Analysis of Load Output Characteristics of 3600kV Impulse Voltage Generator

Abstract: The output characteristics of some 3600kV impulse voltage generator at great capacitive load are analyzed by means of simulation and calculation in this paper. The physical process of impulse wave generation is calculated. Measures of reducing the oscillation are proposed and suggestions about selection of improved circuit parameters are also presented.    

Key words:  Impulse voltage, circuit analysis, load capability, capacitive load  

1. Introduction

With the wide application of electrical equipment such as GIS and HV cable cables, the lightning impulse voltage test at capacitive load needs to be improved. In the test, the load capacitance is an index of measuring the capability of impulse voltage generator. It is also called load capability of generator. The structure design of some 3600kV impulse voltage generator is original. The body is three-column type and each stage has two 100kV main capacitance double polarity charging. The voltage of series charging is 200kV and the insulation per stage decreases to 100kV (see Fig.1 (a). Because the body is large, the influence of circuit inductance and stay capacitance on waveform should be taken into account. Main parameters of impulse voltage generator are as follows: main capacitance per stage 2×MCY100-2 in series; there are 18 stages in all; the value per capacitance is 0.056μF and the inductance is 1μH; arc wire and circuit contact resistance is 10Ωor so; the length of wave front resistance R1 is 1.2m and residual inductance is around 1μH; the length of wire per stage is about 2.6m; the inductance per stage is 5.6μH if estimating at 1μH; the wire inductance of external circuit is estimated at 20μH and 120μH for total circuit inductance.