Low-frequency Calibration for Electromagnetic Voltage Transformer of GIS Combined Electrical Apparatus
Huang Li-pin · East China Electric Power · 2013
This paper analyzes the GIS combined electrical apparatus in terms of its equivalent capacitance in primary circuit and its influence on the equivalent circuit of the electromagnetic voltage transformer. The method is proposed to calibrate the low voltage error and load error of the electromagnetic transformer. The low-voltage and low-frequency method is applied to measure the voltage transformer excitation characteristics,and the calculation formula is derived for converting to the excitation characteristic of power frequency and obtaining the nonlinear data of excitation characteristics. Finally,in combination with transformer equivalent circuit,the error of transformer under rated voltage factor can be calculated. The measurement results by this new method show less than 0. 05% deviation from the measurement results by conventional method.