Method for assessing risks and weak links of power grid, with double fault probability characteristics considered

Abstract

Provided is a method for assessing risks and weak links of a power grid, with double fault probability characteristics considered. Firstly, system basic technical data, system running constraint condition data and component reliability data are acquired from an electric power system planning department. Then, the basic power flow distribution situation of the system is calculated. According to the load shedding amount and the system N-1 fault state probability of the N-1 condition and the load shedding amount and the system N-2 fault state approximate probability of the N-2 condition, risk participation factors of the Expected Power Not Supplied (EPNS) of the system of an electric generator or power transmission equipment are calculated. The risk participation factors are ranked. If the risk participation factor of some component is relatively large, then the component is relatively weak in the power grid and is a weak link of the power grid. In the invention, since double fault and probability information is considered, calculation results are relatively accurate and achieve relatively great reference value. The method of the invention significantly reduces computing resource consumption and shortens the computing time while guaranteeing the accuracy of system probability indexes.

Description

technical field [0001] The invention belongs to the technical field of power grid planning, and relates to a power grid risk and weak link evaluation method considering probability and dual faults. Background technique [0002] In the power system planning stage, the most typical method for evaluating the security of the power grid is the N-1 static security analysis. This criterion requires that after any element is disconnected in the power system, the system can still maintain safe operation, that is, the N-1 criterion. This kind of method is widely used in the planning, design and operation of power system. However, the repeated occurrence of severe power outages has prompted a realization that the N-1 guidelines, which have been adopted by the power industry for many years, are no longer sufficient to maintain a reasonable level of risk in the power system. [0003] There are two main problems in the N-1 criterion evaluation method: 1) There is no probability modeling...

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Problems solved by technology

However, repeated occurrences of severe blackouts have prompted the realization that the N-1 criterion adopted by the power industry for many years is no longer sufficient to maintain a reasonable level of risk in the power system

[0003] There are two main problems in the evaluation method of the N-1 criterion: 1) without probabilistic modeling of the components in the network, it can only provide the consequences caused by the fault, but cannot provide the probability information of the fault event. There are more and more uncertain factors, and it is difficult to obtain better results in solving uncertain problems

2) Furthermore, the N-1 criterion is a single component failure criterion. In the current complex network system, serious accidents in the system are often caused by multiple failures. In this case, the N-1 criterion cannot be considered

However, in order to obtain accurate system indicators, a large number of Monte Carlo sampling must be carried out, which leads to the problem of large consumption of computing resources and long calculation time

Especially in the actual power system, the calculation time often takes tens of hours, which greatly limits its application

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