Experimental measuring of the touch voltages in large compensated networks

Abstract

A connection between a phase conductor and the ground in MV networks is called earth fault. The fault current in this case does not depend on the point of the fault, but only on the total capacity (size) of a network. Distribution system operator (DSO) sometimes needs to operate the large network which means operating of the network with big capacitive current (in Czech Republic more than 800A). This operation puts the emphasis not only on the setting of the earth fault relays but on the safety of the point of fault too. The paper describes the tests in real compensated distribution network with capacitive currents 300A and 800A. There were tested low-ohmic and arc fault. The first results show that the operation of large network is possible with using of the automatics of additional earthing of affected phase. The touch and step voltages were reduced under level allowed by standard EN 50522.