Abstract: An instrument current transformer for a main power cable which is composed of three power cables for three phases disposed in a power cable laying hole and three current transformer coils for the three phases, each of the three current transformer coils surrounding a corresponding one of the three power cables, the instrument current transformer including: a plurality of upper circumferential installation unit members disposed near an end portion of the power cable laying hole along circumference sides of an opening portion of the power cable laying hole, each of the upper circumferential installation members being provided with at least one securing portion extending in a radial direction and the upper circumferential installation unit members being secured to the end portion of the power cable laying hole via respective at least one securing portions; three axial installation members for the three phases, each extending along corresponding ones of the three power cables, first ends of the axial installation

Abstract: A gas insulated switchgear system having two gas insulated switchgear equipments, each of which consists of first disconnecting switches, circuit breakers, and second disconnecting switches, three phase gas insulated buses which are respectively connected to the first disconnecting switches of the two gas insulated switchgear equipments in every three phases thereof, a single phase reserve buses which are commonly connected to all of the second disconnecting switches of the two gas insulated switchgear equipments, and an operating device for opening the circuit breakers and the first disconnecting switches in only one phase of the gas insulated switchgear equipments and closing the second disconnecting switch in only the one phase. A gas insulated switchgear system having single phase reserve bus is economical and switches one of the three phase main buses to the single reserve bus without forming short circuit.