Comprehensive risk based operational status assessment of transmission line

The security problem of transmission line is very prominent since it exposures in the natural environment for long period. To precisely assess the real time condition of transmission line is the main basis of reasonable operation strategy and maintenance plan. Existing analysis methods such as artificial neural networks, Beyesian networks, fuzzy set theory and expert system, etc., to a large extent depend on the parameter information of objects available. Actually to obtain this kind of information is very difficult in practical engineering. And the methods still have few shortages in considering factor is not comprehensive and easily ignoring the actual operation status of the system, so that it is reflected in accuracy of evaluation is not high and applicability of engineering is not good. Therefore, to consider the impacts including internal and external factors to power transmission line, a Markov chain model based running status evaluation and its risk assessment method was proposed in this paper. First of all, the running status, initial fault probability caused by external factors was deduced by Markov chain. And furthermore combining system power flow, the reality fault probability of transmission line was calculated. Secondly, considering the system operation constraints, a few indices of fault severity and theirs weights based on hierarchy analysis of an integrated index were defined and so that the "impact" of fault to the system was quantified by these indices. Finally, the running status was evaluated based on risk assessment thought combining the probability and the quantified impact. Simulation results showed that because of considering more influence factors and covering more risk factors, the method had a better ability to recognize the transmission line which was working at a high risk level and would do great damage to the system in case of a fault. Meanwhile it had avoided the difficult for missed information obtaining problem. The fruit of this research could be a reference to transmission line condition based maintenance work.