柔性直流交流连接区故障分析

描述常规特高压直流输电工程现状,展望柔性直流输电前景,介绍基于VSC模块化多电平换流器(modular multi-levelconverter)技术直流输电的基本原理。根据渝鄂背靠背直流输电工程柔性直流一次拓扑结构,搭建实时数字仿真器(RTDS)仿真模型。结合仿真验证结果,分析交流连接线区充电软启电阻切除前、解锁软启电阻切除后故障时的故障暂态及稳态特性。通过对柔性直流阀侧故障特性及阀侧故障时阀控本体过压过流现象的研究,设计针对于柔性直流的保护配合策略。

Fault analysis of flexible DC/AC connection area

This paper describes the current situation of a conventional HVDC transmission project, looks forward to the future of flexible DC transmission, and introduces the basic principle of DC transmission based on VSC modular multilevel converter technology. A Real Time Digital Simulator (RTDS) simulation model is built according to the flexible DC primary topology of the Y-E back to back DC transmission project. Based on the simulation results, the fault transient state and steady state characteristics are analyzed before charging soft open resistor removal and after unlocking soft open resistor removal. Through the study of the fault characteristics of the flexible DC valve side and the overpressure overflow of valve body in case of valve side failure, a protection and cooperation strategy for flexible DC is designed. This work is supported by Science and Technology Project of the Headquarter of State Grid Corporation of China (No. 52170218000M):Research on Fault Protection and Adaptive Coincidence Method of Hybrid Multi-terminal HVDC Transmission Lines.