Impact of Unbalanced Penetration of Single Phase Grid Connected Photovoltaic Generators on Distribution Network

Inhalt:
UK government has set a target to generate 15% of energy by renewable resources. To achieve this target government is taking various measures to encourage different groups of society to invest in renewable generations. One of the measures is feed in tariffs, to encourage the development of roof mounted PV, micro CHP, small wind turbine etc. In order to benefit from it and save on energy bills a number of households, businesses and organizations may opt for roof mounted photovoltaic technology. Generally these roof mounted photovoltaic generators will be grid connected and have no back up energy storage. They will generate electrical energy, feed it back to the grid and claim remuneration for each kWh generated. It will be important to investigate effects of introduction of "Grid Connected Photovoltaic" on Medium Voltage (MV) and Low Voltage (LV) distribution networks which were designed decades ago, when any such developments were not anticipated. Installation of such facilities will be voluntary, so utility might not have any control on penetration levels and distribution on the network (e. g. a large number of households on Phase R want to install and no other house hold on other phases want to install). As these installations will inject current back into the network, voltage profile, voltage unbalance and harmonics distortion level can be affected. Especially in the case of single phase generators, it can have significant effect on voltage unbalance. To investigate any such effects studies should be performed on a typical distribution network, with a typical load profile on network and with meteorological data for particular place. This paper investigates effects of single phase Grid Connected Photovoltaic installation on a LV Unbalance Distribution Feeder. The case studies carried out on the IEEE 34 bus system are presented.