WWW.HIMALAYAL.COM.CN

T: 86 21 61016212 Himalayal, always by your side. Copy right © HIMALAYALinfo@himalayal.com Page:1 All right reserved

Overshoot and Calculation Method of Standard

Lightning Impulse Voltage

Cui Dong, Wang Jiansheng, Zhang Xiaoyong

HIMALAYAL - SHANGHAI - CHINA

Abstract: The lightning impulse overshoot requirement is always an importantparameter for lightning impulse withstand voltage test. With the development oftest and measuring technologies and improvement of voltage grade, the currentstandard cannot meet the requirement of lightning impulse overshoot. Inaddition, it has been found that previous de�initions and requirements havemutation possibility and average curve. In order to solve great uncertainty, latestrevised IEC standards and national standards rede�ine the overshoot and itscalculation method. Concrete examples are presented in this paper.

1. Introduction

It has been more than 10 years sincethe current version GB/T16927.1 wasissued and enforced in 1997. Duringthat period, the electric powerequipments have rapidly developed,especially in China. With years ofdevelopment and application of800kV and 1100kV equipment, testvoltage has reached power frequency1200kV, switching impulse 1950kVand lightning impulse 2700kV.Regulations in the original version arenot been suitable for such high voltage,especially lightning impulse. IEC60060-1 latest revised versionrede�ines the overshoot of lightningimpulse and its calculation method.Combing with actual examples, thedifference between both is comparedand analyzed in this paper.

According to GB/T 16927.1-1997,relevant information about lightningimpulse test of high voltage productand voltage waveform of standard

lightning impulse is as follows:

— As for smooth lightning impulsewave, the test voltage is peak;

— As for some test circuit, oscillationovershoot may occur at the impulsepeak. If the oscillation frequency is noless than 0.5MHz or overshoot time isno higher than 1μs, a average curveshould be drawn to facilitate themeasurement. Maximum amplitude ofthe curve, also known as the peak, isde�ined as test voltage value;

As for smooth lightning impulse wave,it is believed that the overshoot doesnot exist; while if the oscillationfrequency is higher than 0.5MHz, theovershoot exists. The overshoot isde�ined as per oscillation peakexceeding test voltage peak extent.

Problems are as follows:

(1) The lightning impulse full-wavewaveform is divided into twocategories: smooth lightning impulse

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV

HV