Middle voltage distribution networks operate with compensated neutral which offers a lot of advantages. One major advantage is that during a single phase to ground (SPG) fault the faulty operation can be maintained, due to the small rms of the fault currents. This way the continuous supply of the consumers is sustainable if the value of the touch voltage remains small.
The compensation with Petersen coil also comes with a great disadvantage, as the localization of a SPG fault is very complicated.
The first part of the thesis is a short review of the compensated neutral and the distribution system operators’ (DSO) current practices to locate the fault. This part is about the problems related to the DSOs’ test switching method and Tunglioc device.
New faulty feeder selection and fault location methods published in the literature are summarized. Afterwards, two of the fault location methods are evaluated based on computer simulations using EMTP software.
A new innovative device developed by the colleges of BME Department of Electric Power Engineering is presented shortly. The device operates in two Hungarian DSOs in test mode. An evaluation of the operation will be given based on available real field measurement data.