Risk Assessment And Pre-control In Power Transmission Line Field Maintenance Work Based On Fuzzy Fault Tree Analysis

With the development of ultra-high voltage, high-capacity, long-distance transmission lines on the modern power grid, the security and stability problems of power system have caused wide public concern. More uncontrollable uncertain factors existed in the power network of increasingly scale and complexity, which make the power system planning, operation and maintenance faced with great challenges.The safety of the transmission line operation and maintenance plays a central role, so it is of great significance to make risk assessment and safety pre-control for the transmission line field maintenance work on the basis of traditional risk identification, risk analysis, and the theory of probabilistic safety assessment. Based on Hall model, risk analysis was carried out on the transmission line maintenance, to determine main risk items and risk factors in each operation step. The fault tree models were established based on the results of risk identification. Then the fuzzy fault tree method is proposed, aiming to deal with the inadequate statistics and the uncertain probability of the bottom events. Associated with expert judgment, the Delphi method is used to transform fuzzy language to triangular fuzzy numbers, finally the possibility and severity probability values are calculated. The risk values of the top event and relevant risk items are all calculated to determine risk level, which is conducive to remind staff pay attention to the key risk and make real-time tracking.Finally, based on risk value analysis and risk matrix diagram, risk early warning system is formed. And the risk pre-control measures are proposed based on event tree analysis, aiming to realize the early prevention and control of all kinds of accidents. This thesis expatiated the methods and steps of the theory in details combining the Hebei project^Risk identification and monitoring for field maintenance work)). The examples of typical transmission line field maintenance work were presented.