Zhou Zhicheng

Research on lightning trips and protection measures of overhead transmission lines

This paper presents some statistical analysis of lightning trips of overhead transmission lines in Jiangsu power grid and lightning activities across the province from 2005 to 2013 and analyzes the effects of lightning activities, topography, tower structure and insulation configuration and other factors along line corridors on lightning trips. Based on existing lightning protection measures such as reducing the lightning protection angle of transmission lines, increasing the length of composite insulators and long bar porcelain insulator with parallel gaps, this paper proposes lightning protection measures for new and existing overhead transmission lines to provide references for operation and maintenance.

Analysis and characterization of the shunt reactor switching over-voltages interrupted by SF6 circuit breakers with chopping current

Shunt reactor interruption by circuit breakers may produce current chopping and cause severe overvoltages. The four-legged reactor interrupting transients are elucidated with equivalent circuit analysis, and the mechanism of beat frequency oscillation is also characterized, further, a 3-D portfolio of the beat frequency, specifically regarding shunt reactor interrupting with a short line distance is given to describe the variation trend versus the shunt reactors parameters. Based on the available parameters from an installed 750kV transmission line in China, simulations of the four-legged reactor interruption process are carried out with adoption of an appropriate arc model for SF6 circuit breakers, and the scenario of the switching overvoltages is presented for the shunt reactor interrupting. The research results present useful reference for future construction and operation of the EHV and UHV transmission lines.

Distributed lightning current monitoring and its application to lightning protection on transmission line

To correctly record the process of lightning strike on power line and locate the fault site fast, serving to summarize their features and further take targeted protection measures against lightning strike, a distributed lightning current monitoring technology is proposed based on the simulation result. Its able to obtain necessary parameters of transient current, therefore make recognition of lightning fault and distinction of strike type, thus maximizing the effectiveness of protection measures. Preliminary trial operation suggests it works.

Simulation research on distribution of short-circuit current of transmission lines after lightning flashover

Based on the principle of calculating asymmetric faults, this paper made accurate simulation research on distribution of short-circuit current and its factors affecting it using electromagnetic transient analysis program ATP-EMTP for 220kV transmission lines. Conculsions are gotten that most of short-circuit current is dispersed by lightning conductors and and shunt coefficient under operating frequency is very different from that under lighting current. This is of great significance theoretically for checking and selection of the lightning conductor on thermal stability[1], potential increase and positioning of flashover towers, electromagnetic influences on adjacent communication lines, economical design of grids and so on.