JPS59128714A - Dc breaker - 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 a DC circuit breaker, and particularly to a DC circuit breaker suitable for application to a high voltage, large current DC power transmission system.

[Prior art]

In DC circuit breakers applied to DC transmission systems, as the voltage of the systems to which they are applied increases, the number of breaking points is increased to a plurality to cope with the increase in voltage, similar to circuit breakers for current transformation systems.

As the number of cutoff points increases, a pressure dividing device becomes necessary to make each cutoff point function effectively. For AC circuit breakers,
This is handled by connecting a capacitor in parallel to the interrupting point, but with a DC breaker, it is necessary to equalize the voltage sharing at each interrupting point by using a capacitor during transients and a resistor during steady state, so a voltage divider consisting of a capacitor and a resistor is used. The disadvantage is that the device becomes larger.

Figure 1 shows an example of the basic circuit of a DC breaker. The interrupter l is normally closed, the closing switch sFi is always open, and the capacitor 9 is constantly charged from the DC line 12 via the charging resistor 11. At the time of inference, each breaking point 2, 3 of the breaking section 1 is opened, the closing switch 8 is turned on, and the capacitor 9 is turned on.
By discharging the electric charge through the reactor 10,
A high-frequency oscillating current is superimposed on the direct current flowing through the interrupting part 1 to generate a current zero point and interrupt the current.

In this DC breaker, capacitors 6.7 are connected in parallel to the breaking points 2 and 3 in order to equalize the voltages applied to the breaking points 2 and 3 during breaking. Further, in the steady state after the cutoff, the resistors 4 and 5 must be connected in parallel to the cutoff point 2°3.

In order to effectively utilize multiple cutoff points in this way, a large-scale pressure dividing device is required.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a DC circuit breaker whose voltage dividing device can be downsized.

[Summary of the invention]

The key point of the present invention is to connect the midpoint of the interrupting section and the midpoint of the parallel capacitor and reactor through a device with electrical connection and separation functions, thereby controlling the shared voltage at each interrupting point during a transient interrupting operation. This eliminates the need for parallel capacitors required for equalization.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIG. In the figure, the closing switch 8 is connected to the midpoint of the cutoff point 2°3 of the cutoff part 1,
The middle point of the capacitor 9 and the reactor 10, that is, the second
In the figure, capacitor 9 and reactor 10 are capacitors 9-1 and 9-2, and reactors 10-1 and 10-2, respectively.
When the cut-off switch 8 is turned on, the capacitor 9-1 is discharged via the axle 10-1, and the capacitor 9-2 is connected to the reactor 10-2. discharge through. The generated high-frequency oscillating current causes a current zero point at the cutoff points 2 and 3, but during this cutoff transition, the shared voltage at the cutoff point 2.3 is equalized by the capacitors 9-1 and 9-2. , capacitor 6.7, which was previously required as a voltage dividing device.
becomes unnecessary.

It is desirable to use a normal AC circuit breaker used in AC systems as the circuit breaker 1. A high-voltage AC circuit breaker with multiple breaking points is provided with parallel capacitors in order to equalize the shared voltage at each breaking point.

Since the DC circuit breaker according to this embodiment eliminates the need for a capacitor as a voltage dividing device, it is possible to install a resistor in that space, and it can be used as a DC circuit breaker without changing the structure of the AC circuit breaker. can.

Note that the number of interception points is not limited to two, but may be four or six.

〔Effect of the invention〕

According to the present invention, it is possible to eliminate the need for a parallel capacitor as a device provided only for equalizing the voltage shared by each breaking point of a DC breaker having a plurality of breaking points.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional DC breaker, and FIG. 2 is a circuit diagram of a DC breaker according to an embodiment of the present invention. 9-1.9-2...Capacitor, 10-1.10-Kaya 1 Eye 2 Hard

Claims (1)

[Scope of Claims] 1. A DC circuit breaker comprising a interrupting section provided on a DC transmission line having a plurality of interrupting points, and a capacitor and an accelerator connected in parallel to the interrupting section so as to cause a high-frequency current to flow through the interrupting section, One terminal of a device having an electrical closing function and a separating function is placed in the center of the cut-off part, and there is a +17i connection between the device and the device. Connect it so that the number of breaking points on both sides of the connection point is equal, and connect the other terminal to the midpoint between the capacitor and the reactor so that the capacitance of the capacitor and the capacity of the reactor on both sides of the connection point are equal. A DC circuit breaker featuring: 2. A patent characterized in that the midpoint between the capacitor and the accelerator, the connection point of the device having the electrical closing function and separation function, and the earth or neutral point are connected via a resistor or a switch. A DC circuit breaker according to claim 1.