特高压混合直流工程LCC换流阀短路保护优化研究

Optimization of LCC Converter Valve Short Circuit Protection in UHV Hybrid DC Project

首先基于昆柳龙直流工程与云广直流工程控制保护系统RTDS仿真实验数据,通过对比分析阀区故障时的故障特征及换流阀短路保护的动作特性,发现传统LCC换流阀短路保护判据在特高压混合直流系统中存在误动的风险。根据特高压混合直流系统与常规直流输电系统在系统结构和运行特性上的不同,分析出传统LCC换流阀短路保护判据直接应用于特高压混合直流系统时存在的缺陷。针对这一缺陷,改进了LCC换流阀短路保护判据,并通过仿真分析验证了新判据的有效性,为特高压混合直流输电工程的送端常直阀短路保护提高了有效的解决方案。

Based on the simulation experimental data of Kunliulong DC engineering and Yunguang DC engineering control and protection system RTDS,by comparing and analyzing the fault characteristics of valve zone failure and the action characteristics of converter valve short-circuit protection,it was found that the traditional LCC converter valve short-circuit protection criterion had the risk of misoperation in UHV hybrid DC system.According to the difference in system structure and operating characteristics between the UHV hybrid DC system and the conventional HVDC transmission system,the defects of the traditional LCC converter valve short-circuit protection criterion were analyzed when directly applied to the UHV hybrid DC system.In view of this defect,the short-circuit protection criterion of LCC converter valve was improved,and the effectiveness of the new criterion was verified by simulation analysis.This study improves an effective solution for the short-circuit protection of the normally straight valve at the sending end of UHV hybrid HVDC transmission project.