Multi-infeed direct-current transmission receiving end alternating-current system equivalent evaluation method

Abstract

The present invention belongs to the power transmission and distribution technical field and relates to a multi-infeed direct-current transmission receiving end alternating-current system equivalent evaluation method. The method includes the following steps that: according to the network topological structure of a multi-infeed direct-current system, one of LCC-HVDC (line commutated converter based high voltage direct current) subsystems is selected as an equivalent subsystem; operating impedance related to the operating status of the LCC-HVDC subsystem is defined, and the operating impedance of each LCC-HVDC subsystem is solved on the basis of the definition of the operating impedance; on the basis of the operating impedance of each LCC-HVDC subsystem, the node network equation of the multi-infeed direct-current system is listed according to the obtained operating impedance and the network topological structure of the multi-infeed direct-current system; the equivalent impedance Zeq of the alternating-current bus-bar of the LCC-HVDC equivalent subsystem is solved according to the node network equation; and the equivalent effective short-circuit ratio (SCRLCC) of the multi-infeed direct-current receiving end alternating-current system can be obtained through calculation according to the equivalent impedance Zeq. With the evaluation method provided by the invention adopted, the strength of the multi-infeed direct-current receiving end alternating-current system can be effectively evaluated, and theoretical guidance can be provided for the improvement of the operating characteristics of the multi-infeed direct-current system.

Description

technical field [0001] The invention belongs to the technical field of power transmission and distribution, and in particular relates to an equivalent evaluation method for an AC system at a receiving end of a multi-infeed direct current transmission. Background technique [0002] With the development of society and economy, the demand for electricity continues to increase, and the development of power electronics technology provides new options for the transmission of electric energy. High Voltage Direct Current Transmission (HVDC for short) has matured after decades of development. It is mainly used in long-distance large-capacitance power transmission, asynchronous networking of AC systems, light DC power transmission, solar energy, wind energy, photovoltaics and other new technologies. Energy transmission. There are two types of converters currently in use, one is the voltage source converter (Voltage Source Converter, VSC), the other is the grid commutated converter (L...

AI Technical Summary

Problems solved by technology

However, with the increase of DC transmission capacity, the strength of the receiving end AC system of the multi-infeed DC system composed of multiple DC lines with close electrical distances and the AC receiving end grid becomes weaker.

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