A method of using a diverter valve to realize the quick conversion of the metal return line of the earth return line

Abstract

The invention relates to a method for achieving quick switching between a ground return wire and a metal return loop through employing a converter valve. Through the functional characteristics of a converter valve switching bypass pair and a characteristic that the switching-off time of the converter valve is short, the converter valve switching bypass pair is controlled firstly in an operation process of switching to the metal return wire from the ground return wire, thereby achieving the quick switching between the ground return wire and the metal return wire.

Description

technical field [0001] The invention belongs to the technical field of electric power and electronics, and in particular relates to a method for realizing rapid conversion of earth return line metal return line by using a bypass pair of a converter valve in a high-voltage direct current transmission system. Background technique [0002] There are many modes of operation for the DC transmission system, including bipolar operation, single pole ground return line operation, and single pole metal return line operation. When one pole of DC is overhauled or fails, the other pole can continue to operate through the single-pole ground loop operation mode, which greatly improves the reliability of the DC transmission system. However, long-term geodetic operation has the following disadvantages: [0003] 1) The DC current flows into the transformer through the neutral point of the AC system transformer, causing the transformer to generate DC bias, which seriously affects the normal o...

AI Technical Summary

Problems solved by technology

[0003] 1) The DC current flows into the transformer through the neutral point of the AC system transformer, causing the transformer to generate DC bias, which seriously affects the normal operation of the transformer

[0004] 2) Excessive ground current will cause corrosion to metal components and pipelines along the way

[0005] 3) Excessive ground current will affect the ecological environment near the ground electrode,

[0007] The existing earth-to-metal scheme needs to use an isolating switch for the metal return line to form a current path. Due to the slow action speed of the isolating switch, the closing and opening time are in seconds, and it is difficult to realize the rapid connection between the earth return line and the metal return line. convert

During the conversion process, there will be a large ground current, which will have a negative impact on the surrounding power equipment and the ecological environment near the ground electrode.

In the case that there is no ground pole or the ground pole is unavailable, if the fast conversion from the earth return line to the metal return line cannot be realized, it will cause double-pole blocking and reduce the reliability and stability of the system

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