Reactive Power Coordinated Control Method for Hybrid Multi-infeed DC System with Reduced Filter Switching

Abstract

The invention discloses a reactive power coordination control method of a hybrid multi-feed direct current system that reduces filter switching, and belongs to the field of reactive power control of a hybrid multi-feed direct current transmission system. Before the reactive power injected by the AC power grid into the LCC-HVDC rectifier station exceeds the reactive power adjustment range of the VSC-HVDC receiving end, the invention preferentially uses the VSC-HVDC system to adjust the reactive power, reduces the switching of the filter, and relieves the frequency of the filter Switching problems, prolonging the service life of primary equipment and reducing losses; when the reactive power injected by the AC grid into the LCC‑HVDC rectifier station exceeds the reactive power adjustment range of the VSC‑HVDC receiving end, the reactive power is immediately compensated, which improves the short-term The internal reactive power response can more effectively suppress the transient low voltage and transient overvoltage of the commutation bus of the LCC-HVDC system, and improve the transient stability of the power grid. The present invention makes full use of the advantage of fast reactive power adjustment speed of the VSC-HVDC system, assists the filter to perform switching, suppresses the sudden change of reactive power at the moment of switching and slows down the voltage fluctuation.

Description

technical field [0001] The invention belongs to the field of reactive power control of a hybrid multi-infeed direct current transmission system, and more specifically relates to a reactive power coordination control method for a hybrid multi-infeed direct current system that reduces filter switching. Background technique [0002] The hybrid multi-infeed direct current transmission system (HMIDC) formed after VSC-HVDC and LCC-HVDC are connected to the same AC grid. In the hybrid multi-fed DC system, Line Commutated Converter based High Voltage Direct Current (LCC-HVDC) and Voltage Sourced Converter based High Voltage Direct Current (Voltage Sourced Converter based High Voltage Direct Current, VSC-HVDC) usually operate independently, there is no coordination between them, and the reactive capacity of the VSC-HVDC system cannot be utilized to give full play to its advantages of dynamically adjusting reactive power. Moreover, when the LCC-HVDC system is running, the filter is s...

AI Technical Summary

Problems solved by technology

However, none of the above existing studies can alleviate the problem of frequent switching of filters in LCC-HVDC systems, and since VSC-HVDC adopts constant AC voltage control, reactive power is only compensated when the converter bus voltage deviates from the set value, VSC-HVDC Compensation of reactive power slow response speed

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