Pembroke B Power Station – High Voltage Project

A new 2000MW combined cycle gas turbine (CCGT) has been built in Pembroke, on the site of the old oil-fired station. Hornbill Engineering played a key role in the construction phase of this project by providing the technical expertise needed to install a number of permanent facilities integral to the electrical infrastructure of the plants operations.

A key part of any generation facility is the connection between the generators and the National Grid's infrastructure. At Pembroke Power Station, Hornbill assembled all five High Voltage 21kV to 400kV step up transformers, all of which were all Areva K26 512 MVA units. The assembly stage comprised of the installation of the forced air oil cooling system and associated pipe-work, valves, pumps, radiators and cooling fans. Hornbill's remit also included the installation of the transformer protection, pressure relief devices and gas pick up relays. Owing to their fragile nature, the assembly and installation of the high and low voltage bushings and turrets on either side of the transformer were a particular challenge. Each bushing was successfully assembled and installed with great care by our highly trained and skilled engineers.

The final stage of the generator transformer project involved filling and processing each of the transformers with Gemini X insulating oil to tight vacuuming levels as required by the Areva specification.

Hornbill's High Voltage Team completed the specialised task of erecting and installing the 400kV earth switches, surge arrestors and sealing end structures in each of the five compounds of which included the overhead line connections between each structure. Hornbill were also asked to install the steel works and surge arrestors in the 400kV National Grid Extra High Voltage substation adjacent to the site.

In addition, Hornbill were responsible for the construction, installation and pre-commissioning of all five site services transformers, including installing the neutral earth resistors, conservators, radiators and cable boxes for each unit.

The final part of this project involved the installation of the station maintenance transformer. We installed the conservator, cable boxes and filled the unit with the appropriate electrical insulating oil.

Hornbill Engineering completed this large High Voltage project on time and on budget and have been invited back to perform repairs on warranty equipment.