Coordinated control method for suppressing continuous commutation failure

Abstract

The invention discloses a coordinated control method for suppressing continuous commutation failure. When an inverter station is in normal operation, through initial configuration, namely, constant DCvoltage control, constant DC current control, constant turn-off angle control and low voltage current limiting control, stable control of the inverter station is performed. At this time, the additional turn-off angle adjustment dynamic control and the additional DC current control are not working, which have no effect on the normal operation control; when a single-phase ground fault occurs on theAC side of the inverter station, operation is started based on the minimum turn-off area constant principle and the additional turn-off angle adjustment dynamic control of the specific influence of the single-phase fault, and the turn-off angle setting value is dynamically adjusted to ensure the turn-off margin of a converter valve. The method can be widely applied to the control of a conventional direct current transmission system.

Description

technical field [0001] The invention relates to the field of direct current transmission system control, in particular to a coordinated control method for suppressing continuous commutation failure. Background technique [0002] The traditional DC transmission system has a large power transmission capacity, and at the same time takes into account the advantages of low transmission loss, fast and flexible transmission power adjustment or reversal, high transmission reliability, and strong asynchronous contact capability. It is widely used in power transmission and other aspects. At present, my country has become the country with the most direct current transmission lines and the largest transmission capacity in the world. [0003] However, traditional DC transmission uses thyristors without self-shutoff capability as commutation components, and accidents such as AC faults easily lead to commutation failures. Commutation failure will cause unfavorable factors affecting syste...

AI Technical Summary

Problems solved by technology

[0003] However, traditional DC transmission uses thyristors without self-shutoff capability as commutation components, and accidents such as AC faults can easily lead to commutation failures.

Commutation failure will cause unfavorable factors affecting system operation such as DC voltage drop and short-term increase of DC current; continuous commutation failure will easily cause derating operation of the DC system, and even cause valve group blocking or pole blocking

With the increase of MIDC scale and the decrease of the electrical distance between DC landing points, when the AC system at the receiving end fails, multiple DC commutation failures may occur simultaneously or successively; when the AC fault is serious, multiple DC commutation failures may occur. The occurrence may lead to the interruption of DC power transmission, which seriously threatens the safe and stable operation of the DC system

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