time GT2 ₃ (= 100 ms). At time t ₂ shown in FIG. 14B, the third trip signal T _DG3 is output from the _first power receiving terminal ground fault direction relay device 122 ₁ to the third circuit breaker 4 ₃ .
Thus, the third circuit breakers 4 ₃ of, and FIG. 13 (b) in as indicated by × mark, from ground fault occurrence third timed coordination time GT1 ₃ and the third zero-phase free vibration lockout time GT2 ₃ and a time t ₃ shown in FIG. 14B after the total time (= GT1 ₃ + GT2 ₃ + T _CB = 500 ms + 30 ms = 530 ms) of the circuit breaker breaking time T _CB (= 30 ms) of the third breaker 4 ₃ . It is completely cut off.

When the third circuit breaker 4 ₃ is completely cut off in this way, the second to fourth zero-phase currents I _{02 to} I ₀₄ do not flow, and the first zero-phase current I ₀₁ larger than the set value. Since only the first power transmission line 1L flows in the inner direction, the first power transmission terminal ground fault direction relay device 121 ₁ continues to operate as shown by the hatching in FIG. 13C, but the second power transmission The terminal ground fault direction relay device 121 ₂ and the first power receiving terminal ground fault direction relay device 122 ₁ do not operate, and the second power transmission terminal ground fault direction relay device 121 ₂ remains inactive.

In the first power transmission terminal ground fault direction relay device 121 ₁ , the relay determination circuit 131 (see FIG. 10) of the first power transmission terminal ground fault direction relay device trip signal generation circuit 130 at the time of occurrence of a ground fault occurs. It is determined that “a ground fault has occurred in the direction of the own line” based on the zero-phase current I ₀₁ and the transmission-end zero-phase voltage V _OS , and the high-level first fault line determination result signal S ₁ is logically ANDed. It is output to the circuit 133. Further, the high-level first OVG output signal S _OVG1 is delayed by the first time cooperation time GT1 ₁ by the first delay circuit 122 ₁ and input to the AND circuit 133. For this reason, the output signal of the AND circuit 123 changes from the low level to the high level at time t ₄ shown in FIG. 14B when the first time cooperation time GT1 ₁ (= 800 ms) has elapsed since the occurrence of the ground fault.
As a result, a total time (= GT1 ₁ + GT2 ₁ = 800 ms + 100 ms = 900 ms) elapses from the occurrence of the ground fault accident by the first time cooperation time GT1 ₁ and the first zero-phase free vibration malfunction prevention time GT2 ₁ (= 100 ms). At time t ₅ shown in FIG. 14 (b) was first trip signal T _DG1 is output from the first sending end ground fault direction relay device 121 ₁ to the first breaker 4 _1.
Thus, the first breaker 4 _1, 13 as indicated by × mark (c), the a ground fault occurs first timed coordination time GT1 ₁ and the first zero-phase free vibration lockout time GT2 ₁ and the time t ₆ shown in FIG. 14B after the total time (= GT1 ₁ + GT2 ₁ + T _CB = 900 ms + 30 ms = 930 ms) of the _first circuit breaker 41 and the circuit breaker breaking time T _CB (= 30 ms). It is completely blocked.

When a ground fault occurs near the power receiving end of the first power transmission line 1L when the power transmission terminal ground fault line selective relay device 111 and the power receiving terminal ground fault line selective relay device 112, which are main protections, are not used in this way. It is possible to determine that the third circuit breaker 4 ₃ has already been disconnected and that the first power transmission terminal ground fault direction relay device 121 ₁ is “a ground fault has occurred in the direction of the own line”. In spite of the above, the circuit breaker breaking time T _CB between the first time limit coordination time GT1 ₁ and the first zero-phase free vibration malfunction prevention time GT2 ₁ until the _first circuit breaker 4 ₁ is cut off, Therefore, the first time period set for the time cooperation with the other ground fault direction relay device installed in the power transmission line behind the power receiving end of the first power transmission line 1L is required. The removal of the ground fault is delayed by the cooperation time GT1 ₁ minute.

  In addition, in the conventional ground fault protection relay system, in addition to the two problems described above, the ground fault direction relay device is used for back-up protection, and therefore a ground fault line selection relay device as the main protection is required. There was also a problem.

  It is an object of the present invention to provide a ground fault protection relay system that can prevent two lines from being interrupted and the accident duration can be prolonged when main protection (ground fault line selection relay device) is not used, and can eliminate main protection. There is.

The ground fault protection relay system according to the present invention eliminates a balanced two-line transmission line composed of first and second transmission lines (1L, 2L) laid between a power transmission end bus and a power reception end bus from a ground fault. It is a ground fault protection relay system for protection, and it has been determined that an overvoltage relay device for ground fault detection on its own end has been operated, that a ground fault has occurred in the direction of its own line, The other ground fault direction relay device installed on the local line side of the network does not determine that a ground fault has occurred in the direction of the local line, and is installed on the local line side of the local line and the adjacent line. Trip signal to shut off the circuit breaker installed on its own line, provided that the two circuit breakers (4 ₁ , 4 ₂ : 4 ₃ , 4 ₄ ) are both on. Ground fault direction relay equipped with trip signal instantaneous generation means that instantly generates (T _{DG1 to} T _DG4 ) The apparatus (11 ₁ , 11 ₂ , 12 ₁ , 12 ₂ ) is provided.
Here, the trip signal instantaneous generation means may instantaneously generate the trip signal on the condition that the short-circuit detection ground fault undervoltage relay device on its own end side is inoperative.
When the ground fault direction relay device is set to operate with the minimum ground fault current regardless of the failure point at the time of an internal failure in the protection section, and is used as one line protection for the balanced two-line transmission line May be set to operate with the minimum ground fault current at the time of the other end bus failure when two lines are used in parallel.
First and second power transmission terminal ground fault direction relay devices (11 ₁ , 11 ₂ ) installed on the power transmission end side of the first and second power transmission lines, respectively, and the first and second power transmission lines First and second power receiving end ground fault direction relay devices (12 ₁ , 12 ₂ ) respectively installed on the power receiving end side of the first power transmitting end ground fault direction relay device, It has been determined that the first ground fault detection overvoltage relay device installed on the power transmission end bus has been operated, “a ground fault has occurred in the direction of the own line”, and the second power transmission end ground fault direction relay. The first and second circuit breakers (4 and 4) installed on the power transmission end sides of the first and second transmission lines, respectively, that the electric device has not determined that “a ground fault has occurred in the direction of the own line” _1, 4 ₂₎ it is oN state together, and, the first for short detection that the installed in the sending end bus On condition that the first UVG output signal from絡不undervoltage relay device indicating that the size of the transmission neat phase voltage of the balanced 2-circuit transmission line falls below a set point (S _UVG1) is not input And a first trip signal instantaneous generating means for instantaneously generating a first trip signal (T _DG1 ) for interrupting the first circuit breaker, wherein the second power transmission terminal ground fault direction relay device comprises: The first ground fault detection overvoltage relay device has been operated, it has been determined that a ground fault has occurred in the direction of the own line, and the first power transmission terminal ground fault direction relay device has That it is not determined that a ground fault has occurred in the line direction, that both the first and second circuit breakers are on, and that the first UVG output signal is not input. A second trip to break the second breaker on condition A second trip signal instantaneous generating means for instantaneously generating a signal (T _DG2 ), wherein the first power receiving end ground fault direction relay device is installed on the power receiving end bus for detecting a second ground fault It is determined that the overvoltage relay device has been operated, “a ground fault has occurred in the direction of the own line”, and the second power receiving terminal ground fault direction relay device has “a ground fault has occurred in the direction of the own line”. That the third and fourth circuit breakers (4 ₃ , 4 ₄ ) installed on the receiving end sides of the first and second transmission lines are both in the on state, and The second UVG indicating that the magnitude of the positive phase voltage at the receiving end of the balanced two-line transmission line has become equal to or less than a set value from the second short-circuiting detection ground fault undervoltage relay device installed at the receiving end bus. on condition that the output signal (S _UVG2) is not input, blocking the third A third of the third trip signal instantaneously generating means for generating a trip signal (T _DG3) instantaneously for blocking, the second receiving end earth fault direction relay apparatus, the second ground fault It is determined that the detection overvoltage relay device has been operated, “a ground fault has occurred in the direction of the own line”, the first power receiving terminal ground fault direction relay device has “a ground fault has occurred in the direction of the own line” The fourth UVG output signal is not input, and the third UVG output signal is not input. You may provide the 4th trip signal instantaneous generation means to generate _| occur _{| produce} the 4th trip signal ( _TDG4 ) for _{interrupting |} blocking a circuit breaker instantaneously.

The ground fault protection relay system of the present invention has the following effects.
(1) Even if a ground fault occurs near the other end of the balanced two-line transmission line when the main protection ground fault line selective relay device is not used, overvoltage relay for ground fault detection on the own end side It is determined that the equipment has been operated, “a ground fault has occurred in the direction of its own line”, other ground fault direction relay devices installed on its own side of the adjacent line are “ground faults in the direction of its own line” If all four conditions are met, that is, it has not been determined that ”has occurred” and that both of the two circuit breakers installed on the own line side and the adjacent line side are on. Since the tripping relay device instantaneously generates a trip signal, the circuit breaker installed on the own end of the own line can be shut off at high speed, so this ground fault can be removed at high speed. .
(2) It is possible to give priority to short-circuiting by making it a further condition that the short-circuiting detection ground fault undervoltage relay device on its own end side is inoperative.
(3) Since a ground fault can be removed at high speed, it is possible to prevent a reduction in reliability of the power system.
(4) Since the main protection function can be installed in the ground fault direction relay device, the main protection ground fault line selection relay device can be made unnecessary.
(5) Since a ground fault accident can be removed at high speed, an accident that progresses from a ground fault to a short circuit can be prevented.

  For the above purposes, it is determined that the overvoltage relay for detecting the ground fault on the local end side has been operated, “a ground fault has occurred in the direction of the local line”, and other installations on the local end side of the adjacent line. The ground fault direction relay device has not determined that a ground fault has occurred in the direction of its own line, and two circuit breakers installed on its own side and the adjacent side of the adjacent line are both entered. This is realized by the fact that the ground fault relay device instantaneously generates a trip signal (without waiting for the elapse of the first time cooperation period) when all four conditions of being in the state are satisfied.

Hereinafter, embodiments of the ground fault protection relay system of the present invention will be described with reference to the drawings.
The ground fault protection relay system according to the embodiment of the present invention is different from the conventional ground fault protection relay system shown in FIG. 9 in the following two points.
(1) a first sending end ground fault direction relay device 11 ₁ installed on the sending end side of the first transmission line 1L as shown in FIG. 1, an overvoltage relay device for leaving the first ground-fault operation was possible, it determines that it has determined that "ground fault has occurred in the own line direction", "ground fault has occurred in the own line direction" second sending end ground fault direction relay device 11 ₂ The first and second circuit breakers 4 ₁ and 4 ₂ are both in the on state, and the first short-circuit detection ground fault undervoltage relay (UVG) (not shown) is inoperative. On the condition, the first trip signal _TDZ1 is _generated instantaneously (without waiting for the elapse of the _first time cooperation time _GT11 ).
In order to give priority to short-circuiting, the first short-circuit detection ground fault undervoltage relay device is assumed to be non-operational, but this condition is not necessary when it is not necessary to give priority to short-circuiting.
The second transmission line 2L second sending end ground fault direction relay device 11 ₂ and the first and second transmission line 1L installed in the power transmission end of the first respectively installed on the receiving end side of the 2L The same applies to the _second power receiving end ground fault direction relay devices 12 ₁ and 12 ₂ .
Thus, the main protection function is mounted on the first and second power transmission terminal ground fault direction relay devices 11 ₁ and 11 ₂ and the first and second power reception terminal ground fault direction relay devices 12 ₁ and 12 _2. be able to.

(2) The main protection power transmission terminal ground fault line selection relay device 111 and power reception terminal ground fault line selection relay apparatus 112 shown in FIG. 9 are not provided.
That is, as described above, the first and second power transmission terminal ground fault direction relay devices 11 ₁ and 11 ₂ and the first and second power reception terminal ground fault direction relay devices 12 ₁ and 12 ₂ have a main protection function. Therefore, the main protection power transmission terminal ground fault line selection relay device 111 and the power reception terminal ground fault line selection relay apparatus 112 can be eliminated.

Therefore, the first power transmission terminal ground fault direction relay device 11 ₁ includes a relay determination circuit 21, first to third delay circuits (timers) 22 _{1 to} 22 _3, and first to _third as shown in FIG. The first power transmission terminal ground fault direction relay device trip signal generation circuit 20 having the logical product circuits 23 ₁ to 23 ₃ and the logical sum circuit 24 is provided.

Similar to the relay determination circuit 131 shown in FIG. 10, the relay determination circuit 21 performs the _fault line determination based on the first zero-phase current I ₀₁ and the power transmission end zero-phase voltage V _0S , 1 of earth fault in the transmission line 1L) direction to output a first accident line determination result signals S ₁ of high level if it is determined that occurred ".
However, the first fault line determination result signal S ₁ is output to the first and third AND circuits 23 ₁ and 23 ₃ and also to the second power transmission terminal ground fault direction relay device 11 _2. Is done.
Further, the setting in the relay determination circuit 21 is performed as follows, unlike the relay determination circuit 131 shown in FIG.
(1) Protection section (section between the power transmission end bus and the power reception end bus) When an internal failure occurs, the settling is performed with the minimum ground fault current regardless of the failure point.
(2) When used as one line protection for a balanced two-line transmission line, settling is performed with the minimum ground fault current when the power receiving end bus (mating end bus) fails when two lines are used in parallel.
Here, the minimum ground fault current is an incomplete ground fault current equivalent to 30% in the high resistance grounding system, and the NGR capacity used to calculate the ground fault current is connected when system separation due to work and accidents is taken into consideration. The minimum capacity of the neutral grounding resistor (NGR). The maximum ground fault current is the complete ground fault current in the high resistance grounding system, and the NGR capacity used for calculating the ground fault current is the total capacity of the neutral point grounding resistor that is always used in the system.
For example, there are two neutral point grounding resistors with NGR capacity of 150A and one neutral point grounding resistor with NGR capacity of 100A in the same system, and 100A neutral point grounding resistors are always in the system. Taking the case of “OFF” as an example, the minimum ground fault current is 100A × 1 unit × 30% = 30A. That is, the minimum ground fault current is the same as that of the other 150A neutral point grounding resistor while the 100A neutral point grounding resistor is being used instead of the operation of one 150A neutral point grounding resistor. It becomes a ground fault current when an incomplete ground fault occurs when the instrument becomes unusable due to a failure and is operated with only one 100A neutral grounding resistor. Further, the maximum ground fault current in this example is 150 A × 2 units = 300 A.
In this example, since the minimum NGR capacity is the minimum single machine capacity, assuming that the NGR rating (INGR) is 100A, the ground fault current is shunted to 1/2 when the receiving end bus fails when two lines are used in parallel. The set value of 21 is set to INGR × 30% × 1/2 = 100 A × 30% × 1/2 = 15 A.

Similar to the _first delay circuit 132 ₁ shown in FIG. 10, the first delay circuit 22 ₁ delays the first OVG output signal S _OVG1 by the first time cooperation time GT1 ₁ (= 800 _ms ).
Similar to the AND circuit 133 shown in FIG. 10, the _first AND circuit 23 ₁ uses the first fault line determination result signal S ₁ and the first delay circuit 22 _{1 to} generate a first time-coordinated time GT1 _{1. ANDed} with the first OVG output signal S _OVG1 delayed by.
Second AND circuit 23 _2, the first contact signal S _CB1 (first breaker 4 ₁ is not ON state (disconnected state) in the high level input from the first breaker 4 ₁ signal) and the second contact signal S _CB2 (second circuit breaker 4 ₂ inputted from the second circuit breaker 4 ₂ ANDing the high-level signal) is input state.
The third AND circuit 23 ₃ includes the first OVG output signal S _OVG1 , the first _fault line determination result signal S ₁ , the output signal of the second AND circuit 23 ₂ , and the second power transmission terminal ground fault direction. A signal obtained by inverting the polarity of the _second fault line determination result signal S ₂ input from the relay device 11 ₂ and a first UVG output signal S _UVG1 input from the first short-circuit detection ground fault undervoltage relay device. The logical product of the signal with the polarity reversed is obtained. Here, the first short-circuit detecting ground fault undervoltage relay device outputs the high-level first UVG output signal S _{UVG1 when} the magnitude of the positive phase voltage at the transmission end of the balanced two-line transmission line becomes equal to or less than a set value. .
The second delay circuit 22 ₂ delays the output signals of the first and _second AND circuits 23 ₁ and 23 ₂ by the first zero-phase free vibration malfunction prevention time GT2 ₁ (= 100 ms).
The third delay circuit 22 _3, like the third delay circuit 132 ₃ shown in FIG. 10, for delaying the first OVG output signal S _OVG1 only first OVG breaking time GT3 _1.
The logical sum circuit 24 takes the logical sum of the output signal of the _second delay circuit 22 _{2 and} the output signal of the third delay circuit 22 _{3 in} the same manner as the logical sum circuit 134 shown in FIG.

As shown in FIG. 3, the second power transmission terminal ground fault direction relay device 11 ₂ includes a relay determination circuit 31, first to third delay circuits (timers) 32 _{1 to} 32 _3, and first to third logics. A second power transmission terminal ground fault direction relay device trip signal generation circuit 30 having product circuits 33 _{1 to} 33 ₃ and an OR circuit 34 is provided.
The relay determination circuit 31 performs fault line determination based on the second zero-phase current I ₀₂ and the power transmission end zero-phase voltage V _0S, and “a ground fault occurs in the direction of the own line (second power transmission line 2L)”. If it is determined that the second fault line determination result signal S ₂ at a high level is output. The second fault line determination result signal S ₂ is output to the first and third AND circuits 33 ₁ and 33 ₃ and also to the first power transmission terminal ground fault direction relay device 11 _1. . The relay determination circuit 31 is set in the same manner as the relay determination circuit 21 described above.
The first delay circuit 32 ₁ delays the first OVG output signal S _OVG1 by the second time cooperation time GT1 ₂ (= 800 _ms ).
The first AND circuit 33 ₁ includes the second fault line determination result signal S ₂ and the first OVG output signal S _OVG1 delayed by the _first delay circuit 32 ₁ by the second time cooperation time GT1 _2. The logical product of
The second AND circuit 33 ₂ is a logic circuit between the first contact signal S _CB1 input from the first circuit breaker 4 ₁ and the second contact signal S _CB2 input from the second circuit breaker 4 _2. Take the product.
The third AND circuit 33 ₃ includes the first OVG output signal S _OVG1 , the second _fault line determination result signal S ₂ , the output signal of the _second AND circuit 33 ₂ , and the first power transmission terminal ground fault direction. A signal obtained by inverting the polarity of the first fault line determination result signal S ₁ input from the relay device 11 ₁ and a first UVG output signal S _UVG1 input from the first short circuit detection ground fault undervoltage relay device. The logical product of the signal with the polarity reversed is obtained.
The second delay circuit 32 ₂ delays the output signals of the first and second AND circuits 33 ₁ and 33 ₂ by the second zero-phase free vibration malfunction prevention time GT2 ₂ (= 100 ms).
The third delay circuit 32 ₃ delays the first OVG output signal S _OVG1 by the second OVG cutoff time GT3 ₂ .
The logical sum circuit 34 takes a logical sum of the output signal of the _second delay circuit 32 _{2 and} the output signal of the third delay circuit 32 ₃ .

As shown in FIG. 4, the _first power receiving end ground fault direction relay device 12 ₁ includes a relay determination circuit 41, first to third delay circuits (timers) 42 _{1 to} 42 _3, and first to third logics. A _first power receiving terminal ground fault direction relay device trip signal generating circuit 40 having product circuits 43 ₁ to 43 ₃ and an OR circuit 44 is provided.
Similar to the relay determination circuit 141 shown in FIG. 11, the relay determination circuit 41 performs _fault line determination based on the third zero-phase current I ₀₃ and the receiving-end zero-phase voltage V _0S , outputs one of the transmission line 1L) third accident line determination result of the high level when it is determined that a ground fault has occurred "in the direction signal S _3. However, the third fault line determination result signal S ₃ is output to the first and third AND circuits 43 ₁ and 43 ₃ and also to the _second power receiving terminal ground fault direction relay device 12 _2. Is done. Further, the relay determination circuit 41 is set in the same manner as the relay determination circuit 21 described above.
Similarly to the _first delay circuit 142 ₁ shown in FIG. 11, the first delay circuit 42 ₁ delays the second OVG output signal S _OVG2 by the third time-coordinated time GT1 ₃ (= 400 ms).
Similarly to the AND circuit 143 shown in FIG. 11, the _first AND circuit 43 ₁ uses the third fault line determination result signal S ₃ and the first delay circuit 42 _{1 to} generate the third time cooperation time GT1 _{3. ANDed} with the second OVG output signal S _OVG2 delayed by.
Second AND circuit 43 _2, third breaker 4 blocking ₃ third contact signal S inputted from _CB3 (high level signal in the third circuit breakers 4 ₃ ON state) of the fourth vessels 4 ₄ 4 inputted from the contact signal S _CB4 (fourth breaker 4 ₄ of the high-level signal is input state) ANDing the.
The third AND circuit 43 ₃ includes the second OVG output signal S _OVG2 , the third _fault line determination result signal S ₃ , the output signal of the second AND circuit 43 ₂ , and the second power receiving terminal ground fault direction. A signal obtained by inverting the polarity of the _fourth fault line determination result signal S ₄ input from the relay device 12 ₂ and a second UVG output signal S _UVG2 input from the second short-circuit detection ground fault undervoltage relay device. The logical product of the signal with the polarity reversed is obtained. Here, the second short-circuit detection ground fault undervoltage relay device outputs the high-level second UVG output signal S _{UVG2 when} the magnitude of the positive phase voltage at the receiving end of the balanced two-line transmission line becomes equal to or lower than the set value. .
The second delay circuit 44 ₂ delays the output signals of the first and second AND circuits 43 ₁ and 43 _{2 by} a third zero-phase free vibration malfunction prevention time GT 2 ₃ (= 100 ms).
Similarly to the _third delay circuit 142 ₃ shown in FIG. 11, the third delay circuit 42 ₃ delays the second OVG output signal S _OVG3 by the third OVG cutoff time GT3 ₃ .
OR circuit 44, similarly to the OR circuit 144 shown in FIG. 11, a logical sum of the second delay circuit 42 and _second output signal and the third delay circuit 42 ₃ of the output signal.

As shown in FIG. 5, the _second power receiving end ground fault direction relay device 12 ₂ includes a relay determination circuit 51, first to third delay circuits (timers) 52 _{1 to} 52 _3, and first to third logics. A second power receiving terminal ground fault direction relay device trip signal generating circuit 50 having product circuits 53 _{1 to} 53 ₃ and an OR circuit 54 is provided.
The relay determination circuit 51 determines the fault line based on the fourth zero-phase current I ₀₄ and the receiving-end zero-phase voltage V _0S, and “a ground fault occurs in the direction of the own line (second transmission line 2L)”. If it is determined that the error has occurred, a high-level fourth accident line determination result signal S ₄ is output. The fourth fault line determination result signal S ₄ is output to the first and third AND circuits 53 ₁ and 53 ₃ and also to the _first power receiving terminal ground fault direction relay device 12 _1. . The relay determination circuit 51 is set in the same manner as the relay determination circuit 21 described above.
The first delay circuit 52 ₁ delays the second OVG output signal S _OVG2 by the fourth time cooperation time GT1 ₄ (= 400 ms).
The first AND circuit 53 ₁ includes the fourth fault line determination result signal S ₄ and the second OVG output signal S _OVG2 delayed by the _first time delay circuit 52 ₁ by the fourth time cooperation time GT1 _4. The logical product of
Second AND circuit 53 _2, the logic of the fourth contact signal S _CB4 that the third contact signal S _CB3 inputted from the third breaker 4 ₃ inputted from the fourth breaker 4 ₄ Take the product.
The third AND circuit 53 ₃ includes the second OVG output signal S _OVG2 , the fourth _fault line determination result signal S ₄ , the output signal of the _second AND circuit 53 ₂ , and the first power receiving terminal ground fault direction. second UVG output signals inputted from the third accident line determination result inverted signal and the second short detection site絡不undervoltage relay device the polarity of the signal S ₃ which is input from the relay device 12 ₁ S _UVG2 The logical product of the signal with the polarity reversed is obtained.
The second delay circuit 54 ₂ delays the output signals of the first and second AND circuits 53 ₁ and 53 ₂ by the fourth zero-phase free vibration malfunction prevention time GT2 ₄ (= 100 ms).
The third delay circuit 52 ₃ delays the second OVG output signal S _OVG3 by the fourth OVG cutoff time GT3 ₄ .
OR circuit 54 takes the logical sum of the second delay circuit 52 and _second output signal and the third delay circuit 52 ₃ of the output signal.

Next, FIGS. 6 (a) embodiment where the ground fault occurs at time t ₀ shown in Figure 8 (a) at the transmission end close to the first transmission line 1L as shown in by the ground fault protective relay The operation of the electric system will be described with reference to FIGS. 6B and 6C and FIG.
6A to 6C, the first power transmission end ground fault direction relay device 11 ₁ is “DG _S1 ”, and the second power transmission end ground fault direction relay device 11 ₂ is “DG _S2 ”. ”, The first power receiving ground fault direction relay device 12 ₁ is expressed as“ DG _R1 ”, and the second power receiving end ground fault direction relay device 12 ₂ is expressed as“ DG _R2 ”.

When a ground fault occurs near the power transmission end of the first power transmission line 1L, a power transmission end zero-phase voltage V _{0S that} is equal to or higher than the set value is generated on the power transmission end bus, and therefore, the high-level first OVG output signal S _OVG1 is Output from the first ground fault detection ground fault overvoltage relay device to the first and second power transmission terminal ground fault direction relay devices 11 ₁ , 11 _2, and a power receiving end zero phase greater than a set value at the power receiving end bus Since the voltage V _0R is generated, the high-level second OVG output signal S _OVG2 is transferred from the second ground fault detection ground fault overvoltage relay device to the first and second power receiving end ground fault direction relay devices 12 ₁ , 12 ₂ is output.
On the other hand, since the magnitude of the positive phase voltage at the power transmission end is smaller than the set value, the first UVG output signal S _{UVG1 at} the low _level is _sent from the first short-circuit detection ground shortage relay device to the first and second power transmissions. Since it is output to the terminal ground fault direction relay devices 11 ₁ and 11 ₂ and the magnitude of the positive phase voltage at the receiving end is smaller than the set value, the low-level second UVG output signal S _UVG2 is the second short-circuit detection ground. Output from the undervoltage relay device to the first and second power receiving ground fault direction relay devices 12 ₁ and 12 ₂ .

The first zero-phase current I ₀₁ is greater than the minimum ground-fault current flows through the first transmission line 1L inwardly, feeding a second zero-phase current I ₀₂ less than the minimum ground-fault current is the second A third zero-phase current I ₀₃ that flows in the inner direction through the electric wire 2L and flows in the inner direction through the first transmission line 1L that is smaller than the minimum ground fault current, and a fourth zero-phase current I that is smaller than the minimum ground fault current. ₀₄ flows through the second power transmission line 2L to the outside. Therefore, as shown by the shaded area in FIG. 6 (b), only the first power transmission end ground fault direction relay device 11 ₁ operates, and the second power transmission end ground fault direction relay device 11 ₂ and the first and It does not operate with the _second power receiving end ground fault direction relay devices 12 ₁ and 12 ₂ .
That is, in the first sending end ground fault direction relay device 12 _1, the relay determining circuit 21 of the first sending end ground fault direction relay device trip signal generating circuit 20 (see FIG. 2) is first zero-phase Based on the current I ₀₁ and the power transmission terminal zero-phase voltage V _OS , it is determined that “a ground fault has occurred in the direction of the own line”, and a high-level first fault line determination result signal S ₁ is output. On the other hand, in the second sending end ground fault direction relay device 12 _2, relay determining circuit 31 of the second sending end ground fault direction relay device trip signal generating circuit 30 (see FIG. 3), a second zero-phase Based on the current I ₀₂ and the power transmission end zero-phase voltage V _OS , it is not determined that “a ground fault has occurred in the direction of the own line”, and the low-level second fault line determination result signal S ₂ remains output. . Similarly, the first receiving end earth fault direction relay device 12 _1, the relay determining circuit 41 of the first receiving end earth fault direction relay device trip signal generating circuit 40 (see FIG. 4), a third zero based on the phase current I ₀₃ and receiving end zero-phase voltage V _oR without determining the "ground fault in the self-line direction occurs", remains outputting the third fault line determination result signal S ₃ of the low level In addition, in the second power receiving end ground fault direction relay device 12 ₂ , the relay determination circuit 51 (see FIG. 5) of the second power receiving end ground fault direction relay device trip signal generation circuit 50 is the fourth zero. Based on the phase current I ₀₄ and the receiving-end zero-phase voltage V _OR , it is not determined that “a ground fault has occurred in the direction of the own line” and the low-level fourth fault line determination result signal S ₄ remains output. Become.

As a result, in the first power transmission terminal ground fault direction relay device 11 ₁ , the third AND circuit 23 ₃ of the first power transmission terminal ground fault direction relay device trip signal generation circuit 20 has a high level first. The first accident line determination result signal S ₁ and the low level second accident line determination result signal S ₂ are inverted signals (high level signal), the high level first OVG output signal S _OVG1 and the low level first signal. A signal (high level signal) obtained by inverting the polarity of one UVG output signal S _UVG1 is input. Further, since the first and second circuit breakers 4 ₁ and 4 ₂ are both in the “on state”, the first and second contact signals S _CB1 and S _CB2 at the high level are converted into the second AND circuit 23 _2. Therefore, the output signal of the _second AND circuit 23 _{2 at} the high level is input to the third AND circuit 23 ₃ . Therefore, since the output signal of the _third AND circuit ₂₃₃ changes from the low level to the high level, the first trip signal T _DG1 becomes the relay determination time T _RY (= 20 ms) of the relay circuit 21 from the occurrence of the ground fault. The first power transmission at time t ₁ shown in FIG. 8A when the total time (= T _RY + GT2 ₁ = 20 ms + 100 ms = 120 ms) with the first zero-phase free vibration malfunction prevention time GT2 ₁ (= 100 ms) has elapsed. Output from the ground fault direction relay device 11 ₁ to the first circuit breaker 4 ₁ .
Accordingly, the first breaker 4 _1, as indicated by × mark in FIG. 6 (b), the relay determination time T _RY and first zero-phase free vibration lockout time GT2 ₁ and the first breaker 4 at time t ₂ shown in the _first circuit breaker interruption time T _CB (= 30ms) and the total time of _{(= T RY + GT2 1 +} T CB = 120ms + 30ms = 150ms) 8 which has elapsed (a), is completely blocked.

In this manner, when the first breaker 4 ₁ is completely cut off, the first zero-phase current I ₀₁ is not flow, a bypass current by a second zero-phase current I greater than the minimum ground-fault current ₀₂ flows through the second transmission line 2L in the inner direction, and the third zero-phase current I ₀₃ larger than the minimum ground fault current flows through the first transmission line 1L in the inner direction and is larger than the minimum ground fault current. since the zero-phase current I ₀₄ of 4 through the second transmission line 2L to the outside direction, FIG. 6 (c) to a second, as shown by hatching sending end ground direction relay device 11 ₂ and the first The power receiving end ground fault direction relay device 12 ₂ starts to operate, the first power transmitting end ground fault direction relay device 11 ₁ does not operate, and the second power receiving end ground fault direction relay device 12 ₂ does not operate. Will remain.
That is, the first fault line determination result signal S _{1 changes} from the high level to the low level after the relay determination time T _RY of the relay determination circuit 21 has elapsed, and the second and third fault line determination result signals S ₂ and S ₃ are relays. made from a low level to a high level after the relay determination time T _RY course of the determination circuit 31, 41, the fourth accident line determination result signal S ₄ of the remains at a low level.

As a result, the first receiving end earth fault direction relay device 12 _1, the third AND circuit 43 ₃ of the first receiving end earth fault direction relay device trip signal generating circuit 40, the high-level first No. ₃ fault line determination result signal S ₃ and a low level second accident line determination result signal S ₂ , a signal obtained by inverting the polarity (high level signal), a high level second OVG output signal S _OVG2 and a low level first signal. A signal (high level signal) obtained by inverting the polarity of the second UVG output signal S _UVG2 is input. Since the third and fourth circuit breakers 4 ₃ and 4 ₄ are both in the “on state”, the third and fourth contact signals S _CB3 and S _CB4 at the high level are converted into the second AND circuit 43 _2. Therefore, the output signal of the _second AND circuit 43 _{2 at} the high level is input to the third AND circuit 43 ₃ . Therefore, since the third logic output signal of the AND circuit 43 ₃ is changed from the low level to the high level, the third trip signal T _DG3 is, the relay determination time T _RY relay determining circuit 41 from the first breaker 4 ₁ blocked (= 20 ms) and the third zero-phase free vibration malfunction prevention time GT2 ₃ (= 100 ms) The total time (= T _RY + GT2 ₃ = 20 ms + 100 ms = 120 ms) has elapsed at time t ₃ shown in FIG. is output from the first receiving end earth fault direction relay device 12 ₁ to the third circuit breakers 4 _3.
Accordingly, the third breaker 4 _1, as indicated by × mark in FIG. 6 (c), the relay determination time T _RY and third zero-phase free vibration lockout time from the first breaker 4 ₁ blocked The time t shown in FIG. 8A when the total time (= T _RY + GT2 ₃ + T _CB = 120 ms + 30 ms = 150 ms) of GT2 ₃ and the circuit breaker breaking time T _CB (= 30 ms) of the third circuit breaker 4 ₃ has elapsed. ₄ , completely blocked.

On the other hand, in the second power transmission end ground fault direction relay device 11 ₂ , the third AND circuit 33 ₃ of the second power transmission end ground fault direction relay device trip signal generation circuit 30 has a second high level signal. Accident line determination result signal S ₂ and a low level first accident line determination result signal S ₁ , a signal obtained by inverting the polarity (high level signal), a high level first OVG output signal S _OVG1, and a low level first signal. the UVG but polarity inverted signal of the output signal S _UVG1 and (high level signal) is input, the first breaker 4 ₁ a first low level in order to be "oFF state" of the contact signal S _CB1 Is input to the second AND circuit 33 ₂ , the output signal of the low-level _second AND circuit 33 ₂ is input to the third AND circuit 33 ₃ . For this reason, the output signal of the _third AND circuit 333 remains at a low level.
Further, since the first OVG output signal S _OVG1 at the high level is delayed by the second time cooperation time GT1 ₂ (= 800 _ms) by the first delay circuit 32 ₁ , as described above, the third circuit breaker is used. When 4 ₃ is completely cut off, the output signal of the _first delay circuit 32 ₁ remains at the low level. Further, since the ground fault is eliminated when the third circuit breaker 4 ₃ is completely cut off, the second fault line judgment result signal S ₂ output from the relay judgment circuit 31 changes from the high level to the low level. . Therefore, the output signal of the _first AND circuit 331 remains at a low level.
As a result, since there is no the second circuit breaker 4 ₂ is cut off, it is possible to solve the second line blocking problems as shown in FIG. 12 (c).

In addition, the time required to cut off both the first and third circuit breakers 4 ₁ and 4 ₃ and eliminate the ground fault is as shown in FIG. 8A, the relay determination time T _RY and the first zero. phase free vibration lockout time GT2 ₁ and the circuit breaker interruption time T _CB relay determination time T _RY and third zero-phase free vibration lockout time GT2 ₃ and the third circuit breakers 4 ₃ breaker interruption time T _CB of (= (T _RY + GT2 ₁ + T _CB ) + (T _RY + GT2 ₃ + T _CB ) = GT2 ₁ + GT2 ₃ +2 (T _RY + T _CB )). In contrast, the conventional ground fault protective relay system shown in FIG. 9, the time required to remove the ground fault from the first timed coordination time GT1 ₁ as shown in FIG. 14 (a) the first zero-phase free vibration lockout time GT2 ₁ breaker interruption time T _CB relay determination time T _RY and third zero-phase free vibration lockout time GT2 ₃ breaker breaking time T _CB and total time of ( = (GT1 ₁ + GT2 ₁ + T _CB ) + (T _RY + GT2 ₃ + T _CB ) = GT1 ₁ + GT2 ₁ + GT2 ₃ + T _RY + 2T _CB ) Therefore, the ground fault protection relay system according to the present embodiment has a time (= (GT1 ₁ + GT2) obtained by subtracting the relay determination time T _RY from the first time cooperation time GT1 _{1 as} compared with the conventional ground fault protection relay system. ₁ + GT2 ₃ + T _RY + 2T _CB ) − {GT2 ₁ + GT 2 ₃ +2 (T _RY + T _CB )} = GT1 ₁ −T _RY = 800 ms−20 ms = 780 ms) As soon as possible, the ground fault can be eliminated.

In the case where incomplete ground fault occurs in the sending end close to the first transmission line 1L is internal only the first zero-phase current I ₀₁ is greater than the minimum ground-fault current is a first transmission line 1L Since the second to fourth zero-phase currents I _{02 to} I ₀₄ do not flow, only the first power transmission ground fault relay device 11 ₁ operates and the second power transmission ground fault direction The relay device 11 ₂ and the first and second power receiving terminal ground fault direction relay devices 12 ₁ and 12 ₂ do not operate.
Therefore, even in this case, the ground fault protective relay system according to this embodiment, the third breaker after ground fault as described above is cut off the first breaker 4 ₁ operates as if it were generated Since the second circuit breaker 4 ₂ is not cut off only by blocking 4 ₃ , the problem of the two-line interruption can be solved.

Next, as shown in FIG. 7A, the operation of the ground fault protection relay system according to the present embodiment when a ground fault occurs near the power receiving end of the first transmission line 1L will be described with reference to FIG. , (C) and FIG. 8 (b).
7A to 7C, the first power transmission terminal ground fault direction relay device 11 ₁ is “DG _S1 ”, and the second power transmission terminal ground fault direction relay device 11 ₂ is “DG _S2 ”. "said first receiving ground fault direction relay device 12 ₁ and the" DG _R1 ", a second receiving end earth fault direction relay device 12 ₂ is described as" DG _R2 ".

When a ground fault occurs near the power receiving end of the first power transmission line 1L, a power transmission end zero-phase voltage V _{0S that} is equal to or higher than the set value is generated on the power transmission end bus, and therefore, the high-level first OVG output signal S _OVG1 is The first ground fault detection ground fault overvoltage relay device outputs the first and second power transmission terminal ground fault direction relay devices 11 ₁ and 11 _2, and the power receiving end bus has a receiving end zero phase equal to or higher than the set value. Since the voltage V _0R is generated, the high-level second OVG output signal S _OVG2 is transferred from the second ground fault detection ground fault overvoltage relay device to the first and second power receiving end ground fault direction relay devices 12 ₁ , 12 ₂ is output.
However, since the magnitude of the positive phase voltage at the transmission end is smaller than the set value, the first UVG output signal S _{UVG1 at} the low _level is _supplied from the first short-circuit detection ground fault shortage relay device to the first and second transmission end ground faults. Since it is output to the direction relay devices 11 ₁ and 11 ₂ and the magnitude of the positive phase voltage at the receiving end is smaller than the set value, the low-level second UVG output signal S _UVG2 is the second short-circuiting detection ground fault voltage. The power is output from the relay device to the first and second power receiving end ground fault relay devices 12 ₁ and 12 ₂ .

In addition, since the ground fault current flows in half to the first transmission line 1L and the second transmission line 2L, the first zero-phase current I ₀₁ larger than the minimum ground fault current is the first A second zero-phase current I ₀₂ flowing in the internal direction through the transmission line 1L and larger than the minimum ground fault current flows in the second transmission line 2L through the second transmission line 2L and larger than the minimum ground fault current. Since I ₀₃ flows through the first power transmission line 1L in the inner direction and the fourth zero-phase current I ₀₄ larger than the minimum ground fault current flows through the second power transmission line 2L to the outside, FIG. As shown by the shaded area, the first and second power transmission terminal ground fault direction relay devices 11 ₁ and 11 ₂ and the first power receiving terminal ground fault direction relay device 12 ₁ operate, and the second power receiving end. ground fault direction relay device 12 ₂ does not operate.
That is, in the first sending end ground fault direction relay device 12 _1, the relay determining circuit 21 of the first sending end ground fault direction relay device trip signal generating circuit 20 (see FIG. 2) is first zero-phase Based on the current I ₀₁ and the power transmission terminal zero-phase voltage V _OS , it is determined that “a ground fault has occurred in the direction of the own line”, and a high-level first fault line determination result signal S ₁ is output. Similarly, in the second power transmission terminal ground fault direction relay device 12 ₂ , the relay determination circuit 31 (see FIG. 3) of the second power transmission terminal ground fault direction relay device trip signal generation circuit 30 is the second zero. based on the phase current I ₀₂ and the sending end zero-phase voltage V _OS determines "ground fault has occurred in the own line direction", and the output of the high-level second accident line determination result signal S _2, also in the first receiving end earth fault direction relay device 12 _1, the relay determining circuit 41 of the first receiving end earth fault direction relay device trip signal generating circuit 40 (see FIG. 4), a third zero-phase current Based on I ₀₃ and the receiving-end zero-phase voltage V _OR , it is determined that “a ground fault has occurred in the direction of the own line”, and a high-level third fault line determination result signal S ₃ is output. On the other hand, in the second receiving end earth fault direction relay device 12 _2, relay determining circuit 51 of the second receiving end earth fault direction relay device trip signal generating circuit 50 (see FIG. 5), the fourth zero-phase Based on the current I ₀₄ and the receiving end zero-phase voltage V _OR , it is not determined that “a ground fault has occurred in the direction of the own line”, and the low-level fourth fault line determination result signal S ₄ remains output. .

As a result, the first receiving end earth fault direction relay device 12 _1, the third AND circuit 43 ₃ of the first receiving end earth fault direction relay device trip signal generating circuit 40, the high-level first 3, the fault line determination result signal S ₃ , the low level fourth accident line determination result signal S ₄ , the inverted signal (high level signal), the high level second OVG output signal S _OVG2, and the low level first signal. The second UVG output signal _SUVG2 is inverted in polarity (high level signal). Since the third and fourth circuit breakers 4 ₃ and 4 ₄ are both in the “on state”, the third and fourth contact signals S _CB3 and S _CB4 at the high level are converted into the second AND circuit 43 _2. Therefore, the output signal of the _second AND circuit 43 _{2 at} the high level is input to the third AND circuit 43 ₃ . Therefore, since the output signal of the _third AND circuit ₄₃₃ changes from the low level to the high level, the third trip signal T _DG3 is set to the relay determination time T _RY (= 20 ms) of the relay determination circuit 41 and the third zero. At the time t ₁ shown in FIG. 8B when the total time (= T _RY + GT2 ₃ = 20 ms + 100 ms = 120 ms) with the phase free vibration malfunction prevention time GT2 ₃ (= 100 ms) has elapsed, the first power receiving end ground fault direction The power is output from the relay device 12 ₁ to the third circuit breaker 4 ₃ .
Accordingly, the third breaker 4 ₃ of FIG. 7 as indicated by the × mark (b), the relay determination time T _RY and the third zero-phase free vibration lockout time GT2 ₃ third circuit breakers 4 _When the total time (= T _RY + GT2 ₃ + T _CB = 120 ms + 30 ms = 150 ms) with the circuit breaker breaking time T _{CB of 3} (= 30 ms) has elapsed, the circuit breaker is completely cut off at time t ₂ shown in FIG. The

On the other hand, in the first power transmission terminal ground fault direction relay device 11 ₁ , the third AND circuit 23 ₃ of the first power transmission terminal ground fault direction relay device trip signal generation circuit 20 includes the second high-level signal. Since the signal (low level signal) obtained by inverting the polarity of the fault line determination result signal S ₂ is input, the output signal of the _third AND circuit 23 ₃ remains low.
Further, since the first OVG output signal S _OVG1 of the high level is delayed by the first time limit coordination time GT1 ₁ (= 800 ms) by the first delay circuit 22 ₁ , as described above, the third circuit breaker At the time when 4 ₃ is completely cut off, the output signal of the _first delay circuit 22 ₁ remains at the low level. Therefore, the output signal of the _first AND circuit 23 ₁ remains at a low level.
Therefore, the first trip signal T _DG1 is not output from the first power transmission terminal ground fault direction relay device 11 ₁ to the first circuit breaker 4 ₁ before the _third circuit breaker 4 ₃ is cut off.

Similarly, in the second power transmission terminal ground fault direction relay device 11 ₂ , the third AND circuit 33 ₃ of the second power transmission terminal ground fault direction relay device trip signal generation circuit 30 has a high-level first circuit. Since the signal (low level signal) obtained by inverting the polarity of the ₁ fault line determination result signal S ₁ is input, the output signal of the _third AND circuit 333 remains at the low level.
Further, since the first OVG output signal S _OVG1 at the high level is delayed by the second time cooperation time GT1 ₂ (= 800 _ms) by the first delay circuit 32 ₁ , as described above, the third circuit breaker is used. When 4 ₃ is completely cut off, the output signal of the _first delay circuit 32 ₁ remains at the low level. Therefore, the output signal of the _first AND circuit 331 remains at a low level.
Therefore, the second trip signal T _DG2 is not output from the second power transmission terminal ground fault direction relay device 11 ₂ to the second circuit breaker 4 ₂ before the _third circuit breaker 4 ₃ is cut off.

When the third circuit breaker 4 ₃ is completely cut off as described above, the second to fourth zero-phase currents I _{01 to} I ₀₄ do not flow, and the first zero phase larger than the minimum ground fault current Since only the current I ₀₁ flows through the first power transmission line 1L in the inner direction, only the first power transmission end ground fault direction relay device 11 ₁ continues to operate as shown by the shaded area in FIG. The second power receiving end ground fault direction relay device 11 ₂ and the first power receiving end ground fault direction relay device 12 ₁ do not operate, and the second power receiving end ground fault direction relay device 12 ₂ does not operate. Will remain.
In other words, the first accident line determination result signal S ₁ remains at a high level, and the second and third accident line determination result signals S ₂ and S ₃ are transmitted after the relay determination time T _RY of the relay determination circuits 31 and 41 has elapsed. changes from high level to low level, the fourth accident line determination result signal S ₄ of the remains at a low level.

As a result, in the first power transmission terminal ground fault direction relay device 11 ₁ , the third AND circuit 23 ₃ of the first power transmission terminal ground fault direction relay device trip signal generation circuit 20 has a third cutoff. When passed from vessel 4 ₃ blocked by the relay determination time T _RY relay determining circuit 21, by inverting the first polarity of the accident line determination result signals S ₁ and the second accident line determination of the low result signal S ₂ at the high level signal (high level signal) and the high level of the first OVG output signal S _OVG1 a low level first UVG output signal S _UVG1 polarity inverted signal (high level signal) is inputted. Further, since the first and second circuit breakers 4 ₁ and 4 ₂ are both in the “on state”, the first and second contact signals S _CB1 and S _CB2 at the high level are converted into the second AND circuit 23 _2. Therefore, the output signal of the _second AND circuit 23 _{2 at} the high level is input to the third AND circuit 23 ₃ . For this reason, since the output signal of the _third AND circuit 23 ₃ changes from the low level to the high level, the first trip signal T _DG1 is _switched to the relay determination time T _RY (= 20 ms from the time when the _third circuit breaker 4 ₃ is cut off. ) And the first zero-phase free vibration malfunction prevention time GT2 ₁ (= 100 ms), at the time t ₃ shown in FIG. 8B when the total time (= T _RY + GT2 ₁ = 20 ms + 100 ms = 120 ms) has elapsed. Is output from the power transmission terminal ground fault direction relay device 11 ₁ to the first circuit breaker 4 ₁ .
Accordingly, the first breaker 4 _1, as indicated by × mark in FIG. 7 (c), the third circuit breakers 4 ₃ disconnected from the relay determination time T _RY and first zero-phase free vibration lockout time The time t shown in FIG. 8B when the total time (= T _RY + GT2 ₁ + T _CB = 120 ms + 30 ms = 150 ms) of GT2 ₁ and the circuit breaker breaking time T _CB (= 30 ms) of the first circuit breaker 4 ₁ has elapsed. ₄ , completely blocked.

As a result, ground fault relay determination time T _RY and third zero-phase free vibration lockout time GT2 ₃ breaker interruption time T _CB relay determination time T _RY and first zero-phase free vibration lockout time GT2 ₁ and the circuit breaker breaking time T _CB (= (T _RY + GT 2 ₃ + T _CB ) + (T _RY + GT 2 ₁ + T _CB ) = GT 2 ₃ + GT 2 ₁ +2 (T _RY + T _CB )).
In contrast, the conventional ground fault protective relay system shown in FIG. 9, the time required to remove the ground fault from the first timed coordination time GT1 ₁ as shown in FIG. 14 (b) This is the total time (= GT1 ₁ + GT2 ₁ + T _CB ) of the first zero-phase free vibration malfunction prevention time GT2 ₁ and the circuit breaker cutoff time T _CB .
Therefore, the ground fault protective relay system according to this embodiment, as compared with the conventional ground fault protective relay system, the third zero-phase free vibration lockout time GT2 ₃ and relay judging from the first timed coordination time GT1 ₁ time T _RY twice the time as the circuit breaker breaking time T _CB and the minus time _{(= (GT1 1 + GT2 1} + T CB) - {GT2 3 + GT2 1 +2 (T RY + T CB)} = GT1 1 -GT2 3 −2T _RY −T _CB ) = 800 ms−100 ms−2 × 20 ms−30 ms) = 630 ms) earlier, the ground fault can be eliminated.

Even when an incomplete ground fault occurs near the power receiving end of the first power transmission line 1L, the ground fault current is shunted by half to the first power transmission line 1L and the second power transmission line 2L. Therefore, the first zero-phase current I ₀₁ larger than the minimum ground fault current flows through the first transmission line 1L in the inner direction, and the second zero-phase current I ₀₂ larger than the minimum ground fault current is the second The third zero-phase current I ₀₃ flowing in the inner direction through the first power transmission line 2L and flowing through the first transmission line 1L in the inner direction and larger than the minimum ground fault current is greater than the minimum ground fault current. Since the current I ₀₄ flows outward through the second transmission line 2L, the first and second power transmission terminal ground fault direction relay devices 11 ₁ and 11 ₂ and the first power receiving terminal ground fault direction relay device 12 _{1 are used.} And the second power receiving terminal ground fault direction relay device 12 ₂ does not operate.
Therefore, even in this case, the ground fault protection relay system according to the present embodiment operates in the same manner as when the above-described ground fault occurs, and can remove the incomplete ground fault at high speed.

In the conventional ground fault protection relay system shown in FIG. 9, the malfunction of the power transmission terminal ground fault line selection relay device 111 and the power receiving terminal ground fault line selection relay device 112 due to the zero-phase circulating current is shown as follows. There was a problem that the supply reliability was lowered due to the above.
The power transmission terminal ground fault line selection relay device 111 and the power reception terminal ground fault line selection relay device 112 used as the main protection are 50% of the protection section (the section between the power transmission terminal bus and the power reception terminal bus) ( It is set so as to operate with a minimum zero-phase current at the time of a failure at the line intermediate point (an incomplete zero-phase current corresponding to 30% of the protection interval).
For example, assuming that the minimum NGR capacity in the system is 100 A, the value of the current input to the power transmission terminal ground fault line selection relay device 111 and the power reception terminal ground fault line selection relay device 112 is (100 A × 0.3). ) / 2 = 15A, so that the set values of the power transmission terminal ground fault line selection relay device 111 and the power reception terminal ground fault line selection relay device 112 are 15A.
For this reason, when the zero-phase circulating current flows over 7.5 A, the relay input zero-phase current (the first and second zero-phase current transformers 3 ₁ and 3 ₂ connected to each other are connected to the power transmission terminal ground fault line. Zero-phase current input to the electric device 111 and zero-phase current input from the third and fourth zero-phase current transformers 3 ₃ and 3 _{4 connected} to each other to the power receiving terminal ground fault line selection relay device 112 ) Is twice the zero-phase circulating current (15A or more) and becomes a set value or more, so that the power transmission terminal ground fault line selection relay device 111 and the power reception terminal ground fault line selection relay device 112 malfunction. This leads to a decline in supply reliability.
In addition, when the power transmission terminal ground fault line selection relay device 111 and the power reception terminal ground fault line selection relay device 112 are set so as not to malfunction due to the zero-phase circulating current, the protection range is narrowed and an unprotected section is generated. In addition, a ground fault line selection relay device with a zero-phase circulating current countermeasure (for example, zero by calculating the difference between the effective amount of the zero-phase current at the time of the accident flowing through the difference circuit and the effective component of the zero-phase current before the accident) Change detector (variation width type) that calculates the operation amount by removing the influence of the circulating current of the phase (variation width type) Ground fault line selection relay device and compensation to remove the zero-phase circulating current from the zero-phase current of the relay input When a compensation type ground fault line selection relay device is applied, the cost increases.
On the other hand, in the ground fault protection relay system according to the present embodiment, the power transmission terminal ground fault line selection relay device 111 and the power receiving terminal ground fault line selection relay device 112 can be made unnecessary, and the first and since the second sending end ground fault direction relay device 11 _1, 11 ₂ and the first and second receiving end earth fault direction relay device 12 _1, and 12 ₂ do not work with zero-phase circulating current, supply reliability Can be avoided.

Further, for example, when a ground fault (external ground fault) occurs in the power transmission line behind the first power transmission line 1L, the first and second power transmission terminal ground fault direction relay devices 11 ₁ and 11 ₂ Although it operates (that is, it is determined that “a ground fault has occurred in the direction of the own line”), the first and second power transmission end ground fault direction relay devices 11 ₁ and 11 ₂ operate together. And the second circuit breakers 4 ₁ and 4 ₂ are not disconnected at high speed.

In the above description, the first and second power transmission terminal ground fault direction relay devices 11 ₁ and 11 ₂ are individually configured, but may be configured integrally. The same applies to the first and second power receiving terminal ground fault direction relay devices 12 ₁ and 12 ₂ .

It is a figure which shows the structure of the ground fault protection relay system by one Example of this invention. Is a block diagram showing the configuration of the first sending end ground fault direction relay device trip signal generating circuit 20 to the first sending end ground fault direction relay device 11 ₁ shown in FIG. 1 is provided. Is a block diagram showing the configuration of the second sending end ground fault direction relay device trip signal generating circuit 30 in which the second sending end ground fault direction relay device 11 ₂ shown in FIG. 1 is provided. It is a block diagram showing a configuration of a first receiving end earth fault direction relay device trip signal generating circuit 40 to first receiving end earth fault direction relay device 12 ₁ shown in FIG. 1 is provided. It is a block diagram showing a configuration of a second receiving end earth fault direction relay device trip signal generating circuit 50 in which the second receiving end earth fault direction relay device 12 ₂ shown in FIG. 1 is provided. It is for demonstrating operation | movement of the ground fault protection relay system shown in FIG. 1 at the time of the occurrence of a ground fault near the power transmission end of the first transmission line 1L. It is for demonstrating operation | movement of the ground-fault protection relay system shown in FIG. 1 when a ground-fault accident generate | occur | produces near the receiving end of 1 L of 1st power transmission lines. It is for demonstrating operation | movement of the ground fault protection relay system shown in FIG. 1 at the time of the occurrence of a ground fault in the vicinity of the power transmission end and the power receiving end of the first power transmission line 1L. It is a figure which shows the structure of the conventional ground fault protection relay system which uses a ground fault line selection relay apparatus as main protection, and uses a ground fault direction relay apparatus as backup protection. It is a block diagram which shows the structure of the 1st power transmission terminal ground fault direction relay apparatus trip signal generation circuit 130 with which the 1st power transmission terminal ground fault direction relay apparatus 121 ₁ shown in FIG. 9 is provided. Is a block diagram showing a configuration of a first receiving end earth fault direction relay device trip signal generating circuit 140 in which the first receiving end earth fault direction relay device 122 ₁ shown in FIG. 9 is provided. It is a figure for demonstrating the problem in the ground fault protection relay system shown in FIG. It is a figure for demonstrating the problem in the ground fault protection relay system shown in FIG. It is a figure for demonstrating the problem in the ground fault protection relay system shown in FIG.

Explanation of symbols

3 _{1 to} 3 _{4 1st} to _4th zero-phase current transformers 4 ₁ to ₄ 4 _1st to _4th circuit breakers 5 ₁ and 5 ₂ 1st and 2nd earthing-type instrument transformers 11 ₁ and 11 _2, 121 _1, 121 ₂ first and second sending end ground fault direction relay device 12 _1, 12 _2, 122 _1, 122 ₂ first and second receiving end earth fault direction relay device 20, 30 first First and second power transmission terminal ground fault direction relay device trip signal generation circuits 40, 50 First and second power reception terminal ground fault direction relay device trip signal generation circuits 21, 31, 41, 51, 131, 141 Relays the decision circuit 22 ₁ to 22 _3, 321 _to 323, 42 ₁ to 42 _3, 52 ₁ to 52 _3, 132 ₁ to 132 _3, 142 _{1 to 142 3} first to third delay circuit (timer)
23 _{1-23 3,} 33 _to 333, 43 ₁ to 43 _3, 53 ₁ to 53 ₃ first to third AND circuit 24,34,44,54,134,144 OR circuit 111 sending end locations Power line selection relay device 112 Power receiving end ground fault line selection relay device 130 First power transmission end ground fault direction relay device trip signal generation circuit 140 First power receiving end ground fault direction relay device trip signal generation circuit 133 143 aND circuit 1L, 2L first and second transmission line I ₀₁ ~I ₀₄ first to fourth zero-phase current V _0S sending end zero-phase voltage V _0R receiving end zero-phase voltage S ₁ to S ₄ first To fourth _fault line determination result signals S _OVG1 and S _OVG2 first and second OVG output signals S _UVG1 and S _UVG2 first and second UVG output signals S _{CB1 to} S _CB4 first to fourth contact signals GT1 ₁ ～GT1 ₄ first to fourth timed coordination time GT2 ₁ ～GT2 ₄ first乃The fourth zero-phase free vibration lockout time GT3 ₁ ～GT3 ₄ first to fourth OVG interruption time T _RY relay judgment time T _CB breaker interruption time T _DG1 through T _DG4 first to fourth trip signal t ₀ ~ T ₆ time

Claims (4)

A ground fault protection relay system for protecting a balanced two-line power transmission line composed of first and second power transmission lines (1L, 2L) laid between a power transmission end bus and a power reception end bus from a ground fault. There,
It is determined that the overvoltage relay for detecting the ground fault on its own side has been operated, “a ground fault has occurred in the direction of its own line”, and other ground fault direction relays installed on its own side of the adjacent line. The electric device does not determine that “a ground fault has occurred in the direction of its own line” and two circuit breakers (4 ₁ , 4 ₂ : 4 installed on the own side of the own line and the adjacent line, respectively) ₃ , 4 ₄ ) Trip signal that instantaneously generates trip signals (T _{DG1 to} T _DG4 ) for breaking the circuit breaker installed on the own end of the own line on condition that both are in the on state A ground fault protection relay system comprising a ground fault direction relay device (11 ₁ , 11 ₂ , 12 ₁ , 12 ₂ ) provided with an instantaneous generation means.   2. The trip signal instantaneous generation means instantaneously generates the trip signal on the condition that the short-circuit detection ground shortage voltage relay device for detecting a short circuit on its own side is inoperative. Ground fault protection relay system.   When the ground fault direction relay device is set to operate with the minimum ground fault current regardless of the failure point at the time of an internal failure in the protection section, and is used as one line protection for the balanced two-line transmission line The ground fault protection relay system according to claim 1, wherein the ground fault protection relay system is set to operate with a minimum ground fault current at the time of failure of the counterpart bus at the time of parallel use of two lines. First and second power transmission terminal ground fault direction relay devices (11 ₁ , 11 ₂ ) respectively installed on the power transmission terminal side of the first and second power transmission lines;
First and second power receiving end ground fault direction relay devices (12 ₁ , 12 ₂ ) installed on the power receiving end sides of the first and second power transmission lines, respectively,
That the first power transmission terminal ground fault direction relay device operates the first ground fault detection overvoltage relay device installed in the power transmission terminal bus, "a ground fault has occurred in the direction of the own line" That the second power transmission end ground fault direction relay device has not determined that “a ground fault has occurred in the direction of the own line”, and the power transmission end sides of the first and second power transmission lines. The first and second circuit breakers (4 ₁ , 4 ₂ ) respectively installed in the circuit are in the on state, and a first short-circuit detection ground fault undervoltage relay device installed in the power transmission terminal bus On the condition that the first UVG output signal (S _UVG1 ) indicating that the magnitude of the positive phase voltage at the transmission end of the balanced two-line transmission line has become equal to or less than the set value is not input. first occurring first trip signal for interrupting the vessel to (T _DG1) instantly Equipped with a lip signal instant generating means,
The second power transmission terminal ground fault direction relay device has determined that the first ground fault detection overvoltage relay device has been operated, “a ground fault has occurred in the direction of the own line”, 1 that the power transmission terminal ground fault direction relay device does not determine that “a ground fault has occurred in the direction of the own line”, that both the first and second circuit breakers are in an on state, and Second trip signal instantaneous generating means for instantaneously generating a second trip signal (T _DG2 ) for _breaking the second circuit breaker on condition that the first UVG output signal is not inputted. Prepared,
The first power receiving end ground fault direction relay device is operated by the second ground fault detection overvoltage relay device installed in the power receiving end bus, "a ground fault has occurred in the direction of the own line" That the second power receiving end ground fault direction relay device has not determined that “a ground fault has occurred in the direction of the own line”, the power receiving end side of the first and second power transmission lines The third and fourth circuit breakers (4 ₃ , 4 ₄ ) respectively installed in the power supply are in the on state, and a second short-circuiting detection ground fault undervoltage relay device installed on the power receiving end bus On the condition that the second UVG output signal (S _UVG2 ) indicating that the magnitude of the positive phase voltage at the receiving end of the balanced two-line transmission line has become less than or equal to the set value is not input. third trip signal for interrupting the vessel (T _DG3) instantly third generated Equipped with a lip signal instant generating means,
The second power receiving end ground fault direction relay device has determined that the second ground fault detection overvoltage relay device has been operated, "a ground fault has occurred in the direction of the own line", 1 that the receiving end ground fault direction relay device has not determined that “a ground fault has occurred in the direction of the own line”, that both the third and fourth circuit breakers are in an on state, and A fourth trip signal instantaneous generating means for instantaneously generating a fourth trip signal (T _DG4 ) for _breaking the fourth circuit breaker on condition that the second UVG output signal is not inputted; Prepare
The ground fault protection relay system according to any one of claims 1 to 3, wherein