Investigating the Impact of PV Penetration on the Distribution Network: Case of Nairobi North Distribution Network

Abstract

Photovoltaic (PV) systems are fast gaining a strong integration into today's distribution network. The distribution network was not initially designed to accommodate generation; hence this technology could lead to an increment in fault current, voltage swells, and distribution network unbalance. That notwithstanding, the increasing number of PV systems in the distribution network could benefit the network in decreasing active and reactive power losses and enhancing the network transient stability. This research focused on the impact of PV systems on the transient voltage and current of the distribution network. Nairobi North, a section of the Nairobi distribution network is used as the test network. An arbitrary load bus in the network is chosen and a line-to-ground fault applied on it, and the behavior of the swing bus voltage and the voltage and current of the faulted bus are observed. ETAP software is used for transient analysis at different levels of PV penetration (0%, 1%, 2%, 3%, 4%, and 5%). The results obtained demonstrate the effectiveness of the PV systems in leveling the voltage dips and current spikes which happen during network restoration after the line-to-ground fault is cleared. As from 4% PV penetration, the current spikes and voltage dips completely disappear.