JPS6336203B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to reclosing control of a protective relay device in a power system.

Protection relay devices for power systems generally have a "reclosing" function in important power systems in order to stabilize the power supply and take measures to stabilize the power system.

The concept of "reclosing" is extremely generalized, so we will not discuss its details here, but there are various methods called three-phase reclosing, single-phase reclosing, polyphase reclosing, etc. has been put into practical use.

The following conditions are generally used for reclosing the circuit.

(1) The conditions for the torn phase to reclose are met. For example, in a single-phase reclosing circuit, only one phase is disconnected, and in a multi-phase reclosing circuit, two or more phases in total remain in two circuits.

(2) The air pressure conditions for the breaker must be met. This means that if there is still an accident when you put it in,
This is to ensure that the sheath can be cut reliably with the shear cutter.

(3) A certain amount of time has elapsed from the time of failure until the accident no longer occurs.

(4) There must be no accidents in the system when the power is turned on.

In the above conditions (1) to (4), condition (4) may or may not be used, but (1) to (3)
The conditions are always used. In other words, a phase break detection circuit detects whether the phase that has been broken satisfies the conditions determined by the re-closing method, a circuit detects whether the air pressure conditions of the break breaker are satisfied,
It consists of circuits that detect that there are no accidents in the system. The re-closing circuit is activated by the shield disconnection command from the protective relay device, and the shield phase disconnection detection circuit detects that the shield phase disconnection meets the conditions and that the shield disconnection pressure condition is established. The delay circuit is activated under certain conditions, and the circuit breaker is turned on after a certain period of time under the condition that there is no system failure.

Naturally, if an accident occurs internally when the circuit breaker is closed due to the reclosing circuit, the shock to the entire system will be extremely large unless it is disconnected again at high speed. may impair the stability of For this reason, as mentioned above, the pressure conditions of the disconnector must be included in the reclosing conditions to ensure that the disconnector is re-opened, but even if the disconnector is normal, If the protective relay device that gives the disconnection command to the disconnector becomes defective for some reason, it will not be possible to disconnect the circuit again in the event of an accident when the circuit is turned on again. Conventionally, in order to start re-closing, the protective relay device must be activated, so even when the re-closing is started, the protection relay device is operated under the premise that the short circuit or disconnection of the protective relay device is normal. , whether the protective relay device is closed or the disconnection circuit is normal is not used as the closing condition for re-closing.

This is due to the fact that it is quite difficult to detect whether or not the protective relay circuit is normal during the no-voltage period, and the fact that it is quite difficult to detect whether the protective relay circuit is normal or not during the no-voltage period, and that This is because the probability of the product suddenly becoming defective is extremely low.

However, in recent years, in important systems that use reclosing circuits, it can be said that most of the protection of the system uses the carrier relay method in a broad sense. The conveyance relay method includes a power line conveyance direction comparison conveyance method,
There are phase comparison carrier methods, frequency modulation (hereinafter referred to as FM) current differential methods, pulse number modulation (hereinafter referred to as PCM) current differential methods, etc., but the characteristics of these methods are that some type of signal transfer with the other end is required. The purpose is to use the transmission line in a certain way.

Therefore, in these carrier relay systems, the transmission system itself is in a sense a part of the protective relay device, and if there is a defect or abnormality in this transmission system, it means that there is an abnormality in the protective relay device in a broader sense. it is conceivable that. There are various causes of disturbances to the transmitted signal in the transmission system, but it is impossible to predict when they will occur, and even if things are normal now, we do not know whether they will be normal a few seconds later. Furthermore, it changes from moment to moment depending on weather conditions, Taiyo activity, etc.

Therefore, in the transmission system, if the transmission signal is disturbed due to disturbance, the reclosing circuit can be used to re-energize the signal, and even if there is an internal system fault, the transfer relay device can be used to quickly disconnect the signal again. Therefore, the disturbance in the transmission system must be removed or the back-up protection device must be used to disconnect it. Therefore, the time for re-rupture will be delayed by a considerable amount, and the impact on the system will be extremely large.

In view of the above points, the present invention provides a protective relay device that uses a carrier relay method as a protective relay method.
The purpose of this is to control re-closing in the event of a transmission line failure or abnormality.

The configuration of the present invention is shown in FIG. In the figure, 1 is a reclosing circuit start output circuit, 2 is a bridge or disconnection pressure condition detection circuit, 3 is an AND circuit, 4 is a delay circuit, 5 is a system failure detection circuit, and 6 is a transmission system failure detection circuit. The transmission line defect detection circuit 7 is a negative circuit.

That is, if a failure is detected in the transmission line failure detection circuit 6 when the circuit is turned on by re-closing, the AND circuit 3a is made to fail through the negation circuit 7, and the closing command 3b of the breaker is blocked.

When there is no defect in the transmission line and the output of the transmission defect detection circuit 6 is "0", it can be turned on.

There are two types of transmission failure detection, such as FM relays and PCM relays, which can detect transmission path failures within their own protective relay devices, and those that cannot be detected by the protective relay device itself, such as phase comparison relays and direction comparison relays. However, in the latter case, which cannot be detected by the protective relay device, it is sufficient to receive the conditions for detecting a transmission failure in the signal transmission device.

Furthermore, as is well known, devices such as FM carrier relay devices that perform FM modulation and demodulation within protective relay devices detect various transmission signal abnormalities (referred to as noise detection), and detect defects in the relay. If this is not acceptable, the system uses a method to block the output of the relay itself. In this case, there is no particular provision of the transmission path failure detection circuit 6, and the noise detection circuit of the FM relay may be shared.

For FM carrier relays, after detecting noise,
Even if the noise recovers, taking into account transient phenomena such as frequency _/ voltage modulation circuits, the
FM relay output is blocked. Therefore, in this case, if the only condition is that there is no transmission line failure as shown in Figure 1, the protection function will be in a blind state for several milliseconds to several tens of milliseconds, so the protection function will be in a blind state as shown in Figure 2. It is also easily inferred from the configuration of the present invention that it is confirmed that no transmission path failure has been detected for a certain period of time (T ₃ seconds) before issuing the input command.

FIG. 2 shows a modification of the present invention, in which the condition is that there is no transmission line failure for a certain period of time before re-closing. 8 is a delay circuit and its time is
If T is ₃ seconds, the relationship with the FM relay noise detection blocking time T ₂ seconds may be T ₃ T ₂ .

FIG. 3 shows the passage of time (hereinafter referred to as a time chart) in the case of FIG. 2.

In addition, with respect to differential principle relays such as FM relays, if only one terminal cannot be disconnected normally for some reason in the event of an internal fault, the circuit will be reclosed from the terminal that was normally disconnected. The impact on the system is extremely large.

In addition, Fig. 3a shows output 3c, and Fig. 3b shows output 4.
a, Figure 3e is output 5a, Figure 3d is output 6a,
FIG. 3e shows output 7a, FIG. 3f shows FM relay blocking, FIG. 3g shows output 8a, and FIG. 3h shows output 3b.

Figure 4 shows the system when only one end is broken due to an internal accident. 9, 9a are busbars, 10, 10a are current transformers 11, 11a are wires and disconnectors, 12 is power transmission line, 1
3 and 13a are differential relays for each terminal. In Fig. 4, if an accident occurs at internal point _F1 , differential relay 13,
13a operates and issues a shear disconnection command to the shear disconnectors 11 and 11a to eliminate the accident. However, if for some reason the differential relay 13 is unable to operate and only the differential relay 13a operates, then Although the disconnector 11a is normally disconnected, the disconnector 11 cannot be disconnected.

In the state shown in Fig. 4, the fault _F1 remains unremoved, and therefore the normally shriveled terminal must not be re-closed using the re-closing circuit. In order to prevent re-closing in such a case, if you take advantage of the fact that the differential relays 13 and 13a at both ends continue to operate in the state shown in Figure 4, it is possible to prevent re-closing when the differential relays are operating. It can be easily inferred from the present invention that re-injection can be prevented.

An example of the configuration in this case is shown in FIG. 1 in Figure 5
4 is a differential relay, and 15 is an OR circuit. As shown in Fig. 4, the output of the differential relay 14 is always "1" (operating) when only one terminal is disconnected.
It is possible to prevent the OR circuit 15 and the negative circuit 17 from being re-closed from the power transmission line 12.

As described above, according to the present invention, it is possible to prevent re-closing when a transmission line is abnormal or when only one end of the differential relay system is normally ruptured, and the system is It is possible to prevent the system from being re-entered into a system where it is known that a shock or accident has occurred.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of a reclosing circuit showing one embodiment of the present invention, FIG. 2 is an explanatory diagram showing another embodiment, FIG. 3 is an explanatory diagram of the time chart of FIG. 2, and FIG. 5 is a system explanatory diagram with only one end cut away, and FIG. 5 is a configuration explanatory diagram showing another embodiment of the present invention. 6...Transmission line defect detection circuit, 7...Negation circuit,
8...Delay circuit, 9...Bus bar, 10...Current transformer,
11...Shipping breaker, 13...Differential relay, 14...
...Differential relay, 15...Selection circuit.

Claims (1)

[Scope of Claims] 1. In a protective relay system for a power system, in which a transmission system is used to exchange signals with a partner electrical station, if only one end is broken due to an internal accident, the said broken terminal The reclosing control device is characterized in that the reclosing command is blocked when there is a defect or abnormality in the transmission system or when a current differential relay operates. 2. The reclosing control device according to claim 1, wherein the reclosing is performed on the condition that there is no failure in the transmission system for a certain period of time before the power is turned on.