First results concerning localisation of earthfaults in compensated 20-kV-networks based on travelling waves

Abstract

Due to today´s increased demands on grid operation management, new methods for earth fault localization and detection are needed. The fault localisation should be performed as quickly as possible and under the condition, that the fault current at the fault location will not be significantly increased. Fault location method based on the travelling wave (TW) theory is already in use in some countries for transmission networks. In today's 20 kV grid, almost every feeder in the substation has capacitive sensors to supervise the voltage of the three phases. First tests have shown that these sensors are suitable for voltage measurement up to some MHz. Due to the change of technology in the last 10 years the discussion starts, to use travelling waves also in distribution networks. The task is to evaluate, if it is possible to make, for compensated networks, a central distance estimation in secondary substations for the distribution network, based on the evaluation of the voltages travelling waves. This paper will present the first results of this evaluation.