Challenges in detection of high impedance faults on broken conductors in MV lines

Abstract

The weather conditions in Saudi Arabia are harsh and the inland areas are very hot, dry and sandy. Thousands of kilometers of medium voltage overhead lines (13.8 kV) are located in deep desert areas feeding loads that are located in remote desert areas. Such medium and low voltage distribution networks face difficulties regarding fault detection and localization. High Impedance Fault (HIF) resulting from a broken conductor in MV overhead lines represent the most challenging problem in such environments. Such condition may cause damage, fire or electric shock hazards resulting in life threatening situations. This study reports on a study of electrical characteristics of inland desert sand and typical characteristics of HIF fault when a MV line conductor breaks and touches such sand. It is shown that the arid desert sand has extremely high resistivity and it is difficult to detect the fault by using conventional protective devices. The study presents results of measurements and simulations and suggests that innovative approaches have to be employed to achieve the desired protection in such environments. © Maxwell Scientific Organization, 2014.