JPS6320087B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a protective relay device for protecting an electric power system, and more particularly to an improvement in a direction comparison relay device of a constant sending type.

Generally, when protecting a power system including non-power terminals, undervoltage relays are mainly used to detect short-circuit accidents. However, in a multi-terminal system, even in the event of an internal fault, the voltage hardly decreases, and it may be difficult to detect the fault.

FIG. 1 shows an example of a case in which the non-power terminal cannot detect an accident in the event of an accident at one end in a three-terminal system. In Fig. 1, A, B, and C are the terminals of A, B, and C stations, and RY-A, RY-B, and RY-C are terminals of A, B, and C, respectively.
A protective relay device installed at B and C, EA, is a power source for terminal A, and each terminal A, B, and C are interconnected by a power transmission line L. Also, the A terminal is treated as a power supply terminal, the B and C terminals are treated as non-power supply terminals, and the A terminal is a large power supply (that is, the impedance behind the A terminal is small), the distance between A and J is short, and between J and C. is a long-distance system.

In the system shown in FIG. 1, if a short-circuit accident occurs at the lower point, the voltage at point J will not drop that much.
Therefore, there is not much voltage drop at the B terminal, and
The undervoltage relay, which is a terminal fault detection relay, may not operate. Therefore, even if the A terminal, which is a power supply terminal, detects an internal fault due to distance relay operation, a lock signal will be received from the B terminal, so not only the B terminal, which is a non-power supply terminal, but also the power terminal Terminal A, which is , also becomes impossible to trip.

Hereinafter, such problems will be explained in detail using specific circuits. Figures 2, 3, and 4 show the circuit configuration of a conventional direction comparison relay device of a constant sending type. 3 shows a control sequence circuit, FIG. 3 shows a carrier wave transmission control circuit, and FIG. 4 shows a circuit breaker tripping circuit.

In FIG. 2, 11 is a ground fault internal detection direction relay, 23 is an auxiliary relay energized by its output, 12 is a short circuit internal detection distance relay, 24 is an auxiliary relay energized by its output, and 13 is an auxiliary relay energized by its output. 26 is an auxiliary relay that is energized by its output, and 14 is a distance relay for short-circuit external detection; 27 is an auxiliary relay that is energized by its output. This is an auxiliary relay. Further, 15 is a ground fault external detection direction relay, and 16-1 and 16-2 are receiving circuits for receiving a carrier wave from a partner terminal, and send out an output of "1" when a lock signal is received from the partner terminal. 17 is an undervoltage relay for detecting a short circuit accident; 30 is an auxiliary relay energized by its output; 18 and 22 are in-bit circuits; 19 is an on-delay timer; 20 is an off-delay timer; 21 and 32 are OR circuits; is an and circuit,
Reference numerals 25, 28, and 29 are auxiliary relays constructed as shown in the figure.

On the other hand, in Fig. 3, SP-SN is a terminal for transferring to and from the communication device, and is configured to send out a lock signal when SP-SN is "open" and send out a trip permission signal when it is "short-circuited." There is. 25b is a normally closed contact of the auxiliary relay 25, which is a so-called sequential countermeasure contact; 27b is a normally closed contact of the auxiliary relay 27; 26b is a normally closed contact of the auxiliary relay 26; 23a
are the normally open contacts of the auxiliary relay 23, and the terminals SP,
It is provided in series between SN. Further, 24a ₁ is a normally open contact of the auxiliary relay 24 provided in parallel with the contacts 27b, 26b, and 23a, and 28a ₁ is the normally open contact of the auxiliary relay 24 provided in parallel with the contacts 27b, 26b, and 23a.
This is a normally open contact of the auxiliary relay 28 provided in parallel with b, 27b, 26b, and 23a, and is a conditional contact that causes the contact _28a1 to "close" when a non-power supply internal is detected and sends a trip permission signal to the other end. .

Furthermore, in FIG. 4, P is a control power supply bus, 24
a ₂ , 26a, 30a, 28a ₂ are the normally open contacts of the auxiliary relays 24, 26, 30, 28, and 29
b is contact 26a, 30a, 28a ₂ or contact 24
Trip output occurs when the AND condition with condition a ₂ is met.
This is the normally closed contact of the auxiliary relay 29 that sends out Tp.
In the direction comparison relay device having the configuration shown in FIGS. 2 to 4, it is possible to protect either the power supply terminal or the non-power supply terminal, and the terminals A, B, and C in FIG. In the case of a carrier relay device having the circuit configuration shown in the figure, the response of the power supply terminal A and the non-power supply terminal B in the event of a point F accident will be considered below.

In addition, since this method is a direction comparison relay device, it is necessary to coordinate the setting of each relay, but the relay has a ground fault internal detection relay 11 of its own terminal, a ground fault external detection relay 15 of its own terminal, and a ground fault external detection relay 15 of its own terminal. Short circuit internal detection relay 12, short circuit external detection relay 14 of the other terminal, high sensitivity undervoltage relay 13 of own terminal and low sensitivity undervoltage relay 17 of the other terminal, ground fault external detection relay 15 of own terminal and ground fault of the other terminal These are a short-circuit internal detection relay 11, a short-circuit external detection relay 14 of its own terminal, a short-circuit internal detection relay 12 of its own terminal, a low-sensitivity undervoltage relay 17 of its own terminal, and a high-sensitivity undervoltage relay 13 of its partner terminal. The response of RY-A in the event of a short circuit accident at the lower point in Figure 1 is as follows.

(B) Response of relay device PY-A at electric station A terminal Since the electric station A terminal is a power supply terminal, the short circuit internal detection relay 12 operates, and the short circuit external detection relay 14 does not operate.

The operation of the internal short-circuit detection relay 12 causes the auxiliary relay 24 to operate and the contact 24a ₁ in FIG. 3 to "close".

Further, due to the operation of the short-circuit internal detection relay 12, the auxiliary relay 25 becomes inoperable, and its contact 25b continues to be in the "closed" state.

By closing these contacts 25b and _24a1 , terminals SP and SN are short-circuited, and a trip permission signal is sent to the other terminal.

On the other hand, in FIG. 4, the contact _24a2 is "closed" due to the operation of the auxiliary relay 24, but B
In order to receive the lock signal from the terminal, the auxiliary relay 29 continues to operate due to the output of "1" from the receiving circuit 16-1, even though its contact 29b is "open" and there is an internal fault. Unable to trip.

(b) Response of relay device RY-B of B electric station terminal Since B electric station terminal is a non-power terminal, short circuit internal detection relay 12 and external detection relay 1
4 are both inactive and depend on the response of the short-circuit accident undervoltage detection relay 13.

In this case, as described above with reference to FIG. 1, since the voltage drop at point J is small, the undervoltage relay 13 at the B electric station terminal does not operate.

In addition, the external detection relay 14 does not operate,
Since the ground fault external detection relay 15 is inoperative and the received signal from the other terminals (A terminal and C terminal) is a trip permission signal, the output of the external detection relay 14 is "0", and the output of the ground fault external detection relay 15 is "0". The output of the AND circuit 31 becomes "0".

From this, although the output of the OR circuit 21 is "0", the output of the undervoltage relay 13 is "0" due to inoperation, so the output of the inhibit circuit 22 is "0" and the auxiliary relay 28 does not operate.

Therefore, due to the "open" state of the contact _28a1 , the non-power supply stop-return condition is not satisfied, and a lock signal is sent to the other terminal.

On the other hand, in FIG. 4, auxiliary relays 24 and 28 are inoperative, making tripping impossible.

In this way, since the short-circuit accident undervoltage detection relay 13 cannot operate at the B terminal, it not only trips its own terminal but also trips the other terminal.

(c) Response of the relay device RY-C of the C electric station terminal Since the C electric station terminal is also a non-power terminal, both the internal detection relay 12 and the external detection relay 14 do not operate.

However, since the voltage at the C station terminal drops, the undervoltage relay 13 operates.

Therefore, the output of external detection relay 14 is "0", the output of external direction relay 15 is "0", and A
By receiving the trip permission signal from the terminal and the lock signal from the B terminal, the output of the receiving circuit 16-2 becomes "0", the output of the AND circuit 31 becomes "0", and the output of the OR circuit 32 becomes "0".
“1”, 21 output = “0”, inhibit circuit 2
2 output = “1”, relay 28 operates, 29
becomes the action.

Due to the operation of this auxiliary relay 28, a trip permission signal is sent to the other terminal, but at the own terminal, contact 2 is caused by the operation of the auxiliary relay 29.
The "open" of 9b results in a trip lock.

As explained above, the conventional relay device
In the system shown in the figure, the voltage at the B terminal hardly decreases, so the undervoltage relay 13 as a short-circuit accident detection relay cannot operate, and the non-power supply cutoff condition is not satisfied. Therefore, it becomes impossible to trip not only the B terminal but also the A terminal which is the power supply terminal.

SUMMARY OF THE INVENTION An object of the present invention is to provide an extremely reliable direction comparison relay device that can improve the detection ability of a short-circuit accident detection circuit for non-power supply stop-return and reliably protect a system.

In order to achieve the above object, the present invention provides a non-power supply cut-off device that operates when the following conditions are met: no lock signal is received from the other terminal, no external fault is detected on the own terminal, and internal short-circuit fault is detected on the own terminal. In a direction comparison relay device that is equipped with a short-circuit detection circuit and protects the power system using a carrier wave constant transmission method, an undervoltage relay that becomes inoperable due to a single-wire ground fault is used as a short-circuit detection relay for the short-circuit priority circuit. use,
Further, as a short-circuit accident detection relay for the short-circuit accident detection circuit for non-power supply stop-back, an undervoltage relay with a voltage change width set to be more sensitive than an undervoltage relay is used.

First, the basic idea of the present invention will be described. In general, an undervoltage relay with a voltage change range has a higher ability to detect faults than a simple undervoltage relay.
However, if the conditions of the relay 13 in FIG. 2 are simply replaced from an undervoltage relay to an undervoltage relay with a voltage change range, the following problems will occur.
In other words, the contact 26b in FIG. 3 is used to prevent unnecessary response of the contact 23a of the auxiliary relay 23 for ground fault internal direction relay in the event of an accident involving two or more wires, and is a short-circuit priority condition contact. On the other hand, since the voltage change range undervoltage relay is highly sensitive, there is a possibility that it will operate even in the event of a one-line ground fault. Therefore, the basic idea of the present invention is to use an undervoltage relay that becomes inoperable in a single-wire ground fault as the short-circuit detection relay used in the short-circuit priority circuit, and to use a short-circuit detection relay for non-power supply cut-off. As the short-circuit accident detection relay used for this purpose, a voltage change under-voltage relay that is set to be more sensitive than the above-mentioned under-voltage relay for the short-circuit priority circuit is intended to be used.

An embodiment of the present invention will be described below with reference to the drawings. 5, 6, and 7 show specific examples of circuit configurations of the direction comparison relay device according to the present invention, in which FIG. 5 shows a control sequence circuit, FIG. 6 shows a carrier wave transmission control circuit, and FIG. The figures show the disconnector tripping circuit, and the same parts in Figs. 5 to 7 as in Figs. 2 to 4 are given the same reference numerals and explanations are omitted. I will only talk about. In FIG. 5, reference numeral 41 denotes a voltage change range undervoltage relay for detecting short-circuit accidents as a short-circuit accident detection relay for a short-circuit accident detection circuit for non-power supply stop-back, and the above-mentioned undervoltage relay 13 for short-circuit priority circuits. The sensitivity is set to be higher than that of the previous one. Also,
42 is an auxiliary relay energized by its output;
3 is an inhibit circuit which uses the output of this relay 41 as its gate input and the output of the OR circuit 21 as its inhibit input, and 44 represents a non-power supply stop return auxiliary relay energized by the output of this inhibit circuit 43. It is.

Further, in FIG. 6, 44a ₁ is a normally open contact of the auxiliary relay 44 shown in FIG. 5, which is provided in place of the contact 28a ₁ shown in FIG. 3. Furthermore, in FIG. 7, 42a and 44a ₂ correspond to the contacts 26a and 28 in FIG.
The normally open contacts of the auxiliary relays 42 and 44 provided in place of a ₂ are shown, respectively.

Next, using FIGS. 5 to 7, a description will be given of the response of this relay device when the F point accident shown in FIG. 1 occurs. In this case, since the responses of the devices at the A and C station terminals are the same as described above, the description will focus on the response of the relay device RY-B at the B station terminal in question.

Since the B electric station terminal is a non-power terminal, both the internal detection relay 12 and the external detection relay 14 do not operate.

On the other hand, since the voltage change range undervoltage relay is set to be highly sensitive, it detects undervoltage and operates, and its output becomes "1".

In addition, since the external detection relay 14 is inoperative, the ground fault external detection relay 15 is inoperative, and the signals received from the other terminals (A terminal and C terminal) are both trip permissible signals, each receiving circuit 16-1, 1
Since both outputs of 6-2 are “0”,
The output of the AND circuit 31 is “0”, the OR circuit 32
The output of the OR circuit 21 is “0”, and the output of the OR circuit 21 is “0”.
Then, the output of the inhibit circuit 43 becomes "1", the auxiliary relay 44 is activated, and the auxiliary relay 29 is deactivated.

On the other hand, the undervoltage relay 17 is inoperative due to its low sensitivity, and the auxiliary relay 30 is inoperative.

Further, the operation of the auxiliary relay 44 causes its contact _44a1 to be "closed", and a trip permission signal is sent to the other terminal. However, since the auxiliary relay 30 is inactive, its contact 30a is "open" and the self-terminal trip is not performed at this point.

On the other hand, the A terminal and the C terminal can be tripped because the trip lock signal from the B terminal becomes a trip permission signal, so that the A terminal is tripped by the power supply and the C terminal is tripped by the non-power supply.

Furthermore, as the A and C terminals trip, the voltage at the B terminal drops significantly and the undervoltage relay 17 operates, which also operates the auxiliary relay 30 and closes its contact 30a, causing a non-power supply trip. It turns out. In other words, the B terminal will undergo a series trip.

As described above, in this embodiment, the condition is satisfied that no lock signal is received from the other terminal 16-1, 16-2, no external fault is detected 14, 15 at the own terminal, and internal short circuit fault is detected at the own terminal. In a direction comparison relay device that is equipped with a short-circuit accident detection circuit for non-power supply return that operates and protects the power system by a carrier wave constant transmission method, it is used as a short-circuit accident detection relay for a short-circuit priority circuit to fail due to a single-wire ground fault. It is configured by using an undervoltage relay 13 that is activated, and an undervoltage relay 41 with a voltage change width set to be more sensitive than the undervoltage relay 13 as a short circuit accident detection relay for a short circuit accident detection circuit for non-power supply cutback. So,
It is possible to increase the sensitivity of the short-circuit accident detection circuit for non-power supply stop-back and improve its detection ability. As a result, the A terminal, which is a power supply terminal, can be quickly disconnected without causing a trip delay, and the B terminal, which is a non-power supply terminal, can also be disconnected quickly by series tripping.

Next, other embodiments of the present invention will be described with reference to the drawings. FIGS. 8 to 10 show an example of a configuration in which the present invention is applied to a directional comparison relay device with countermeasures for zero-phase circulating current. In addition, Figures 8 to 1
The ground fault direction relay used in Figure 0 uses a sensitivity scanning method, and uses the carrier signal of its own terminal and the carrier signal from the other terminal to adjust the sensitivity of the ground fault direction relay in the positive direction (non-operating direction) and negative direction (operating direction). direction) to take measures against outflow current. Afterwards,
The ground fault direction relay is only an internal direction relay.

Figures 8 to 10 are circuits corresponding to Figures 5 to 7, where Figure 8 is a control sequence circuit, Figure 9 is a carrier wave transmission control circuit, and Figure 10 is a breaker trip circuit. This shows the configuration. In FIGS. 8 to 10, the same circuits as those in FIGS. 5 to 7 have the same numbers. In FIG. 8, 51 is a sensitivity scanning type ground fault direction relay, 52 is an auxiliary relay energized by its output, 53 is a ground fault overvoltage relay, 54 is a knock circuit that inverts its output, and 55 and 56 are OR circuits. , 57 is an inhibit circuit, and 58 is an auxiliary relay for detecting non-power supply cut-off which is energized by the output thereof.

On the other hand, in FIG. 9, 52a is the contact point 2 in FIG.
The normally open contact _58a1 of the auxiliary relay 52 provided in place of the contact 3a is a normally open contact of the auxiliary relay 58 provided in place of the contact _44a1 .

Further, in FIG. 10, 58a ₂ indicates a normally open contact of the auxiliary relay 58 provided in place of the contact 44a ₂ of FIG. 7. In other words, Figures 8 to 10
The difference between the diagram and Figures 5 to 7 is that in the case of Figure 5, the non-operation of the ground fault external detection relay 15, which is the condition of no external ground fault detection, is used in the condition of no power supply return. 8, instead, an OR condition between the operation of the sensitivity scanning type ground fault internal detection relay 51 and the non-operation of the ground fault overvoltage relay 53 is used. In FIG. 8, the condition of the undervoltage relay 17 is used as the input condition of the OR circuit 55 because it is expected that the undervoltage relay 17 will respond when the voltage drops sufficiently.

Next, the response of the relay device RY-B of the B electric station terminal in FIG. 1 will be explained using FIGS. 8 to 10.

(E) Response of relay device RY-B when 2 wires are short Internal detection relay 12 and external detection relay 1
4 do not work together.

On the other hand, the voltage change width undervoltage relay 41 operates and its output becomes "1".

Since the received signals from the A terminal and C terminal, which are the other terminals, are trip permission signals, the outputs of each receiving circuit 16-1 and 16-2 are both "0", and therefore the output of the AND circuit 31 =
The output of the OR circuit 32 becomes "0" and the auxiliary relay 29 does not operate.

In addition, due to the short circuit accident, the ground fault overvoltage relay 53 does not operate and its output is “0”.
The output of the NOT circuit 54 is "1", the OR circuit 5
5 output is “1”, and external detection relay 1
4 output = “0”, OR circuit 56 output “0”,
Output of voltage change width undervoltage relay 41 = “1”
As a result, the output of the inhibit circuit 57 becomes "1" and the auxiliary relay 58 for turning off the power supply is operated.

On the other hand, the undervoltage relay 17 does not operate, its output is "0", and the auxiliary relay 30 also does not operate.

Then, the contact _58a1 is "closed" by the operation of the auxiliary relay 58, and a trip permission signal is sent to the other terminal. However, at this point, since the auxiliary relay 30 is inactive, its contact 30a is "open" and its own terminal cannot be tripped.

The A terminal and the C terminal can receive or disconnect the trip permission signal from the B terminal.

When the A and C terminals are suddenly disconnected, the voltage drops significantly, so the B terminal undervoltage relay 17 operates and the auxiliary relay 30 operates, causing the contacts 42a to "close" and the contacts 30a to "close". When _58a2 is "closed" and 29b is "closed", the B terminal can be disconnected.

(f) Response of relay device RY-B in case of 2-wire ground fault Internal detection relay 12 and external detection relay 1
4 do not work together.

On the other hand, the voltage change width undervoltage relay 41 operates and its output becomes "1".

The received signals from the A terminal and C terminal are trip permissible signals, and each receiving circuit 16-1, 1
The output of the AND circuit 31 is "0", the output of the OR circuit 32 is "0", and the auxiliary relay 29 does not operate.

Due to the two-wire ground fault, the ground fault overvoltage relay 53 operates and its output becomes "1".
The output of the NOT circuit 54 becomes "0", but since it is an internal ground fault, the sensitivity scanning type ground direction relay 51 operates and the output of the OR circuit 55 becomes "1".
Further, since the output of the voltage change width undervoltage relay 41 is "1" and the output of the OR circuit 56 is "0", the output of the inhibit circuit 57 becomes "1", and the auxiliary relay 58 for detecting non-power supply is activated. do.

Furthermore, since the undervoltage relay 17 is inoperative, the auxiliary relay 30 is inoperative.

Due to the operation of the auxiliary relay 58, its contact _58a1 is "closed" and a trip permission signal is sent to the A terminal and the C terminal. However, in this case, the auxiliary relay 30 at its own end is inoperative, so it cannot be tripped at this point.

On the other hand, the A terminal and the C terminal fail to receive the trip permission signal from the B terminal.

Then, as the A terminal and C terminal are briefly disconnected, the voltage decreases significantly, and the undervoltage relay 17 operates at the B terminal, and the auxiliary relay 30 operates, so that the contact 42a
“Closed”, 30a “Closed” 58a ₂ “Closed” and 29b
It becomes "closed" and the B terminal can be disconnected.

As mentioned above, by using a voltage change range undervoltage relay in a direction comparison relay device using a sensitive scanning ground fault direction relay, it is possible to improve the non-power supply return detection ability and reliably eliminate system faults. I can do it.

It should be noted that the present invention is not limited to the above embodiments, and can be implemented with various modifications without changing the gist thereof.

As explained above, according to the present invention, the short circuit for non-power supply return operates when the following conditions are met: no lock signal is received from the other terminal, no external fault is detected on the own terminal, and internal short circuit fault is detected on the own terminal. In a direction comparison relay device that is equipped with an accident detection circuit and protects the power system using a carrier wave constant transmission method,
An under-voltage relay that becomes inoperable due to a single-wire ground fault is used as a short-circuit detection relay for short-circuit priority circuits, and a short-circuit detection relay with higher sensitivity than undervoltage relays for short-circuit detection circuits for non-power supply cutbacks. Since it is configured using an undervoltage relay with a fixed voltage change range, it is an extremely reliable directional comparison relay that can improve the detection ability of the short-circuit fault detection circuit for non-power supply return and reliably protect the grid. Electrical equipment can be provided.

[Brief explanation of the drawing]

Fig. 1 is a system diagram for explaining the problems of the conventional device, Figs. 2 to 4 are diagrams showing the circuit configuration of the conventional device, and Figs. 5 to 7 are overviews showing one embodiment of the present invention. 8 to 10 are schematic diagrams showing other embodiments of the present invention. 11...Ground fault internal direction relay, 12...Short circuit internal distance relay, 13, 17...Undervoltage relay,
41... Voltage change width undervoltage relay, 14... Short circuit external distance relay, 15... Ground fault external direction relay, 16-1, 16-2... Receiving circuit, 51...
Sensitivity scanning type ground fault direction relay, 53... Ground fault overvoltage relay, 23, 24, 25, 26, 27, 28,
29, 30, 42, 44, 52, 58...Auxiliary relay.

Claims (1)

[Claims] 1 Equipped with a short-circuit accident detection circuit for non-power supply cutback that operates when the following conditions are met: no lock signal is received from the other terminal, no external failure is detected on the own terminal, and internal short-circuit is detected on the own terminal, and carrier wave is constantly transmitted. In a direction comparison relay device designed to protect the power system, an undervoltage relay that becomes inoperable due to a one-wire ground fault is used as a short-circuit accident detection relay for a short-circuit priority circuit, and an under-voltage relay that becomes inoperable due to a one-wire ground fault is also used to detect short-circuit accidents for the non-power supply return circuit. A direction comparison relay device characterized in that it is constructed using an undervoltage relay with a voltage change width set to be more sensitive than the undervoltage relay as a short circuit accident detection relay for a detection circuit.