Power Quality and System Stability Analysis in Grid-forming solar power generators with energy storage integrated

Abstract

The increasing penetration of renewable energy sources, such as wind and solar power, introduces significant uncertainties and challenges to conventional power grids. These challenges primarily arise from system frequency instability and voltage fluctuations due to the lack of inertia typically provided by conventional synchronous generators (SG). To enhance grid resilience and mitigate potential power quality issues, synthetic inertia is emulated by Grid-Forming (GFM) inverters, imitating the dynamics of conventional synchronous generators.

This thesis addresses these challenges by investigating the integration of supercapacitors (SC) and the implementation of advanced GFM control strategies, such as Virtual Synchronous Generator (VSG) control, within solar power generators. The primary objective is to ensure power quality and enhance system stability, particularly in scenarios involving high penetration of renewable energy, where the absence of conventional inertia can lead to significant voltage and frequency deviations. In this research, a comprehensive solar power generation system is designed, integrating a 200kW photovoltaic (PV) system with a 100kW SC storage system on the DC bus. The design aims to mitigate the adverse effects of frequency and voltage fluctuations while providing synthetic inertia through the integration of the SC energy storage system and the implementation of VSG control. These strategies are crucial for maintaining system stability and ensuring a rapid response to grid disturbances.

Extensive simulations and analyses are conducted to evaluate the performance of the proposed system under various operational scenarios. Case studies are performed under different assumptions. The results demonstrate that the synthetic virtual inertia significantly enhances the system’s ability to manage voltage and frequency deviations, providing a robust and reliable solution to maintain grid stability in the GFM solar power generator.

This thesis implements the proposed design of a solar power generator that can effectively ensure system stability in power systems with high levels of renewable energy penetration.