The Automatic Protection System Applied Discharging Gap for High Resistance Ground Fault of DC Electric Raliway

Abstract

Because of relatively high short circuit resistance, most of the ground fault accidents between power feeders and supporting structures can not be detected by the conventional protection systems at the DC electric railway substations. A novel protection system has been successfully developed which reduces such a short circuit resistance to the detectable level. The unit pulsed power swiching controls consists of a CR-integrator, a master pulse generator gap, a decoupling gap switch and two main arc gap switches in a series connection, and installed between the rail and the supporting structures. The large scale field test has demonstrated that these inexpensive protection systems function well and may improve the reliability of the DC railway systems.