Reliable Frequency Control Support Scheme Based on Wind Power Generator Combined with Rechargeable Energy Storage System Applying Adaptive Power Reference

Abstract

To reduce carbon emissions in the atmosphere, the utilization of renewable energy sources has been on the rise. However, as their integration level increases, grid system operators require higher performance of the frequency response service for renewable energy sources, especially wind power generators (WPGs). Conventional frequency control schemes release kinetic energy depending on the fixed and adjustable gains in the system difference loop between the standard and current system frequency; however, these conventional schemes cannot provide frequency support outside of the rotor’s speed operating region. In this work, a frequency regulation support strategy employing a WPG and lithium-ion battery based on an adaptable power reference is implemented. This is accomplished by assigning different roles to the WPG and battery. As the primary frequency control support, the WPG uses a frequency deviation loop with adaptable gain which depends on the speed of the rotor and the difference in frequency. Additionally, to assist with the frequency control support, the battery operates based on its state-of-charge (SOC) and rotor speed of the WPG. For investigating the capability of the suggested technique, an IEEE 14-bus system is employed. Qualitative wake effect analysis is further presented in the study to determine the feasibility of the proposed approach which consists of the hybrid WPP–battery system for frequency regulation. The main limitations of this study and further research studies that can be performed in the future to improve the performance of the proposed technique are presented. The scenario study results show that the minimum frequency point during a synchronous generator trip obtains a higher value than conventional ones in the suggested strategy by releasing more stored energy from the WPG and the battery.