Bowers Electricals Ltd were contacted by a major customer over a failure of their Ferranti 20MVA 33KV to 11KV transformer at the end of January 2019. The transformer powered one of the largest wind tunnels in the UK had served them well, being manufactured in 1971 but had suffered a catastrophic internal failure. The customer had planned to use the wind tunnel extensively and would be losing revenue each day it was out of action so a quick response was required.
Bowers Electricals Ltd initially looked at considerations to dismantle and return the transformer to their Heanor facility for rewind and repair but then looked at alternative supply of a replacement on an urgent basis. The typical manufacture of a new transformer of this type would be on a lead time of 26-30 weeks. However, Bowers were able to leverage its strategic partnerships and secure a suitable unit from one of its international suppliers. The transformer was very quickly identified and confirmed by the Bowers technical team to be a suitable size and rating to replace the failed unit – once this was done it was all systems go to get this project running and the replacement in place as soon as practically possible.
The order to remove the failed transformer, supply and install the new one was placed under an NEC3 short form contract with Bowers Electricals undertaking the CDM Co-ordinator, Principle Designer and Principal Contractor roles. The contract was complimented with a requirement for substantial Neutral Earthing Resistor, Remote Tap changer Control Cabinet (RTCC) and extensive Earthing system upgrades.
Site works were predominantly conducted by the Bowers sister company Electrical Power Engineering Services Ltd (EPES), part of the Bowers Group of Companies. The unit was supplied into the UK within 8 weeks and Bowers oversaw all logistical elements to get it, and the ancillaries delivered to site.
For expediency, the old transformer had been removed and site preparations completed before the arrival of the new transformer. Site excavation works to expose the supply cables for jointing, amendments to the concrete plinth base and preliminary wiring of the RTCC were all done in advance to keep the program on track. Bowers Electricals Ltd then arranged for the offloading via 100 Tonne crane and installation within the compound. The unit was erected, assembled, oil filled and processed before testing and commissioning within the strict EHS and site procedures. From the first telephone conversation on 31st January 2019 the entire project including removal of the redundant failed unit, supply and installation of the replacement was completed, commissioned and handed to the client on 14th May 2019 – 103 Calendar days.
No safety events or concerns were raised during any of the works and feedback from the customer has been exemplary.