Design and Commissioning Management of a 500kW Hybrid Mini-Grid for a Remote Community in Taraba State

This study documents and analyses the design and commissioning management processes for a 500kW solar-diesel hybrid mini-grid project deployed for a remote riverine community in Taraba State, North East Nigeria, under the Rural Electrification Agency's Interconnected Mini-Grid Acceleration Scheme. The community, comprising approximately 1,800 households and several small commercial and institutional loads, had no prior electricity access. The design process entailed a detailed load assessment survey, HOMER Pro energy system optimisation, power systems modelling of the 11kV distribution network layout, and protection coordination design for the mini-grid's islanded operation. The commissioning management phase is examined through a retrospective analysis of the commissioning programme, including pre-commissioning inspection records, relay settings verification, battery system commissioning procedures, and load acceptance test results. Critical commissioning challenges encountered included scheduling integration between the PV system, battery storage, and diesel genset commissioning teams, calibration of the energy management system dispatch algorithm, and initial earthing resistance readings that failed to meet design targets requiring additional electrode installation. The mini-grid achieved full operational capability 14 days beyond its planned commissioning date, primarily due to delayed customs clearance of the battery inverter system. Post-commissioning performance data for the first three months shows a renewable energy fraction of 74 percent and a system availability of 96.2 percent. Recommendations focus on tightening the commissioning management framework for future mini-grid projects. Keywords: mini-grid, commissioning, hybrid power system, rural electrification, Taraba State.