GPT ADDITIONAL GROUND VOLTAGE SUPPRESSOR

PROBLEM TO BE SOLVED: To provide a GPT additional ground voltage suppressor having a function for suppressing an abnormal potential rise in a non-grounding three-phase distribution wire way associated with the occurrence of ferroresonance. SOLUTION: The primary winding 111 of GPT is wound in Y-connection connected to three wires applied with three-phase voltage with its neutral point N grounded. A secondary winding 112 transforms the three-phase voltage applied to the primary winding 111, and outputs to an external device 140. A tertiary winding 113 is wound in open Δ-connection, with a load resistor 120 provided between a pair of open terminals. The ground voltage suppressor 130 has a discharge gap 131 connected to the open terminal O1 at its one end and a load resistor 132 provided between the other end of the discharge gap 131 and the open terminal O2. When the discharge gap is electrified at the time of an abnormal potential rise, the resistor elements 120, 132 are in the state of parallel connection and the grounding resistance at the neutral point N increases to promote discharge, suppressing the potential rise. COPYRIGHT: (C)2008,JPO&INPIT