基于结构相似度与平方误差的新能源场站送出线路纵联保护综合判据  

Comprehensive Criteria of Pilot Protection Based on Structural Similarity and Square Error for Outgoing Line from Renewable Power Plants

作　　者：郑黎明 贾科 毕天姝 任龙飞 杨哲 ZHENG Liming;JIA Ke;BI Tianshu;REN Longfei;YANG Zhe(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources(North China Electric Power University),Changping District,Beijing 102206,China;Northwest Branch of State Grid Corporation of China,Xi’an 710048,Shaanxi Province,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京市昌平区102206 [2]国家电网公司西北分部,陕西省西安市710048

出　　处：《电网技术》2020年第5期1788-1795,共8页Power System Technology

基　　金：国家重点研发计划项目(2018YFB0904104);国家自然科学基金项目(51725702,51777071);国家电网公司科技项目(SGNW0000DKJS1900197)。

摘　　要：电力电子装置在新能源电力系统中的广泛应用,改变了传统电力系统的故障特性,使得传统保护动作性能下降、甚至存在误动和拒动风险,从而给电网的安全稳定运行带来挑战。在分析新能源送出线路两侧故障波形差异的基础上,提出了基于结构相似度与平方误差的纵联保护综合判据。该方法首先利用小波变换实时提取两侧电流中各频段的信息,通过结构相似度与平方误差综合判据识别区内、外故障。将所提综合判据固化在保护装置中,通过硬件在环动模仿真实验验证了所提原理的有效性:所提方法可解决新能源接入后差动保护动作性能下降问题,适应不同类型新能源场站,具有耐受过度电阻能力,与现有基于新能源暂态电流特征的保护相比,在新能源电源弱出力以及重合于永久性故障时动作性能更好。现场录波数据也验证了所提方法的有效性。Wide application of power electronic components in power systems with renewable energy sources changes the fault characteristics of traditional power systems, resulting in performance degradation of traditional protections, even the risk of maloperation and action refusal. This brings challenges to safe and stable operation of power grid. The waveform differences between both sides of transmission line during internal faults are analyzed, and a comprehensive criterion of pilot protection based on structural similarity and square error is proposed. Wavelet transform is used to extract the information of each frequency band in the currents on both sides in real time, and the internal and external faults are identified with the synthetical criterion of structural similarity and square error. The proposed comprehensive criterion is solidified in industrial protection device, and effectiveness of the proposed principle is verified with dynamic hardware-in-loop simulations. The proposed protection solves the problem of performance degradation of differential protection with integration of renewable energy power plants, suitable for all kinds of renewable energy power plants and robust for high resistance faults. Compared with the existing protections based on the transient current characteristics of renewable energy sources, it also shows better performance when the capacity of renewable energy sources is small and reclosed on permanent faults. Validity of the proposed method is also verified by field-recorded data.

关 键 词：新能源场站 结构相似度 平方误差 纵联保护 综合判据 

分 类 号：TM721[电气工程—电力系统及自动化]