微电网改进负荷功率分配策略与并网稳定性分析  

Improved load power allocation strategy for microgrid and grid-connection stability analysis

作　　者：郑连清[1,2] 庄琛[1] 马世强[2] 王晓旭[1] 

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400044 [2]新疆生产建设兵团兴新职业技术学院,新疆乌鲁木齐830074

出　　处：《电力自动化设备》2015年第4期17-23,共7页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(51277191)~~

摘　　要：由于低压微电网孤岛运行受线路阻抗特性等因素的影响,采用传统下垂控制无法按分布式电源(DG)单元容量合理分配功率,且孤岛微电网的电压和频率与大电网不同,并网前需进行同步控制。在分析并联逆变器功率分配机理的基础上,提出了改进的负荷功率分配控制策略。重新设计了Q-U下垂控制环,增加无功误差积分修正项,优化了微电网内部的功率分配。对微电网进行了并网同步控制,并建立了控制系统小信号模型,对改进负荷功率分配策略与并网同步控制的系统稳定性进行了分析。仿真结果表明采用所提控制策略后,无功功率可被合理分配,并网暂态过程平滑稳定。Due to different influencing factors,such as the line impedance,the traditional droop control cannot be applied to allocate the power of islanded low-voltage microgrid according to the capacity of DG（Distributed Generation） unit. Furthermore,the voltage magnitude and frequency of islanded microgrid should be synchronized before grid-connection. The power allocation mechanism of parallel inverter is analyzed and an improved load power allocation strategy is proposed,which optimizes the power allocation within the microgrid by redesigning the Q-U droop control loop with additional reactive power error integral term. A small-signal model of control system is built for the grid-connection synchronization of microgrid and the system stability of grid-connection synchronization control with the proposed load power allocation strategy is analyzed. Simulative results show that,with the proposed strategy,the reactive power can be reasonably allocated and the transient process of grid-connection is smooth and stable.

关 键 词：微电网 负荷功率分配 负荷管理 并网 同步 稳定性 控制 孤岛 下垂控制 分布式发电 

分 类 号：TM72[电气工程—电力系统及自动化]