Mitigating Impact of High Power Ramp Rates in Utility Grid Integrated Wind–Solar System Using an RLMAT Adaptive Control Strategy

Abstract

With the unremitting progress in renewable energy based systems into a sizeable contributor in global energy mix, the need to address challenges associated with their inherent power variability has also risen. The high power-ramp rates experienced during sudden wind gusts and cloud passing are known to impact the security of the power grid, especially in remotely-located wind-solar systems. These challenges are further intensified with sudden connection/disconnection of large local loads in the system, which demand power at a high ramp rate. This work deals with the use of a coordinated control strategy for power converters, to limit the grid power-ramp rate during the aforementioned high power-ramp events (HPREs). The deficit power during HPREs is absorbed by the energy storage system (ESS). The reference currents for ramp rate limiting control are computed using a robust least mean absolute third (RLMAT) adaptive filter. The RLMAT filter further assists in improving the grid currents power quality in presence of nonlinear, unbalanced and poor power factor local loads in the system. The effectiveness of the control strategy is evaluated through both simulation analysis and test results obtained from a laboratory-scale prototype.