Unified Power Quality Conditioner Based Power Quality Improvement in Micro-Grid

Maintaining power quality is a critical challenge due to deviations in voltage, current, and frequency, which can lead to equipment malfunction. The increasing energy demand, rising fossil fuel costs, and climate concerns have accelerated the adoption of distributed generation systems like microgrids. These small-scale systems, often based on renewable energy, offer efficiency and reliability but face challenges such as power quality issues caused by nonlinear and unbalanced loads, leading to system instability. Various devices, including active and passive filters, voltage regulators, FACTS devices, dynamic voltage re-storers, and unified power quality conditioners (UPQC), have been employed to address these issues. Among these, the UPQC, which combines series and shunt active filters, has proven to be highly effective in mitigating voltage and current-related disturbances. In order to reduce power quality disturbances such as voltage swells, sags and harmonics in microgrids, this study analyzes the performance of UPQC with Dynamic Voltage Restorer (DVR). Simulation models for both devices were developed in MATLAB/Simulink and tested under various fault conditions. Results demonstrate that UPQC, combining series and shunt active filters, outperforms DVR in response time and mitigation capability. UPQC effectively restores voltage waveforms to sinusoidal form, reduces Total Harmonic Distortion (THD) within acceptable limits, and ensures voltage stability. The findings highlight UPQC as a robust solution for enhancing power quality in microgrids, making it highly suitable for systems with significant renewable energy integration, ensuring operational efficiency and reliability.