Cost Savings Oriented Microgrid Control Strategy Considering Battery Degradation

In this paper a cost savings oriented centralised control strategy for grid connected hybrid microgrid consisting of renewable energy sources and energy storage systems is proposed. In this work, cost savings are achieved by a power management algorithm (PMA) which takes battery degradation cost and grid pricing into account. In-addition the proposed PMA always operates battery within SOC limits and also ensures microgrid reliability. The cost savings are computed as the difference between battery degradation cost and electricity cost. However, the battery degradation cost is calculated using depth of discharge (DOD) which is computed on a real time basis. In this work, hybrid energy storage system (HESS) is introduced to absorb the sudden transients and oscillations in battery current thereby increasing battery performance and life span. Apart from cost savings analysis, power quality aspects such as harmonic mitigation, reactive power support and unity power factor are achieved. The proposed control strategy is simulated using a MATLAB based simulink environment during both excess and deficit modes of microgrid by taking PV variations into account.