基于有限元仿真的EVT电场影响误差分析

相较于传统互感器,电子式互感器具有抗铁磁谐振与磁饱和,并能够将互感器二次信号直接数字化的优点,随着智能变电站建设力度的加大,电子式互感器将会得到越来越多的应用.同时,目前在运行中的电子式互感器依然暴露出了诸多问题,其中杂散电容与邻近效应等因素造成的电场干扰问题,将影响电子式互感器的计量精度,影响其进一步应用.基于互感器分压原理,分析了杂散电容与邻近效应的干扰机理与数学模型,建立了有限元计算模型,在此基础上仿真计算得到了接地体、相对位置以及运行电压等因素对EVT误差的影响情况,并对高压端屏蔽罩屏蔽效能进行了评估.

When compared with the traditional voltage transformer, electronic voltage transformer （EVT） , which can transfer the secondary voltage into digital signal, has the advantages of resisting ferromagnetic resonance and magnetic saturation. With the strength of smart substation construction, EVT will be applied more and more. However, there still exist many problems in the running EVT. With the factors of stray capacitance and proximity effect included, electric field interference will affect the accuracy of EVTs. Interference mechanism and mathematical model of stray capacitance and proximity effect are analyzed on the basis of the principle of voltage divider. Based on the established finite element model, EVT error has been calculated, which influenced by the factors such as grounded object, relative position and operation voltage level. The shielding effectiveness has also been evaluated for the high -voltage terminal shield.