Power transmission network reliability assessment method for invalid relay protection

Abstract

The invention relates to a power transmission network reliability assessment method for invalid relay protection. The method comprises the steps that firstly, a power transmission line Markov model is established; secondly, an initial condition is set; thirdly, system initial state simulation is carried out; fourthly, the line induced failure state at the system state transferring time is corrected; fifthly, the current state duration time Ti, k of a line and the next running state are calculated; sixthly, the current state duration time Dk of the system is calculated; seventhly, the load loss of the system under the state is calculated; eighthly, whether tk+1 is larger than the set time duration or not is judged. A relay protection and breaker failure affected power transmission line integral Markov model is established based on the analysis on the effect of the cooperation of protection two type failure, breaker failure and a protection system on the line running stopping and is made to conform to the actual running situation better, and the system reliability and accuracy and credibility of an analysis result are higher. The reliability analysis of an integral electric system is achieved.

Description

technical field [0001] The invention relates to a method for evaluating the reliability of a transmission network, in particular to a method for evaluating the reliability of a transmission network taking into account protection failures. Background technique [0002] Relay protection is one of the important components in the secondary equipment of the power system. Whether its correct operation will directly affect the safety and reliability of the power system operation. In recent years, power system failures caused by relay protection failures have become more and more prominent. . How to scientifically and reasonably consider the influence of relay protection system on the safe operation of primary equipment and system is one of the key strategies to improve the credibility and accuracy of reliability analysis results of large power grids. [0003] The current system reliability analysis literature considering the influence of relay protection can be roughly divided int...

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Problems solved by technology

The literature [Jiang K, Singh C. New models and concepts for power system reliability evaluation including protection system failures [J]. Power Systems, IEEE Transactions on, 2011, 26 (4): 1845-1855] is based on the protection of two A typical failure mode and the coordination and cooperation relationship between adjacent relay protection systems, a 12-state Markov model of transmission line is established, and the reliability of simple and complex systems is analyzed by Markov state space method and Monte Carlo method respectively. The reliability has been evaluated; the method in this paper can be applied to both simple systems and actual large systems, and it is an effective and practical method; however, in the process of protection reliability modeling in this paper, only the maloperation when no fault occurs within the protection range is considered Failure mode, without considering the more common non-selective misoperation failure, that is, under the premise of short-circuit and other faults in the adjacent next-level equipment of the protected equipment, the operating environment parameters of the relay protection device (grid operation mode , protection setting value, etc.) caused by non-selective tripping; in addition, this paper does not consider the failure of the circuit breaker of the protective device actuator, but according to the actual operation experience and the relevant statistical analysis of power system faults, the failure probability of the circuit breaker is related to the secondary The failure probability of the protection system is of the same order of magnitude. If the impact of the circuit breaker failure is not considered, the analysis result will be too optimistic

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