摘要
针对励磁涌流和内部故障识别这个变压器差动保护关键问题，利用Prony算法求取原信号中基波和二次谐波的幅值和衰减因数，建立了一种新判据：二次谐波与基波幅值之比（Id2/Id1）及衰减系数之比（α2／α1）当励磁涌流时，Id2/Id1〉O．15，α2/α1〈2；而当变压器内部故障时，Id2/Id1＜O．15，α2/α1＞2。这一结果是通过分析基于PSCAD／EMTDC建立的变压器发生励磁涌流和内部故障时的仿真图得到的。所建议的识别励磁涌流和内部故障的新判据据具有高的灵敏度。
Aiming at the identification of inrush current and internal fault, which is the key issue of transformer differential protection,and adopting the ampitudes and attenuation tactors of me runaamental wave and second harmonic in the original signal with Pronyalgorithm, a new criterion based on Id2/Id1 and α2/α1 is established in this paper. When the inrush current occurs,Id2/Id1=O.617〉0.15,α2/α1=1.67〈2while the intemal fault occurs,Id2/Id1〈O.15,α2/α1=∞〉2 This result is obtainedthrough analysis on the simulation data of transformer inrush current and internal fault from calculations with PSCAD / EMTDC software. The proposed criterion can significantly improve the sensitivity for identification of the inrush current and internal fault.
出处
《南方电网技术》
2011年第A01期51-54,共4页
Southern Power System Technology
