Abstract:
The focus of this research is on unit selection (type) and sizing (capacity) of distributed energy resources (DERs) in a microgrid which comprises solar power generation system, diesel generator, converter/inverter, battery energy storage system (BESS) and an external grid. It is associated with priority and deferrable loads. Due to the volatility of PV (photovoltaic) power and variable load demand, optimal configuration of DERs along with their respective powers must be selected and evaluated in order to earn the cost effective advantages of microgrid. The multi-objectives of this research are to minimize total net present cost (TNPC), unmet load (UL) fraction and simultaneously minimize pollutant emissions in the life cycle. The optimal planning is carried out for the next 25 years. These objectives have been achieved through stochastic chance constrained programming (CCP) of battery autonomy. Batteries are expensive components of microgrid which are key to its reliability hence; it has been tried to improve the battery autonomy by applying chance constraint as probability index for the first time in this research. This is to ensure the best selection of battery size and other sources and that; BESS is definitely used by the system in different power scenarios. The general constraints include system power balance, generator within capacity limits, battery operating in state of charge (SOC) limits; PV size stays within deployed space and emissions within threshold level. The simulations for optimal system have been carried out in HOMER beta software. The results of deterministic planning and stochastic programming have been plotted and compared with each other as Pareto fronts to show the optimal configuration and sizes of DERs while achieving the defined objectives.
