Power Quality Problems Research Articles

Aspects Regarding of Passive Filters Sustainability for Non-Linear Single-Phase Consumers

The efficient use of electrical energy (an important component of sustainability) has become increasingly important for electrical consumers (industrial and non-industrial) as we face the challenges of climate change and the need to protect the environment. This theme is essential for guaranteeing a secure and sustainable future for both present and future generations. The power quality and the efficiency of electrical energy are connected to each other. Some power quality problems are caused by natural and unpredictable events, but many disturbances affecting power quality are caused by suppliers and consumers. One of the most important parameters in power engineering is the power factor, which indicates the degree of efficient use of electrical energy. Harmonics is the most important dynamic component of power quality, which affects the operation of electrical equipment and, at the same time, reduces the power factor. Harmonic sources in power systems are generally associated with nonlinear loads. To analyze the operating of passive filters (series L, shunt LC, T type LCL), two groups of experiments (relevant consumers were chosen for the industry as well as from the household sector) were carried out with single-phase nonlinear consumers: in the first group of experiments, a variable-frequency drive is used to supply a three-phase induction motor with variable load; in the second group of experiments, compact fluorescent lamps and LED lamps were used. Following the experiments, it was found that the difficulty of calibrating coils (to size a filter), especially the coils with a core, and the change in electrical properties over time for capacitors. For a certain type of consumer, the improvement of the current waveform depends on the type of filter used, the possibility of improving the power factor (to use electrical energy efficiently), and the role of the source impedance, which is particularly important to improve the efficiency of passive filters. Through the appropriate choice of the passive filter, a decrease in the deforming regime is obtained, with a slight decrease in the active power, and by increasing the power factor, a decrease in the losses of electrical energy from the electrical networks is obtained, with direct implications for the emission of greenhouse gases.

Efficient Framework to Manipulate Data Compression and Classification of Power Quality Disturbances for Distributed Power System

There is some risk of power quality disturbances at many stages of production, transformation, distribution, and energy consumption. The cornerstone for dealing with power quality problems is the characterization of power quality disturbances (PQDs). However, past research has focused on a narrow topic: noise disruption, overfitting, and training time. A new strategy is suggested to address this problem that combines efficient one-dimensional dataset compression with the convolutional neural network (CNN) classification algorithm. First, three types of compression algorithms: wavelet transform, autoencoder, and CNN, are proposed to be evaluated. According to the IEEE-1159 standard, the synthetic dataset was built with fourteen different PQD types. Furthermore, the PQD classification procedure integrated compressed data with the CNN classification algorithm. Finally, the suggested method demonstrates that combining CNN compression and classification methods can efficiently recognize PQDs. Even in noisy environments, PQD signal processing achieved up to 98.25% accuracy and managed the overfitting.

Fault-Tolerant Method of Modular Railway Power Conditioner Based on DC Bus Voltage Regulation

With the development of high-speed electrified railway, many serious power quality problems have arisen and caused widespread concern. In order to achieve comprehensive management of power quality, modular railway power conditioner (MRPC) has been applied to traction systems. However, due to the presence of multiple sub-modules (SMs). The reliability of the equipment is threatened as the number of SMs increases. In medium-voltage applications, system reliability can be improved by adding redundant SMs. However, when the redundant SMs are run out, the reliability of the whole system cannot be guaranteed. Therefore, a fault-tolerant method based on DC bus voltage regulation is proposed to improve the reliability of MRPC by modulation signal reconstruction. The proposed method not only achieves fault ride-through to maintain normal operation and improves the SMs voltage stress on the opposite converter, but also effectively improves the over-modulation. The effectiveness of the proposed method is verified by down-scale experiments.

Meeting Power Challenges with TCSC and Next Generation TCSC: SPLIT TCSC

The electricity demand is continuously increasing due to population growth and development. There is a lack of generation and transmission facilities, so the existing system is used to transfer more power to meet the rising power demand. This causes overexploitation of the present power system and gives rise to stability problems. The power transfer capacity of the existing transmission lines can be increased by using fixed capacitors by varying the impedance of the transmission lines, but they have associated SSR problems. In this situation FACTS devices TCSC are used to control power flow in the system. TCSC mitigate power oscillation, stability problems and various power quality problems like voltage sag and voltage swell created due to disturbances or faults. In the proposed work the TCSC is used to increase the power flow capacity of the system without the need for investment in new lines and systems. The active power transfer with different controllers is discussed. The two modules of TCSC with different ratings are taken and analysed. Then there are some problems in ordinary TCSC too. On tuning the ordinary TCSC in the critical region of the reactance characteristic curve there is observed a large gap of reactance at both the inductive and capacitive critical regions. Because of the large elapse/gap of reactance in this region small change of power demand is not possible in the power system which reduces the flexibility of the power system, and it becomes rigid. These challenges of ordinary TCSC are met here by the next generation device of TCSC: Split TCSC in the power system. Split TCSC tunes the critical region reactance with many firing points and hence elapse of reactance is very small which allows for fine tuning of power flow over the transmission line thus mitigating the problems of ordinary TCSC. Split TCSC includes all the other benefits of ordinary TCSC such as increased power flow, stability improvement, damping oscillations, and mitigating SSR as it belongs to the family of TCSC. Thus, in the proposed work the power challenges are met using TCSC and Split TCSC.

Power quality stabilization system for grid connected large-scale solar power system

This paper presents solution to power quality issues when integrating a 1.5 MW photovoltaic array (PVA) with a unified power quality conditioner (UPQC) into the power grid. A modified unit vector template control scheme is used to generate a reference load voltage signal, and a synchronous reference frame (SRF) is created using a low-pass filter to control UPQC. Furthermore, the PVA is interfaced with the grid through a common DC link of shunt and series converters. The series converter mitigates power quality problems allied with the grid side, such as 3rd, 5th, and 7th harmonics, voltage sag, and voltage swell, by introducing signals in phase and out of phase voltage, respectively, at the point of common coupling (PCC). The shunt converter mitigates nonlinear load current harmonics and compensates for reactive power using SRF. The suggested methodology is implemented using MATLAB Simulink with both linear and nonlinear loads under different power quality conditions. Total harmonic distortions are maintained below 5% at PCC, as per IEEE-519 standards.

Research on DC Voltage Stability Control of Railway Power Conditioner Based on Impedance Matching Principle

When the Railway Power Conditioner (RPC) is used to solve the power quality problem of the electrified railroad, the DC impedance will have a negative impedance characteristic during the bidirectional transmission of RPC power, and this negative impedance characteristic will affect the accuracy of RPC power compensation, cause the fluctuation of RPC DC bus voltage, and affect the effect of negative sequence current management on the grid side. In view of the above problems, this paper proposes an RPC control strategy based on the impedance matching principle, which optimizes the negative impedance characteristics into positive impedance characteristics by the cooperative control of DC voltage and power, increases the phase angle margin of the system, improves the stability and dynamic performance of DC voltage under the bidirectional flow of RPC power, and improves the effect of grid-side negative sequence current management. Firstly, this paper performs small-signal modeling of the DC-side port impedance and analyzes its impedance characteristics. Secondly, the working principle of the RPC control strategy based on the impedance matching principle is analyzed. Finally, the proposed control strategy is effectively verified by building a simulation model and an experimental platform.

Enhanced proportional integral controller for DSTATCOM with particle swarm optimization algorithm in power system

Power system expansion planning is supported by using distributed generation (DG) instead of installing new main power system generators. The portability and autonomous operation of the DG make it capable of integrating into the distribution system. Power electronics devices for home loads, mainly electric vehicles, mobile phones, and laptops, introduce harmonics and related power quality issues to the distribution system. This load creates power quality issues like an increase in total harmonic distortion (THD) and a reduction in power factor. This paper uses the DG to supply important power electronics devices for the mitigation of power quality problems in distributed systems with non-linear loads, such as electric vehicles, called the “distributed static compensator (DSTATCOM)”. Wind and photovoltaic (PV) generators supply power to a common DC source. To improve power quality D-STATCOM powered by PV and wind energy systems at the DC link is incorporated. The direct axis/quadrature axis method (DQ method) controls the real and reactive components of the power. Proportional integral (PI) and particle swarm optimization (PSO) based PI controller parameter estimation are developed, and results are compared for power quality performance. In terms of improving power quality, the PSO-based parameter estimate of the PI controller performs better than the traditional PI controller.<br /><div class="extension_reset_css AnnotateNet_widget AnnotateReviewNotesButton" style="display: none; z-index: 2147483644;" data-id="ExtensionWidget"><div class="extension_reset_css AnnotateNet_widget annotateclickable" style="z-index: 8; display: none;" title="Resize" data-id="Widget"> </div></div>

A novel fuzzy-logic controller-MDsUPQC topology for power quality improvement in multi-feeder distribution system

In the current situation, the significant usage of massive non-linear functioned power electronic loads has been increased in domestic and industrial applications. The main problem of power-quality (PQ) deterioration in both voltage quality and current quality from nominal values and also damaging the single/multi feeder distribution systems. The major contribution is to alleviate the PQ issues by employing novel multi-devices unified power-quality conditioner (MDsUPQC) topology in a multi-feeder distribution system. This MDsUPQC comprises multiple voltage source inverter (VSI) devices connected with a common direct current-link (DC-link) capacitor which is controlled by a proportional-integral (PI) controller. However, this controller has some technical issues that are not suited for the regulation of common DC voltage at the desired level because of improper selection of gain values. The contribution of this work is proposing an intelligent fuzzy-logic (FL) DC-link controller-driven MDsUPQC device which evidences the intelligent knowledge base for better regulation of PQ issues. The technique and performance of the suggested strategy for PQ improvement, load sharing between feeders, and simulation results are presented with comparative analysis utilizing the MATLAB/Simulink software tool.

Power Quality Conditioners-Based Fractional-Order PID Controllers Using Hybrid Jellyfish Search and Particle Swarm Algorithm for Power Quality Enhancement

Power quality (PQ) is a major issue in today’s electrical system that affects both utilities and customers. The proliferation of power electronics devices, smart grid technology, and renewable energy sources (RES) have all contributed to the emergence of PQ concerns in today’s power system. The Unified Power Quality Conditioner (UPQC) is a versatile tool that can be used to fix distribution grid issues caused by irregular voltage, current, or frequency. Several tuning parameters, however, restrict the effectiveness of the Fractional-Order Proportional Integral Derivative (FOPID) control technique, which is proposed to improve UPQC performance. To move beyond these restrictions and find the optimal solution for the FOPID controller problem, a hybrid optimization strategy called the Hybrid Jellyfish Search Optimizer and Particle Swarm Optimizer (HJSPSO) is employed. To meet the load requirement during PQ issue periods, the suggested model incorporates a renewable energy source into the grid system. Whether the load is linear or non-linear, the design maintains PQ problems to a minimum. Furthermore, the FOPID control technique is compared with other controllers. Results show that grid-connected RES systems using the proposed FOPID control approach for UPQC have fewer PQ problems. The presented UPQC with HJSPSO strategy significantly outperformed, with the shortest computing time of 127.474 s and an objective function value of 1.423.

Supraharmonic Detection Algorithm Based on Interpolation of Self-Convolutional Window All-Phase Compressive Sampling Matching Pursuit

With the increase in the use of high-frequency power electronic devices, the harmonics injected into the power grid show a trend of high-frequency development. The continuous rise of the supraharmonic emission level in the distribution network has become one of the power quality problems that needs to be solved urgently in the power grid. In this paper, an algorithm based on the Interpolation of the Self-convolutional Window All-phase Compressive Sampling Matching Pursuit (ISWApCoSaMP) is proposed. Firstly, the self-convolution operation is used for the maximum sidelobe decay (MSD) window, and then the compressed sampling matching pursuit model based on the All-phase is constructed, leading to the All-phase Compressive Sampling Matching Pursuit (ApCoSaMP). Finally, the four-spectrum-line interpolation is combined to utilize spectrum line information to improve the accuracy of signal parameter detection in the frequency domain. The introduced All-phase greatly improves the phase measurement accuracy because the initial phase of the supraharmonic signal is selected for phase estimation. In addition, the self-convolutional window and four-spectrum-line interpolation make full use of the information in the time and frequency domains, thus optimizing the measurement results of amplitude and frequency. The algorithm achieves high accuracy in the measurement results of simulated signals and accurately measures supraharmonics.

Green energy-sourced AI-controlled multilevel UPQC parameter selection using football game optimization

The power quality (PQ) has been significantly affected by the integration of intermittent non-conventional sources (NCS) into the local distribution system in addition to the adoption of power electronic technologies to regulate non-linear loads. This article combines the H-bridge cascade five-level unified power quality conditioner (5L-UPQC) with the wind power generation system (WPGS), solar photovoltaic power generation system (SPVGS), and battery storage system (BSS) as an effective approach to address PQ problems. The utilization of the Levenberg–Marquardt backpropagation (LMBP)-trained Artificial neural network controller (ANNC) in the UPQC is recommended for generating appropriate reference signals for the converters. This eliminates the requirement for conventional complex conversions, such as abc, dq0, and αβ. Moreover, the artificial neuro-fuzzy interface system (ANFIS) is recommended for achieving a DC-link balance. Football game optimization (FBGO) is utilized to determine the optimal shunt and series filter characteristics. The major objectives of the proposed system are to reduce the current waveform irregularities, resulting in a decrease in the total harmonic distortion (THD), an enhancement in the power factor (PF), the mitigation of supply voltage imbalances and disturbances, and the maintenance of a steady direct-current link capacitor voltage (DLCV), despite the variations in the load, solar irradiation, and wind velocity. The efficiency of the suggested strategy is assessed using four case studies that involve different loads, variable wind velocities, and source voltage balancing conditions. Based on the simulation studies and obtained results, the suggested method significantly decreases the THD to values of 2.91%, 3.63%, 3.75%, and 3.50%. Additionally, it achieves a power factor of unity, which is considerably lower compared to other multilevel schemes that use the traditional symmetrical reference frame (SRF) and instantaneous reactive power (pq) methods. This design has been executed using the MATLAB/Simulink program.

Methodology for the Detection and Classification of Power Quality Disturbances Using CWT and CNN

Energy generation through renewable processes has represented a suitable option for power supply; nevertheless, wind generators and photovoltaic systems can suddenly operate under undesired conditions, leading to power quality problems. In this regard, the development of condition-monitoring strategies applied to the detection of power quality disturbances becomes mandatory to ensure proper working conditions of electrical machinery. Therefore, in this work we propose a diagnosis methodology for detecting power quality disturbances by means of the continuous wavelet transform (CWT) and convolutional neural network (CNN). The novelty of this work lies in the image processing that allows us to precisely highlight the discriminant patterns through spectrograms into 2D images; the images are cropped and reduced to a standard size of 128x128 pixels to retain the most relevant information. Subsequently, the identification of six power quality disturbances is automatically performed by a convolutional neural network. The effectiveness of the proposed method is validated under a set of synthetic data as well as a real data set; the obtained results make the proposal suitable for being incorporated into the monitoring of power quality disturbances in renewable energy systems.

One High Voltage Regulation Method and Related Control Strategy in the DC Transmission System

Background: With the development of power transmission system, the problem of small transmission capacity and low power quality of traditional AC power distribution methods is becoming increasingly prominent. The DC power distribution method promotes its own rapid development because of its suitability of connection between distributed generation and grid, high power quality, large power supply capacity, low line cost and high reliability. Objective: In order to improve the transient performance when the system power fluctuates, a control method that can perform voltage regulation to the DC system is designed in the process of calculating the power command value of each converter station at the system level control. Simulation results show that the designed control method can effectively improve the inertial characteristics and transient response of DC transmission system. Methods: Aiming at the shortcomings of slow response speed and poor stability when the traditional dual closed-loop PI controller is used as a converter level controller, a sliding mode controller is designed. Simulation results show that the designed sliding mode controller can improve transient characteristics of voltage regulation. Results: Voltage control strategy of the DC transmission network based on the converter station is verified. Conclusion: A voltage control strategy based on distributed generation and secondary load switching is designed. The simulation verifies the effectiveness of the designed control strategy.

The research on power quality management technology of station area based on distributed photovoltaic scale access

The intermittency, randomness and fluctuation of low voltage distributed photovoltaic power generation bring problems such as overvoltage, harmonic overlimit and reverse overload to rural distribution network, which seriously affect the power supply quality of low voltage distribution network. This paper mainly analyzes the power quality problems caused by large-scale distributed photovoltaic connected to rural distribution network, such as terminal overvoltage, transformer reverse overload, harmonic overlimit, and three phase unbalance. The power quality management strategy of low voltage station area based on distributed energy storage system is proposed, and the power quality management business module of low voltage station area is built based on the power information acquisition system to verify the reliability of the power quality management strategy of low voltage station area. The application effect of distributed energy storage system in controlling overvoltage, reverse overload and harmonic overlimit in low voltage station is verified through pilot construction.

Modeling and Power Quality Enhancement of PV Interfaced with Power Grid System

Recently, photovoltaic (PV) technology has significantly contributed to the utilization of renewable energy sources. It plays a crucial role in addressing the challenges posed by climate change, enhancing energy affordability, ensuring power supply stability, and facilitating energy accessibility. PV technology represents a significant opportunity for addressing the issue of energy access among distant areas that now lack reliable access to electricity. Using a traditional grid is limited due to cost and feasibility constraints. These difficulties are to be addressed in the appropriate timeframe to improve the dependability of the supply. The expansion of the grid into these regions diminishes the overall resilience of the grid system. This leads to a situation where PV systems are integrated into an AC grid with low power quality (PQ) or limited capacity. Nevertheless, the integration of solar power into an AC grid with low capacity. The presence of PQ problems imposes limitations on the levels of penetration. Other factors impose limitations and penetration levels encompass several factors such as non-linear loads, dynamic loads, fluctuating irradiations, and partial shade, among others. This article aims to address the PQ difficulties that arise from a weak electrical infrastructure. The purpose of this compilation is to provide engineers with a readily accessible resource, offering them a distinct advantage in their professional endeavors and scholars engaged in this field of investigation. In this context, the photovoltaic (PV) array is methodically organized into 86 parallel strings. The aforementioned strings are meticulously constructed, consisting of a sequence of seven SunPower SPR-415E solar modules that are intentionally interconnected.

Power quality analysis of Gas Metal Arc Welding process operating under different drop transfer modes

. This work deals with power quality analyses related to the effect of different drop transfer modes in Gas Metal Arc Welding (GMAW) processes. The different drop transfer modes of GMAW process could be classified into: short-circuiting, globular, spray and pulsed. The correct choice of GMAW parameters is essential for optimal performance of the welding process. On the other hand, optimal parameters (from the point of view of the welding process) can lead to different power quality problems on the AC side of the local electric utility, according to the desirable transfer mode. In this sense, some power quality analysis based on metering results related to voltage fluctuations, harmonics and interharmonics will be presented to investigate the relationship between power quality problems and GMAW process operating under different drop transfer modes.

A Computational and Experimental Performance Analysis of an Electromagnetic Voltage Regulator Proposal throughout Controlled Series Voltage Injection

Power quality problems related to short or long time voltage variation have motived the search for voltage compensator techniques capable to provide dynamic voltage regulation to accomplish voltage supply levels in accordance with electrical energy agencies acceptable levels. Although one could recognize that a variety of products already offered in the market are capable of attending general electrical power system requirements the available technology comprises quite simple devices till very sophisticate ones. Having in mind the combination of simplicity, competitive cost, low maintenance need and an attractive performance at recovering the voltage deviations, then an electromagnetic concept to restore the desirable voltage within the established voltage levels is here proposed. The control strategy to be used can provide properties that enable this new device at proving the time response in accordance with the needs for long term and short term voltage variations. Concerning the proposed compensator physical topology it consists in extracting the necessary electrical power throughout a shunt transformer and the injection via a series unit. Besides the arrangement, the paper goes further by establishing a computational time domain model and a laboratory experiment to highlight the overall structure effectiveness at compensating voltage changes.

A Study of the Induction Motor/ASD Immunity in the Presence of Voltage Sags

Adjustable speed drives (ASDs) are sensitive to power quality problems, especially voltage sags. The effect of the magnitude and duration of voltage sags on ASD behavior is related to the energy deficit. On the other hand, the induction motor operation is sensitive to voltage sags in regard to the re start possibility as well as the drop in the motor speed. ASD and induction motor immunities need to be coordinated, being presented the required methodology. A complete study of the involved equipment immunities is needed in order to obtain a better behavior in the presence of voltage sags.

Determining the Source of Dips Using Data of One Monitor in the MV Network

This work discusses about a method that could be used to determine the source of voltage dips based on voltage and power measurements from a single monitor in the MV distribution network. The method uses information of active powers of each feeder connected to the primary substation measured before, during and after the dip events. The ratios of during-dip and post-dip powers to the pre-dip power are used to distinguish the origin and cause of the disturbance. As a power quality problem related to the highest financial losses for industrial customers, knowing the origin and cause of voltage dips is very important in order to identify the weakest part(s) of the network and to take corrective measures that improve the power quality levels and reduce the potential impact of dips to customers.

Power Quality in Renewable Energy Systems  Challenges and Opportunities

Power quality in traditional power systems is concerned with voltage problems caused by abnormal operation or nonlinear load behavior. The integration of renewable energy into the power grid introduces new power quality problems. In addition to the intermittency of renewable production, which leads to more frequent voltage fluctuation, and the switching in the power electronics interfaces, which injects high-frequency harmonics into the system, harmonic resonance and other dynamics power quality problems become more prevalent due to the complex and fast dynamics and control of power electronics interfaces. This paper reviews the sources of harmonic resonance involving renewable energy and presents a systematic method to identify and characterize such dynamic power quality problems. A distributed generation test-bed is also presented as an experimental platform for the study of system harmonic resonance and other control-related power quality and stability problems. Measurement results involving single-phase solar and three-phase wind inverters are presented to validate the analysis method and to demonstrate possible mitigation techniques. The need for advanced autonomous control that enhances system stability and mitigates system harmonic resonance are discussed. Issues related to electromagnetic interference (EMI) generated by renewable energy sources and the need to develop EMI compliance requirements for such sources are also discussed.