Key transmission section identification-based cascading failure analysis method for alternating current/direct current power network

Abstract

The invention provides a key transmission section identification-based cascading failure analysis method for an alternating current / direct current power network. The method comprises the following steps: (A) searching all transmission sections between a direct current transmitting end and a direct current receiving end by a graph theory-based transmission section traversal algorithm, forming a node set S0={vS} from a node vS of the direct current transmitting end, searching all cut sets of branches between S0 and the adjacent point thereof, and finishing traversal searching in a manner of expanding the node set S0 outwards step by step; (B) further identifying key transmission sections which can cause a relatively large cascading failure risk by indexes of a power flow transfer coefficient and section maximum overload rate; and (C) giving cascading failure sets with relatively large risks and key branches which should be mainly monitored in the key transmission sections through transient stability calculation. By the method provided by the invention, the key transmission sections and the key braches, which are prone to cascading failures after a direct current monopole is locked can be effectively determined.

Description

technical field [0001] The invention relates to a method for analyzing cascading faults of AC and DC power grids based on identification of key transmission sections. Background technique [0002] In recent years, there have been many blackouts at home and abroad, which have caused great impact and serious losses. Studies have shown that most of the blackouts are caused by cascading failures, among which the cascading failures caused by successive overloads of transmission lines caused by power flow shifting are one of the important reasons. The cascading overload tripping faults of transmission lines mostly occur on the transmission section. If the relevant transmission section can be identified and monitored first, it is of great significance to block the chain tripping of the line and prevent blackouts. [0003] For example, the China Southern Power Grid is the largest power grid in my country for west-to-east power transmission. It has the characteristics of long-distan...

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Problems solved by technology

[0005] The above methods mainly study the transmission section and cascading failure mode related to the AC line. Since the power flow transfer of the AC line is local, it is mostly limited to several nearby lines. After the DC block, it involves the DC sending end and the receiving end converter station. Therefore, the analysis method of AC line power flow transfer cannot be directly used for the search of transmission sections and the identification of cascading faults related to DC blocking

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