Locally Weighted Filtering for Photovoltaic Power Fluctuation Control and Time Delay Reduction with Battery Energy Storage

The increase in energy demand needs to be met with environmentally friendly resources to lower the production of greenhouse gases. Solar power is a popular choice as it is available in abundance and is relatively cheap. However, the large-scale penetration of intermittent solar Photovoltaic (PV) power causes multiple instabilities in the grid such as frequency issues and voltage deviations. To counteract these instabilities, Battery Energy Storage System (BESS) is integrated in the grid as it reduces the PV fluctuations and promotes optimal operation. However, storage systems are expensive and thus smoothing filters are also coupled with the BESS for cost reduction and power smoothing. Traditional filters such as Low Pass Filters (LPF) and Moving Average (MA) filters are capable of solar power smoothing but have poor power tracking capabilities. To compensate for the delayed power tracking, larger energy storage systems are required which in turn adds to the operational costs. This paper proposes a locally weighted filter for solar PV smoothing with BESS. The proposed filter has significantly better power tracking capabilities than both the LPF and MA filters. Thus, as compared to the conventional LPF and MA filters, the proposed filter can achieve better solar power smoothing with reduced time delay and optimum battery storage capacity.