自然环境特高压直流绝缘子长串动态覆冰放电机制及其数值模拟

Insulators’ icing is a traditional tough problem which has been continuously studied at home and abroad but has not been effectively solved yet. In recent years, flashover accidents of ice-covered insulators occur frequently on transmission lines still, which have given an important impact on the interconnection and intelligent development of large power grids. The flashover performance of insulators covered with artificial ice has been investigated in artificial icing conditions at home and abroad. Because the artificial icing conditions are different from the natural environment, the flashover performance and the static model for its flashover process obtained in the artificial icing conditions can not characterize completely the natural icing law and dynamic flashing process of insulators. Based on the previous research, and upon the favorable icing conditions at Xuefeng Mountain Natural Icing Test Base in which there are a long icing period of 150d/a and all kinds of ice types, and depending on ±1200kV testing system combined with a series of advanced techniques such as high speed imaging, spectrographic analysis and numerical simulation method, as well as multi-discipline knowledge, this project will investigate and reveal characteristics of ice-growth for energized EHV/UHV DC insulators in natural icing environment, and effect of ice type, ice distribution and ambient temperature, etc. on the kinetic characteristics of ice-surface arcs, generating and developing of ice-surface streamers, which will be compared with the results obtained in an artificial climate chamber. Then, the model will be established for natural icing numerical simulation of long insulator string and dynamic temperature of ice surface and dynamic icing flashover voltage, and arc dynamic characteristic parameters are obtained, which are to propose a criteria for estimating the flashover of EHV/UHV DC iced insulator strings and its numerical calculation method, and advance ice research from the empirical formula and static model to the development of numerical simulation and dynamic process.

绝缘子覆冰是国内外长期研究但其基础问题并未解决的传统难题。近年输电线路仍多次发生多次冰闪，影响大电网互联及智能化发展。国内外研究了人工覆冰绝缘子闪络特性，因自然环境与人工覆冰的差异，人工覆冰及冰闪特性和静态闪络模型并不能表征绝缘子自然覆冰规律和动态闪络过程。本项目在前期研究基础上，利用雪峰山自然覆冰试验基地长达150(天/年)的各类覆冰条件和±1200kV试验系统，采用高速成像和光谱分析等测试技术、数值模拟方法，应用多学科知识研究特高压直流绝缘子长串带电自然覆冰特性规律及覆冰类型、分布与温度等对其放电发展过程中冰面流注产生、运动电弧动力学特性和发展的影响，通过与人工模拟覆冰试验的对比，建立绝缘子长串自然覆冰数值模型和基于冰面温度动态变化的直流冰闪动态模型，得到其电弧动态特性参数，提出特高压直流绝缘子冰闪判据与冰闪电压数值计算方法，推进覆冰研究从经验公式和静态模型向数值模拟和动态过程的发展。

绝缘子覆冰是国内外长期研究但其基础问题并未解决的传统难题。近年输电线路仍多次发生多次冰闪，影响大电网互联及智能化发展。国内外研究了人工覆冰绝缘子闪络特性，因自然环境与人工覆冰的差异，人工覆冰及冰闪特性和静态闪络模型并不能表征绝缘子自然覆冰规律和动态闪络过程。本项目在前期研究基础上，利用雪峰山自然覆冰试验基地长达150(天/年)的各类覆冰条件和±1200kV试验系统，采用高速成像和光谱分析等测试技术、数值模拟方法，应用多学科知识研究特高压直流绝缘子长串带电自然覆冰特性规律及覆冰类型、分布与温度等对其放电发展过程中冰面流注产生、运动电弧动力学特性和发展的影响，通过与人工模拟覆冰试验的对比，建立绝缘子长串自然覆冰数值模型和基于冰面温度动态变化的直流冰闪动态模型，得到其电弧动态特性参数，提出特高压直流绝缘子冰闪判据与冰闪电压数值计算方法，推进覆冰研究从经验公式和静态模型向数值模拟和动态过程的发展。