Unnecessary Simultaneous Trip in Distribution Networks

Sabra, H., D. K. Ibrahim, and M. Gilany, "Unnecessary Simultaneous Trip in Distribution Networks", 17th International Middle East Power Systems Conference, MEPCON 2015; Mansoura University, Egypt, December, 15-17, 2015., 2015.


In medium voltage distribution network, the phenomena of having a simultaneous false trip on healthy feeder/feeders during a real fault on another feeder is common. It affects badly the continuity of service. In this paper, three different causes of this unnecessary simultaneous tripping in distribution networks are discussed. The earth fault element problems caused by these phenomena are also evaluated. A practical solution for this problem is proposed by using the custom logic scheme exists in the digital protection relay. The proposed method is applied to an actual system utilizing the existing protective digital relays. Actual records for faulty phase current and calculated zero sequence currents were captured and analyzed by means of digital fault recorders exist in the protection relay. The obtained results are encouraging and indicate the suitability and advantages of the proposed method.