Method and device for online withdrawal of voltage source converter in hybrid direct current transmission system

Abstract

The present invention provides a method and device for online withdrawal of a voltage source converter in a hybrid direct current transmission system. The inverter converter station of the hybrid direct current transmission system includes at least one group of voltage source type converter units and a fourth bypass switch connected in parallel with them, and the voltage source type converter units include series-connected voltage source type converters and diode valves, The cathode of the diode valve is connected to the anode of the voltage source type converter, and the method includes: controlling and switching on the bypass thyristor valve group, the bypass thyristor valve group is connected in series with the series switch and then connected in parallel with the voltage source type converter unit, and the anode of the diode valve is connected to the bypass thyristor valve group. Turn on the positive pole of the thyristor valve group; close the fourth bypass switch; block the voltage source converter; block the bypass thyristor valve group; disconnect the series switch; when the rectifier converter station detects that the inverter converter station exits a converter After that, exit either the high-side thyristor converter or the low-side thyristor converter. The invention has simple structure and convenient operation, can effectively reduce current impact and power loss, and protect equipment safety.

Description

technical field [0001] The invention relates to the technical field of hybrid direct current transmission, in particular to a method and a device for online withdrawal of a voltage source converter of a hybrid direct current transmission system. Background technique [0002] HVDC transmission system can be divided into two types, one is conventional DC transmission system based on thyristor technology (LCC-HVDC), the other is flexible DC transmission system based on fully controlled voltage source converter (VSC-HVDC) . [0003] Among them, the advantages of the conventional direct current transmission system (LCC-HVDC) are low cost, low loss, and mature operation technology. The station occupies a large area. The new generation of flexible HVDC transmission system has the advantages of decoupling control of active power and reactive power, power supply to passive network, compact structure and small footprint, and no commutation failure on the inverter side. There are de...

AI Technical Summary

Problems solved by technology

At present, the on-line switching technology of thyristor-type converters in conventional HVDC transmission systems is relatively mature, and the online switching-on and off-line technology of voltage source converters in hybrid HVDC transmission systems is still under study.

Images