Studies on Mitigating Power Quality Issues Using PV: Transformerless Dynamic Voltage Restorer System with Modified Marine Predator Algorithm

J. Inst. Eng. India Ser. B https://doi.org/10.1007/s40031-024-01165-1 ARTICLE OF PROFESSIONAL INTERESTS Studies on Mitigating Power Quality Issues Using PV: Transformerless Dynamic Voltage Restorer System with Modified Marine Predator Algorithm V. Kaviya1 · V. Kirubakaran1 Received: 9 April 2024 / Accepted: 30 September 2024 © The Institution of Engineers (India) 2024 Abstract Power quality issues are a serious concern due to integrating renewable energy sources into the power grid, often resulting in costly consequences like line disruptions or sensitive load interruptions. Therefore, having a steady voltage with acceptable quality is essential. Dynamic Voltage Restorers (DVR) is a promising solution for resolving power quality issues. Even in the event of grid voltage disturbances, DVR has the ability to restore the voltage on the load side. This research presents a transformerless inverterbased DVR configuration integrated with solar system for a medium voltage power grid and controlled by proportionalintegral. The recently developed metaheuristic optimization method namely the Modified Marine Predator Algorithm has been proposed to optimize the gains of the PI controller. DVR reference voltages are computed using a d-q synchronous reference frame-based approach. Simulation results are provided to verify the functionality of the proposed DVR circuit, and the controller’s resilience and sensitivity to various situations such as voltage sag, voltage swell and faults are confirmed. The system’s THD is compared against various optimization methods, and the results are displayed in time-domain simulations using MATLAB/SIMULINK. The proposed DVR controller successfully maintains the load voltage during sag and swell, with deviation of 0.3 and 0.28% from the reference voltage and THD is reported as 1.10 and 1.29% respectively within the IEEE limits. * V. Kaviya V. Kirubakaran 1 Gandhigram Rural Institute (Deemed to be Institute), Centre for Rural Energy, Dindigul, India Vol.:(0123456789) J. Inst. Eng. India Ser. B Graphical Abstract Keywords Solar energy · Quality power · Voltage sag and voltage swell · Dynamic voltage restorer · Transformerless inverter · Energy storage Introduction Power quality is the capability of an electrical system to deliver a clean, noise-free sinusoidal waveform with stable voltage and frequency. With the extensive usage of nonlinear loads, the modern power grid confronts numerous issues, including voltage fluctuations and short circuit faults. Harmonics, voltage swings, reactive power correction, limited integration, and operational issues are also among the concerns. These issues have been exacerbated by the rapid adoption of green energy. Solar Photovoltaic (PV) systems connected to the grid can also cause power quality, voltage Fig. 1  Conventional DVR connected to a system management, and stability issues in both the solar site as well as the utility side due to harmonics and fluctuations in solar radiation. Since the distribution network is more subject to electrical failures than the generation and transmission systems, it is chosen as the key emphasis area for sustaining the power quality. The sensitive loads experience major interruption due to voltage fluctuations like voltage sag and swell [1]. Voltage sag is also known as voltage dip or voltage drop. According to the Institute of Electrical and Electronics Engineers (IEEE) 1159 standard, voltage sag is defined as a decline in Root Mean Square (RMS) voltage from 0.9 to 0.1 p.u during J. Inst. Eng. India Ser. B a period of 0.5 cycles to less than sixty seconds. Faults such as single-line-to-ground, double-line, and three-phase symmetric faults are among the major sources of voltage sags. Other factors include big-capacity motors, equipment failure, lightning, tree branches falling on power lines, and switching system performance. The design of electrical equipment to mitigate voltage sag depends on its characterization [2]. Voltage swell is just the opposite of voltage dip. It is defined as arising in the RMS voltage above 1.0 p.u during a brief period of 0.5 cycles lasting less than sixty seconds. The causes for this voltage swell are arc furnaces, large welders, and motors. The other reasons are during the de-energization of the large loads and the energization of a large capacitor bank. The effects of voltage swell are a rise in the voltage level on the healthy phases during fault time and similarly, sudden changes in ground reference also raise the voltage in ungrounded systems or floating delta systems. To mitigate voltage swell and sag [3], voltage instability, and harmonics, a reactive power compensation device is required. Such devices are distribution static synchronous compensators (D-STATCOM), static VAR compensators (SVCs), and Dynamic Voltage Restorer (DVR). DVR is a series compensation system [4] and when compared to other shunt compensation devices it is very effective and reliable for reducing the effect of the issues related to power quality on the system and also for protecting electrical loads from these issues by flow control of reactive as well as active power between the DVR and the electricity distribution system [5]–[8]. Siemens is the first manufacturer of DVR in year 1996, rating of 2 MVA with three voltage source inverter. DVR claims to be the best compensator for improving the current power system because they provide stable voltage for loads and have a quick response in terms of time. In comparison to static compensators based on thyristors, they can offer high power quality and reduce power losses. The size of a standard DVR is determined by the magnitude, duration, and intensity of the sags. Also, understanding how DVR operates in the distribution line give knowledge of the energy loss resulting from the voltage source converter’s switching action during the compensation process. In general, DVR [9, 10]consists of a Voltage Source Converter (VSC), DC charging circuit, protection system, harmonic filter, injection/ booster transformer, and energy storage. A conventional type DVR structural is shown in Fig. 1. To get the most out of a DVR, it is necessary to consider the proper inverter topology and control algorithm. VSIs are popular for DVR due to their low harmonic level output voltage, but their buck-type voltage characteristics limit their maximum output voltage. Z-source inverters offer benefits like enhanced dependability, tolerance to Electromagnetic Interference (EMI) noise, and voltage buck-boost capabilities. Multilevel inverters are suitable for medium voltage and high voltage distribution systems due to their low harmonic distortion and high voltage. Topologies include flying capacitors [11, 12] diode clamps [13], and cascading multilevel inverters [14]–[16]. Flying capacitor topology is more flexible but more complicated for high power lines. Cascade inverters [17]use a different DC source to achieve greater voltage levels, (...truncated)