一种适用于风电场送出的混合型高压直流输电系统拓扑

Topology of a Hybrid HVDC Transmission System for Wind Power Grid Connection

混合型高压直流输电系统两端分别由传统电网换相换流器(LCC)和电压源换流器(VSC)构成,是一种新型拓扑,可以合理结合二者的优点,具有广泛的应用前景。其运行特性、控制策略和故障特性等方面不同于LCC高压直流输电系统和VSC高压直流输电系统,有必要对其进行研究分析。文中研究了整流侧采用VSC、逆变侧采用LCC的混合型高压直流输电系统,设计了不同的控制策略,在电磁暂态仿真软件PSCAD/EMTDC下进行了正常和故障情况下的仿真,对比采用不同控制策略时对系统换相失败的影响和故障恢复特性,选择了适用于此类系统的最优控制策略。

Hybrid high voltage direct current（HVDC） system is a new topology consisting of a line commutated converter（LCC） and voltage source converter（VSC）.It combines the advantages of LCC and VSC,and has a wide range of application prospects.It is necessary to study its operating characteristics,control strategy and failure characteristics which are different from that of LCC-HVDC system and/or VSC-HVDC system.This paper studies a hybrid HVDC system with rectifier using VSC while inverter using LCC technology.Simulation under normal and fault conditions are carried out,and the ability to reduce the impact of commutation failure and recovery time with different control strategies is compared using PSCAD/EMTDC.Furthermore,the optimal control strategy for this hybrid structure is proposed.