Optimal PV Inverter Active & Reactive Power Control to Improve the Performance of Low Voltage Distribution Network
Authors: Surendra Chaudhary, Nav Raj Karki, Akhileswor Mishra, Mahammad Badrudoza
Abstract— The connection and use of renewable energy sources (RES) such as grid connected photovoltaic (GCPV) systems in distribution networks have been increasing over the last few decades. As the number of grid tied inverters increases, their usage as volt ampere reactive (VAR) compensators will help in grid voltage regulation and reduce the need of expensive capacitor banks. However, integrating a high penetration level of small-scale rooftop grid connected PV systems at random locations with various ratings into the low voltage distribution system (LVDS) could cause operational problems. One of the technical issues is a possible voltage rise along distribution network as a result of reverse power flow, especially at low demand and high generation conditions that are restricting the ability of networks to accommodate further connections. Another issue is a possible voltage drop along the network during no PV generation, especially at high demand and no PV generation conditions. Based on the latent reactive power capability and real power curtailment of single phase inverters, this paper proposes a new comprehensive PV operational optimization strategy to improve the performance of significantly LVDS with residential GCPV penetrations. Optimal PV inverter reactive power control and real power curtailment to improve the performance of low voltage distribution system is studied on the Butwal Distribution Centre, Kalika Feeder, Shiva Mandir Chowk Network. The node data (Load and PV generation) for each hour of the day is taken from the load and PV generation pattern for the domestic consumer of urban area. Three scenarios of PV penetration level Low PV Generation w.r.t. consumer load (LPVCL), high PV Generation w.r.t. consumer load (HPVCL) and Medium PV Generation w.r.t. consumer load (MPVCL) are considered during the study. The proposed algorithms are coded using MATLAB. LPVCL has low PV generation w.r.t. load during entire hours of the day and simulation result shows that reactive power capability limits of PV inverters are insufficient to maintain the desire voltage limit during peak load time (18:00 to 21:00). HPVCL has high PV generation w.r.t. load during 9:00 to 17:00 hour and the simulation result shows that reactive power capability limits of PV inverters are insufficient to maintain the desire voltage limit during 11:00 to 15:00 hour due to power loss constraints. So, it requires real power curtailment to the PVs. In last scenario, MPVCL has high PV generation during 10:00 to 16:00 but lower than HPVCL and the simulation results shows that reactive power capability limits of PV inverter are sufficient to maintain the desire voltage limit (±5% of rated voltage) during entire hours of the day with minimal real power curtailment. As a result of optimal reactive power control and real power curtailment (if necessary), voltage profile of the network improved, ensuring the benefit of PV installation. This proposed algorithm is to provide a basis for power distribution companies to use it for the rooftop PV penetration in low voltage system to enhance the operational performance of the networks
Keywords— PV Inverter, grid connected, low voltage distribution
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Published In: International Conference on Role of Energy for Sustainable Social Development (RESSD-2023)
Date of Conference: 14th-15th May 2023
Conference Location: Kathmandu, Nepal
Publisher: IEEE Power and Energy Society Nepal Chapter
Cite the paper as:
S. Chaudhary, N. R. Karki, A. Mishra, M. Badrudoza, “Optimal PV Inverter Active & Reactive Power Control to Improve the Performance of Low Voltage Distribution Network”, International Conference on Role of Energy for Sustainable Social Development, 14th-15th May 2023, Kathmandu, Nepal