Technical Report No.1349

No. 1349

The technical trend of insulation system on Medium-Voltage Switchgear

Investigating R&D Committee on Insulation System of Medium-Voltage Switchgear

Keyword :

Medium-Voltage Switchgear, Insulation system, COP3, Consumption reduction of SF6 gas, Substitutes of SF6 gas

Medium-voltage (MV) switchgears are used in an extensive range of equipment from power generation through power transmission to power receiving, and those are essential to steady supply of electric power. Therefore, improvements and developments of switchgears have been always carried out to meet the needs of the times, which are improvement of safety and the reliability, downsizing and lightening, labor saving of the maintenance, environmental suitability, reduction of Life Cycle Cost, etc.
Particularly, because the SF6 gas which has been used widely as an insulating and an extinguishing medium of MV switchgears was appointed in one of the discharge reduction object gas at COP3 in 1997, the actions which are downsizing of the switchgears and application of mixed gases with the N2 for consumption reduction of SF6 gas, a substitute to dry air or N2 gas, application of solid insulation and composite insulation for the SF6 gasless, are performed lively in late years.
Based on such situation, it is very significant to investigate the recent technical trend of the insulation system that greatly affect the performance, the reliability and size of MV switchgears.
In this technical report, the change of the insulation systems, the characteristics and significant differences, the application situation of various insulation systems are arranged systematically and the prospects in the future of various insulation systems are commented on.