Concurrent UPQC Schemes for the Power Quality Improvement in Solar Photovoltaic Systems

Abstract

Aims: Aim of this research is to propose a novel concurrent UPQC scheme for improving the power quality issues in grid integrated solar photovoltaic (PV) systems. Background: The power quality is a major issue for the grid integration of renewable energy sources. Issues like voltage sag, voltage swell, harmonics & non-linear load variations are certainly observed in the distributed energy system and it is mandated that any system has to depend on advanced controllers to improve power quality and stabilize the electrical parameters. Controller related power quality improvements are a bit easier to design but the tuning of power is difficult in this aspect. Objective: In order to overcome the aforesaid limitation, this particular paper proposes a new concurrent UPQC scheme for improving the four different power quality issues in grid integrated solar photovoltaic (PV) system such as voltage sag, voltage swell, non-linear load variations and current harmonics. Methods: The operating regions of each power quality issues are examined in the I-V curves of PV specifications and the new operating modes of PV systems are mapped for every quality improvement considering the power, current and frequency of the grid and load as well. The pool of solutions is developed from the real power, reactive power and converter duty cycle and verified with the proposed solutions. Additionally, the designed switching frequency of the proposed system has a 5% variation for practical irradiance. The PV uniform irradiance profile matches the real power for various proposed concurrent UPQC schemes. Results: Finally, the simulation results are presented to validate the operation of the proposed concurrent UPQC schemes for PV system. The comparative study of the proposed concurrent UPQC scheme for PV system with appropriate literature is presented. The superiority of the proposed schemes infers studying the odd harmonic components up to 100th order after implementing the proposed concurrent UPQC scheme for PV system. Conclusion: From the measured results, it is concluded that a new concurrent optimization scheme enhances the operation of solar PV system that integrates with the grid. The power quality issues like voltage & current swell, voltage & current sag, voltage imbalance, and harmonics are reduced compared to existing methods. The validation of the schemes is achieved through the group constraints and the operating slopes in each region.