How to Conduct the Applied Withstand Voltage Test for A Fully-insulated Single Impulse Transformer

1. Introduction

After a set of single-phase 220kV fully-insulated impulse transformer (hereinaftr referred to as impulse transformer) is inspected in some company, applied withstand voltage test is recommended for high or low voltage winding.

The model of the impulse transformer is IDJ-60000/220, and connection group is II0. The high-voltage winding is full insulation, and rated voltage is 220kV. Rated voltage of low- winding is 11kV. The impulse voltage is single-phase and has double bodies. The magnetic circuit of one body is independent from another. Each concentric bushing has high-voltage winding and one low-voltage winding. The high-voltage winding of transformer is composed of four paralleling high-voltage winding on the two bodies. Four low-voltage winding of two bodies can be connected in series or in parallel. Total capacity of high-voltage winding of impulse transformer to low-voltage winding and earth reaches 7.9nF.

According to available national standards and technical conditions  impulse transformer, test voltage of high and low voltage winding are 320kV and 184kV respectively. Test method, test wiring and various used equipment are briefly introduced as follows.