JPS63213414A - Bus bar protector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in the detection function of automatic monitoring of a current differential bus protection device including an automatic inspection circuit.

[Conventional technology]

During bus bar switching that includes an automatic inspection circuit that is protected by conventional multi-bus bars, that is, when small buses are connected to each other by a circuit disconnector, it is necessary to introduce input circuit information into one judgment circuit. Therefore, it is necessary to configure the output of the input circuit to be connected to the input of one determination circuit. Therefore, it is not possible to introduce information on the inspection current from all input circuits to the disconnected judgment circuit.

In view of the above, it was necessary to configure the sequence circuit so that inspection cannot be activated during bus bar switching.

[Problem that the invention seeks to solve]

As mentioned above, the condition for starting automatic inspection of the conventional bus bar protection device including the automatic inspection circuit that protects the multi-bus bar is that the bus bar is not being switched.

That is, when the bus bar is switched, automatic inspection for monitoring malfunction of the determination circuit cannot be performed, which reduces the ability of automatic monitoring of the bus protection device to detect defects.

In addition, in a busbar protection device that includes an automatic inspection circuit that protects various multibusbars with a disconnect switch installed in the RJII switch between the sections between buses A, the conditions for busbar switching are complex, and the conditions must be adjusted according to the busbar configuration. Therefore, it is necessary to configure and respond to one condition each time in the internal and external sequence circuits of the automatic inspection circuit, which poses a problem that becomes an obstacle to the standardization of busbar protection devices including automatic inspection circuits.

The present invention aims to solve these problems.

Furthermore, as described in the prior art, when a defect is detected during constant monitoring to monitor malfunctions of non-operating parts such as determination circuits, it is necessary to disable automatic inspection. Constant monitoring failure is a device abnormality, and if automatic inspection is started,
This is because there is a possibility of erroneous output at the final stage.

[Means for solving problems]

In a bus protection device that includes an automatic inspection circuit that protects multiple buses applying the current differential method, an analog switch and an adder are newly installed between the input circuit and the judgment circuit. When switching bus lines, there is no need to combine the input circuits into either one.

Therefore, the input circuit of the bus connection (hereinafter referred to as bus connection) is not disconnected from the judgment circuit, and even when switching the bus of multiple buses, the input circuit connected to the bus connection is automatically superimposed with a dotted current. Inspection startup is now possible.

From the above, it is possible to start automatic inspection regardless of the bus connection conditions, so it is possible to improve the failure detection ability of automatic monitoring of bus protection devices including automatic inspection circuits, and The complexity of external sequence circuits can be eliminated, and bus protection devices including automatic inspection circuits can be standardized.

[Effect]

Even when switching the buses of a multi-bus, the information of each input circuit is introduced into the determination circuit for each small bus through an analog switch and an adder controlled by the bus connection conditions. That is, the information of the input circuit connected to each small bus bar is introduced into the adder through the analog switch. The adder adds this information to the information of the input circuit connected to the small bus that is originally the target of protection, and then inputs the information to the determination circuit for each small bus.

As a result, during bus switching, that is, when two small buses are connected by a line disconnector, the determination circuit for each small bus will treat the two small buses as one bus,
Performs busbar internal accident determination.

There is no need to switch the input circuit connected to the bus to either one depending on the bus connection conditions, and the input circuit connected to the bus is always connected to the judgment circuit to be inspected, so even when switching the bus, Automatic inspection becomes possible.

〔Example〕

FIG. 2 shows a bus bar protection system for electrical stations using a conventional current differential system.

The two small buses IA and IB are provided with judgment circuits 6A and 6B of a current differential type bus protection relay. When the disconnector 11A is closed, the disconnector 11B is open, and the line 11C is connected only to the small bus IA, an amount proportional to the current flowing in and out of the line 11C is transferred from the current transformer 12G to the input circuit 13G. to be introduced. The input circuit 13G obtains the introduced vector quantities and scalar quantities, and passes them through the line switching circuit 14G controlled by the opening/closing conditions of the disconnector 11B.
It is introduced into the determination circuit 6A. Further, the input circuit 23A generates a vector quantity and a scalar quantity from information on the current flowing in and out from the mother chain, and introduces the generated vector quantity and scalar quantity into the determination circuit 6A.

The determination circuit 6A uses the sum of vector quantities proportional to the current flowing in and out of the sub-bus IA as an operating force, and the sum of scalar quantities as a restraining force to determine an internal fault in the sub-bus IA.

That is, assuming that the sum of the vector quantities introduced into the judgment circuit 6A is the operating force (0) and the sum of the scalar quantities is the restraining force (R), depending on the magnitude of (○) and (R), it is determined whether the fault is internal to the bus bar or external. Determine whether

In a bus internal fault, current flows into the bus from all circuits and bus links, so in principle, (0) = (R), and (0) and (R) have a suppression coefficient k (usually k =0.3~
The magnitude relationship of the values multiplied by 0.5) is (○)>k・(R
), and an internal busbar accident is detected. On the other hand, in the case of an external fault on the busbar or in normal conditions, the current flowing into the busbar is equal to the current flowing out of the busbar, so the sum of the vector quantities that become the operating force is, in principle, (0)=0, and (○)<k・(R), it is determined that this is an accident outside the bus bar.

When an internal fault on the bus is detected, a tripping circuit is configured to trip the line connected to the bus IA and the circuit breakers 15C and 25C of the bus.

Similarly, the sum of vector quantities proportional to the current flowing in and out of the small bus IB is used as an operating force, and the sum of scalar quantities is used as a restraining force, which are introduced into the judgment circuit 6B of the small bus IB. Based on similar judgment conditions.

A circuit is configured to trip the line and bus circuit breaker connected to the small bus IB.

FIG. 3 shows an automatic inspection system for monitoring malfunctions of the judgment circuit of this protection system. In the automatic inspection circuit, the control force is separated from the judgment circuit by the inspection command, and the circuit is configured so that only the operating force is introduced into the judgment circuit, and the inspection current is connected to the bus link that does not require the opening/closing conditions of the disconnector. The circuit is configured so as to be superimposed on the input circuit to be used. As a result, since there is zero difference current flowing in and out of the small bus except for internal bus faults, only the vector amount of the 1-inspection current is transmitted to the judgment circuit as operating force, so (○)>k・( R),
The determination circuit operates. From the above principle.

Based on the inspection command, the inspection current is superimposed on the input circuit connected to the bus link, and the output of the judgment circuit at that time is monitored to check whether the judgment circuit is operating normally or not. It can be performed.

That is, when automatically inspecting the determination circuit 6A, the 1-inspection current is superimposed on the input circuit 23A connected to the bus link by the operation of the inspection command 8A. In the input circuit 23A,
The obtained vector quantity is directly introduced into the determination circuit 6A, but the scalar quantity is separated by the inspection command 8A and is therefore not introduced into the determination circuit 6A. Normally flows into the busbar.

Since the differential current that flows out is 0, the operating force introduced into the judgment circuit 6A is only the vector amount of the inspection current.
Since the suppressing force is disconnected by inspection command 8A, O
Therefore, the operation determination formula of the determination circuit is (○)<k
- (R), the determination circuit 6A operates. 1 by monitoring the operation of the output cuff A of the determination circuit 6A.
It is possible to monitor malfunctions of the determination circuit 6A.

Although not shown in FIG. 3, the determination circuit 6B in FIG. 2 can be automatically inspected in the same manner as described above.

The protection system shown in Figure 2 and the automatic inspection system shown in Figure 3.

At the time of bus switching, that is, the disconnectors 11A and IIB of the line IC shown in FIG. 2 close simultaneously, and the small buses IA and IB
It does not take into account the connection conditions of the busbars, which are connected and appear to be one busbar.

FIG. 4 shows a conventional bus bar protection system that takes into consideration the above bus bar connection conditions.

As shown in Fig. 4, a line switching circuit is added to either one of the input circuits connected to the bus, and a disconnector 11A
, IIB by subbus IA.

When the IBs are connected, it is necessary to introduce information from all input circuits into one judgment circuit and to protect two different small buses at once.

That is, in this case, the input circuit 23A connected to the motherboard
A line switching circuit 24A is newly installed between the input circuit 23A and the judgment circuit 6A, and the auxiliary relay 16G is operated under the condition that the disconnectors 11A and IIB are both closed.
The configuration is such that the information obtained in the above is switched to be introduced into the determination circuit 6B.

As a result, the information obtained from the input circuit 13G of the line and the input circuit 23A connected to the motherboard is introduced into the 1 judgment circuit 6B through the line switching circuits 14C and 24A, including the information obtained from the input circuit 23B. The tripping circuit is configured so that the judgment circuit 6B performs a judgment on whether an accident occurs inside or outside the bus, and protects both the small buses IA and IB at once.

When the small buses LA and IB are connected by disconnectors 11A and IIB, in the conventional automatic inspection method shown in FIG. 3, all input circuits are connected to one judgment circuit. Automatic inspection of the disconnected judgment circuit is not possible.

That is, the small buses IA and IB are the disconnector 11A.

When connected by 11B, input circuit 13C:
, 23A, and 23B are all connected to the judgment circuit 6B, so even if the inspection command 8A shown in FIG.
Since information on the inspection current is not introduced, automatic inspection of the determination circuit 6A cannot be performed.

From the above, the conditions during bus bar switching, that is, the small bus fil
Under the condition that A and IB are connected by disconnectors 11A and IIB, it is necessary to add a condition that bus bar switching is not in progress to the automatic inspection activation condition so that automatic inspection cannot be performed. Therefore, the conventional system has a drawback in that the failure detection ability of automatic monitoring is reduced when bus operation during bus bar switching is taken into account.

In addition, on the busbars of overseas electrical stations, sectional switches (
Section) is often equipped with a disconnect switch. Therefore, there is a drawback that a complicated sequence circuit must be constructed in order to configure the conditions during bus bar switching.

The present invention aims to eliminate these drawbacks. A typical example of the present invention will be described below with reference to FIG.

The circuit shown in FIG. 1 is an input circuit and a determination circuit 6A.

6B, an adder 10A and an IOB, and an analog switch 10C are provided at the positions shown in the figure.

The operation of this circuit will be explained below.

In line 11C, disconnector 11A closes, 11B opens fJ,
When connected only to the bus IA, the switching contact in the analog switch 10C is opened and the judgment circuits 6A, 6
B is independent. In this state, the judgment circuits 6A and 6B corresponding to an accident on the bus IA or IB independently determine whether an internal fault on the bus is an external fault on the bus.

In the line 11C, when the disconnector 11B is closed and the disconnector 11A is opened, and it is connected only to the small bus IB, the switching contact in the analog switch 10C is opened, and the judgment circuits 6A, 6
B is independent. In this state, the small bus line L
The determination circuits 6A and 6B of A and IB determine the operation within the bus line and the number of external events.

In this case, the automatic inspection method is similar to the conventional method, in which the inspection current is supplied to the input circuit 23A connected to the motherboard by the inspection command 8A.
The determination is made by the operation of the output cuff A of the 1 determination circuit 6A. Similarly, an inspection current is inputted to the input circuit 23B connected to the bus link according to the inspection command 8B, and a judgment is made by the operation of the output cuff B of the judgment circuit 6B.

During line switching, that is, disconnector 11A of line 11C
When IIB and IIB are closed at the same time, the auxiliary relay 16C operates, the switching contact in the analog switch 10c closes, and the information on the small bus IB is introduced through the IOC into the judgment circuit 6A of the small bus IA, and the information is added. Small bus bar I with 10A
The vector quantity (0) added to the information of A is introduced as the operating force, and the added scalar quantity (R) is introduced as the restraining force.

Similarly, 6B also has the same vector quantity (0) and scalar quantity (
R) is introduced.

Therefore, even when the buses IA and IB are connected by a line disconnector, the determination circuit 6A.

With the 6B output, buses IA and IB can be protected simultaneously, and there is no problem in terms of system protection.

Furthermore, automatic inspection can be performed in the same way even when the busbar connection conditions 11A and IIB are both closed.

That is, when performing automatic inspection of the determination circuit 6A.

The inspection command 8A is operated to superimpose an inspection current on the input circuit 23A connected to the bus link. Information on the vector quantity of the inspection current is introduced into the determination circuit 6A through the adder 10A, but information on the scalar quantity of the inspection current is not introduced because it is separated by the 1-inspection command 8A. Therefore,
What are the conditions for determining operation?

゛(○)>k·(R), and the 1 determination circuit 6A operates.

The same applies when automatically inspecting the 1 judgment circuit 6B.
This is done by activating the inspection command 8B and superimposing an inspection current on the input circuit 23B connected to the bus link.

In other words, in the conventional method, it was necessary to combine all input circuits into one judgment circuit depending on the bus connection conditions, whereas in the method of the present invention, all input circuits were connected to a bus chain depending on the bus connection conditions. This is because there is no need to switch between input circuits, and information on the check current is introduced into the 1 judgment circuit by superimposing the check current on a specific input circuit, regardless of the bus connection conditions. .

〔Effect of the invention〕

According to the present invention, it is possible to overcome the disadvantage of not being able to perform inspection activation during busbar switching and reducing the defect detection capability, and to improve the defect detection capability of automatic monitoring of the busbar protection device.

In addition, since the automatic inspection circuit does not require bus bar connection conditions,
It is possible to standardize bus protection devices including automatic inspection circuits, which has great practical benefits.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing the principle of the present invention, Fig. 2 is a circuit diagram showing a conventional bus bar protection system, Fig. 3 is a circuit diagram showing a conventional automatic inspection system, and Fig. 4 shows the bus bar connection conditions. FIG. 2 is a circuit diagram of a conventional bus protection method taken into consideration. LA, IB...Small busbar, IIA, IIB...Disconnector. 11C...Line, 12C, 22A, 22B...Current transformer. 13G, 23A, 23B...Input circuit, 15C925
C...breaker, 21C...mother chain. $21Zl Kaya 3

Claims (1)

[Scope of Claims] 1. In a busbar protection device including an automatic inspection circuit that protects multiple busbars at an electric station, the power transmission lines connected to the busbar, transformers, and CT secondary such as busbar connections, etc. An analog switch and an adder are provided between an input circuit that introduces current and a judgment circuit that is arranged for each sub-bus that separates the multi-bus bar by a sectional switch and that detects an internal fault in each sub-bus. A busbar protection device characterized in that a check current is superimposed on the input circuit connected to the busbar connection that is connected only to each of the determination circuits, regardless of connection conditions of the busbar protection device.