Study on the Surrounding Influence of Electric Field on Accuracy of Electronic Voltage Transformer with Capacitive Voltage Divider
Yue Feng · Electrical Measurement & Instrumentation · 2014
A lot of problems occur in the application of electronic transformer for smart substation,where stray capacitance and proximity effects caused by the surrounding electric field are the main factors for capacitive electronic voltage transformer accuracy. Interference mechanism and mathematical model are analyzed firstly with studying the influence of electric field on the accuracy of EVT. The finite element model of a typical capacitance-divide EVT in operation has been built. The influence of stray capacitance and proximity effect on EVT accuracy has been simulated and the shielding effectiveness has also been evaluated for the high voltage terminal shield. The simulation results show that the stray capacitance of ground terminal is greater than the that of high voltage terminal,EVT divide ratio effected by stray capacitance will be reduced along with the enlarged distance between EVT or between EVT and grounded objects,the divide ratio and ratio error will get greater when the voltage of adjacent phase increased,and the high voltage terminal shield can reduce the influence of proximity effect by improving potential distribution which reduced the horizontal component of electric field. The conclusion can be taken as the ssvaluable reference for optimization design of EVT.