Medium Voltage Grid Conventional Control in the Presence of a Large Scale Photovoltaic System

This paper presents simulation results of the conventional control strategy applied to distribution grid equipped with photovoltaic (PV) power generation. The investigated network is a part of an existing 11kV distribution grid located in Queensland, Australia with mostly semi-rural loads and PV installation of more than 3MWp in one site. The studied case is very interesting because it shows in detail the grid dynamics and the influence of intermittent clouds conditions to the distribution grid with significant PV generation. The research was performed with utilization of Real-Time Digital Simulator's (RTDS) RSCAD software environment. In the result, it is demonstrated that uncertain power generation can be very challenging to existing local control schemes. In particular, typical weather conditions can cause line voltages drops below and rises above allowed limits. Moreover, the long regulation time and high number of operations indicates that major control system improvements should be considered for modern distribution grids.