Power Quality Effect of Solar Rooftop Penetration on Power Quality in Distribution Networks

With Thailand’s Power Development Plan (PDP) targeting a substantial increase in photovoltaic (PV) generation (from 4 GW to 7.5 GW by 2037), particularly via solar rooftop installations, concerns arise regarding the technical implications for the existing grid infrastructure, notably the low voltage (LV) distribution network. The current unidirectional design of this network is ill-equipped for the bidirectional power flow necessitated by high levels of distributed generation. This study investigates the effects of various PV penetration levels on power flow, voltage fluctuation, and harmonic injection within a representative Thai LV distribution network. Employing static load data within DIgSILENT PowerFactory, aligned with the Provincial Electricity Authority (PEA) Distribution System Planning Framework, we establish optimal PV penetration thresholds and assess the efficacy of various mitigation strategies. Our findings indicate that while PV penetration up to 75% introduces observable impacts, these can be maintained within international and national power quality standards through the implementation of appropriate mitigation measures.