FIELD: high-voltage power networks. SUBSTANCE: device includes power transformer which neutral is grounded through arc-control reactor, voltage transformer which neutral is grounded through high-resistance resistor. Neutrals of transformers are interconnected through low-resistance resistor shunted with switch. Single-phase transformer with voltage relay placed in its secondary winding is linked to neutral of power transformer. Current relay is connected in grounding circuit of arc-control reactor. Outputs of both relays are placed in switching-on circuit of switch shunting resistor. EFFECT: improved operational reliability. 1 dwg
