Experimental measuring of the earth faults currents in MV compensated networks

The MV compensated Networks in Czech Republic are operated as nonsymmetrical, that means as networks with non-transposed lines. In these networks the fault currents depend on the affected phase because the Petersen coil is tuned only for one value of earth current. The paper deals with influence of fault type on size of fault current and on the length of its transient phenomena. There are described experiments which were realized in distribution network held by E.ON Czech Republic. There were made a few different fault (low-impedance, spark gap arc, damaged MV cable, 1.6 k??, 4 k?? and unearthed console of concrete tower) for three different places, for tuned and untuned Petersen coil and for some types of faults for all phases too, that means forty eight experimental faults. During each experiment the shunting of affected phase was applied.