基于自适应负序电压正反馈的孤岛检测方法  

Islanding detection based on adaptive positive feedback of negative-sequence voltage

作　　者：王雪[1] 雷胜华[1] 胡文平[2] 赵莹[1] 

机构地区：[1]华北电力大学新能源电力系统国家重点实验室,河北保定071003 [2]国网河北省电力公司电力科学研究院,河北石家庄050021

出　　处：《电力自动化设备》2016年第12期36-42,共7页Electric Power Automation Equipment

基　　金：国家科技支撑计划资助项目(2015BAA09B01);国网河北省电力公司科技项目(KJ2014-052)~~

摘　　要：孤岛发生后,在负序电压正反馈环节作用下,并网点产生的负序电压持续增大,通过判断并网点负序电压幅值是否超过阈值进而判断孤岛是否发生。但是,过大的反馈系数会导致逆变器注入负序扰动过大,过小的反馈系数会导致孤岛检测失败。根据负序电压正反馈法的原理提出了基于自适应负序电压正反馈的孤岛检测方法,其具有足够孤岛检测能力的正反馈系数取决于逆变器实时输出功率的大小。改进后的方法在逆变器并网运行时能有效减小注入大电网的负序扰动分量,且孤岛发生后能够在规定时间2 s内实现孤岛检测。通过理论分析和仿真研究,验证了所提方法的可靠性。Due to the positive feedback of negative-sequence voltage,the negative-sequence voltage of PCC（Point of Common Coupling） will increase continuously after the occurrence of islanding,which can be used as a criterion to detect the occurrence of islanding. However,too large feedback coefficient will induce too large injection of negative-sequence disturbance into the inverter while too small feedback coefficient will cause the failure of islanding detection. An improved method of islanding detection based on the adaptive positive feedback of negative-sequence voltage is proposed,which modifies the positive feedback coefficient adaptively according to the real-time output power of inverter. The improved method can effectively reduce the injection of negative-sequence disturbance component into grid when multiple grid-connected inverters are operating in parallel while realize the islanding detection within the prescribed time of 2 s after the occurrence of islanding. Theoretical analysis and simulation results verify its reliability.

关 键 词：孤岛检测 负序电压 自适应反馈系数 多机并联 负序扰动 

分 类 号：TM71[电气工程—电力系统及自动化]