Quality Of Electrical Energy Research Articles

Power quality analysis in Durango’s sewage treatment plant

This energy study is developed within a wastewater treatment plant by aerated lagoons, where a series of problems such as activation of temperature protections, phase loss and thermal protections are presented. When analyzing the electrical installation and the constitution of each motor, the hypothesis of a possible presence of harmonics outside the established ranges that are producing distortion and increase of the voltage and current signal, as well as a possible resonance, was raised. For this reason, it is intended to carry out an Electrical energy quality analysis in electrical machines of the PTAR de Aguas del Municipio de Durango, through specialized equipment and based on international standards. The power quality analysis contemplates the analysis of: voltage, current, individual harmonic content, THDv, THDi. The methodology proposed by Dugan, McGranaghan, Santoso, & Beaty (2004) and the performance of energy diagnoses according to what was established by Sifuentes et al (2016) were used. As a result, the confirmation of the hypothesis is obtained where the motor that contains power electronics is a source of harmonics that are amplified by the capacitor bank.

Introduction of state-of-the-art low-voltage distribution network devices

Trends towards the development of distributed generation involve a number of problems related to maintaining the quality of electric energy in medium and, especially, low-voltage networks. The article examines the impact of monitoring the quality of electricity of low voltage classes on the reliability of the electrical network. MSZ EN 50160 and Hungarian Energy and Utilities Regulatory Office (MEKH) standards are considered. In accordance with MSZ EN 50160, the main indicators of the quality of electric energy are considered, such as: frequency, voltage fluctuations, rapid voltage changes, Flicker dose, voltage dips, short-term voltage interruptions, long voltage interruptions, temporary overvoltages of industrial frequency, transient overvoltages between current-carrying conductors and voltage ground , harmonic voltage fluctuations, interharmonic voltage fluctuations. SAIFI and SAIDI are calculated according to the Hungarian Energy and Utilities Regulatory Office. The devices for monitoring the quality of electricity of low-voltage networks are analyzed. The factors affecting the choice of the place of installation of monitoring devices are considered. It is presented how power quality monitoring systems can reduce the number of malfunctions in the 0.4 kV network, and the influence of monitoring systems on the quality of electric power in 6-35 kV networks is considered.

APPLICATION OF CLUSTER ANALYSIS IN SMART GRID NETWORKS

The task of developing and improving intelligent multi-agent control systems, which provide opportunities for intelligent online analysis of the electrical power supply system provided by the smart grid system, is considered. The purpose of the article is the formation of clusters of sections of the electrical network, the initial parameters of which are the main indicators of the quality of electrical energy in accordance with the accepted standards. Total harmonic distortion coefficient of voltages, coefficient of unsymmetry of supply voltages, reactive power of loads are chosen as such parameters. The results of the hierarchical clustering of power supply network sections are summarized in the corresponding dendogram. The method of full connection is used to form a dendogram of sections of the power supply system. This method defines the distance between clusters as the largest distance between any objects in different clusters or the most distant neighbors. The measure of closeness was determined by the Euclidean distance. The obtained treeshaped diagram demonstrates the distribution of the sections of the power supply system into four natural clusters, which visually divides the sections of the power supply system into separate groups according to certain characteristics, namely the main parameters of the quality of the power system. It is shown that the mathematical apparatus of cluster analysis allows solving the problem of classification of sections of the power supply system when the main parameters of the quality of electric energy deviate from the normally permissible values. It is proved that the classification can be carried out not only by one parameter, but also by using a combination of several parameters. The results of the conducted analysis provide an opportunity to further form production rules for the selection of measures to improve the quality of electric energy, which are applied to one or another section of the power supply system.)

Analysis of the traction motor electrical parameters of the trolleybus

The technical equipment of modern trolleybuses (increased power of traction motors, regenerative-rheostatic braking, anti-slip and anti-lock systems, an on-board computer for monitoring and controlling the operation of the traction drive, GLONASS satellite systems, Internet access) increases the requirements for the quality of electrical energy and the electromagnetic compatibility of the installed equipment. In the course of the study, the electrical performance of the trolleybus traction asynchronous motor (voltage, current, voltage sinusoidal shape, total coefficient of harmonic voltage components) has been analyzed. Due to difficulties in the supply of foreign electrical equipment, primarily power electronics elements used to control the operation of the traction motor, there is an increasing need to improve measures for the maintenance of trolleybuses to increase the reliability and uptime of the equipment. The advantages of using the methods of quantitative thermography, analysis of the quality of electrical energy and control of the hardness of cable insulation have been experimentally established. With the help of an analyzer of electric energy quality, measurements of the quantitative indicators of the operation of the electric motor have been carried out; the thermal imager has been used to assess the thermal state of contact connections and cable routes. The use of new diagnostic methods is of particular relevance in the course of continuous long-term operation of electric transport in the Far North.

Distribution Transformer Synchronization Simulation with Two Different Vector Groups using the Matlab Simulink

Nowadays, the quality of electrical energy really needs to be improved especially for industrial purposes that require a good level of reliability in the distribution of electrical energy. Maintenance of distribution transformers is routinely carried out to ensure that the quality of electrical energy produced is in accordance with standards. This maintenance is done using the customer’s load from the distribution transformer to the mobile substation transformer, that can be done using synchronization. This synchronization requires the same distribution transformer vector groups, otherwise it will produce non-standard output. The aim of this research is to determine the vector groups effect on parallel transformer installation system, the method to overcome the synchronous problem of different vector groups based on simulating and testing the synchronization of a 20 / 0.4 kV distribution transformer with the Dyn5 and Dyn11 vector groups. The results obtained from this research are two transformers that have different vector groups can be synchronized with an abnormal connection (changing the position of the secondary terminal cable connection and the primary terminal cable) so that it will produce the same voltage phase. This will abnormal treatment of distribution transformers maintenance that do not have a back-up transformer with the same vector group still can use the different vector group transformers.

PROBLEMS OF OPERATION OF AN INFORMATION AND MEASUREMENT SYSTEM FOR MONITORING THE QUALITY OF ELECTRICITY IN URBAN CONDITIONS

The article considers the types of metrological equipment for measuring the parameters of the quality of electrical energy in electrical installations, outlines the directions for improving the quality of power supply, including a proposal for the introduction of a set of metrological equipment that meets modern requirements for the normalization of electricity quality parameters and has an interface with the ASKUE.

Інтелектуальна діагностика електричних мереж

As follows from the conducted analysis [1-2], artificial intelligence has a great impact on modern energy as a whole, and it has also reached the electric power sector, especially "intelligent" networks with a high degree of automation, which closely interact with renewable energy sources. Here, artificial intelligence has gained widespread use in order to predict the level of illumination of a photovoltaic panel and estimate the output power of solar power plants. Considering the fact that artificial intelligence is a powerful and popular tool that is widely used in renewable energy (in particular, in photovoltaic), it is important to understand to what extent this tool can be used when creating a forecast of the generation of electrical energy at the output of a photovoltaic plant. It is becoming clear that with the help of artificial intelligence, it is necessary to increase both energy efficiency and accuracy values in the power grid, since electronic computing machines can process more data than an operator can in a given time period. When diagnosing the quality of electrical energy in a photovoltaic plant, it is important to observe certain provisions, namely: - adequate, for a specific task, the time of control. As a rule, this parameter must be installed in the system in advance; – determination of the number of electrical equipment and/or power system nodes for monitoring; – assignment of the limit level of parameters for measurement; – the choice of the method for performing the analysis of the measured data; – choosing the type and location for saving the received data, also here it is worth providing for compatibility with other devices in the electrical network, for example, control or signaling devices. In order to indicate the main tasks for the diagnostics system in the photovoltaic plant, which will include artificial intelligence, a structural diagram was created that indicates what tasks must be done in each link of the electrical network. It is worth noting that the structure of the diagnostic system can be divided into several components according to their physical location in the system under study. So, for example, sensors are responsible for all data collection in the power grid. Of greater interest are the links that perform monitoring in the power grid, as well as develop conclusions based on the conducted monitoring and accumulate databases for decision-making. An artificial neural network is responsible for fulfilling these requirements, and its data set for training and retraining can serve as a database.

Possibilities to reduce the impact of vfd on the quality of electric power in the networks of enterprises and the cost of its use

Purpose. Simulation modeling of internal power supply systems and comparative assessment on its basis of the total distortion coefficients of the sinusoidal voltage curve. Methodology. Methods of simulating modeling of internal power supply systems. Numerous methods for processing the obtained results. Methods for calculating the discrete Fourier transform. Findings. To increase the level of automation of technological processes in industrial electrical installations, frequency converters are widely used. Together with all the advantages of using a variable frequency drive, it leads to a distortion of the sinusoidal shape of the voltage graph. The article evaluates the total distortion factor of the sinusoidal voltage curve for two options for constructing an internal network of an industrial enterprise. The proposed solution makes it possible to improve the shape of the voltage curve by reducing the number of non-linear semiconductor elements in the power supply system and reduce the influence of higher harmonic components on the power grid. At the same time, this makes it possible to reduce the cost of using VFD at the enterprise. Originality. Through experimental research, it has been established that the use of a common rectifier in combination with a common DC bus and individual inverters can reduce the total distortion coefficient of the sinusoidal voltage curve. Practical value. The developed simulation models of the workshop network’s operation make it possible to study the indicators of the electric energy quality both in stationary and in transient modes of operation.

STUDY OF NON-SYMMETRICAL MODES OF THREE-PHASE FOUR-WIRE NETWORKS WITH DISTRIBUTED GENERATION

The use of distributed generation electric energy sources allows efficient use of energy resources, including available renewable energy sources, contributes to the reduction of harmful emissions during traditional electric energy generation, improves the quality of electric energy for consumers and reduces overloading of transmission lines. Meanwhile, if the load supplied by the source of distributed generation is asymmetrical, then the voltage at the zero point of the inverter interface feeding the neutral conductor can deviate quite noticeably from the set level. The easiest way to provide a neutral point for connecting the neutral conductor is to use two capacitors with balancing resistors connected in parallel to them, that is, to create a zero voltage by dividing the total voltage of the direct current link in half. Circuits with voltage separation in the direct current circuit are widely used in electric drives with three-level energy converters, since in this case there is no need to connect the zero point of the direction to the load, and the main purpose of this electrical circuit is to obtain equal halves of the total voltage in the direct current circuit. This will lead to asymmetry of the output voltage, that is, to a decrease in its quality, the presence of significant constant components in alternating voltages, as well as to the flow of a significant current in the neutral conductor. In this regard, a three-dimensional space-vector pulse-width modulation method was proposed for controlling a four-arm inverter, which differs from the existing ones by the possibility of minimizing the components of negative and zero-sequence voltages in networks with distributed generation with parallel connection of three- and four-arm inverters . To develop approaches to control the inverters of such systems, it is necessary to obtain analytical dependencies that describe the flow of active and reactive power between inverters depending on the parameters of their generated output voltages.

УЗАГАЛЬНЕНИЙ ІДЕНТИФІКАТОР НАЯВНОСТІ СПОТВОРЕНЬ ЯКОСТІ ЕЛЕКТРИЧНОЇ ЕНЕРГІЇ

Development of measures to ensure the quality of electricity is possible only after assessing the actual state of electricity quality in all nodes of the electricity network. Therefore, the system of ensuring the required quality of electricity should be based on its monitoring system. An approach to building a real-time electricity quality monitoring system by developing a generalized identifier for the presence of electricity quality distortion regardless of its type is presented, time of occurrence and duration based on the construction of spatio-temporal distribution of the information signal and subsequent orthogonal analysis of frequency-temporal changes of its spectral components. This allows the creation of a system of real-time monitoring of electricity quality in contrast to existing methods, when using which the sequential processing of the measuring signal is carried out to determine certain indicators of the quality of electric energy, which makes it impossible to conduct it in real time. References 10, figures 2.

Electric Power Quality through Analysis and Experiment

The quality of electrical energy is of particular importance for power engineering. This study presents an analysis of articles made in the Special Issue “Analysis and Experiments for Electric Power Quality”. As techniques and technology advance, electrical consumers and equipment become more sensitive to disturbances in the electrical network (in particular, low- and medium-voltage). It can lead to costly outages and lost production, which affect productivity. The analyzed articles present interesting technical studies made on industrial and nonindustrial consumers, of low- and medium-voltage, from the point of view of the quality of electricity. Voltage and current harmonics, voltage sags and swells, interruptions, unbalance, and low power factor will lead to higher electricity bills, overloading, and rapid aging of electrical networks and electric equipment. The power quality depends not only on the supplier but also on all consumers connected to the same power network; some can cause disruptive influences in the supply network, affecting the operation of other consumers. Ensuring the power quality of industrial and nonindustrial applications is an objective difficult to achieve.

Wind turbine doubly-fed induction generator defects diagnosis under voltage dips

Voltage dips are brief but frequent disturbances that can be defined as the most important problem affecting all electrical grids, it cannot be completely avoided and represent the main priority for the industry. This study remains part of monitoring the quality of electrical energy’s field. Its aim is to apply two approaches signals for improving the failure recognition in wind turbine conversion chain. One is based on the combination of spectral analysis of stator current by fast Fourier transform and Lissajous curves technique of grid currents. The second approach is based on the stator current analysis by discrete wavelet transform which is considered an ideal tool for this purpose due to its time-frequency localization. These defects diagnosis methods have shown their efficiency in detection, visualization and analysis of voltage dips in order to develop a control strategy for a wind turbine requiring continuity of its service despite the presence of voltage dips.

ANALYSIS OF EXISTING APPROACHES AND METHODS OF DIAGNOSTICS OF ON-LOAD TAP CHANGER OF POWER TRANSFORMERS

In electrical networks of almost all voltage classes, the main link in the work on the transmission of electrical energy is a power transformer. At the moment, about 60% of them are operated in our country with a significant excess of service life, which increases the requirements for their technical control and diagnostics of all units. Switching devices are an integral part of power transformers. They are necessary to regulate voltage on substation busbars depending on the load of consumers. Not only the reliability of power supply of industrial enterprises, cities and agriculture, but also the quality of electrical energy depends on their operation. At the same time, they are one of the vulnerable nodes of voltage converters. Although the parameters of diagnostic signs for switching devices are not as extensive as the power transformer itself, they nevertheless require special attention from the operating personnel. This is due not only to the variety of switchgear types that exist, but also to the methods used to diagnose them. For this reason in this work an attempt has been made to analyze the existing approaches and methods of diagnosing these mechanical controlled voltage regulators. We propose a new approach in terms of diagnostics of high-voltage equipment, including power transformers – introdiagnostics. It is based on methods of non-destructive (without opening tanks and draining dielectric liquids) control of parameters that characterize the state of electrical equipment. We present an original method of diagnosing the on-load tap changer, based on oscillography and subsequent analysis of operation of the on-load tap changer contact system without draining transformer oil from the diverter switch’s tank.

Power Management and Power Quality System Applied in a Single-Phase Nanogrid

This work aims to present an electrical power management system, between a photovoltaic generation system and a battery energy storage system, by using a low-power dual-stage microinverter connected to the electrical distribution network, configuring a nanogrid. The presented system is capable of performing the active power injection of the photovoltaic arrangement, increasing the availability of electrical energy through a maximum power point tracking algorithm. The system is also able to manage the processes of the charge and discharge of the battery system, where the energy storage system will serve as grid support when renewable power is not available. Furthermore, to ensure the quality of electric energy the proposed microinverter also has the characteristic of parallel active filter for suppression of harmonic currents and reactive compensation of local load current, ensuring the quality of electric energy. As a result, this work presents the system topology, modeling and control of electronic converters, the management strategy with its modes of operation and the results of numerical validation of the proposed system.

Increasing the performance of the Far Eastern Railway traction power supply system

Introduction. The purpose of the study is to develop measures determined by the strategic programmes for the development of Russian railway transport based on the analysis of power supply schemes for the traction network of the Far Eastern Railway, a branch of Russian Railways.Materials and methods. Evaluation of the performance of the traction power supply system was made based on the analysis of the actual performance of the Far Eastern Railway section, as well as the theories of electrical engineering and power supply of the 25 kV AC electrified railway system.Results. Based on the analysis of the joint operation of the external and traction power supply systems of the Far Eastern Railway, four traction substations with low technical and economic indicators were identified. Network sections that feed the substations are a bottleneck in the traction power supply system. It is proposed to increase the efficiency by switching the connection of the windings of transformers of traction substations to the systems of external and traction power supply according to the typical star – delta scheme. Such a connection will ensure an increase in the speed of trains, a reduction in train succession time and losses of electricity, an increase in the quality of electric energy in the external power supply system and electric networks of the Far Eastern Directorate for Energy Supply (a structural subdivision of Transenergo, a branch of Russian Railways).Discussion and conclusion. Normalisation of the connection of four traction substations according to the feeding scheme is ensured by changing the phasing in such a way that the power supply of the two legs of one winding of the power transformer is transferred to two windings. Alignment of the current modules in the windings of transformers of traction substations makes it possible to reduce the voltage drop in the most loaded phase and, accordingly, increase the voltage in the traction network, which ensures an increase in the speed of trains and a reduction in passing intervals. Switching the power supply of the arms from one winding of the transformer to two reduces the loss of electrical energy in power transformers and the external power supply system. Reducing the current unbalance in the windings of the power transformer improves the quality of electrical energy in the system of external and district power supply. An increase in the service life of the power transformer is ensured by a decrease in the intensity of thermal wear of the insulation of the most loaded winding.

Thyristor AC Voltage Regulators to Improve the Quality of Electrical Energy in 0.4-kV Distribution Networks

Thyristor AC Voltage Regulators to Improve the Quality of Electrical Energy in 0.4-kV Distribution Networks

A Fuzzy-PSO-PID with UPFC-RFB Solution for an LFC of an Interlinked Hydro Power System

An LFC plays a vital part in passing on quality electric energy to energy consumers. Furthermore, with cutting-edge designs to move to modern and pollution-free energy generation, it may be conceivable to have a major hydropower in the future. Hydro plants are not suitable for continuous load alteration due to the large response time of hydroturbines. Hence, this paper shows a novel control design for an LFC of a hydro-hydro interlinked system based on joint actions of fuzzy logic with PID effectively optimized through particle swarm optimization (PSO) resulting in a Fuzzy-PSO-PID. The outcome of Fuzzy-PSO-PID is evaluated for step load variation in one of the regions of hydropower, and the outcomes of Fuzzy-PSO-PID are compared with a recently published LFC with respect to integral time absolute error (ITAE) value, values of PID, and graphical outcomes to show the impact of the proposed LFC action. The numerical results show that the ITAE value (0.002725) obtained through the proposed design is minimum in comparison to error values achieved through other LFC actions, and the pickup values obtained on these error values are considered to achieve the desired LFC. However, there is still scope for LFC enhancement as responses of hydropower are sluggish with higher oscillations; hence the UPFC and RFB are integrated into the interlinked hydro-hydro system, and the application outcomes are evaluated again considering the non-linearity, standard load alteration, random load pattern, and in view of parametric alterations. It is seen that the ITAE value reduces to 0.002471 from 0.002725 when UPFC is connected to the tie-line, and it further reduces to 0.001103 when a UPFC-RFB combination is used with Fuzzy-PSO-PID for a hydro leading system. The positive impact of the UPFC-RFB for hydropower is also seen from the application results.

Impact Analysis of a Battery Energy Storage System Connected in Parallel to a Wind Farm

Increasing wind generation insertion levels on electrical grids through power converters may cause instabilities in the AC grid due to the intermittent wind nature. Integrating a Battery Electric Energy Storage System (BESS) in wind generation can smooth the power injection at the Common Coupling Point (PCC), contributing to the power system voltage and frequency stability. In this article, it is proposed to analyze the operation of a lithium-ion battery technology based 1 MW/1.29 MWh BESS connected in parallel with wind generation with a capacity of 50.4 MW. The main characteristics investigated are power smoothing and power factor correction. Experimental results show that BESS contributes to smoothing the active power and correcting the power factor of wind generation, improving the quality of electrical energy at the PCC.

Electricity quality problems investigation in networks with a voltage of 0,4 kV

THE PURPOSE. Consider the issues of electricity quality in power supply systems and the results obtained by the authors of the article when monitoring the electrical energy quality in urban electrical networks with a voltage of 0.4 kV. The results of these measurements indicate that at some facilities there are violations of the electricity quality in almost all indicators. Therefore, to ensure proper quality, it is necessary to develop comprehensive measures to maintain power quality indicators within the established limits.METHODS. When solving the problem, methods of comparison and analysis of experimental data were used. RESULTS. We indicate the main problems which inevitably arise when the quality of electrical energy decreases. Present the causes of the electricity low quality. It is shown that in this case there is a violation of the various electrical receivers operation.CONCLUSION. We indicate that earlier investigations of the electrical energy quality mainly considered power supply systems and power receivers of industrial enterprises. We present the examples of poor electricity quality, including in the event of voltage fluctuations. Therefore, when developing measures to maintain the electricity quality within acceptable limits in urban electrical networks, monitoring of electricity quality indicators should be carried out. Only on the basis of its results it is necessary to develop a set of measures to improve the electricity quality. This approach is also expedient because the electricity consumers can potentially order monitoring of the electric energy quality to specialized organizations and, in case of non-compliance with the requirements of GOST 32144-2013, file lawsuits against power supply organizations about violations of the electricity quality with great chances of satisfying them.

Selection of circuit and technical solutions for improvement the quality of electricity in adaptive networks with traction AC power

THE PURPOSE. Analysis of existing circuit and technical solutions for improving the quality of electricity in networks with traction load and assessment of their compliance with new properties of the electric network when switching to an active adaptive platform. Determination of the features of the operation of electric networks with traction load during the transition to an active-adaptive platform. Review of existing technical means and circuit solutions for improving the quality of electricity in electric networks with traction load and their analysis for compliance with new properties of the electric network.METHODS. To solve the tasks set, a structural analysis of existing technical and circuit solutions was performed to improve the quality of electricity in electric networks with traction load.RESULTS. In this article, the systematization of the compliance of technical means with the solved problems in the field of electricity quality is carried out. The features of the operation of electric networks with traction load during the transition to an active-adaptive platform are determined. Modern technical means and circuit solutions corresponding to the new properties of the electrical network are revealed. A variant of combining technologies for a complex effect on the quality of electricity is proposed.CONCLUSION. When switching electric networks with traction load to an active adaptive platform in order to improve the quality of electricity, it is advisable to use technical means capable of providing PCE within acceptable limits in real time, depending on the operating modes of the power system and traction load. Such means include distributed generation, electric energy storage, active filter-compensating and balancing devices, FACTS technologies of the second generation. Classical approaches to solving problems with the quality of electrical energy based on the use of passive technical devices do not correspond to the new properties of active-adaptive networks with alternating current traction.