双馈风电场送出线类四边形距离纵联保护方案

Quadrilateral Distance Longitudinal Protection Scheme for Transmission Lines of Doubly-Fed Wind Farms

双馈风电场送出线发生短路故障时,风场侧短路电流与传统电源短路电流差异较大,可能会使传统保护的动作性能下降,甚至出现保护拒动、误动现象.鉴于此,为风电场送出线量身定制了计及频偏和过渡电阻影响的类四边形距离Ⅱ段方向元件,在全面分析其动作性能的基础上,将其应用于纵联保护中,构建了基于类四边形的距离纵联保护方案.仿真结果表明,该保护方案在考虑短路电流频偏特性、过渡电阻、风速变化、噪声干扰、混叠频率、无功补偿、出力变化和数据延时等影响因素下,都能够准确判断出故障方向,可靠识别出区内、区外故障,为风电场送出线提供了一种较为可靠的保护方案.

When a short-circuit fault occurs on the output line of the doubly-fed wind farm,the short-circuit current on the wind farm side is different from the traditional power line,which may degrade the performance of the traditional protection,and even cause protection failure or malfunction.In view of this,a quadrangle like distance II directional element considering the influence of frequency offset and transition resistance is customized for the outgoing line of the wind farm.Based on the comprehensive analysis of its action performance,it is applied to the pilot protection,and a distance pilot protection scheme based on the quadrangle is constructed.The simulation results show that the protection scheme can accurately determine the fault direction and reliably identify the area failure outside the zone,considering the short-circuit current frequency offset characteristics,transition resistance,wind speed change,noise interference,aliasing frequency,reactive power compensation,wind farm capacity and data delay.It provides a more reliable protection scheme for the outgoing lines of wind farms.