Evolution of an environmentally friendly “green” compact three-phase 27kV, 630A switchgear to improve network reliability

The need of a major urban utility to improve network reliability and feeder processing has generated the development of a series of switchgear devices. Size is an important issue since some applications are in existing 32-inch manhole structures and in vaults where space is limited. In addition environmental concerns were addressed with designs consisting of vacuum bottle switching with solid EPDM rubber insulation, eliminating the concern of leakage of greenhouse gases or liquid contaminants. This new switchgear reduces the time of feeder processing to restore repaired or changed networks to normal conditions, in some cases from days to hours. Three devices evolved to meet different requirements. The requirements included different combinations of loadbreak and/or loadmake with or without 40kA fault close capability and with or without SCADA control. This paper describes the function and application of these devices.