Peak Shaving and Duck Curve Mitigation With BES Based Ramp Rate Limit Strategy for Power Quality Enhancement of SPV-BES Microgrid

Variability of power generated by renewable energy sources and load power fluctuations reflect as grid power ramps. These power ramps monitored at point of common coupling (PCC) of individual microgrids may lead to penalties imposed by grid operator for violating grid power ramp rates specified by the IEEE std. 1547-2018. Since grid is dominated by alternators having high mechanical time constant, it imposes power ramp limit to utility grid, violating which, may lead to grid instability issues. During daytime, high solar generation leads to a rapid reduction in grid side demand curve resembling a duck shaped curve. Evening peak load situation results into a sudden ramp in grid demand curve. Variability in generation and demand lead to rapid grid power ramps. Therefore, in this work, a battery interfaced to a solar photovoltaic (SPV) array-based grid connected microgrid. Novel contributions of this work include power coordination maintaining grid side ramp rate within standard limits, prevention of duck curve formation and providing peak load shaving features using battery satisfying its constraints. These enhancements are embedded within solar inverter control without any additional cost of power electronics. Distribution static compensator (DSTATCOM) features are incorporated into the control for load harmonic, DC offset and reactive current compensation. A novel third order generalized integrator with frequency locked loop (NTOGI-FLL) control is used with improved filtering ability, DC rejection, low computational burden, and improved dynamics, comparable to advanced filters, for rapid and accurate actuation. System operation is validated through simulation and hardware results.