The Ghana Grid Company Limited (GRIDCo) has successfully installed and commissioned a new 120/145MVA Siemens Energy power transformer at its Afienya Substation, significantly boosting electricity transmission capacity for Accra, Dawhenya, and surrounding communities.

The upgrade replaces an earlier 66MVA transformer, effectively more than doubling the substation’s capacity and strengthening the National Interconnected Transmission System (NITS) to meet growing electricity demand.

According to Ing. Dr. Benefit E.A.K. Patu, supervisor for electrical maintenance, the project was undertaken due to rising overload pressures on the existing infrastructure.

“The [capacity] of the original transformer (50/66MVA) was nearing its limit due to increasing demand from ECG’s extended distribution lines. With the new 120/145MVA transformer, we now have the capacity to accommodate more load and extend reliable power supply to more communities,” he said.

He explained that the upgrade not only improves supply reliability but also positions the grid to meet both current and future demand growth.

The installation process involved several technical stages, including positioning the transformer on its foundation, assembling components and accessories, and carrying out oil filtration to properly fill the transformer core and conservator.

The team also prepared the OLTC unit with oil to ensure efficient operation. During oil treatment, engineers focused on reducing moisture content to acceptable parts per million (PPM) levels, with results recorded in single digits and subsequently validated and approved by technical services.

The Protection and Control (P&C) team, led by Ing. Francis Koomson, also played a key role by decommissioning old cables, installing new wiring, and conducting protection and trip tests to ensure the system responds correctly under fault conditions.

“Our responsibility was to ensure the transformer operates safely. We verified that in the event of a fault, the system will trip as expected,” Ing. Koomson said.

Following comprehensive testing and technical validation, the transformer was cleared for commissioning.

The project was fully executed by GRIDCo engineers led by Ing. Dr. Benefit E.A.K. Patu, with support from Ing. Francis Koomson and Mr. Albert Baiden-Amissah, supervisor for line maintenance.

GRIDCo says the successful commissioning underscores its commitment to operational excellence, innovation, and reliable power transmission while strengthening its role as a backbone of Ghana’s electricity supply system.