Compensation of the Reactive Power Consumed by the Transformer of the Mamou Electrical Substation

The continuous growth in electricity demand imposes increasing constraints on power transmission and distribution infrastructures, particularly in developing electrical networks. Among the key components of these systems, power transformers play a central role, while simultaneously contributing to reactive power consumption that affects voltage regulation and network efficiency. This study focuses on the compensation of reactive power absorbed by the power transformer of the Mamou electrical substation in Guinea. The investigated transformer is an oil-immersed unit rated at 15 MVA with a voltage level of 110 kV/30 kV. An analytical approach based on transformer operating characteristics is adopted to evaluate the reactive power requirements associated with magnetizing and leakage reactances. Using these formulations, the required rating of a shunt capacitor bank is determined in order to fully compensate the reactive energy consumed by the transformer. The results indicate that a capacitor bank rated at 2422.5 kVAr allows a significant reduction in apparent power and line current on the high-voltage side. Consequently, copper losses, Joule losses in the transmission line, and associated greenhouse gas emissions are reduced, leading to an annual energy saving of approximately 36,104 kWh. The findings highlight the technical and economic relevance of reactive power compensation for improving the operational performance of substations in emerging power systems.