Grid Integration Challenges and Solutions for Large-Scale Solar Farms Proposed for the Nigerian Transmission Network

This study examines the grid integration challenges and engineering solutions associated with the planned connection of large-scale solar photovoltaic farms to the Nigerian Transmission Company's 132kV and 330kV network under the Presidential Power Initiative and related renewable energy procurement programmes. The scale of proposed solar capacity additions, totalling over 1,000MW across multiple sites in North Central, North West, and South West Nigeria, presents significant challenges for a transmission network designed around large thermal and hydropower stations with stable synchronous generation characteristics. The study synthesises grid integration issues through a combination of literature review of African large-scale PV integration experience, analysis of TCN network characteristics using published data from the Nigerian Electricity Regulatory Commission, and a series of steady-state and dynamic power flow simulations conducted in ETAP for three representative integration scenarios. Identified integration challenges include voltage regulation at the PV plant point of connection during rapid irradiance changes, fault level reduction as synchronous generation is displaced, reactive power management requirements, and frequency stability implications of high instantaneous PV penetration. Solutions evaluated include advanced inverter reactive power control mode deployment, static VAR compensators at key PV plant substations, synchronous condensers to maintain fault levels, and grid-scale battery energy storage for frequency regulation support. Recommendations include updating TCN's Grid Code to establish technical requirements for large solar plant grid connection applications. Keywords: solar grid integration, large-scale PV, transmission network, TCN, Grid Code.