The Ghana Grid Company Limited (GRIDCo) has commissioned a new 120/145MVA Siemens Energy power transformer at the Afienya Substation, more than doubling the station’s capacity and significantly strengthening electricity supply across Accra, Dawhenya, and surrounding communities in the Greater Accra Region.
The project, completed entirely by GRIDCo’s own engineers without external contractor support, replaces a 50/66MVA transformer that had reached its operational limit under growing demand pressure from the Electricity Company of Ghana’s (ECG) expanding distribution network.
Dr. Benefit E.A.K. Patu, Supervisor for Electrical Maintenance and lead engineer on the project, said the upgrade became unavoidable as load growth outpaced the old transformer’s capacity. “With the new 120/145MVA transformer, we now have the capacity to accommodate more load and extend a reliable power supply to more communities,” he said.
The installation involved multiple technical stages. Engineers positioned the transformer on its foundation, assembled all components and accessories, and carried out oil filtration to properly fill the transformer core and conservator. The On-Load Tap Changer (OLTC) unit was also prepared with oil to support efficient operation. During oil treatment, engineers reduced moisture content to single-digit parts per million (PPM) levels, which were submitted for technical validation and approved before commissioning proceeded.
The Protection and Control team, led by Francis Koomson, played a central role in the final commissioning phase. The team decommissioned old cables, installed new wiring, and ran comprehensive protection tests including trip testing to confirm the system would respond correctly to a fault. “Our responsibility was to ensure the transformer operates safely. We verified that in the event of a fault, the system will trip as expected,” Koomson said.
The upgraded transformer strengthens the National Interconnected Transmission System (NITS), improving stability and capacity headroom for both current demand and future load growth in one of Ghana’s fastest-developing urban corridors.
The project was executed under Dr. Patu’s leadership, with support from Koomson and Albert Baiden-Amissah, Supervisor for Line Maintenance.
