Impact Assessment of High Penetration of Rooftop PV in Urban Residential Networks

There is an increasing global trend of grid connected distributed PV systems and their proliferation may subject the grid into technical challenges such as voltage rise, equipment overload, power quality and protection violations. The lack of regulations and interconnection studies conducted on South African networks has resulted in a growing concern amongst utilities on how the increasing customer-owned rooftop PV systems uptake will impact the existing networks. This paper investigates the technical (voltage and thermal) impact of high penetration of rooftop PV system by determining grid hosting capacity (HC). PV capacities are restricted by the available roof space and PV allocation is randomly distributed based on Monte Carlo simulation. The proposed HC methodology is implemented on real urban residential feeders modeled and simulated in DIgSILENT PowerFactory. This study has found thermal violation as the main limiting factor in urban residential networks and penetration level above NRS097-2-3 limits may he achieved depending on feeder characteristics.