Manufacturer: Hitachi Energy
Original publication date: 4 June 2026
Topic: Lifecycle modernization of 500 kV gas-insulated switchgear
China General Nuclear Power Group has selected Hitachi Energy to provide replacement and upgrade solutions for the 500 kV GIS at Daya Bay Nuclear Power Station in Shenzhen.
Scope and schedule
The installed GIS has been in service for more than 30 years. Hitachi Energy reports that all 15 bays will be addressed in phases over an estimated eight-year period. The work is to be coordinated with nuclear-plant and grid maintenance windows so that the station can continue supplying power during the program.
The project requires retrofit solutions adapted to existing infrastructure rather than a simple like-for-like greenfield installation. The supplier also notes the contractual and technical demands associated with nuclear liability, availability and operational stability.
Engineering challenges
- Matching new equipment to existing bus, enclosure and control-system interfaces.
- Planning outages and temporary operating states over multiple years.
- Maintaining protection, interlocking and documentation consistency as bays are upgraded in stages.
- Managing spare parts and service support for equipment that spans old and new generations.
Why it matters
Much of the world’s GIS fleet is approaching an age where condition assessment, obsolescence and serviceability become as important as original nameplate ratings. Daya Bay illustrates that lifecycle modernization can be a long engineering program, especially where complete shutdown is not acceptable. For asset owners, early interface surveys, records recovery and outage planning may be as critical as the replacement hardware itself.
Source note: This is an independent editorial summary prepared by Learn Switchgear. Project details are attributed to Hitachi Energy. Read the original Hitachi Energy press release.