A frequency curves analysis-based method for transformers differential protection

作者：Fani B^*; Golshan M E Hamedani; Saghaian nejad M

来源：European Transactions on Electrical Power, 2011, 21(1): 987-996.

DOI：10.1002/etep.491

• transformer differential protection
• inrush current
• fault current
• frequency curve
• skewness measure

This paper uses different geometrical structure of inrush current with respect to that of fault current for the identification of transformer magnetizing inrush. For this purpose, the differential current is considered as a stochastic signal, and a scheme based on stochastic analysis of differential currents is proposed. The scheme converts changes in slope of inrush and fault currents as a major feature of difference between them into a quantitative description by using the skewness concept of frequency curves. Skewness is the degree of asymmetry of a curve, usually taken relative to a normal curve. Internal faults are discriminated from inrush conditions by investigating the signs of the skewness coefficients corresponding to three-phase differential currents. Various experimental cases verify the dependability, security, and fast operation of the proposed algorithm.

• 出版日期2011-1