低压微电网中并网逆变器主动移频式孤岛检测技术  

An Islanding Detection Method on Active Frequency Drifting for Grid-connected Inverters in Low Voltage Microgrids

作　　者：阚加荣[1] 谢少军[2] 姚志垒[1] 胡国文[1] 陈荣[1] 

机构地区：[1]盐城工学院电气工程学院,江苏省盐城市224051 [2]南京航空航天大学自动化学院,江苏省南京市210016

出　　处：《电力系统自动化》2012年第7期33-37,共5页Automation of Electric Power Systems

基　　金：国家自然科学基金资助项目(51077070);国家自然科学基金青年基金资助项目(51107108)~~

摘　　要：在低压微电网中,线路阻抗、逆变器输出阻抗呈阻性,可以采用有功调幅、无功调频的间接电流型并网逆变器控制策略,该控制策略具有一定的反孤岛能力。推导了电阻、电感和电容负载的幅值和相角的表达式,给出了并网逆变器在孤岛运行时的无功表达式,由此得到电网故障后逆变器输出电压的频率变化数学模型,得到了有功调幅、无功调频的控制策略下逆变器孤岛检测盲区图。提出了频率正反馈的逆变器孤岛检测方法,通过在无功调频控制策略中引入频率正反馈环节,可大大减小逆变器孤岛检测盲区,给出了频率正反馈系数的选取原则。仿真结果表明,理论分析正确,所提出的孤岛检测方法可行。In a low voltage microgrid,because the impedances of transmission lines and inverters mainly consist of resistances,the output active and reactive powers of a grid-connected inverter can be regulated by respectively adjusting the voltage amplitude and phase.This control strategy has a certain anti-islanding capability.The expressions of phase and amplitude for a parallel RLC load are derived.The reactive power expression of a grid-connected inverter in the islanding mode is given.Based on these expressions,the mathematical model of variable frequency of grid-connected inverter in the islanding mode is developed,and the non-detection zone（NDZ）is obtained.In order to reduce the NDZ,a method with positive frequency feedback is proposed,and the selection principle for coefficient of positive frequency feedback is discussed.Simulation results show the feasibility of the proposed detection method.

关 键 词：分布式电源 间接电流控制 主动移频 孤岛检测 并网逆变器 微电网 

分 类 号：TM464[电气工程—电器]