Voltage Harmonics Research Articles

VSC-STATCOM Performance Under Different Fault Sensing using PSO Tuned Hybrid SMC

In this paper, we investigate the PSO-tuned hybrid SMC performance based VSC-STATCOM under different conditions of fault using hybrid renewable energy sources (HRES). A hybrid renewable energy resource system (HRES) consists of PV, wind power, and batteries. Here the Irradiance is the PV input and the wind energy is Wind Input. The storage of energy is used for battery. The battery is used for changing weather condition or the changing the condition of the environment. Hybrid VSC-STATCOM controller based on SMC to reduce power quality issues like sag, swell, harmonics etc. associated with HRES system mainly due to non-linear load conditions. The novelty of our proposed PSO-tuned hybrid Sliding Mode Controller (SMC) method lies in its integration of Particle Swarm Optimization (PSO) as a tuning mechanism within the SMC framework. The Harmonic reduction and efficiency improvement is verified by using the Simulation. Therefore, the proposed system performance is simulated and to optimize the terms are real and reactive power, Total Harmonic Distortion (THD) and Voltage Sag.

Power Quality Improvement in Hybrid Power System using STATCOM :

Meeting the escalating electricity demands posed by population growth and industrial expansion presents a significant challenge. Utilizing renewable energy sources like wind, biomass, and hydro co-generation has become imperative to satisfy energy requirements. In this proposed framework, a model featuring a grid-integrated wind energy generation system and nonlinear load is developed using MATLAB/Simulink. Integrating wind energy into the power grid impacts electricity quality, notably manifesting in voltage fluctuations, harmonics, flicker, and poor power factor at the source. The efficacy of a wind turbine and, consequently, electricity quality are assessed. To enhance power quality, the project advocates for the implementation of a STATCOM control strategy in grid-connected wind power systems. A bang-bang controller, based on hysteresis current control, is devised for STATCOM. Integrating STATCOM with the Point of Common Coupling (PCC) mitigates power quality issues. In this envisioned scheme, the FACTS device STATCOM is linked with battery power storage (BESS) at the PCC to alleviate power quality concerns. Incorporating Battery Energy Storage Systems aids in stabilizing the real power source during wind power fluctuations and facilitates the rapid injection of reactive power at the PCC. Keywords: Wind energy, Solar Energy, STATCOM, Electric grid, IGBT, PWM.) etc.

Exploring gradual material rigidity degradation effects on the nonlinear coupled axial-transversal nonlinear response of a capacitive micro-beam

The accumulation of damage in materials due to crack propagation can lead them to unpredicted failures. This phenomenon is particularly relevant in materials science, engineering, and other fields where structures or components are subjected to repeated loading, cyclic stresses, or environmental factors. In this paper, the mechanical behavior of a microelectromechanical system subjected to cyclic loads has been modeled, when the stiffness of the material gradually is decreased. As a case study the dynamic response of a micro-beam to DC bias voltage as a static load and AC harmonic voltage as a cyclic load has been studied. The nonlinear coupled equations have been formed and converted to time-dependent ones using a spatial discretization method. Due to long-term integration over time, to achieve more accurate results besides direct 4th order Runge-Kutta integration method, a temporal decomposition method has been used to solve the coupled nonlinear ordinary differential equations. To realize this method, a temporal decomposed solution based on the physical nature of the problem is presented in the form of slow-growing terms and fast-altering harmonic terms with gradually-growing amplitudes. To find the coefficient of these terms a least square method has been utilized to minimize a cost function in a given dynamic time-interval, where the independency of the results to this interval has been assessed. Also, the nonlinear frequency behavior of the proposed model has been studied when the system has suffered various damages. Due to considering gradual rigidity degradation of the material interesting dynamic responses have been observed, that can help to expand the insight in the design of structures.

Additional Power Losses Under Non-Sinusoidal Conditions in a 22 kV Overhead Power Line

Non-sinusoidal conditions in the electrical networks cause active power losses at the fundamental frequency, corresponding to the first harmonic, and at harmonic frequencies, which are a multiple of the fundamental frequency. Non-sinusoidal currents flow through network components and create additional active power losses. One of the non-sinusoidal current sources is electronic equipment used in industrial plants to control process equipment. In Vietnam, coal mines use frequency-controlled induction motors when processing coal. The induction motors consume non-sinusoidal current, which creates additional active power losses in the supply network. The harmonic active power does not perform useful work. It causes economic damage to both the supply network and industrial enterprises. The power supply systems in industrial areas of Vietnam, where coal is mined, are characterized by low power quality. Companies engaged in coal mining and processing are forced to pay for additional losses of active power due to the low power quality under non-sinusoidal conditions, which reduces the economic efficiency of the companies' operations. The paper presents a review of the literature on the assessment of additional active power losses in overhead power lines at harmonic frequencies. An example of calculating additional losses of harmonic active power is given for a 22 kV overhead power line, through which electrical energy is supplied to the coal grading plant of the Kua Ong-Vinacomin company. Additional losses are calculated using the measurements of harmonic voltage and current at the point of the supply network connection to the 22 kV overhead power line, through which electrical energy is supplied to the coal mine and the coal grading plant. To assess the influence of the electrical equipment of the coal grading plant on the power quality in the supply network, measurements were carried out on 0.4 kV buses of electrical substation of the coal mine.

Research on intelligent auxiliary regulation technology of large power grid section based on artificial intelligence

In the modern era, large-scale renewable energy systems are integrated with advanced power systems and provide efficient operations. Also, optimized power systems require accurate energy generation and effective control systems to manage and ensure a stable power supply. Nevertheless, uncertainties are the intermittent balance of supply and high electricity demand. In addition, conventional power sources are not applicable for this challenging task and increase electricity costs. Therefore, an efficient Neuro Fuzzy Single phase Unified Power Quality Conditioner with Maximum Power Point Tracking (NF-SP UPQC -MPPT) strategy is developed for enhancing the grid-connected power systems. Here, Neuro-fuzzy logic is used as dynamic reactive power compensation in the grid. Also, this logic can efficiently handle the Energy storage system (ESS). Then SP UPQC was used to enhance power quality in electrical distribution systems. It combines both series and shunt compensators to mitigate various power quality issues such as voltage sags, harmonics, and unbalance. After that MPPT was utilized to extract the maximum power from the grid system. Model Predictive Control (MPC) controller to determine the overall stability and performance of the system. Moreover, the developed model was implemented on the MATLAB platform and performance is analyzed in terms of voltage deviation, grid current, reactive power fluctuations and Total Harmonic Distortion (THD).

Harmonic Distortion Study of a Photovoltaic Generator in a Microgrid under Disturbances

This paper describes research on the harmonic-distortion capacity of a single-stage photovoltaic (PV) 3.68 kWp generator in a microgrid configuration. An overview of various harmonic compensator methods used in PV generators is presented to evaluate their advantages and disadvantages. Proportional-resonant (PR) structures with harmonic compensators (HCs) are designed, modeled, and validated through real-time tests. The modeling of harmonic compensation structures for a photovoltaic inverter using MATLAB/SIMULINK R2022a is explained in detail. The harmonic compensation capacity of a PV generator inverter is studied under voltage harmonics, grid frequency variation, and voltage unbalance. The contributions of this work are, firstly a bibliographic analysis of various strategies currently used for harmonic compensation in grid-connected inverters and secondly, a detailed explanation of the modeling of harmonic compensation structures using MATLAB/SIMULINK. Finally, a demonstration of the improvement in energy quality that results from using harmonic compensation techniques in photovoltaic generators in microgrid configurations affected by grid disturbances is performed. The obtained results show that harmonic compensation strategies based on resonant filters are a good alternative for the reduction of harmonic voltage distortion in the presence of grid disturbances such as frequency variation and voltage unbalance.

Even‐Order Harmonic Distortion Observations During Multiple Geomagnetic Disturbances: Investigation From New Zealand

AbstractLarge geomagnetic storms are a space weather hazard to power transmission networks due to the effects of Geomagnetically Induced Currents (GICs). GIC can negatively impact power transmission systems through the generation of even‐order current and voltage harmonics due to half‐cycle transformer saturation. This study investigates a decade of even‐order voltage total harmonic distortion (hereon referred to as Even‐Order Total Harmonic Distortion (ETHD)) observations provided by Transpower New Zealand Ltd., the national system operator. We make use of ETHD measurements at 139 locations throughout New Zealand, monitored at 377 separate circuit breakers, focusing on 10 large geomagnetic disturbances during the period 2013–2023. Analysis identified 5 key substations, which appeared to act as sources of ETHD. The majority of these substations include single phase transformer banks, and evidence of significant GIC magnitudes. The ETHD from the source substations was found to propagate into the surrounding network, with the percentage distortion typically decaying away over distances of 150–200 km locally, that is, at a rate of −0.0043 %km−1. During the study period some significant changes occurred in the power network, that is, removal of the Halfway Bush (HWB) single phase bank transformer T4 in November 2017, and decommissioning of the New Plymouth substation in December 2019. Decommissioning of these two assets resulted in less ETHD occurring in the surrounding regions during subsequent geomagnetic storms. However, ETHD still increased at HWB with increasing levels of GIC, indicating that three phase transformer units were still susceptible to saturation, albeit with about 1/3 of the ETHD percentage exhibited by single phase transformers.

Signal Envelope-Based Adaptive Power Swing Blocking

This research paper proposes detection of faults during power swings by using a peak envelope-based method to prevent incorrect distance relay operation. Distance relays should not operate during power swings except to remove a correctly detected fault event. In this study, distinction between faults and power swings is achieved by correctly observing fault occurrence based on dynamic thresholds generated by peak envelopes. The method utilizes a DC offset current in determining the fault inception and fifth harmonic voltage to assess the fault clearance. If the current surpasses the calculated threshold due to fault existence, the relay is allowed to operate. Re-blocking the relay after fault clearance is achieved in the case of a higher value of the voltage than the threshold value. Current and voltage data obtained from two different test systems simulated in PSCAD for various scenarios have been used in the proposed algorithm developed in MATLAB. In order to show the effectiveness of the proposed method, the results on the second test system have also been compared to the results of selected methods in the literature. It has been perceived that the developed method has a high accuracy and provides an appropriate time range for relay and breaker operation.

Research on the Effects of Voltage Sags and Harmonics on the Output Characteristics of Switching Power Supply

Switching power supply is widely used in industrial equipment, household appliances, and other fields due to the advantages of high integration and lightweight. Voltage sags can seriously affect the output voltage of switching power supply and the working condition of its power supply equipment; at the same time, the working scenarios of power equipment using switching power supply often have different level of harmonic problems. Considering the continuous innovation of switching power supply technology, the previous analysis and test results on the effect of voltage sags and harmonics on switching power supplies may no longer be applicable. The paper reveals the mechanism of the effect of harmonic alone as well as voltage sag superimposed harmonics on the output voltage of the switching power supply. Then the test research program was developed, and four different brands switching power supplies were selected for the test research, with which the effects of different amplitude voltage sags, harmonics with different frequencies and distortion, as well as voltage sag superimposed harmonics on the output voltage of switching power supplies were investigated. The results show that the tolerance ability of switching power supplies to voltage sags has been improved compared with previous switching power supplies, and the harmonic itself has less effect on the output voltage of switching power supply, but the joint action of harmonics and voltage sags will have a greater effect on the output voltage of switching power supply. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Unified power quality conditioner-based solar EV charging station using the GBDT–JS technique

This manuscript proposes a novel hybrid artificial intelligence (AI) approach for a unified power quality conditioner (UPQC) designed specifically for electric vehicle charging stations (EVCSs). The aim is to integrate multiple vehicle-to-grid (V2G) functionalities, thereby mitigating the challenges associated with electric vehicle (EV) grid integration and the incorporation of distributed energy resources (DERs). The hybrid technique presented in this manuscript combines the gradient boosting decision tree (GBDT) algorithm and the jellyfish search (JS) algorithm, referred to as the GBDT–JS technique. This innovative approach involves utilizing the charging station to offer EV charging services and facilitating the discharge of EVs to the power grid. Integration of the UPQC with DERs, such as photovoltaic (PV), is implemented to decrease the power rating of converters and fulfill power demand requirements. The initial converter within the UPQC is employed to manage the direct current (DC) voltage, while the second converter oversees the power charging or discharging processes of EVs. Additionally, it mitigates the impact of battery voltage fluctuations. The UPQC with vehicle-to-grid functionality minimizes the load pressure on the grid, preventing over-current issues. The presented approach regulates the UPQC converters to mitigate power quality issues such as harmonic currents and voltage sags. Subsequently, the effectiveness of this technique is demonstrated using the MATLAB/Simulink operating platform. The evaluation of GBDT–JS performance involves a comparative analysis with existing techniques. This assessment reveals that the proposed method effectively alleviates power quality issues, specifically reducing total harmonic distortion (THD), and delivers optimal outcomes.

Integration of electric vehicle into smart grid: a meta heuristic algorithm for energy management between V2G and G2V

Recently, Electric Vehicles (EV) have been providing fast response and substantial progress in the power generation model. Further, EVs are exploited as adaptable Energy Storage Systems (ESSs) and show a promising performance in ancillary service markets to increase the demand of Smart Grid (SG) integration. The expansion of Vehicle-to-Grid concept has created an extra power source when renewable energy sources are not available. Yet, numerous operational problems still are required to be considered for EV implementation to turn out to be extensive. Even the development of Photo-Voltaic (PV) technology creates a problem in SGs when used for EV charging. Because of this, the Energy Management System (EMS) is required to handle charging requirements and deal with the intermittent generation. Here, in this research, an Improved Honey Badger algorithm (IHBA) is proposed for integrating SGs with EV parking lot, solar panels, and dynamic loads at the Point of Common Coupling (PCC). The proposed IHBA uses a dynamic programming method to optimize the charging Grid-to-Vehicle (G2V) or discharging Vehicle-to-Grid (V2G) profiles of the EVs using the forecasts of PV generation. This algorithm considers user preferences while also lowering reliance on the grid and maximizing SG effectiveness. The study’s findings show that the Honey Badger method is efficient in resolving issues involving large search spaces. The developed method is used to optimize charging and discharging of EV which is tested in MATLAB to obtain a stable load profile. From the evaluation of obtained results, it is evident that the IHBA controller outperforms the WOA and EHO controllers in terms of total harmonic distortion voltage (3.12%), power loss (0.197 kW) and efficiency (98.47%).

Harmonizing power systems with a 13-level modified Packed U-Cells multi-level inverter: Design and implementation

Traditional multilevel inverter designs often face complexity challenges, prompting the need for a simplified solution. This study introduces and evaluates the performance of a Modified Packed U-Cells (MPUC) inverter in the realm of multilevel inverter technology. The study addresses challenges associated with conventional multilevel inverters and proposes the MPUC inverter as a solution to simplify the design complexity. The MPUC inverter, utilizing three DC sources and eight switches, presents a groundbreaking thirteen-level output waveform. The primary focus lies in assessing the inverter's performance in terms of Total Harmonic Distortion (THD) and output voltage. Utilizing MATLAB/Simulink, the inverter's performance is evaluated with and without Pulse Width Modulation (PWM) strategies. The results reveal a notable reduction in THD, from 26.25% to 9.91% post-filtering when PWM is not employed. Various multi-carrier Level-Shifted PWM strategies, including PDPWM, PODPWM, APODPWM, and COPWM, are explored to enhance output waveform smoothness and efficiency. Unequal Carrier strategies, specifically UEAPDPWM and UEAPODPWM, emerge as superior in THD management at different frequency ranges. The study further incorporates real-time hardware implementation of the proposed 13-level MPUC topology, highlighting the success of the UEAPD-PWM strategy in improving waveform quality. The research aims to establish a multilevel inverter design protocol meeting international standards and emphasizes the pivotal role of PWM techniques in enhancing waveform quality. This comprehensive evaluation contributes to advancing the field of multilevel inverter technology and sets a benchmark for future research in this domain.

Investigation of class-F power amplifier in the presence of the second and fourth harmonics of input voltage

In this paper, a thorough theoretical investigation of high-efficiency class-F power amplifier (PA) is undertaken to drive, considering the second and fourth harmonics of input voltage. The precise analytical expressions of the gate-source voltage, drain current, output power, and efficiency are extracted. Maximum normalized output power and maximum drain efficiency from the initial phase and amplitude of the second and fourth harmonics of input gate-voltage can be achieved. The simulation of class-F PA using a GaN CGH40010F transistor has been done to validate the theoretical analysis. Addition of the fourth harmonic gate voltage along with the second harmonic improves the output power and efficiency of the PA by 0.7 dBm and 4.1%. Based on the simulation with realistic elements, a highly efficient PA operating from 1.8 to 2.2 GHz is implemented. The fabricated PA provides an efficiency of 72–87.6%, PAE of 65–80% and an output power of 39.3–41 dBm.

Power quality improvement in grid-connected photovoltaic system under partial shading condition

ABSTRACT Solar systems are becoming widely used renewable energy source since photovoltaic cell generates high power output. However, during partial shading conditions (PSC), the existing MPPT techniques failed to determine the actual maximum point of the photovoltaic (PV) cell, and the photovoltaic system is stuck at a local maximum thus output is gradually reduced. The Optimized Grid-Connected Photovoltaic system aims to extract the most power from the solar array under partial shading conditions. It uses an optimisation algorithm named Sovereign Butterfly Optimization Algorithm and a sequence controller to optimize power value selection. The voltage harmonics and phase delay cause the system to be in an unbalanced state, so the proposed model uses an anomaly obliteration filter fusion technique in which the Butterworth filter is utilised for reducing voltage harmonics and removing phase delay completely by avoiding negative sequence by converting three-phase current to dq0 frames. To increase the overall power quality in the photovoltaic system without synchronization problems, a Subsystem Synchronization Control Strategy is applied which effectively synchronizes the active and non-active currents injected into the grid. Simulated results using the proposed model showed high tracking accuracy of 99.23% and minimum power oscillation of 2.53%, thus enhancing the overall power quality.

Dead-Time Compensation Using ADALINE for Reduced-Order Observer-Based Sensorless SynRM Drives

The inverter dead time effect is non-negligible for the control performance of sensorless synchronous reluctance motor (SynRM) drives at low speeds. In this paper, a reduced-order observer-based sensorless control method for SynRM drives combined with the adaptive linear neurons (ADALINE)-based dead-time compensation is proposed. The reduced-order observer-based sensorless control method is presented, for which is parameter tuning is easy. On this basis, the dead-time compensation strategy using ADALINE filters is proposed to reduce the voltage harmonics effect on the estimation performance of the reduced-order observer. With ADALINE filters, the sixth current harmonic can be successfully filtered out by compensating the voltage directly or fitting the current to compensate the voltage. In this way, the low-speed estimation performance of the reduced-order observer is improved. The effectiveness of the proposed method is verified on a 3 kW SynRM experimental platform.

Effects of Temperature and Moisture Content on the Enhancement of Dielectric Loss of OIP Bushings Under Harmonic Voltages

Effects of Temperature and Moisture Content on the Enhancement of Dielectric Loss of OIP Bushings Under Harmonic Voltages

A wide drive frequency matching method for harmonic suppression and voltage stabilization of ultrasonic motors.

To reduce harmonic components, balance system impedance, and stabilize driving voltage, an additional matching circuit is required for ultrasonic motors (USMs) driver. However, the performance of inductor or capacitor matching can be seriously weakened with changes in driving frequency. Therefore, this paper presents a simple and effective LC matching method against driving frequency adjustment for USMs. First, the driving scheme of the USM is proposed and the electromechanical coupling model is analyzed. Subsequently, the output characteristics of the full-bridge inverter are derived theoretically when the driving frequency deviates from the mechanical resonant frequency. Then, the impedance circular transform method is proposed, which can intuitively analyze the effect of matching parameters on the voltage amplitude. A matching objective function is established that can consider both the voltage stabilization and harmonic suppression. The matching parameters are solved using random weight particle swarm optimization. Simulations and experiments demonstrate that within the operating frequency of the USM, the proposed matching method can effectively prevent overvoltage and suppress harmonic components. Furthermore, compared with the existing resonant matching method, the proposed matching method can realize more stable driving capability at different frequencies. The proposed method could be useful for USMs' variable-frequency driver design.

Extremely Low Frequency PS-PWM Based Technique for Cascaded H-Bridge Converters With Grid Voltage Compensation Capability

Cascaded H-Bridge Converters (CHB) are good candidates for many industrial applications. Among the modulation techniques that can be applied to CHB converters, the Phase-shifted PWM method (PS-PWM) provides very good harmonic quality being the most popular modulation technique at the expense of presenting high switching losses. On the contrary Block Switching technique as well as Selective Harmonic elimination/mitigation (SHE/SHM) techniques provides lower switching frequency and losses with a lower harmonic quality. Additionally with these techniques the converter operation becomes stiff. In this work a modification of PS-PWM based on an extremely low frequency carrier is proposed with the objective of achieving both low switching losses and an acceptable harmonic quality, simultaneously. The main advantage of the proposed solution is the capability of adjusting the phase-shift angle among the carriers to compensate for harmonic grid voltage disturbance. Several experimental results have been reported to demonstrate the good performance of the proposed modulation technique.

An Experimental Analysis of Three-Phase Low-Voltage Power Factor Controllers Used in a Deforming Regime

In industry, to improve the power factor in low-voltage power substations, a power factor controller (the most used method) can be installed which connects capacitors banks (connected, or not, with coils) in the electrical installation. The most important parameters of power engineering are the power factors that indicate the efficiency of energy use. Currently, many non-linear consumers (more single-phase than three-phase) are used on low voltages. Harmonics (currents and/or voltages) are the most important dynamic component of power quality, affecting electrical equipment performance and also reducing power factors. The purpose of this analysis is to increase the displacement power factor and to decrease the total harmonic distortion (for the current) in the conditions where there are linear and non-linear consumers, where the power factor must be improved with capacitors banks. Relevant different consumers have been selected for both the industry and the home sector, as follows: inductive motors that are linear, inductive consumers, compact fluorescent lamps that are non-linear, and capacitive consumers. This analysis was carried out depending on the number of steps used for the power factor controller, the values of the capacitors banks, the AC reactor (connected in series with all consumers), and the LC shunt filters. For a slight deformation regime, a large number of capacitors banks with different values ensure a finer adjustment of the displacement factor. The maximum number of steps that regulators can command should not necessarily be used (the reliability of the installation decreases with the increase in the number of capacitors banks), but a reduced number of steps can be used, which can lead to higher values of displacement power factors. To improve the deforming regime and to increase the displacement power factor, the use of LC shunt filters, connected to a small number of steps, will also increase the displacement power factor (over 0.9) and decrease the total harmonic distortion (up to 7–10%) for the current. Weaker results were obtained with AC reactors connected to the power supply phases of consumers and, if a larger number of stages were used, to which LC shunt filters were connected, these filters become difficult to calibrate (resonances occur).

A Fast Repetitive Control Strategy for a Power Conversion System

With the expansion of renewable energy sources, the stable and high-quality operation of microgrids composed of new energy sources has attracted widespread attention. Among them, the power conversion system (PCS), as an important part of microgrids, plays a crucial role in their operation and management. The PCS operation modes are classified into grid-connected and off-grid modes. However, in off-grid mode, due to the access of nonlinear and unbalanced loads, the output voltage quality of a PCS is worse, and the voltage waveform distortion is serious. To solve these problems, a fast repetitive control (FRC) strategy is proposed for a power conversion system with an Active Neutral Point Clamped (ANPC) architecture of three levels. The voltage loop control strategy can be applied to the voltage/frequency (V/f) mode and the grid-forming mode. The control strategy can effectively realize the suppression of the harmonics of the output voltage and has a 100% capability to carry unbalanced loads. Finally, a 1725 kVA PCS prototype is developed, and the proposed control strategy is verified using the MT3200 HIL semiphysical simulator of ModelingTech in the V/f mode as an example. This practically verifies the feasibility and validity of the proposed control strategy, which has a certain degree of engineering practicability and reference due to the simplicity of the design and the ease of realization.