Replacement of Substations C & D, Elstree

The Opportunity

BPL identified a need to replace 2 No. substations on the service floor of Building 27, on their Dagger Lane site.

This is the first phase of a planned upgrade for the rest of the HV/LV systems serving the building. The two substations are critical to the production and research operations within Building 27.

Substation C supplies power and lighting to the Aseptic Filling Suite (AFS) via the existing 500kVA UPS and six associated Air Handling Units. In addition, it also supplies Autoclaves, Freezedriers, Oversealer and Depyrogenation Tunnels for Filling lines 1 and 2.

Substation D supplies critical refrigeration equipment, AHUs, process equipment, power and lighting for all other production areas.

Both substations are approx. 35 years old with switchgear that is approaching obsolescence.

The existing substations are installed in a multi-use plant room area with complex ductwork and piped services. This location is challenging due to the presence of high voltage switchgear in addition to constraints on space availability internally and externally at ground level.

BPL’s URS noted the following key requirements for the design:

• Detailed understanding of the existing substations’ maximum demand and allowances for future loading.
• Address status monitoring and control of switchgear and safety during operation and maintenance particularly at HV.
• Integration of the new substations and the transfer of existing loads during planned shutdown(s).

The Solution

The technical solution included:

• Replacement substations C & D in weather resistant enclosures for location on the roof of the building.
• New SCADA expandable power management and operation software.
• Assessment of existing building for a new structural steel platform on the roof to accommodate the proposed plant with walkway for maintenance access.
• Extension of the high voltage ring.
• New outgoing cables on the roof structure with allowance on the new platform to accommodate the substations.
• Existing load centres with new sections of cables jointed to existing cables at strategic locations.

The overall approach involved:

• Assessment of existing and future electrical load demands.
• Survey and assessment of the existing area for crane requirements to allow lifting of the substation components to the roof due to limited space.
• Surveys of existing switchgear, routes of existing HV and LV cables.
• Development of phasing sequences for the works to minimise disruption to business.

Austin, in coordination with BPL, developed techniques for implementing the works followed by procurement, engineering support, construction and managing the works on site within BPL’s shutdown periods to successfully implement the requirements on site.