Investing the key Technical Barriers and Solutions for higher Penetration of Photovoltaic systems on urban distribution networks in Uganda.

Abstract

Our country Uganda is endowed with abundance of sunshine with average solar radiation of 5.1kWh/m2/day. Despite this potential for solar energy the exploitation is still very low in the country partly as a result of high initial costs in installation of solar photovoltaic systems. However, trends show that in the future costs related to photovoltaic systems in the country will reduce which will create a possibility for many Ugandans to own residential solar PV systems. It was under this presupposition that the future is likely to be dominated by many Ugandans owning solar Photovoltaic systems that this project drew its main aim to assess the key technical constraints and mitigation measures to increase PV penetration in Uganda’s low voltage urban distribution network assuming these systems will be grid connected. To achieve the above aim, dynamic models of single-phase PV system and a distribution network representative of Uganda’s low voltage urban distribution network were first modeled and validated. These models were then used to carry out both steady state and dynamic performance of the distribution network under different PV penetration levels using simulations in MATLAB/Simulink software. The steady state performance of the distribution network was evaluated in terms of voltage profile, net active power, power factor and the current THD at the secondary of the low voltage substation. The dynamic performance was evaluated in terms of the net fault current both near the low voltage substation and far from the substation. The steady state and dynamic simulations revealed technical barriers such as voltage rise, reverse power flow, power factor deterioration and current total harmonic distortion. Using the steady state and dynamic simulations of the distribution network, the PV hosting capacity of the distribution network was found to be around PV penetration level of 25% and the methods that can be used to increase the hosting capacity of the distribution network are discussed in detail.