随着智能电网建设的不断推进,电子式互感器得到了日益广泛的应用,解决其在运行中的问题具有重要意义。由周边电场所引起的杂散电容与邻近效应是影响电容分压型电子式电压互感器(Electronic Voltage Transformer)精度的重要因素。本文首先分析了周边电场对电容分压型EVT精度的干扰机理与数学模型,其次建立了典型在运电容分压型EVT的有限元计算模型,以此为基础仿真研究了杂散电容与邻近效应对其精度的影响,并对高压端屏蔽罩的屏蔽效能进行了评估。仿真结果表明：地端杂散电容大于高压端杂散电容,杂散电容对EVT分压比的影响随着EVT与接地体之间的距离增大或三相EVT之间的距离增大而减小,EVT分压器的分压比和比值差随着邻近相电压的增大而增大,高压屏蔽罩通过改善电位分布减小水平电场分量从而降低邻近效应的影响。所得结论对于EVT的优化设计具有参考价值。
英文摘要:
With the further progress of smart grid construction, EVT will be used more in power system application. It is of great significance to solve the problems in its operation. Electric field interference will affect the accuracy of EVTs with the influence of stray capacitance and proximity effect. Interference mechanism and mathematical model are analyzed firstly with studying the influence of electric field to accuracy of EVTS. The finite element model of a typical capacitance-divide EVT in operation is built. The influence of stray capacitance and proximity effect to EVT accuracy is simulated and shielding effectiveness is also evaluated for the high voltage terminal shield. The simulation result shows: stray capacitance of ground terminal is greater than the one of high voltage terminal, EVT divide ratio effected by stray capacitance will be reduced along with the enlarged distance between EVTs or between EVT and grounded objects, the divide ratio and ratio error will get greater when the voltage of adjacent phase increased, the high voltage terminal shield can reduce influence of proximity effect by improving potential distribution which reduced the horizontal component of electric field. The conclusion can be valuable reference for optimization design of EVT.