适用于全故障类型的双馈风电场送出线负序电流纵联保护方案

NEGATIVE SEQUENCE CURRENT PILOT PROTECTION SCHEME FOR DFIG OUTGOING LINE WITH ALL-FAULT TYPES

随着双馈风电机组(DFIG)并网容量的增加,给风电场送出线继电保护的整定带来新的挑战,保护动作性能下降甚至会出现拒动和误动的风险。为此,首先分析双馈风电机组负序电流分量特征;然后进一步分析风电场经交、直流并网时交流送出线两侧电流的特征差异,提出一种适用于双馈风电场送出线的负序电流分量纵联保护新方法。该方法利用双馈风电场送出线两侧负序电流的幅值比和相位差构成保护动作判据,同时,利用数据延时在对称故障下构造出负序分量,使其能适用于风电场送出线的各种故障类型,且具有灵敏度高、耐受过渡电阻能力强等优点。最后,在Matlab/Simulink和PSCAD/EMTDC中搭建双馈风电机组电磁暂态仿真模型,仿真分析保护方案在交直流送出线上的适应性。

With the increase of grid-connected capacity of DFIG,it brings new challenges to the setting of relay protection for wind farm outgoing line.When the performance of the protective action is reduced,there is even a risk of rejection and misoperation.To this end,firstly,the characteristics of negative sequence current component of DFIG are analyzed.Then,the characteristic differences of the currents on both sides of the AC outgoing line when the wind farm is connected to the grid by AC or DC are further analyzed,and a new method of negative sequence current component pilot protection for the outgoing line of doubly fed wind farms is proposed.The method uses the amplitude ratio and phase difference of the negative sequence current on both sides of the double-fed wind farm outgoing line to form the protection action criterion.At the same time,uses the data delay to construct the negative sequence component under symmetrical faults,so that it can be applied to various fault types of the wind farm outgoing line,and has the advantages of high sensitivity and strong ability to withstand transition resistance.Finally,the electromagnetic transient simulation model of DFIG is built in Matlab/Simulink and PSCAD/EMTDC,to simulate and analyze the adaptability of the protection scheme on the AC/DC outgoing lines.