摘要
由于电力电子装置耐受冲击电流能力差,直流线路故障后所有换流器(包含非故障区域的换流器)均在1~2ms左右闭锁且闭锁后多变换器间存在较大压差,导致系统恢复速度慢,这极大地降低了直流配电系统的供电可靠性。因此,提出了一种适用于多端柔性直流配电系统故障后的快速恢复方法。该方法首先改进了DC/DC变换器的拓扑,然后分析了直流电压波动机理,利用能量守恒原理提出了波动量引入的直流电压稳定控制,最终将改进的拓扑和所提控制策略相互结合,形成多端柔性直流配电系统故障后的快速恢复方法。该方法解决了多端柔性直流配电系统闭锁后多换流器间存在压差导致系统恢复速度慢的问题,极大地缩短了系统失电时间,使系统可在30ms内恢复可靠供电。最后利用PSCAD/EMTDC仿真软件搭建多端柔性直流配电系统模型,验证了所提方法的有效性。
All converters in power system would be blocked within 1-2 ms due to poor ability of power electronic equipment to withstand fault current.There is voltage differences among multiple converters after all converters are blocked,leading to slow recovery of the system.Hence,the power supply reliability of DC distribution system is low.This paper proposes a fast fault recovery method for multi-terminal flexible DC distribution systems.Firstly,the method improves the topology of DC/DC converters and analyzes the fluctuation mechanism of DC voltage.Then the DC voltage stability control introduced by voltage fluctuation is put forward using energy conservation principle.Finally,the improved topology and the proposed control strategy are combined to form a fast fault recovery method after fault occurrence in flexible DC distribution system.The method solves the problem that the system has a slow recovery speed due to potential differences among the converters after the multi-terminal flexible DC distribution system is blocked,and greatly shortens system power-off time to ensure the system to restore reliable power supply within 30 ms.Finally,a multi-terminal DC power distribution system is built in PSCAD/EMTDC platform to verify the effect of the proposed method.
作者
王聪博
贾科
毕天姝
冯涛
WANG Congbo;JIA Ke;BI Tianshu;FENG Tao(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources(North China Electric Power University),Changping District,Beijing 102206,China)
出处
《电网技术》
EI
CSCD
北大核心
2020年第7期2738-2744,共7页
Power System Technology
基金
国家重点研发计划项目(2018YFB0904104)
国家电网公司科技项目(SGHB0000KXJS1800685)。
关键词
多端柔性直流配电系统
故障恢复
功率平衡
直流电压
multi-terminal flexible DC distribution system
fault restoration
power balance
DC voltage
