JPS6235210B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to direct current and disconnectors.

DC and disconnectors used in DC power transmission systems have a transfer circuit such as an LC circuit connected in parallel to the disconnector because the disconnection current has no zero point and the circuit voltage is high. The method used is to forcibly create a current zero point at the time of shearing, causing the shearing to occur. FIG. 1 shows the configuration of a two-terminal circuit. Power is supplied from the power supply side 3 to the load side 4 through the power transmission line 5. When the shield is disconnected, a commutating current is supplied from the commutation circuit 1 to the shield breaker 2, and the shield breaker 2 is forced to create a current zero point to perform the shield disconnection. Figure 2 shows branching of a DC power transmission system. Number 6 indicates a branching point. Each side disconnector 2a, 2b, 2
The commutation circuits 1a, 1b, and 1c are provided in parallel for each load side, and the above operations are used to cut or break the direct current, and to switch the load side, for example, from the load side 4 to the load side 5, or vice versa. This is a configuration that aims to provide

However, this configuration has disadvantages in that one commutation circuit is required for one shingle breaker, which increases the overall size of the device, increases cost, and complicates the configuration.

The present invention has been made to solve the above-mentioned drawbacks, and is intended to simplify and economically realize the breakage mechanism of a DC power transmission system with a multi-terminal configuration, and is a highly reliable, low-cost system. The purpose of this invention is to provide a multi-terminal system DC and disconnector with a disconnection mechanism.

FIG. 3 shows an embodiment of the present invention. In FIG. 3, in which the same parts as in FIG. 2 are given the same reference numerals, the arrangement of the shingle breaker 2 is the same as the configuration in FIG. 2. However, by attaching the commutation circuit 10 across two sheath breakers, it is possible to reduce the number of commutation circuits by two and obtain the same function as the sheath breaker mechanism described above. That is, a common commutation circuit 10a is provided for the breakers 2a and 2b, and a common commutation circuit 10b is provided for the breakers 2a and 2c, respectively. The operation of this configuration is such that when the power supply to the load sides 4 and 5 is completely stopped, the disconnectors 2a, 2b, and 2c are opened and the commutation circuit 10 is opened.
It is only necessary to operate a and 10b. Further, in the case of stopping the energization of only the load side 4, only the shield breaker 2a is opened and only the commutation circuit 10a is operated. In addition, in the case of stopping the power supply only to the load side 5, the breaker 2c
Only the commutation circuit 10b is opened and only the commutation circuit 10b is operated.

Next, another embodiment of the present invention is shown in FIGS. 4 and 5. FIG. 4 is applied to a three-terminal system similar to FIG. 3, and the difference from FIG. 3 is that a commutation circuit 10c is provided in parallel to the disconnector 2c. Components that are the same as those in FIG. 3 are designated by the same reference numerals. Fifth
The illustrated embodiment shows a configuration applied to a four-terminal system.
From the branch point 6, the power supply side 3 and the load side 4, 5, 7 are connected via disconnectors 2a, 2b, 2c and 2d, respectively.
In the system connected to
A commutation circuit 10a is connected in parallel to the breaker 2.
A commutation circuit 10b is connected in parallel to a and 2c. Furthermore, a commutation circuit 1 is connected in parallel to the circuit breakers 2a and 2b.
0c is connected.

Even with the above configuration, the same effects as those of the embodiments described above can be obtained.

As described above, according to the present invention, the breaker 1
Instead of one commutation circuit per unit, in a multi-terminal system, the system can be disconnected and switched using fewer commutation circuits than the number of disconnectors, resulting in a simple configuration and high reliability. It is possible to provide a low-cost multi-terminal system direct current or disconnector.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a conventional two-terminal DC transmission system, Fig. 2 is a diagram showing the configuration of a breaker near a branch point in a conventional three-terminal DC transmission system, and Fig. 3 is a diagram showing the configuration of a conventional three-terminal DC transmission system. FIGS. 4 and 5 are explanatory diagrams of a three-terminal system direct current and a disconnector showing one embodiment, and FIGS. 4 and 5 are explanatory diagrams showing other embodiments of the present invention, respectively. 10... Commutation circuit, 2... Line breaker, 3... Power supply side, 4, 5, 7... Load side, 6... Branch point.

Claims (1)

[Claims] 1. In a multi-terminal DC power transmission system, in which a commutated current from a commutation circuit is passed through the breakers installed in each system branching from a branch point, the breakers are cut off. A multi-terminal system direct current or disconnector, characterized in that one commutation circuit is connected in parallel to all or a part of the system in which two line disconnectors straddling the branch points are provided.