基于串联VSC的故障限流与动态电压恢复联合控制策略研究

VSC-Based Combined Control Strategies for Fault Current Limiting and Dynamic Voltage Restoring

电压源换流器(VSC)应用在中低压配电网中,通过不同的控制策略,可以对电力系统中多种物理量进行调节。利用串联VSC实现多目标控制,在提高电能质量的同时,保护系统安全,亦可节约能源。具有故障限流与动态电压恢复功能的VSC主要由限流电感和串联电压源换流器组成,开关与限流电感并联,用于在3种运行模式间切换。直流储能装置由电容和恒压源构成,系统可以根据不同运行模式选择合适的储能装置,避免不必要的有功损失。在详细分析装置工作原理的基础上,采用Matlab/Simulink软件对系统进行仿真分析。结果表明,装置控制策略正确,可以作为电力系统保护与改善电能质量的设备。

In low and medium voltage distribution network,many physical quantities in power system can be regulated by voltage source converter（VSC） with different control strategies.Series-Connected VSC can be used to improve power quality,protect power system as well as save energy.The proposed VSC consists of a series reactor and a voltage source inverter connected in series with a power distribution line.A switch is connected in parallel with a reactor for purpose of switching among three operational modes.DC storage consists of capacitor and constant voltage source,and the proposed apparatus can select proper storage for DC side avoiding unnecessary active power loss.The adopted control strategies are illustrated and some simulations are given to confirm its correctness and feasibility.The results obtained in Matlab/Simulink show the effectiveness of the proposed device which can be used for protecting power system and improving power quality.