An evaluation method for the impact of PV installations into distribution systems

For the realization of low carbonate energy supply, installation of renewable energy sources has been reinforced in Japan. In the effort, a major focus is on the photovoltaic system installation to low voltage consumers and thus it is expected that many photovoltaic systems will be connected to low voltage distribution systems. While photovoltaic system installations have various advantages, distribution systems reliability might be degraded because photovoltaic generation capacities are fluctuated depending on weather conditions. In addition, reverse power flows might occur in a state of excess-supply in photovoltaic systems´ owners and sometime these might cause abnormal voltage rise or sag in some segments of distribution systems. This paper proposes a simulation approach to evaluate the status of distribution systems with many photovoltaic systems. In order to simulate fluctuated capacity of photovoltaic systems and consumers´ demand, stochastic approach is adopted and practical simulation results are provided.