Mitigation of Overvoltages in Low Voltage Network by Distributed Battery Energy Storage System

The growing demand for implementing small renewable energy sources, photovoltaic or wind sources, in the distribution system is characteristic of the last decade. On the one hand, the distribution system operator (DSO) needs to meet this growing demand while being responsible for the reliable and safe operation of the network. DSO is therefore forced to analyze the risks associated with growing distributed production, such as overvoltages in the network, and determine their maximum allowed installed capacity, hosting capacity. This paper uses the stochastic methodology and probability power flow calculations to analyze the photovoltaic hosting capacity (PVHC) of an existing rural low-voltage (LV) system in the Slovak Republic. The outcomes show that overvoltages are the primary limiting factor in an analyzed network, and the PVHC depends on the permissible probability of their violation. The article further analyses the possible ways of increasing PVHC by gradual penetration of small battery energy storage systems. The results show that BESS should be considered only as a supplementary device, which will always positively affect the size of the PVHC if it is used to maximize the utilization of photovoltaic generation at the point of consumption.