JPS60102820A - Dc transmission system construction - 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 the configuration of a DC power transmission system, and particularly to the configuration of a bipolar DC power transmission system whose return path is the earth.

[Background of the invention]

As a large-capacity DC power transmission system, the most common is a bipolar power transmission system with a return path to the ground, as shown in FIG.

In this system configuration, for example, the return commutation circuit breaker shown in FIG. 2 is used in order to provide flexibility in the operation of the system, as is employed in CU interconnections, CU interconnects, etc. The system operation in this configuration is shown below.

(1) Change bipolar operation to unipolar operation with a return route to earth. When the faulty pole is stopped due to a ground fault in the power transmission line, and the healthy pole is temporarily operated on a return path to earth, the current from the healthy pole continues to flow to the ground fault point through the bypass pair of the inverter.

It is assumed that the power transmission line 4 has a ground fault, and the switchgear 2 is always “
By opening the switchgear 1, the current that continues to flow from the above-mentioned healthy pole 7 to the faulty pole 6 bypass pair is interrupted by opening the switchgear 1'.
, 3 flows to the ground and can continue operating.

(11) Change the ground return drive to the main line return drive. If you want to stop the faulty pole 6 and use the power transmission line 4 as a return conductor for the healthy pole 7 from the state of return-to-ground operation in (1),
The switchgear 2 and the disconnector 14 are turned on and the switchgear 3 is opened.

0++ > Make main line return operation bipolar operation. The switchgear 3 is turned on, the switchgear 2 is opened, and the operation returns to earth.
The switchgear 1 is turned on, the converter 6 is activated, and bipolar operation is performed.

In this way, the operating state is changed by operating four switchgears and two disconnectors according to the required operating mode,
This allows for flexible driving. Here, the four switching devices 1 to 3 are called return commutation circuit breakers.

However, with this configuration, it is necessary to operate four return commutation circuit breakers with single terminal fingers and two disconnectors in a complicated manner, which is unfavorable in both reliability and economy.

[Purpose of the invention]

An object of the present invention is to provide a DC power transmission system configuration that simplifies the configuration of return commutation circuit breakers and enables flexible system operation with a small number of return commutation circuit breakers.

[Summary of the invention]

The present invention uses a combination of three return commutation circuit breakers to accommodate all required operating modes.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

Figure 3 shows the system configuration. The bipolar converter 6°7 is
The respective low voltage side terminals are connected via a return commutation circuit breaker 16. The connection between the return commutation breaker 16 and the converter 6 and the connection between the return commutation breaker 16 and the converter 7 are each grounded via return commutation circuit breakers 17 and 18. .

Similar to the above explanation, the DC transmission line 4 is connected to the failed line converter 6.
The operation will be explained assuming that this is the failure pole.

(1) Change bipolar operation to unipolar operation with a return route to earth. converter 6
, 7 is normally "open" and opens the return commutation circuit breaker 16.17. Healthy pole 7
The current flows to ground via the return commutation circuit breaker 18.

(11) Change the ground return drive to the main line return drive. Disconnector 1
9, the retrace commutation circuit breaker 16 is closed, and the retrace commutation circuit breakers 17 and 18 are opened. When inspecting the converter 6, disconnectors at both ends of the converter 6 (not shown) are opened.

(iii) Make the main line return operation bipolar operation. The return commutation breaker 18 is closed, the return commutation breaker 16 is opened, the disconnector 19 is opened, and the return commutation breaker 17 is closed.

The return line commutation circuit breaker 16 can be operated either "open" or "closed" at any time.

In this way, the system configuration of FIG. 3 satisfies the same functions as the system configuration of FIG. 2.

〔Effect of the invention〕

As described above, the present invention is excellent in economical efficiency because it is possible to operate the return circuit 61C circuit breaker with three units each having one terminal, and it is also excellent in reliability because the grounding wire can be doubled.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of a bipolar DC power transmission system with the return route to the earth.
FIG. 2 is a circuit diagram of a conventional system configuration, and FIG. 3 is a main circuit diagram of a system configuration according to an embodiment of the present invention.

Claims (1)

[Claims] 1. In a DC power transmission system with a bipolar configuration in which the return path is the ground, the bipolar AC/DC converters are connected via a return commutation breaker, and the return commutation breaker and both AC/DC converters are connected. A DC power transmission system configuration characterized in that one end of each is grounded and the other end of a return commutation circuit breaker is connected to the circuit breaker.