摘要
定子单相接地是发电机的常见故障,如果不及时处理就可能发展为更严重的相间或者匝间短路。20Hz注入式定子接地保护可以单独实现定子100%绕组的保护,可以监测定子绝缘水平的下降,因而越来越多地应用于大型发电机保护。20Hz注入式定子接地保护算法的目的是从包含工频和20Hz成分的采样信号中,准确地提取出20Hz分量,以完成进一步的阻抗计算。针对全波傅氏算法应用于20Hz注入式定子接地保护时数据窗过长的问题,提出采用最小二乘算法提取20Hz分量的改进措施。最小二乘算法与傅氏算法相比,具有可以任意选择拟合模型、数据窗可调等优点。基于这些优点,将最小二乘算法应用于20Hz注入式定子接地保护,并通过分析计算证明:与傅氏算法相比,最小二乘算法的速度更快、精度更高。
The stator grounding fault of generator is a frequent fault, and will develop into phase fault or turn to turn fault if without being promptly processed. The stator grounding fault protection with 20Hz voltage injection can provide 100% winding＇s protection and monitor the drop of stator＇s insulation. So it is widely used in large generator protection. Its algorithm is used to extract 20Hz component accurately from sampling signal containing power frequency and 20Hz components for impedance computation. In order to shorten the data window of the stator grounding fault protection with 20I-Iz voltage injection, the least square algorithm is used to extract the 20Hz component replacing the full-wave Fourier algorithm. Compared with the full-wave Fourier algorithm, the least square algorithm shows advantages in arbitrary fitting models, adjustable data windows. It is used in the stator grounding fault protection with 20Hz voltage injection. Analysis and calculation results prove that the least square algorithm is superior to full-wave Fourier algorithm in efficiency and accuracy.
出处
《现代电力》
2008年第4期7-10,共4页
Modern Electric Power
关键词
定子接地保护
20Hz注入式
最小二乘算法
发电机
继电保护
stator grounding fault protection
20Hz voltage injection
least square algorithm
generator
relay protection
作者简介
董春雨（1983-），男，硕士研究生，主要研究方向为电力系统继电保护；
乔洪新（1982-），男，硕士研究生，主要研究方向为电力系统继电保护；
宣科（1984-），男，硕士研究生，研究方向为电力系统及其自动化。
