Techno-Economic Viability of Large Scale Solar Integration with Battery Storage for Grid Substations: A Case Study for Sri Lanka

Over the past few years, utility scale Solar PV Power plants (SPVPs) are being added to the national grid at Medium Voltage (MV) distribution networks. However, the performance of the distribution networks can adversely be affected, if they are connected without the knowledge of optimum sizes and locations. Challenge in utilization of electricity generated from the weather dependent SPVPs is in its intermittency and non-dispatchability, rendering it hard to match supply and demand which themselves are variable. The difficulties associated with proliferation of SPVPs could be alleviated by the proper use of Battery Energy Storage Systems (BESSs). The impact of installing BESS on the quality of distribution networks during the sizing of battery storage has been considered in this research. In this paper, the optimal placement of SPVPs and B-SPVPs in terms of size and location is evaluated for minimisation of energy loss bounded by voltage constraints preserving the power balance. The required optimization is carried out using Mixed Integer Programming with Genetic Algorithm (MIGA) and Particle Swarm Optimization (PSO) techniques. The proposed approach was utilised to study the techno economic viability of integration of solar Photovoltaic (PV) and battery energy storage systems to a 33 kV practical network in Sri Lanka - Tissa 1 feeder in Hambantota Grid Substation (GSS). A financial evaluation was carried out to inspect the viability of SPVP and B-SPVP in Tissa 1 feeder using the optimized results.