JPS59113721A - Ground switch control system - 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 Application of the Invention] The present invention relates to an earthing switch control system, and particularly to an earthing switch control system suitable for reducing the current capacity of an earthing switch.

[Prior art]

Conventional earthing switches are used to reduce the voltage induced on the idle line from the active line. This device was mainly used to ground the receiving and sending ends of power transmission lines for the purpose of protecting people during maintenance of idle lines. For this reason, the control system does not particularly require high speed, but only reliability.

On the other hand, in the U'HV system, unless countermeasures such as cans are taken, the re-closing time after the accident is removed will be as long as about 6 seconds.

On the other hand, considering system stability, cooperation with back-up protection relays, etc., it is necessary that the re-closing time Fi is within 2 seconds. In this way, in order to achieve high-speed reclosing, it is necessary to adopt a grounding blade hole, and the grounding opening/closing method for this purpose must be capable of opening and closing at high speed, and the conventional offline method method cannot be adopted. Moreover, when the earthing switches at the sending end and the receiving end are closed simultaneously as in the conventional art, there is a drawback that the current capacity increases.

[Purpose of the invention]

An object of the present invention is to provide a grounding switch control system suitable for reducing the current capacity of the grounding switch.

[Summary of the invention]

When a grounding switch closes both ends of a power transmission line at the same time, a current determined by the magnetic induction flows through the grounding switch. Therefore, sleep flow dissipation increases. In order to avoid this, the earthing switch at both ends is controlled so that it is not closed at the same time, so that the earthing switch current is removed from electrostatic induction, and the number of current users of the earthing switch is reduced. It is.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. In Figure 1, electrical stations G+ and G2 are bus lines B, ,
Electric power is transferred and received via the B2 transmission glands Lr and L2. Considering the case where an accident occurs below the point L2 in the figure, the circuit breakers CB at both ends of the power transmission line L2,
CB2 is opened, and after the recovery voltage has decreased, the re-closing circuit breaker cB, CB2 is closed. If you do not perform the above operations between opening and closing the circuit breaker, the transmission line L
The recovery voltage of No. 2 does not drop rapidly. For this reason, as a means to shorten the reclosing time, the earthing switches GSz, G
In S2, both ends of the power transmission line L2 are grounded. By doing so, the recovery voltage decreases rapidly.

In this case, grounding is performed after detecting that both ends of the power transmission line are electrically opened reliably by some method.

At this time, when closing the earthing switch, first one end of the power transmission line is grounded, and after that, for example, the grounded end is switched off at regular intervals, and then the other end is closed off. do. This is repeated for a certain period of time to reduce the secondary arc current.

Figure 2 shows the changes in voltage and current with respect to time. The voltage, which was at its rated value before the accident, decreased due to the accident, and even after the circuit breakers at both ends of the transmission line were opened, countermeasures such as cans were taken. If there is no voltage, the circuit cannot be reclosed until about 6 seconds of no-voltage time has elapsed, and the rated voltage is reached by re-closing the circuit after 6 seconds of no-voltage time (t) has elapsed. On the other hand, by opening the circuit breakers at both ends of the transmission line, by closing the earthing switches, and after a no-voltage time (t, ) of 2 seconds has elapsed, the earthing switches are opened and the circuit can be reclosed. , reaches the rated voltage.

On the other hand, as shown in the figure, before the accident, a current equivalent to a tidal current was flowing; When , opens, the current becomes zero, and after the no-voltage time has elapsed, the circuit recloses, resulting in a current equivalent to a tidal current.

At this time, the earthing switches at both ends are not closed at the same time, so the earthing switch current is only outside of electrostatic induction.
can be significantly reduced.

Next, a specific example will be explained. Figure 3 shows an example of this.
, GS2 is controlled by IIJ. Here, earthing switch G8
What is necessary is to avoid emitting a closing signal to r and GS at the same time. To achieve this, as shown in FIG. 4, the grounding switch GS, outputs a closing signal when the signal is positive, and the grounding switch Gs2 issues a closing signal when the signal is negative, as shown in FIG.

In this way, after a certain period of time has passed after the earthing switch Gs or Gs2 is closed, the earthing switches at both ends are opened, and immediately,
The circuit breakers CB, CB2fc are closed and the circuit is reclosed.

〔Effect of the invention〕

According to the present invention, the time required to restart the faulty line can be significantly shortened, and the effect on stability is extremely large. Moreover, the earthing switch current can be reduced from outside electromagnetic induction to outside electrostatic induction, and the economical effect is extremely large.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing the necessity of a grounding switch, Figure 2 is an explanatory diagram of changes in voltage and current over time in the method of Figure 3,
FIGS. 3 and 4 are explanatory diagrams of embodiments of the earthing switch control system of the present invention, respectively. G+, G2...Electric station, B+, B,! ...
Bus line, LH. L2...power transmission line, CB+ -CBt...breaker,
GS,, GS2...Earth switch, fault point for F, C.

Claims (1)

[Claims] ■In a system where earthing switches are installed at both ends of a power transmission line, an earthing switch control method is characterized by controlling the earthing switches at both ends so that they do not close or close at the same time.