大型光伏电站无功电压控制策略  

Reactive-power and voltage control for large-scale grid-connected photovoltaic plants

作　　者：周林[1] 邵念彬 

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400030

出　　处：《电力自动化设备》2016年第4期116-122,128,共8页Electric Power Automation Equipment

基　　金：国家高技术研究发展计划(863计划)资助项目(2011-AA05A301)~~

摘　　要：对于大型光伏电站,有功出力的波动不仅会造成并网点电压越限,也会造成电站内部局部电压过高,导致保护动作,使得逆变器脱网。分析了光伏电站并网点电压及站内各光伏发电单元并网电压的影响因素,提出了一种考虑站内电压分布的大型光伏电站无功电压控制策略。该控制方法通过实时检测并网点电压,与参考值比较并通过PI控制器自动获取维持并网点电压所需的无功需求量,实现并网点电压的动态调节;通过实时调节逆变器的无功输出,实现站内电压均匀分布。应用灵敏度的分析方法表示无功与电压间的关系,给出了PI控制器参数的设计过程,并将以站内电压均匀分布为目标的无功优化问题转化为可以快速准确求解的带约束条件的非线性规划模型;对该模型进行求解计算出无功补偿装置及各组光伏发电单元的无功参考量,在保证并网点电压稳定的基础上,改善站内电压分布,保证光伏电站的稳定运行。最后通过仿真计算,验证了该控制策略的正确性和可行性。The active-power output fluctuation of large-scale grid-connected photovoltaic plant causes not only the PCC voltage violation but also the higher internal voltage,resulting in the protective action to trip off the inverters. The factors influencing the PCC voltage and the grid-connecting voltage of photovoltaic unit are analyzed and a strategy of reactive-power and voltage control considering the in-station voltage distribution is proposed. It detects the PCC voltage in real time,compares it with the reference,adopts a PI controller to automatically obtain the reactive-power needed for maintaining the PCC voltage,and realizes the dynamic adjustment of PCC voltage;it also regulates the reactive-power output of inverters in real-time to realize the uniform distribution of in-station voltage. The sensitivity analysis is applied to indicate the relationship between reactive-power and voltage,the design of PI controller parameters is given,and the reactive-power optimization with the uniform distribution of in-station voltage as its objective is converted to a nonlinear programming model with constraints,which can be quickly and accurately solved to obtain the reactive-power references for the reactive-power compensation devices and photovoltaic units. The in-station voltage distribution is improved to ensure the stable operation of photovoltaic power station while the stability of PCC voltage is guaranteed. The correctness and feasibility of the proposed control strategy are verified by the simulative results.

关 键 词：光伏 发电 大型光伏电站 电压波动 无功控制 电压控制 灵敏度 电压分布 

分 类 号：TM615[电气工程—电力系统及自动化]