A MULTI BAND POWER OSCILLATION DAMPING CONTROLLER for INTERCONNECTED HYBRID AC MICRO-GRIDS SYSTEM

Abstract

The increasing integration of renewable energy sources (RESs) with conventional energy sources units in a hybrid AC microgrid system has led to the emergence of power oscillation damping (POD) controller for damping low frequency oscillations (LFOs). A local microgrid has limited energy generation capacity and may need to resort to load shedding during a power shortage. Interconnected hybrid AC microgrid systems are essential for enhancing the reliability and stability of power supply by allowing mutual support during outages or power deficiencies. However, the integration of these subsystems often results in oscillatory modes that could compromise stability and operational efficacy. This thesis presents the design and implementation of a multi-band power oscillation damping (MB-POD) controller implemented for an interconnected hybrid AC microgrid system. The proposed MB-POD controller aims to mitigate LFOs across various frequency bands, enhancing the overall stability and reliability of the microgrid. LFOs are caused by integration of generation sources, variety of dynamic load scenarios, and load disturbances in any of the systems. These oscillations could take place locally or between microgrids. This study introduces an energy storage system (ESS)-based POD designed to mitigate such instabilities in an interconnected AC microgrid system. This study also elucidates the complex dynamics of power oscillation in an interconnected AC hybrid microgrid system, highlighting the deficiencies in conventional power oscillation damping methods. Utilizing advanced mathematical models and simulation techniques, we propose a novel approach to dampen the oscillatory modes effectively. Using the proposed multi-band damping controller as well as the extant single-band power oscillation damper (SB-POD), interconnected hybrid AC microgrid system is intended to operate in a MATLAB/Simulink environment. Using time-domain simulations the v proposed controller's performance is evaluated. Simulations and case studies elucidate the damper's efficacy in enhancing system stability while optimizing power flow and reducing the transient response time. The findings indicate substantial improvements in damping multiple oscillatory modes by improving the damping ratio from 9.1% and reducing oscillations by approximately 4-6%, making it a promising solution for modern power systems. MB-POD than SB POD across various microgrids, thus paving the way for more resilient and adaptive interconnected hybrid AC microgrid system.