JPH0767243A - Short circuit line selectively protecting relay - Google Patents

Abstract

PURPOSE:To realize an inexpensive and highly reliable short circuit line selectively protecting relay which does not require a large scale facility and does not function erroneously upon occurrence of bus failure under 1A2B operation. CONSTITUTION:Current 11 and bus voltage VA of line #1 1L are fed through converters 12, 13, a filter 14, a sample & hold 15, a multiplexer 16, and an A/D converter 17 to an operational processing circuit 18 where an impedance ZF is calculated. A failure detecting section 18b delivers the comparison result of ZF1 and a set value ZS1 to a decision section 18c where a decision is made that a failure has occurred when the ZF1 is lower than the ZS1 and has same sign and a signal R1 goes '1'. Similar system is also provided for line #2 2L and a decision section 28c makes a decision that a fault has occurred when the impedance ZF2 of the line #2 is lower than a settled value ZS2 and has same sign and a signal R2 goes '1'. The signals R1, R2 are fed to interruption output sections 28d, 18d and the output section 18d delivers an interruption command signal to a circuit breaker 110 only when R1 is '1' and R2 is '0' whereas the output section 28d delivers an interruption command signal to a circuit breaker 210 only when R2 is '1' and R1 is '0'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a short-circuit selective protection relay for a balanced two-circuit transmission line.

[0002]

2. Description of the Related Art Impedance balanced relay devices are often used as short circuit line selective protection relay devices for balanced two-line power transmission lines in consideration of reliability and operating time. FIG.
FIG. 4 is a schematic diagram of a balanced two-circuit power transmission line system, in which the current is positive in the direction from the power transmission end bus SB to the power reception end bus RB. In FIG. 13, when a short-circuit fault occurs at point F of Line 1L, the fault current I is shunted into Line 1L and Line 2L as I1 and I2, and the current I1 flows through the current transformer CT1. A current I2 flows through the sink CT3. A current -I2 flows through the current transformers CT2 and CT4. Then, the current I1−I2 flows through the protective relay SSA, and the current I2 − (− I2) flows through the protective relay SSB (note that P1).
S is a power supply, PT1 and PT2 are transformers, and L is a load). Further, the magnitudes of the currents I1 and I2 are calculated by the following equation (1
-1) and (1-2). I1 = 0.5 (2-α) I ----- (1-1) I2 = 0.5αI ----- (1-2) However, α is (distance from the transmission end bus SB to point F).
/ (Distance from the power transmitting end bus SB to the power receiving end bus RB).

In the above formula, when 0 <α <1 (within the protection range of the impedance balance protection device), I1> I2, and the current of the faulty line is larger than the current of the sound line at the transmitting end bus SB side, On the bus RB side, the directions (signs) of the fault line current and the sound line current are opposite. Therefore, if the difference current between the 1st line 1L and the 2nd line 2L is obtained, the faulty line can be determined. However, the magnitude of the current differs depending on the system, and the magnitude of the difference current for determining a failure also depends on the individual system. Therefore, the failure detection by the difference current is not preferable. Therefore, by dividing the bus voltage by the transmission line differential current, the unbalanced impedance is calculated, and based on the magnitude of the calculated unbalanced impedance, the impedance balanced relay device is a short-circuit line selection protection relay device. Is often used as

[0004]

By the way, considering an operation in a balanced two-circuit transmission line system having a double-bus line configuration of Kotsu, which does not cause a power supply failure when a single bus line fails,
As shown in FIG. 14, connect Line 1 1L to the Kombus Line and
It is desirable to use 1 Ko 2 Oto, which connects Line 2L to Otsubo.
In the example of FIG. 14, the circuit breakers CB A and CBA1 are connected to the power transmission end side of Line 1L, and the circuit breaker CBB1 is connected to the power reception end side. In addition, circuit breakers CB B and CBA2 are connected to the power transmission end side of Line 2 2L,
A circuit breaker CBB2 is connected to the power receiving end side. And
A circuit breaker CBT is connected between the former bus and the second bus.

[0005] In the operation of No. 1 and No. 2 O, for example, if a trouble occurs on the Otsu bus, a bus protective relay device (not shown)
As a result, among the circuit breakers, CB B, CBT, and CBA2 are tripped, and the former bus and Line 1 1L remain, so that power supply to the power receiving end can be maintained. However, in reality, many Kotsu Otsu double bus systems do not operate 1 Ko 2 Otsu as described above, and operate by connecting Kosei Bus or Otsubo Line to Lines 1 and 2 as well. . This is balance 2
This is because the impedance balance protection relay device, which is mainly used for line power transmission line protection, may perform unnecessary operation when the bus fault occurs and the power receiving end may be completely stopped.

FIGS. 15 to 17 show a balanced two-circuit transmission line system having a double-bus line configuration for the second and third bus lines. Taking a case where a three-line short-circuit fault occurs on the first and second bus lines as an example, impedance balance protection is performed. The problems of the relay device will be described. First, as shown in FIG. 15, when a 3-wire short-circuit fault occurs at point F of the O-bus, a bus protection relay device (not shown) operates and trips the circuit breakers CB O, CBT, and CBA2. The action is taken. In this case, circuit breaker CB B, CBT, CBA
2 may not be interrupted at the same time, and the interrupting timing may be shifted (due to the occurrence of an arc, etc.), for example, the tripping of the circuit breaker CBA2 may be delayed (in FIG. 15, the crosses are interrupted in each circuit breaker). Indicates).

Then, as shown in FIG. 16, a fault current flows in the power transmission line, and the impedance balance protection relay SS
The voltage, current, and impedance seen from A and SSB are as shown in the following equations (2-1) to (2-3) and (3-1) to (3-3). SSA voltage VA = 2ZLI --- (2-1) current IA = I-(-I) = 2I --- (2-2) impedance VA / IA = ZL --- (2-3) SSB voltage VB = ZLI --- (3-1) current IB = (-I) -I = -2I --- (3-2) impedance VB / IB = -0.5ZL --- (3-3) Therefore, relay The device SSA trips the circuit breaker CBA1,
The relay device SSB removes the circuit breaker CBB2.
As shown in Fig. 7, both Line 1L and Line 2L are disconnected from the Kombus Line and Otsubus Line, resulting in a total power failure at the power receiving end. In this way, the impedance balance protection relay is
As mentioned above, there is a possibility of all blackouts, so it was not possible to apply the 1st, 2nd, and 3rd operations.

In addition to the above, as a transmission line protection, there are a carrier protection relay device and a pilot protection relay device which are not likely to malfunction even when operated in the first and second orders, but in principle, communication equipment between terminals is required. Therefore, it is difficult to apply it to equipment other than the important ones because it is very costly to install new equipment. For example, a pilot wire protection relay device is shown in FIG.
In FIG. 18, the protection relay device PR converts the current information of the power transmission line into an electric signal and transmits the electric signal to the transmission device TD. In this transmission device TD, the supplied electric signal is converted into a PCM signal and then converted from a parallel signal into a serial signal. Further, the signal converted into the serial signal is converted into an optical signal and supplied to the optical interface OI. This optical interface OI has
Protection relay signals and control signals from other devices are also supplied. Further, the optical terminal OT performs amplification, information compression, and high-speed transmission of optical signal levels to be transmitted and received so that long-distance communication can be performed. The optical terminal OT is connected to the overhead ground wire OPGW with built-in optical fiber supported at the tops of the plurality of steel towers ST, and signals are transmitted / received to / from a communication device or the like at the power receiving end. As described above, the pilot wire protection relay device requires a large-scale communication facility and is expensive, so that it can be applied only to important lines.

An object of the present invention is to realize a short-circuit line selective protection relay device which has a high reliability without using large-scale equipment, is inexpensive, and does not malfunction even when a bus failure occurs in operation of 1A and 2B. It is to be.

[0010]

In order to achieve the above object, the present invention is configured as follows. In a short-circuit line protection protection device for balanced two lines, a first line determining means for determining whether or not a fault has occurred in line 1 based on the line 1 current and the voltage at the transmitting end bus, and line 2 Based on the current and the transmission end bus voltage, the first Line 2 determining unit that determines whether or not a failure has occurred in Line 2 and the Line 1 determining unit determines that a failure has occurred, and the Line 2 determining unit Only when it is determined that no failure has occurred, the first disconnection command means for supplying an interruption command to the first circuit breaker arranged near the power transmission end of Line 1 and the Line 2 determination means determine that a failure has occurred, and 1 Second disconnection command means for supplying a disconnection command to a second circuit breaker arranged near the power transmission end of line 2 only when the line determination means determines that no failure has occurred, and line 1 current and power receiving end bus voltage To determine whether or not Line 1 has a failure based on No. 1 line judging means, No. 2 line No. 2 judging unit, and No. 2 No. 1 line judging unit for judging whether or not a failure has occurred in No. 2 line based on No. 2 line current and receiving end bus voltage. Third disconnection command means for supplying a disconnection command to a third circuit breaker arranged near the power receiving end of line 1 only when it is determined that a failure has occurred and the second line 2 determination means determines that no failure has occurred Then, only when the second Line 2 determining unit determines that a failure has occurred and the second Line 1 determining unit determines that no failure has occurred, the fourth circuit breaker arranged near the power receiving end of Line 2 is disconnected. And a fourth cutoff command means for supplying a command.

Preferably, in the balanced two-circuit short-circuit line protective protection device, the first and second Line 1 determining means are provided with a Line 1 current and a transmitting end or receiving end bus voltage,
An impedance calculation means for calculating the line 1 line impedance; and a failure judgment means for judging whether or not the calculated impedance is smaller than the settling value and is equal to the sign of the settling value. 1 and second 2
The line determining means calculates impedance of the line 2 line from the line 2 current and the bus voltage at the transmitting end or the receiving end, and the calculated impedance is smaller than the settling value, and the sign of the settling value is positive or negative. And failure determination means for determining whether or not

Preferably, in the balanced two-line short-circuit selection protection relay, the first and second line 1 determining means and the first and second line 2 determining means are digital circuits. A filter circuit configured to extract a fundamental wave signal from a current signal and a voltage signal, a sample hold circuit temporarily holding an output signal of the filter circuit, and a multiplexer circuit to which the output signal of the sample hold circuit is supplied. And an A / D conversion circuit for converting the output signal of this multiplexer circuit into a digital signal, and the output signal from this A / D conversion circuit is supplied to each judging means.

In the balanced two-line short-circuit selection protection relay, preferably, the first and second Line 1 determining means and the first and second Line 2 determining means are digital circuits. The first line 1 determining means and the first line 2 determining means temporarily output a filter circuit for extracting a fundamental wave signal from the line 1 current and line 2 current signals and a voltage signal, and an output signal of the filter circuit. Sample hold circuit that holds the signal, a multiplexer circuit to which the output signal of the sample hold circuit is supplied, and an A / D that converts the output signal of the multiplexer circuit into a digital signal
A signal corresponding to the line 1 current signal and a signal corresponding to the power transmission end bus voltage among the output signals from the A / D conversion circuit are the first line 1 determination means. And a signal corresponding to the line 2 current signal and a signal corresponding to the power transmission end bus voltage are supplied to the first line 2 determination means.

[0014]

The first disconnection command means supplies the disconnection command to the first circuit breaker only when a failure occurs on the transmission end side of the Line 1 and no failure occurs on the transmission end side of the Line 2. Under the conditions other than the above, the breaking command is not supplied to the first breaker. Further, the second cutoff command means supplies the cutoff command to the second circuit breaker only when a failure occurs on the Line 2 power transmission end side and a failure does not occur on the Line 1 power transmission end side, and otherwise. In the case of the above condition, the shutoff command is not supplied to the second circuit breaker.

Similarly, the third disconnection command means supplies the disconnection command to the first circuit breaker only when a failure occurs on the receiving end side of the line 1 and no failure occurs on the receiving end side of the line 2. Then
Under other conditions, the breaker command is not supplied to the first breaker. And the fourth cutoff command means is
A disconnection command is supplied to the second circuit breaker only when a failure occurs on the receiving end side of Line 2 and no failure occurs on the receiving end side of Line 1, and in the case of other conditions, the second No break command is supplied to the breaker. As a result, it is possible to realize a highly reliable short-circuit line selective protection relay device that does not malfunction even if the bus line fails in the operation of No. 1 and No. 2 O.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the embodiments of the present invention, the principle of the present invention will be described. According to the present invention, a distance protection relay device is installed on each of Line 1 and Line 2, and a logic that the distance protection relay of the adjacent line is inoperative and that the distance protection relay of the own line is operating is provided. Depending on the product conditions, the distance protection relay device of the own line issues a breaker trip command. Here, the distance protection relay device measures the line impedance up to the fault point by the bus voltage and line current at the time of transmission line fault, and its value is less than or equal to the value set beforehand (set), and the positive sign. When there is, it gives a command to the circuit breaker and trips it.

That is, if the failure point is closer than the set value of the distance protection relay device, it is judged as a failure, and the protection range of the distance protection relay device is selected according to the distance. Commonly used to protect single-line power lines. In the present invention, the above distance protection relay device is used for short-circuit line selective protection of two balanced lines.

FIG. 6 is a diagram for explaining the principle of the present invention, which is an example in the case of a single bus system. In FIG.
DZ is a distance protection relay installed at the power transmission end of Line 1 1L
A distance protection relay installed at the power transmission end of Lines A1 and D
The distance protection relay installed at the power receiving end of ZA2 and Line 1 is DZB1, and the distance protection relay installed at the power receiving end of Line 2 is DZB2. Further, the distance relays included in the respective devices are RYA1, RYA2, RYB1, and RYB2.

The distance relay RYA1 calculates the line impedance based on the output signals from the transformer PT1 and the current transformer CT1, and when the calculated line impedance is smaller than the set value (however, the sign is positive). , The output signal level becomes "1", and when it is larger than the set value, the output signal level becomes "0". The output signal of the distance relay RYA1 is the AND circuit A of the distance protection relay device DZA1.
The relay R is supplied to one input terminal of ND1.
An inverted signal of the output signal of YA1 is supplied to one input terminal of the AND circuit AND2 of the relay device DZA2. The output signal of the AND circuit AND1 is supplied to the circuit breaker CBA1.

The distance relay RYA2 is a transformer PT.
1 and the output signal from the current transformer CT3, the line impedance is calculated. When the calculated line impedance is smaller than the set value, the output signal level becomes "1", and when it is larger than the set value. Output signal level is "0"
Becomes The output signal of the distance relay RYA2 is supplied to the other input terminal of the AND circuit AND2 of the distance protection relay device DZA2, and the inverted signal of the output signal of the relay RYA2 is supplied to the AND circuit AND1 of the relay device DZA1.
Is supplied to the other input terminal of the. Also, AND circuit AND
The output signal of 2 is supplied to the circuit breaker CBA2.

The distance relay RYB1 calculates the line impedance based on the output signals from the transformer PT2 and the current transformer CT2. When the calculated line impedance is smaller than the set value, the output signal level is "1". When the value is larger than the set value, the output signal level becomes "0". The output signal of the distance relay RYB1 is supplied to one input terminal of the AND circuit AND3 of the distance protection relay device DZB1, and the inverted signal of the output signal of the relay RYB1 is supplied to one of the AND circuit AND4 of the relay device DZB2. Is supplied to the input end of. The output signal of the AND circuit AND3 is supplied to the circuit breaker CBB1.

Further, the distance relay RYB2 is a transformer PT.
2 and the output signal from the current transformer CT4, the line impedance is calculated. When the calculated line impedance is smaller than the set value, the output signal level becomes "1", and when it is larger than the set value. Output signal level is "0"
Becomes The output signal of the distance relay RYB2 is supplied to the other input terminal of the AND circuit AND4 of the distance protection relay device DZB2, and the inverted signal of the output signal of the relay RYB2 is supplied to the AND circuit AND3 of the relay device DZB1.
Is supplied to the other input terminal of the. Also, AND circuit AND
The output signal of 4 is supplied to the circuit breaker CBB2.

As can be understood from the configuration described above,
Each distance protection relay device has a circuit breaker trip command when its own line relay is operating (output signal level "1") and the adjacent line relay is not operating (output signal level "0"). The signal is designed to be output. For example,
The breaker trip command signal of the relay device DZA1 is output when the relay RYA1 is operating and the relay RYA2 is not operating.

Regarding the settling value, in principle, the relays RYA1 and RYA2 should have a line impedance of 1 or more (ZL or more) and the relays RYB1 and RYB2 should have a positive impedance. In consideration of the error of PT, the error of the relay itself, etc., the relay RYA1
And RYA2 are 1.4 times the line impedance (1.4
ZL) and the relays RYB1 and RYB2 are set to twice the line impedance (2ZL).

As shown in FIG. 7, α on Line 1L
If a short-circuit fault occurs at point F (intermediate between the power transmitting end and the power receiving end) of = 0.5, the voltage, current, and impedance seen from each relay are expressed by the following equations (4-1) to (4-3). , (5-
1) to (5-3), (6-1) to (6-3), (7-
It becomes like 1) to (7-3). RYA1 voltage VA = 0.5ZL × 0.75I --- (4-1) current IA1 = 0.75I --- (4-2) impedance VA / IA1 = 0.5ZL --- (4-3) RYA2 Voltage VA = 0.5ZL × 0.75I --- (5-1) Current IA2 = 0.25I --- (5-2) Impedance VA / IA2 = 1.5ZL --- (5-3) RYB1 voltage VB = 0.5ZL × 0.25I-(6-1) Current IB1 = 0.25I-(6-2) Impedance VB / IB1 = 0.5ZL-(6-3) RYB2 Voltage VB = 0.5ZL × 0.25I --- (7-1) Current IB2 = -0.25I --- (7-2) Impedance VB / IB2 = -0.5ZL --- (7-3) Therefore, Relay RYA1 is 1.4ZL> 0.5ZL And the output signal is "1", the relay RYA2 is 1.4Z
Since L <1.5ZL, the output signal is "0". Therefore, the distance protection relay device DZA1 operates and DZA2
Will be inactive. In addition, relay RYB1 is 2.0ZL
> 0.5ZL, so output signal is "1", relay RYB
Since 2 is -0.5ZL, the output signal is "0".
Therefore, the distance protection relay device DZB1 operates and DZB1
B2 becomes inoperative. Therefore, circuit breakers CBA1 and CBA
BB1 is tripped, Line 1 1 is separated from the system, and the fault is removed (in FIG. 7, the relays circled are in the operating state, and the relays not circled are
Indicates an inoperable state).

Next, as shown in FIG. 8, point F of α = 0.9 in Line 1L (position near the receiving end bus RB).
If a short-circuit fault occurs at, the voltage, current, and impedance seen from each relay are calculated by the following equations (8-1) to (8-
3), (9-1) to (9-3), (10-1) to (10
-3) and (11-1) to (11-3). RYA1 voltage VA = 0.9ZL × 0.55I-(8-1) current IA1 = 0.55I-(8-1) impedance VA / IA1 = 0.9ZL-(8-1) RYA2 Voltage VA = 0.9ZL * 0.55I --- (9-1) Current IA2 = 0.45I --- (9-2) Impedance VA / IA2 = 1.1ZL --- (9-3) RYB1 voltage VB = 0.1ZL × 0.45I-(10-1) Current IB1 = 0.45I-(10-2) Impedance VB / IB1 = 0.1ZL-(10-3) RYB2 Voltage VB = 0.1ZL × 0.45I --- (11-1) Current IB2 = -0.45I --- (11-2) Impedance VB / IB2 = -0.1ZL --- (11-3) In this case , Relay RYA1 has 1.4ZL> 0.9 ZL
So the output signal is "1" and the relay RYA2 is 1.4
Since ZL> 1.1ZL, the output signal is "1". Therefore, the distance protection relay devices DZA1 and DZA2 are inoperative. In addition, the relay RYB1 has 2.0ZL>
Since it is 0.1ZL, the output signal is "1", relay RYB2
Is -0.1ZL, the output signal is "0". Therefore, the distance protection relay device DZB1 operates and DZB
2 is inoperative. Therefore, only the circuit breaker CBB1 is tripped. After that, since a current flows as shown in FIG. 9, only the relay RYA1 operates, CBA1 is tripped, and Line 1 1L can be separated from the system.

Further, as shown in FIG. 10, if a short-circuit fault occurs at point F (outside the power receiving end bus) outside the protection section of the transmission line protection relay device, the voltage, current, and
The impedance is expressed by the following equations (12-1) to (12-3),
(13-1) to (13-3), (14-1) to (14-
3) and (15-1) to (15-3). RYA1 voltage VA = ZL × 0.5I --- (12-1) current IA1 = 0.5I --- (12-2) impedance VA / IA1 = ZL --- (12-3) RYA2 voltage VA = ZL × 0.5I ----- (13-1) current IA2 = 0.5I ----- (13-2) impedance VA / IA2 = ZL ----- (13-3) RYB1 voltage VB = about 0 ----- 14-1) Current IB1 = -0.5I --- (14-2) Impedance VB / IB1 = about 0 (sign is-) --- (14-3) RYB2 voltage VB = about 0 --- (15 -1) Current IB2 = -0.5I --- (15-2) Impedance VB / IB2 = about 0 (sign is-) --- (15-3) In this case, the relay RYA1 has 1.4ZL> ZL. So the output signal is "1" and the relay RYA2 is 1.4Z L
Since> 1.1 ZL, the output signal becomes "1". Therefore, the distance protection relay devices DZA1 and DZA2 are inoperative. Further, since the relay RYB1 is about 0 (the sign is negative), the output signal is "0", and the relay RYB2 is also about 0 (the sign is negative), so the output signal is "0". Therefore, the distance protection relay devices DZA1, DZA2, DZB1,
DZB2 becomes inoperative. After all, the relay device does not malfunction. As described above, according to the principle of the present invention, in the single bus system, the operation is similar to that of the impedance balance protection relay device, and the short-circuit line can be selected and protected.

Now, let's consider the case of the operation of the first and second Otsuko, which was a problem in the conventional impedance balance protection relay device. FIG. 11 shows an operating system of 1 Party 2 Party 2 based on the principle of the present invention. In the example shown in FIG. 11, unlike the conventional impedance balance protection relay device, the voltage seen from each distance relay on the transmitting end side is drawn from the instep bus for the relay arranged on the 1st line 1L, and the 2nd line. The relay placed on 2L is pulled in from the Otomo Line.

Now, as shown in FIG. 12, after a failure occurs at point F of the Otsu bus, a busbar protection relay device (not shown) operates, and after the breakers CB O and CBT are tripped, It is assumed that the trip of the circuit breaker CBA2 is delayed. In this case, the voltage, current, and impedance seen from each relay are
-1) to (16-3), (17-1) to (17-3),
(18-1) to (18-3), (19-1) to (19-
It becomes like 3).

RYA1 voltage VA1 = 2ZLI ----- (16-1) current IA1 = I ----- (16-2) impedance VA1 / IA1 = 2ZL ----- (16-3) RYA2 voltage VA2 = about 0 ----- -(17-1) Current IA2 = -I --- (17-2) Impedance VA2 / IA2 = about 0 (sign is-) --- (17-3) RYB1 voltage VB1 = ZLI --- (18- 1) Current IB1 = -I --- (18-2) Impedance VB1 / IA1 = -ZL --- (18-3) RYB2 voltage VB2 = ZLI --- (19-1) Current IB2 = I --- (19-2) Impedance VB2 / IA2 = ZL --- (19-3) In this case, the relay RYA1 has 1.4ZL <2ZL, so the output signal is "0" and the relay RYA2 has a value of about 0 (the sign is negative). So, the output signal is "0". Therefore,
The distance protection relay devices DZA1 and DZA2 are inoperative. Since the relay RYB1 is -ZL, the output signal is "0", and the relay RYB2 is 2.0> ZL, the output signal is "1". Therefore, the distance protection relay devices DZA1, DZA2, DZB1 are inoperative, DZB2 is in operation, and only the circuit breaker CBB2 is interrupted. As a result, the circuit breakers CB, CBA1, and CBB1 remain without being cut off, so that it is possible to prevent a total power failure at the power receiving end.

As described above, according to the present invention, even if the busbar failure occurs during the operation of No. 1 and No. 2 and the interruption of the breaker CBA2 of the transmission line breakers is delayed with respect to the interruption timing of other breakers. , There will be no total power outage at the receiving end. Therefore, it is possible to realize a short-circuit protection relay device which is inexpensive, yet highly reliable, and which is also applicable to the operation of A and B.

An embodiment based on the above-described principle of the present invention will be described below. FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention, in which independent distance protection relays 10 and 20 are installed on the 1st line 1L side and the 2nd line 2L side, respectively.
This is an example of a case where a protective relay operation is executed by transmitting and receiving those distance relay operating conditions.

However, FIG. 1 shows a protective relay device arranged on the transmission line bus side in a balanced two-line transmission line system and constituted by a digital circuit. Although not shown, the protective relay device is shown on the receiving end bus side. A protective relay device similar to the protective relay device shown in FIG. 1 is arranged.

Now, in FIG. 1, current I of Line 1 1L
1 is detected by the line 1 current detector 11, and the detected current is supplied to one input end of the filter circuit 14 via the input converter (transformer) 12.

The power transmission end bus voltage VA is detected by the bus voltage detector 31, and the detected voltage is supplied to the other input end of the filter circuit 14 via the input converter (transformer) 13. It Then, the filter circuit 14 extracts the fundamental wave components of the current I1 and the voltage VA.

The output signal of the filter circuit 14 is supplied to the sample hold circuit 15 and temporarily held. Then, the output signal from the sample hold circuit 15 is supplied to the A / D conversion circuit 17 via the multiplexer circuit 16 and converted from an analog signal to a digital signal.

The digitally converted No. 1 line current I1 and the bus voltage VA are supplied to the arithmetic processing circuit 18. In the arithmetic processing circuit 18, first, the impedance calculation unit 18a calculates the ratio of the bus voltage VA to the Line 1 current I1, that is, the impedance ZF1 on the Line 1 side from the transmission end bus to the failure point according to the impedance calculation program. It

Then, the calculated impedance ZF1
Is supplied to the failure detection unit 18b, and it is determined according to the determination program whether the impedance ZF1 is larger than the set value ZS1 and whether the sign is positive or negative. A signal indicating this determination result is supplied to the determination unit 18c.

In the judging section 18c, the failure detecting section 18
From the determination result supplied from b, the impedance ZF1
Is smaller than the settling value ZS1 and the sign is equal to the settling value ZS1, it is determined that a short circuit fault has occurred within the settling range, and the level of the line 1 side relay operation signal R1 is set to "
If the impedance ZF1 is greater than or equal to the set value ZS1, the level of the operation signal R1 is set to “0”.
Then, this operation signal R1 is supplied to the cutoff output unit 18d and also to the cutoff output unit 28d via the input / output units 19 and 29.

The cutoff output section 18d outputs the operation signal R1
The disconnection command signal is supplied to the circuit breaker 110 only when the operation signal R2 is at the 1 "level and the operation signal R2 is at the" 0 "level. When the operation signals R1 and R2 are other than the above conditions,
No interruption command signal is supplied from the interruption output unit 18d to the circuit breaker 110.

Further, a distance protection relay device 20 having the same structure as that of Line 1 1L is also installed on Line 2L. That is, the line 2 current I2 detected by the line 2 current detector 21 and the bus voltage VA detected by the bus voltage detector 31 are supplied to the filter circuit 24 via the input converters (transformers) 22 and 23, respectively. Supplied. Then, the output signal from the filter circuit 24 passes through the sample hold circuit 25, the multiplexer 26, and the A / D conversion circuit 27, and the impedance calculation unit 28 of the arithmetic processing circuit 28.
is supplied to a.

In the impedance calculator 28a,
The ratio between the bus voltage VA and the line 2 current I2, that is, the impedance ZF2 on the line 2 side is calculated. The calculated impedance ZF2 is supplied to the failure detection unit 28b,
It is determined whether it is larger than the set value ZS2 and whether the sign is positive or negative. A signal indicating this determination result is supplied to the determination unit 28c.

When the impedance ZF2 is smaller than the settling value ZS2 and the signs are equal, the judging section 18c judges that a short-circuit fault has occurred, and sets the level 2 relay relay operation signal R2 to "1". . If the impedance ZF2 is greater than or equal to the set value ZS2, the operation signal R2
The level of is set to "0". Then, this operation signal R2
Is supplied to the cutoff output unit 28d and is also supplied to the cutoff output unit 18d via the input / output units 29 and 19.

The cutoff output unit 28d outputs the operation signal R2
The cutoff command signal is supplied to the circuit breaker 210 only when the operation signal R1 is at the 1 "level and the operation signal R1 is at the" 0 "level. When the operation signals R1 and R2 are other than the above conditions,
No interruption command signal is supplied from the interruption output unit 28d to the circuit breaker 210.

As described above, according to the first embodiment of the present invention, similarly to the above-mentioned principle door of the present invention, in the single bus system, the operation is similar to that of the impedance balance protection relay device, and the short circuit occurs. It is possible to select and protect a line, and even if one bus breaker of the transmission line breakers lags the break timing of other breakers due to a bus line failure during the operation of No. There will be no total power outage at the receiving end.
Therefore, it is possible to realize a short-circuit protection relay device which is inexpensive, yet highly reliable, and which is also applicable to the operation of A and B.

In the example of FIG. 1, the cutoff output unit 18
An example of the configuration of d and 28d is the configuration shown in FIG. That is, in FIG. 2, the cutoff output unit 18d is
The output signal R1 from the determination unit 18c is supplied to one input terminal of the AND circuit 18d. The output signal R2 from the determination unit 28c is input to the other input end of the AND circuit 18d and the input / output units 29 and 19 are connected.
The negative signal is supplied via. The cutoff output unit 28d is also configured by an AND circuit, and the output signal R2 from the determination unit 28c is supplied to one input terminal of the AND circuit 28d. Further, the other input terminal of the AND circuit 28d is supplied with the negative signal of the output signal R1 from the determination section 18c via the input / output sections 19 and 29. The output signal of the AND circuit 18d is the signal R1.
Is "1" and the signal R2 is "0", "1"
(Cutoff command signal). As for the output signal of the AND circuit 28d, the signal R2 is "1" and the signal R1 is "0".
Only in case of, it becomes "1" (cutoff command signal). Therefore, these AN circuits 18d and 28d can configure the cutoff output units 18d and 28d.

Further, in the example of FIG. 1, the electric signals themselves may be used for the transmission and reception of signals between the input / output sections 19 and 29, or the input / output sections 19 and 29 may perform the electro-optical conversion. Alternatively, it may be performed by an optical signal. Furthermore, the input / output units 19 and 2 are converted into acoustic signals by electric-acoustic conversion.
Signals may be transmitted / received to / from 9

FIG. 3 is a schematic configuration diagram of the second embodiment of the present invention. In the example of FIG. 1, Route 1 1L and Route 2 2L.
The distance protection relays 10 and 20 are installed in the above, respectively, but in the example of FIG. 3, one distance protection relay 30 is installed in combination on the 1st line 1L side and the 2nd line 2L side. This is an example of a case where the protective relay device is configured by transmitting and receiving the operating condition of the distance relay on the 1st line side and the operating condition of the distance relay on the 2nd line side inside the device.

Further, this example is an example of a device constituted by a digital circuit on the transmitting end bus side in the balanced two-circuit transmission line system, and a similar device is also installed on the receiving end bus side. Is. In FIG. 3, the current I1 of the line 1L and the voltage VA of the transformer 31 are detected by the line 1 current detector 11, and the detected currents are input converters 12 and 32, a filter circuit 33, and a sample hold circuit 34. , Through the multiplexer 35 and the A / D conversion circuit 36, to the impedance calculation unit 37a of the arithmetic processing circuit 37.

The current I2 of the line 2L is detected by the line current detector 21, and the detected current is input converter 22, filter circuit 33, sample hold circuit 34, multiplexer 35, A / D conversion. It is supplied to the impedance calculator 37e of the arithmetic processing circuit 37 via the circuit 36. The voltage VA of the transformer 31 is also supplied from the A / D conversion circuit 36 to the impedance calculator 37e.

The impedance calculation unit 37a, the failure detection unit 37b, the determination unit 37c, and the cutoff output unit 37d operate in the same manner as the impedance calculation unit 18a, the failure detection unit 18b, the determination unit 18c, and the cutoff output unit 18d in the example of FIG. To execute. In addition, the impedance calculator 37e and the failure detector 3
7f, the determination part 37g, and the interruption output part 37h perform the same operation as the impedance calculation part 28a, the failure detection part 28b, the determination part 28c, and the interruption output part 28d of the example of FIG.
However, the output signals R1 and R2 from the determination units 37c and 37g are supplied to the cutoff output units 37h and 37d without passing through the input / output unit.

In the cutoff output section 37d, the cutoff command signal is supplied to the breaker 110 only when the signal R1 is "1" and the signal R2 is "0". In the cutoff output section 37h, the signal R2 is "1" and the signal R1 is "
Only when it is "0", the breaker command signal is supplied to the breaker 110.

According to the second embodiment of the present invention described above,
The same effect as that of the example of FIG. 1 can be obtained. However, in the example of FIG. 3, one device is larger than the example of FIG. In the example of FIG. 3 as well, as in the example of FIG. 1, the cutoff output units 37d and 37h can be configured by AND circuits as shown in FIG.

FIG. 4 is a schematic configuration diagram of the third embodiment of the present invention. Distance protection relay devices 40 and 50 constituted by analog circuits are installed on the line 1 side and the line 2 side, respectively. This is an example of the case. In addition, this example is an example of a device configured on the transmission end bus side in a balanced two-line transmission line system, similarly to the first and second embodiments, and the same applies to the receiving end bus side. A protective relay device is installed.

In FIG. 4, the current I1 of Line 1 1L is
The current detected by the line 1 current detector 11 and detected is supplied to one input end of the impedance calculation circuit 41 via the input converter 12. Further, the power transmission line bus voltage VA is detected by the bus voltage detector 31, and the detected voltage is supplied to the other input end of the impedance calculation circuit 41 via the input converter 13.

Then, the impedance calculation circuit 41
In, the ratio of the bus voltage VA to the Line 1 current I1, that is, the impedance ZF1 on the Line 1 side from the transmission end bus to the fault point is calculated, and the calculated impedance ZF
A signal indicating 1 is supplied to the failure detection circuit 42. The failure detection circuit 42 determines whether or not the impedance ZF1 is larger than the set value ZS1 and whether the signs are equal, based on the supplied signal. However, ZS1 is previously input to the storage means (not shown) of the failure detection circuit 42. Then, a signal indicating the determination result is supplied to the determination output circuit 43.

When the impedance ZF1 is smaller than the settling value ZS1 and the signs are equal, it is judged that a short circuit fault has occurred within the settling range, and the level of the output signal R1 from the judgment output circuit 43 is "1". Becomes When the impedance ZF1 is other than the above conditions, the output signal R1 is "
The output signal R1 is supplied to the cutoff output circuits 44 and 54.

The cutoff output circuit 44 is supplied with not only the output signal R1 but also the output signal R2 of the determination output circuit 53, which will be described later. In the cutoff output circuit 44, the output signal R1 is "1" level and the output signal R2 is "1" level.
The breaker signal is supplied to the circuit breaker 110 only at the 0 "level.

The current I2 of the line 2L is detected by the line 2 current detector 21, and the detected current is supplied to one input terminal of the impedance calculation circuit 51 via the input converter 22. . Further, the voltage VA detected by the bus voltage detector 31 is passed through the input converter 23,
It is supplied to the other input end of the impedance calculation circuit 51.

The impedance calculation circuit 51
At, the impedance ZF2, which is the ratio between the bus voltage VA and the line 2 current I2, is calculated, and a signal indicating the calculated impedance ZF2 is supplied to the failure detection circuit 52. The failure detection circuit 52 determines from the supplied signal whether the impedance ZF2 is larger than the set value ZS2 and whether the signs are the same. However, ZS2 is previously input to the storage means (not shown) of the failure detection circuit 52. Then, a signal indicating the determination result is supplied to the determination output circuit 53.

When the impedance ZF2 is smaller than the settling value ZS2 and the signs are equal, it is judged that a short circuit fault has occurred within the settling range, and the level of the output signal R2 from the judgment output circuit 53 is "1". Becomes When the impedance ZF2 is other than the above conditions, the output signal R2 is "
The output signal R2 is supplied to the interruption output circuits 54 and 44. The interruption output circuit 54
The output signal R2 is at "1" level, and the output signal R1
A cutoff signal is supplied to the breaker 210 only when is at "0" level.

According to the above-described third embodiment of the present invention,
The same effect as that of the example of FIG. 1 can be obtained. In the example of FIG. 4 as well, similarly to the example of FIG. 1, the cutoff output circuits 44 and 54 can be configured by AND circuits as shown in FIG. Further, in the example of FIG. 4, the impedance calculation circuits 41 and 51 are, for example,
(“Hardware of protective relay (2)”, Mitsuo Watai et al., Densho Shoin, Chapter 7, Transistor distance relay). In addition, the transmission and reception of the signals R1 and R2 between the protective relay devices 40 and 50 may be performed by any of electric signals, optical signals, and acoustic signals.

FIG. 5 is a schematic configuration diagram of the fourth embodiment of the present invention. One distance protection relay device 60 is installed on both the No. 1 side and the No. 2 side, and the No. 1 side distance relay is installed. It is an example of the case where the protective relay device is configured by transmitting and receiving the operating condition and the operating condition of the distance relay on the second line side inside the device. Further, like the first, second, and third embodiments, this is an example of a device configured on the power transmission end bus side in a balanced two-circuit power transmission line system, and the same is true for the power receiving end bus side. A protective relay is installed.

In FIG. 5, the current I1 of Line 1 1L is
The current detected by the line 1 current detector 11 and detected is supplied to one input end of the impedance calculation circuit 61 via the input converter 12. Further, the transmission line bus voltage VA is detected by the bus voltage detector 31, and the detected voltage is supplied to the other input end of the impedance calculation circuit 61 via the input converter 32.

The impedance calculation circuit 61
In, the impedance on the Line 1 side, which is the ratio between the bus voltage VA and the Line 1 current I1, is calculated, and a signal indicating the calculated impedance ZF1 is supplied to the failure detection circuit 62. The failure detection circuit 62 uses the supplied signal to
It is determined whether the impedance ZF1 is larger than the set value ZS1 and whether the sign is positive or negative. However, the settling value ZS1 is previously input to the storage means (not shown) of the failure detection circuit 62. Impedance ZF1 is set value ZS
If it is smaller than 1 and the signs are equal, it is determined that a short-circuit fault has occurred within the settling range, and the level of the output signal R1 of the determination output circuit 63 becomes "1". Then, the output signal R1 is supplied to the cutoff output circuits 64 and 68. The cutoff output circuit 64 supplies the cutoff command signal to the breaker 110 only when the signal R1 is at "1" level and the signal R2 is at "0" level.

The current I2 of the line 2L is detected by the line 2 current detector 21, and the detected current is supplied to one input end of the impedance calculation circuit 65 via the input converter 22. . Also, the transmission line bus voltage VA
Is detected by the bus voltage detector 31, and the detected voltage is supplied to the other input end of the impedance calculation circuit 65 via the input converter 32.

Then, this impedance calculation circuit 65
In, the impedance on the line 2 side, which is the ratio of the bus voltage VA and the line 2 current I2, is calculated, and a signal indicating the calculated impedance ZF2 is supplied to the failure detection circuit 66. The failure detection circuit 66 uses the supplied signal to
It is determined whether the impedance ZF2 is larger than the set value ZS2 and whether the sign is positive or negative. However, the settling value ZS2 is previously input to the storage means (not shown) of the failure detection circuit 66. Impedance ZF2 is set value ZS
If it is smaller than 2 and the signs are equal, it is determined that a short-circuit fault has occurred within the settling range, and the level of the output signal R2 of the determination output circuit 67 becomes "1". Then, the output signal R2 is supplied to the cutoff output circuits 68 and 64. In the cutoff output circuit 68, the cutoff command signal is supplied to the breaker 210 only when the signal R2 is at "1" level and the signal R1 is at "0" level.

According to the above-described fourth embodiment of the present invention,
The same effect as that of the example of FIG. 3 can be obtained. In the example of FIG. 5 as well, as in the example of FIG. 1, the cutoff output circuits 44 and 54 can be configured by AND circuits as shown in FIG. In addition, in the example of FIG. 5, the impedance calculation circuits 61 and 65 are the same as those described in the above (“Hardware of Protection Relay (2)”, Mitsuo Watai et al., Denki Shoin, Chapter 7, Transistor Distance Relay). It can be configured based on. In addition, the transmission and reception of the signals R1 and R2 between the protective relay devices 40 and 50 may be performed by any of electric signals, optical signals, and acoustic signals.

[0069]

Since the present invention is constructed as described above, it has the following effects. In the short-circuit line protection protection device of balanced two lines, the first and second Line 1 for judging whether or not a fault has occurred in Line 1 based on the Line 1 current and the voltage at the transmitting end or the receiving end bus Determination means,
Based on Line 2 current and the voltage at the transmitting or receiving end,
1st and 2nd to judge whether or not a failure has occurred on Line 2
No. 2 line determining means and the first or second No. 1 line determining means determine that a failure has occurred, and the first or second No. 2 line determining means determines that no failure has occurred, the power transmission end of Line 1 or First and third disconnection command means for supplying a disconnection command to the first or third circuit breaker arranged near the power receiving end, and the first or second line 2 determination means determine that a failure has occurred, and Only when the first or second Line 1 determining means determines that no failure has occurred, the second and fourth circuit breakers, which supply the interrupting command to the second or fourth circuit breaker disposed near the power transmitting end or the power receiving end of Line 2, 4 shutoff command means. Therefore, it is possible to realize a short-circuit line protection protection device that has high reliability without using large-scale equipment, is inexpensive, and does not malfunction even when a bus failure occurs in the operation of No. 1 and No. 2 O.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration example of a cutoff output unit in the example of FIG.

FIG. 3 is a schematic configuration diagram of a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a third embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a fourth embodiment of the present invention.

FIG. 6 is a diagram illustrating the principle of the present invention.

FIG. 7 is a diagram showing an example of a case where a short circuit fault has occurred in the example of FIG.

FIG. 8 is a diagram showing another example when a short-circuit fault occurs in the example of FIG.

9 is a diagram showing a state in which the state of FIG. 8 has changed.

10 is a diagram showing still another example in the case where a short circuit fault has occurred in the example of FIG.

FIG. 11 is a schematic configuration diagram in the case where the principle of the present invention is applied to the 1st and 2nd Otsu operational systems.

FIG. 12 is a diagram showing an example of a case where a short circuit fault has occurred in the example of FIG. 11.

FIG. 13 is a schematic configuration diagram of an example of a conventional short-circuit line selection protection relay device.

FIG. 14 shows a conventional short circuit line selection protection relay device 1
FIG. 3 is a schematic configuration diagram when applied to the operation of Exhibit A2.

FIG. 15 is a diagram showing an example of a case where a short circuit fault has occurred in the example of FIG.

16 is an explanatory diagram of a current that flows when the trip timing of a circuit breaker is delayed in the example of FIG.

FIG. 17 is a diagram showing a cutoff state of each circuit breaker when the tripping timing of a circuit breaker is delayed.

FIG. 18 is a schematic configuration diagram of a pilot wire protection relay device.

[Explanation of symbols]

 1L 1 line 2L 2 line 10 1 line distance protection relay device 11,21 current detector 12,13 input converter 14,24 filter 15,25 sample hold circuit 16,26 multiplexer 17,27 A / D conversion circuit 18, 28 Arithmetic processing circuit 19, 29 Input / output section 20 Line 2 distance protection relay device 22, 23 Input converter 30 Distance protection relay 31 Voltage detector 32 Input converter 33 Filter 34 Sample hold circuit 35 Multiplexer 36 A / D conversion circuit 37 Calculation processing circuit 40, 50 Distance protection relay device 41, 51 Impedance calculation circuit 42, 52 Failure detection circuit 43, 53 Judgment output circuit 44, 54 Interruption output circuit 60 Distance protection relay device 61, 65 Impedance calculation circuit 62, 66 Failure detection circuit 63, 67 Judgment output circuit 64 68 interrupting the output circuit SB sending end bus RB receiving end bus

Front page continuation (72) Inventor Nobuhiko Takeuchi 1 20-20 Kitakousan, Otaka-cho, Midori-ku, Nagoya-shi, Aichi Chubu Electric Power Co., Inc. Electric Power Technology Research Laboratory (72) Inventor Shinya Taki, Inazawa, Aichi Chubu-Hitachi Electric Co., Ltd. at 120-Chome (72) Inventor Tatsumi Hibino 1-Chubu Hitachi-Electric Co., Ltd. at 120-Sachimachi, Inazawa, Aichi

Claims (4)

[Claims] 1. A first method for determining whether or not a failure has occurred in Line 1 based on the Line 1 current and the transmission end bus voltage.
The line 1 determination means, the first line 2 determination means for determining whether or not a failure has occurred in the line 2 based on the line 2 current and the transmission end bus voltage, and the line 1 determination means determines that a failure has occurred. And, only when the Line 2 determination means determines that no failure has occurred, a disconnection command is supplied to the first circuit breaker arranged near the power transmission end of Line 1
And the second circuit breaker arranged near the power transmission end of Line 2 only when the Line 2 determination unit determines that a failure has occurred and the Line 1 determination unit determines that no failure has occurred. Second supply
Disconnection command means, second line 1 determining means for determining whether or not a failure has occurred in line 1, based on line 1 current and receiving end bus voltage, and line 2 current and receiving end bus voltage. On the basis of the above, the second Line 2 judging means for judging whether or not a failure has occurred in the Line 2 and the second Line 1 judging means judges that a failure has occurred, and the second Line 2 judging means has failed. Only when it is determined that there is no occurrence, the third disconnection command means for supplying the disconnection command to the third circuit breaker arranged near the power receiving end of the line 1 and the second line 2 determination means determine that the failure has occurred, And a fourth disconnection command means for supplying a disconnection command to the fourth circuit breaker arranged near the power receiving end of the line 2 only when the second line 1 determination means determines that no failure has occurred. The feature is a short circuit line protective protection relay with balanced 2 lines. 2. The balanced two-line short-circuit line protection protection device according to claim 1, wherein the first and second No. 1 line determining means are composed of a No. 1 line current and a transmitting end or receiving end bus voltage.
An impedance calculation means for calculating the line 1 line impedance; and a failure judgment means for judging whether or not the calculated impedance is smaller than the settling value and is equal to the sign of the settling value. 1 and second 2
The line determining means calculates impedance of the line 2 line from the line 2 current and the bus voltage at the transmitting end or the receiving end, and the calculated impedance is smaller than the settling value, and the sign of the settling value is positive or negative. And a failure determining means for determining whether or not the two are equal to each other. 3. The balanced two-line short-circuit line protective protection device according to claim 1, wherein the first and second Line 1 determining means and the first and second Line 2 determining means are: A filter circuit configured by a digital circuit, which extracts a fundamental wave signal from a current signal and a voltage signal, a sample hold circuit which temporarily holds an output signal of the filter circuit, and an output signal of the sample hold circuit, respectively. A multiplexer circuit and an A / D conversion circuit for converting an output signal of the multiplexer circuit into a digital signal, and the output signal from the A / D conversion circuit is supplied to each of the determination means. Balanced 2-line short-circuit line protection protection device. 4. The balanced two-line short-circuit line protection protection device according to claim 1, wherein the first and second Line 1 determination means and the first and second Line 2 determination means are: A first circuit for determining the first line and a circuit for determining the second line, which are configured by a digital circuit, include a filter circuit for extracting a fundamental wave signal from the current signal of the line 1 and the current signal of the line 2, and an output of the filter circuit. A sample and hold circuit for temporarily holding a signal, a multiplexer circuit to which an output signal of the sample and hold circuit is supplied, and an A / A for converting an output signal of the multiplexer circuit into a digital signal.
And a signal corresponding to the No. 1 line current signal and a signal corresponding to the transmission end bus voltage among the output signals from the A / D conversion circuit are the first No. 1 line determination. And a signal corresponding to the line 2 current signal and a signal corresponding to the power transmission end bus voltage are supplied to the first line 2 determination means. apparatus.