Influence of battery energy storage system on generation adequacy and system stability in hybrid micro grids

This paper analyses the influence of Battery Energy Storage System (BESS) on the electrical system in a Hybrid Micro Grid consisting of two 200 kW diesel generators (DGs), one 200 kW wind turbine generator (WTG) and 200 kW photovoltaic (PV) Plant. The BESS in such a system can have a significant role in covering the power fluctuations in battery energy storage system the network. The BESS can cover the power unbalance between the supplied power and the load of the grid by storing the excess energy or supplying the residual demand. An advantage of implementing the BESS is faster provision of power compared to the DGs which can also help improve a system stability. In this paper, the influence of BESS is analyzed by conducting Generation Adequacy analysis and Transient Stability studies using DIgSILENT Power Factory software. Generation Adequacy analysis is carried out using Monte Carlo simulation technique. Typical factors such as Loss of Load Probability (LOLP) and Expected Demand Not Supplied (EDNS) are calculated. Furthermore, the size of BESS required to cover for the intermittent nature of renewables is determined. Dynamic models of DGs, WTG, PV and BESS are developed for the purpose of transient stability studies. Contingencies such as three phase fault, tripping of DG and cloud covering PV field are simulated with and without BESS in order to clearly determine its influence on system stability.