Supply critical in hospital retrofit

Sydney's Westmead Zone Substation after retrofit
Sydney's Westmead Zone Substation after retrofit

Sydney’s Westmead Zone Substation 11kV switchboard, which was functionally sound but based on out-dated technology, has been upgraded to include increased capacity and arc flash safety for substation personnel.

Supplying the Westmead Hospital and the Children’s Hospital, as well as the general area, it was not an option to interrupt any mission critical supply from the substation. With these requirements identified, Endeavour Energy approached RPS Switchgear – the company that supplied the original 11kV switchboard in the mid 1970s – for advice on how to accomplish the sensitive upgrades.

The need for capacity increase led to RPS Switchgear supplying and extending the switchboard with two new 2000A incomer transformer panels and two new 1250A feeder panels, manufactured to IEC/AS 622714.200 A-FLR.

To improve safety for all personnel, and to ensure the substation’s integrity, all old oil circuit breakers were replaced with new vacuum circuit breakers. To also ensure operator safety against arc flash hazards, the circuit breaker doors on all existing panels were replaced with arc flash-proof doors, allowing for racking of the circuit breakers through closed doors. Further safety upgrades included the replacement of pitch-filled cable boxes with air-boxes.

“All existing panels had protection upgraded with modern protection relays and instrumentation. To achieve the latest standard the CT’s in some of the panels were also upgraded to modern slip over type CT’s,” RPS Switchgear national sales manager Mats Jonsson said.

“With adherence to a strict switching plan and supply from a redundant network, it has been possible to upgrade the 11kV switchboard without interrupting any mission critical supply from the substation.”