LCC/VSC混联系统多区域间惯性支撑协调控制策略与仿真

Coordinated Control Strategy and Simulation of Multi-region Inertial Support for LCC/VSC Hybrid Infeed Power System

渝鄂背靠背柔直系统投运后实现了西南和华中异步联网,并形成了包括西南、华东、华中三峡机群、渝鄂、龙政、林枫等接入多类型直流的交直流混联系统。针对此种典型结构下交/直流故障后系统稳定需求,考虑充分发挥电压源换流器(voltage source converter,VSC)和电流源换流器(line commutation converter,LCC)快速可调的特性,提出了涉及交流线路、发电机组、VSC和LCC直流的惯性支撑协调控制系统。该系统的核心在于VSC/LCC的功率/频率协调控制策略,通过整定适应性的频率控制器逻辑和参数,以及执行直流间协同功率调制,能够实现直流对整个多区域混联系统的惯性支撑和辅助一次调频。建立了包含3区域交流电网以及VSC和LCC详细模型的电磁暂态仿真系统,仿真分析了可能引起失稳的典型交/直流故障。仿真结果表明,在惯性支撑协调控制策略的作用下系统能更快恢复至新的稳定运行状态,从而满足多区域间交直流电网动态功率协调控制的需求。

After the Yu-E back-to-back flexible direct current system was put into operation,the asynchronous interconnection of the Southwest and Central China power grids was realized,and an LCC/VSC hybrid infeed power system including the Southwest power grid and Three Gorges generators,VSC and LCC such as Longzheng HVDC was formed.Aiming at the system stability requirements after AC or DC failures under such a typical structure,this paper considers giving full play to the fast adjustable characteristics of VSC and LCC,and proposes a coordinated control system involving AC lines,generator sets,VSC and LCC.The core is the coordinated control strategy of inertial support of VSC/LCC,which can realize the inertia supporting and auxiliary frequency modulation of the entire hybrid system.An electromagnetic transient simulation system including three-region AC power grids and detailed models of VSC and LCC is established,and typical AC and DC faults that may cause instability have also been analyzed and simulated.Under the action of coordinated control strategies,the system can quickly recover to new stability operation status,so as to meet the needs of dynamic power coordinated control of AC/DC power grids in the near area.