适应电流差动保护的光伏电站边界接入容量分析  

The boundary capacity of photovoltaic power plant adapted to current differential protection

作　　者：刘素梅 王丹枫 李伟[2] 夏烨 Liu Sumei;Wang Danfeng;Li Wei;Xia Ye(School of Technology,Beijing Forestry University,Beijing 100083,China;State Key Laboratory of Power Grid Safety and Energy Conservation,China Electric Power Research Institute,Beijing 100192,China)

机构地区：[1]北京林业大学工学院,北京100083 [2]中国电力科学研究院电网安全与节能国家重点实验室,北京100192

出　　处：《可再生能源》2023年第5期644-652,共9页Renewable Energy Resources

基　　金：国家自然科学基金项目(52107069);中央高校基本科研业务费专项资金项目(2018BLRD02)。

摘　　要：光伏电站在电网中的占比持续增加,使得电网的短路电流呈现幅值受限、初相角受控的特征,导致区内故障下差动电流大于制动电流的特有关系不再成立,传统电流差动保护将出现不正确动作风险。文章首先基于光伏发电单元故障响应特性,构建了光伏电站短路电流幅值与初相角的数学模型;然后,通过分析光伏电站接入容量变化对送出线路两侧制动电流与差动电流比值的影响规律,进一步推导获得了适应差动保护的光伏电站边界接入容量解析表达式;最后,利用PSCAD/EMTDC仿真试验,证明了文章所提边界接入容量的计算表达式,以及在评价含光伏电站电网的传统差动保护适应性等方面的有效性。With the increasing capacity of grid-connected photovoltaic power plants(PVPPs),the fault current characteristics are remarkably altered.The limited amplitude and controlled initial phase angle of PVPPs'short-circuit current become highlighted.As a result,the differential current is no longer greater than restraint current at both sides of the protected devices when a fault occurs.It may lead to mal-operation of the current differential protection which is used widely.Firstly,the theoretical model of PVPPs'fault current amplitude as well as its initial phase angle is firstly deduced based on the fault behaviors of photovoltaic generation units.Further,by analyzing the influence of different connected capacity of PVPPs on the ratio of operate-to-restraint current,the analytical expression of the PVPP's boundary capacity is deduced,which is suitable for analyzing the adaptability of differential protection.Finally,the simulation tests were carried out based on PSCAD/EMTDC.The test results show that the aforementioned expression is effective for evaluating the adaptability of current differential protection.

关 键 词：光伏电站 差动保护 短路电流幅值 短路电流初相角 边界接入容量 

分 类 号：TK81[动力工程及工程热物理—流体机械及工程]