Healthy standby power supply

Part of Guy’s and St Thomas’ NHS Foundation Trust, the hospital is upgrading its old standby generator system to meet current and future demands for continuous power.  

In a hospital environment, standby power infrastructure is not just essential; it could mean the difference between life and death. Therefore, continuity of power is business critical. As part of the project, Finning is providing three Cat C175-20 generator sets, each providing an output of 3200ekW.

Guy’s Hospital is currently building a new, state-of-the-art Cancer Centre, which will be a hub for South East London. As part of the ongoing upgrades, the hospital is increasing its electrical standby power capacity. Working with Eta Projects, the Trust’s specialist power engineering consultants, Finning is supplying a generator system that will provide 100% of the standby power requirement to the Cancer Centre in the event of a mains power failure. In the event of a mains power failure across the entire hospital, the generator sets will provide approximately 80% of the standby power.

David Porter, head of compliance at Guy’s and St Thomas’ NHS Foundation Trust said: "The process to upgrade the electrical standby power capacity at Guy’s Hospital began in early 2014. In consultation with Eta Projects, a detailed tender was published through the Official Journal of the European Union (OJUE). Due to the spatial constraints, we considered three different sizes of engines and appointed Finning, which offered the C175-20, because of its compact size and high power output. 

"The small footprint of the C175-20 means that the new units can be housed within the existing generator rooms without any major building modifications.

"The generators are inter-connected to the main 11,000V electrical intake sub-station for the hospital through a dedicated generator distribution switchboard. The generator sets will be linked to the hospital’s existing logic control systems to ensure that standby power is readily available and appropriately prioritised within just 15 seconds in the event of an outage.” 

The generators are designed to operate in synchronous parallel mode and as single systems through manual intervention by the Hospital Estates Engineering team should the need arise.  

Prior to delivery to site, the new generators were subjected to intensive factory testing which included load bank testing for 4h at 100% load and a subsequent 1h test at 110% load. In addition, transient load tests were applied at various step loads from 60 to 100%. As added value and to demonstrate confidence in the generators, the test engineers applied a single load step at 110% and the generators took the load without stalling.