一种适用于大型光伏电站的新型备自投方案  

A new backup automatic switch scheme for large-scale photovoltaic power stations

作　　者：蔡乾 于晓军 吴建云 于小艳 罗美玲 李博通 CAI Qian;YU Xiaojun;WU Jianyun;YU Xiaoyan;LUO Meiling;LI Botong(State Grid Ningxia Electric Power Co.,Ltd.,Yinchuan 750001,China;Ultra-high Voltage Company of State Grid Ningxia Electric Power Co.,Ltd.,Yinchuan 750001,China;School of Electrical and Information Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]国网宁夏电力有限公司,宁夏银川750001 [2]国网宁夏电力有限公司超高压公司,宁夏银川750001 [3]天津大学电气自动化与信息工程学院,天津300072

出　　处：《电力工程技术》2023年第6期91-99,共9页Electric Power Engineering Technology

基　　金：国家自然科学基金资助项目(52177108)。

摘　　要：随着大规模光伏接入电网,备用电源自动投入装置(简称“备自投”)的传统投入策略将受到影响:电网出现故障时,由于光伏电源的存在,故障处母线电压无法满足检“无压”判据,传统备自投不能正确动作。为提高新能源利用率并保证在不解列光伏电源的前提下实现备自投正常动作,文中提出一种基于分布式缓冲电阻的新型备自投方案。首先,重点分析光伏出力与负荷功率不匹配程度对并网点电压的影响;其次,在各光伏发电单元直流电容两端并联分布式缓冲电阻支路,利用缓冲电阻平抑主供电源断开后(备自投动作前)形成孤岛状态下的功率不均衡,实现在不解列光伏电源的前提下备自投安全快速动作;最后,针对光伏与负荷功率极不匹配场景,利用MATLAB/Simulink进行仿真验证,备用电源投入时冲击电流可限制在1.5倍额定电流内,符合相关规范要求,验证了所提新型备自投方案的可行性及有效性。With the integration of large-scale photovoltaic power stations into power grids,the traditional strategy of the backup automatic switch is affected.When a grid fault occurs,due to the existence of photovoltaic power sources,the busbar voltage at the fault point cannot meet the′no voltage′criterion,and the traditional strategy cannot operate correctly.In order to improve new energy utilization and ensure normal input of the backup power supply without disconnecting photovoltaic power sources,a new backup automatic switch scheme based on distributed buffer resistors is proposed.Firstly,the influence of the mismatch between photovoltaic output and load power on the grid-connected point voltage is analyzed.Secondly,distributed buffer resistor branches are connected in parallel at both ends of the DC capacitor in each photovoltaic power generation unit,using buffer resistors to suppress the power imbalance formed in the islanded state after the main power supply is disconnected(before the backup automatic switch operates),realizing safe and fast operation of the backup automatic switch.Finally,MATLAB/Simulink is used to simulate and verify the scenario of extreme mismatch between photovoltaic and load power,and the inrush current can be limited to 1.5 times rated current,which meets the relevant specifications and verifies the feasibility and effectiveness of the proposed new backup automatic switch scheme.

关 键 词：光伏电站 分布式电源 备自投 缓冲电阻 功率均衡 冲击电流 

分 类 号：TM771[电气工程—电力系统及自动化]