In operation,risk arising from power transformer faults is of much uncertainty and complicacy.To timely and objectively control the risks,a transformer risk assessment method based on fuzzy analytic hierarchy process(FAHP) and artificial neural network(ANN) from the perspective of accuracy and quickness is proposed.An analytic hierarchy process model for the transformer risk assessment is built by analysis of the risk factors affecting the transformer risk level and the weight relation of each risk factor in transformer risk calculation is analyzed by application of fuzzy consistency judgment matrix;with utilization of adaptive ability and nonlinear mapping ability of the ANN,the risk factors with large weights are used as input of neutral network,and thus intelligent quantitative assessment of transformer risk is realized.The simulation result shows that the proposed method increases the speed and accuracy of the risk assessment and can provide feasible decision basis for the transformer risk management and maintenance decisions.
电场防护是带电作业安全技术研究的重要内容,关系到作业人员的生命安全。文中分析了500 k V紧凑型同塔双回输电线路的结构特点,建立了作业人员体表场强仿真模型,计算了典型工况下不同作业点人员的体表场强分布,同时分析了塔型和线路运行方式对人员体表场强分布的影响。计算结果表明:同一运行方式下,地电位作业时,直线塔作业人员的头部和脚部场强较耐张塔高出约4倍;等电位作业时,耐张塔作业人员的头部场强较直线塔高243.2 k V/m,手部较之高出1.9倍。同一塔型作业时,相同工况下两回运行相比于一回运行对等电位作业影响较大;地电位仅中间横担处人员体表场强受运行方式影响明显。通过屏蔽效率的计算,校核了不同工况以及不同作业点应采取的安全防护措施。研究结果可以为带电作业的安全防护工作提供理论参考,具有一定的工程实用价值。
