DEVICE FOR DETECTING SINGLE-PHASE GROUND FAULT IN OVERHEAD INSULATED-NEUTRAL NETWORKS Russian patent published in 2005 - IPC

FIELD: warning about ground fault and protecting overhead insulated-neutral power transmission lines.

SUBSTANCE: proposed device has line fault detector connected to air-outlet cells which are connected to potential transformer. Line fault detector has phase comparison units whose number depends on number of joints; input converter whose input is connected to potential transformer and output, to first input of phase comparison unit of each joint under protection and to input of control unit whose first and second outputs are connected, respectively, to second and third inputs of phase comparison unit of each joint under protection, third output being connected to control input of actuating unit; zero-sequence current transformers mounted in respective air-outlet cells with aid of special structure of three flexible insulated wires; secondary-winding leads of zero-sequence current transformer are connected to fourth inputs of phase comparison unit and primary winding is formed by wires of phases A, B, C passed through core opening, some of their ends being connected to high-voltage circuit breaker contacts and other ends, to respective bushing insulators in phase B directly and in phases A and C, through current transformers.

EFFECT: provision for automation and enhanced selectivity of faulty line detection.

3 cl, 1 dwg