Substations often require new equipment to upgrade or expand existing facilities, or to replace damaged equipment....
This can require interfacing to equipment from different manufacturers and technologies of existing equipment. If damage occurs to an in-service substation, replacement parts are required immediately to minimize outage time.

In the case of a retrofit to an existing GIS substation, the ability to design and install a variety of interfaces, and to allow sufficient installation tolerance is paramount. The existing equipment could include GIS supplied by different manufacturers who may follow different design philosophies and operating parameters.

In other retrofit cases, outdated equipment must be replaced. Here again, the challenge is to minimize the outage time required to affect the change, and to use as much existing peripheral equipment as possible to reduce costs.

CGIT offers solutions to the problems faced when retrofitting existing installations. One completed CGIT retrofit project involves the GIS at Seabrook Nuclear Station in New Hampshire.

Seabrook Nuclear Power Plant Substation
The Seabrook gas insulated substation project, consisting of 345 kV ITE GIS and bus, had developed a history of unreliability due to leaks and insulator failures within the bus. This was particularly  a cause of concern within areas of the substation that were not protected by redundant sections of the installation, thereby having no backup in case of section bus failures.

CGIT bus, backed by its established record of reliability in long-term service, was selected to replace the ITE bus for these critical connections. They involved connections from the GIS to both main transformers and to auxiliary transformers.

In addition to offering a reliable bus design, CGIT defined and managed a schedule  to complete the installation within a one-week outage to comply with the NRC approved outage schedule, and under tight space and access conditions.

The first of the Seabrook CGIT bus installations has been in service without fault since its completion in 1990.

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