A leading UK Distribution Network Operator (DNO) notified BRUSH that due to a failure on one of their distribution sites, an urgent requirement was the installation of their strategic spare 15/30MVA, 33/11KV Power transformer.

The Challenge

Brush visited the site on the next working day to assess the requirements and it was evident that the compact spare unit would require converting to separate coolers . The transformer had been held in storage at BRUSH (since 2013) as a strategic spare. The client notified BRUSH that the failed unit must be replaced and the new unit energised within four weeks to avoid any risk to their network. A further challenge for BRUSH was to overcome the width restrictions on route to the site within the already reduced timescales.

The Solution

The stored transformer was originally built as a compact unit, meaning all the ancillary details were tank mounted. The DNO specified a separate cooler bank assembly to match the failed unit, and the transformer required reconfiguring prior to any in-factory testing. The transformer was immediately removed from the BRUSH on site storage facility and taken into the factory for work to commence. The transformer was successfully converted from a compact design to a separate cooler bank.

Following the mechanical build of the transformer within the BRUSH factory, a second Factory Acceptance Test (FAT) was carried out to ensure the unit was functioning correctly prior to despatch to site. Additionally, the transformer was subject to full oil processing and a complete re-spray.

“As you know we were all very impressed and appreciative of the sterling efforts from all your goodselves at BRUSH in helping us achieve a prompt and safe replacement of C1MT at Bradford on Avon back in September / October 2019”

Scottish & Southern Electricity Networks

Following a site visit, it was agreed between the client, BRUSH and the heavy haulage contractor that due to width restrictions on route to site the transformer would have to be transported at a maximum width of 2.75 metres, requiring the unit to be stripped to the minimum width. To achieve this, the HV, LV and neutral cable boxes, disconnecting chamber, tapchanger, auxiliary transformer and cooler control cubicle were removed.

The Result

BRUSH Transformers Service Team successfully delivered the Transformer to site ahead of schedule and worked for ten consecutive days to re-build the Transformer. The Mechanical installation included the previously removed HV, LV & Neutral cable boxes, Disconnecting chamber, Auxiliary Transformer, Tapchanger in addition to the full cooler bank assembly.

Other duties included all Wiring, Oil handling and Cold Commissioning. BRUSH also carried out a full ratio on the Tap changer due to disconnection for transport. Upon completion, the Transformer was handed over to the DNO a week ahead of schedule. The Transformer was successfully energised in October 2019 and BRUSH Transformers Service Team received high praise from the client for the handling of the project, resulting in another BRUSH Transformer becoming part of the network ahead of schedule.