A Novel Way to Distinguish Single Phase Dips Through Potential Gradient Method

Abstract

The majority of faults on a utility system are line-to-ground faults, and it is also the most common cause of voltage dips in industrial system. The disruption of an industrial process due to a line-to-ground fault can result in substantial costs to operation. The dip in the single phase associated with this fault is either type B or D. However, type D is also associated with to line-to-line faults. For the application of a suitable mitigation scheme to voltage dips, it is essential to distinguish between type B and D from measured sag voltages. This article discusses the characteristics of dips associated with line-to-ground and line-to-line faults and presents a new method to detect type B and D with the help of positive- and negative-sequence potential gradient methods derived as a function of distance to fault location. The need to distinguish type B and D, and the advantages of characterization through the sequence component, are also discussed.

Keywords:

• power quality
• potential gradient
• symmetrical component
• voltage dips