scholarly journals Nonlinear load modeling for analysis of non-sinusoidal conditions in electrical networks based on measurements of harmonic parameters

2021 ◽  
pp. 5-20
Author(s):  
L. Kovernikova ◽  
V.C. Luong
Keyword(s):  
Electrical Equipment ◽  
Distribution Functions ◽  
Operating Conditions ◽  
Electrical Network ◽  
Electrical Networks ◽  
Nonlinear Loads ◽  
Nonlinear Load ◽  
Current Harmonics ◽  
Load Models ◽  
Nonlinear Devices

Non-sinusoidal conditions in electrical networks need to be calculated for their control and development of technical measures to maintain harmonic parameters according to the requirements of regulatory documents. These calculations are impossible without electrical network and nonlinear load models that adequately reflect them in computational programs. Nonlinear load models have been developed for a long time. Some studies present general modeling principles and models of various nonlinear devices. Others consider some nonlinear devices as equivalent nonlinear loads connected to low and medium voltage networks. A whole host of high-power nonlinear electrical equipment is connected to high voltage networks. Modeling nonlinear loads connected to these networks is a problem. Research of measured parameters of harmonic conditions in electrical networks has shown that they are random values. The probabilistic nature is determined by the network configuration, a range of network components, the number of nonlinear loads, wave and frequency properties of the network, harmonic source phase currents, voltage at terminals of nonlinear electrical equipment, changes in operating conditions and load power, and many other factors. Nonlinear loads can only be modeled based on the measurements of parameters of harmonic conditions due to their unpredictability. The paper presents an overview of existing methods for modeling nonlinear loads, a methodological approach to modeling nonlinear loads based on measured parameters, an algorithm for modeling harmonics of active and reactive currents, a computational program algorithm designed to identify distribution functions of measured current harmonics, and modeling results for current harmonics of railway transformers supplying power to electric locomotives.

scholarly journals Predicting the influence of the non-sinusoidal network mode on power transformers

2019 ◽  
Vol 114 ◽  
pp. 04005
Author(s):  
Ngo Van Cuong ◽  
Lidiia I. Kovernikova
Keyword(s):  
Service Life ◽  
Electric Power ◽  
Power Quality ◽  
Electrical Equipment ◽  
Operating Conditions ◽  
Transformer Oil ◽  
Power Transformers ◽  
Electrical Network ◽  
Electrical Networks ◽  
Current Harmonics

The parameters of electrical network modes often do not meet the requirements of Russian GOST 32144-2013 and the guidelines of Vietnam. In the actual operating conditions while there is the non-sinusoidal mode in electrical networks voltage and current harmonics are present. Harmonics result in overheating and damage of power transformers since they cause additional active power losses. Additional losses lead to the additional heat release, accelerating the process of insulating paper, transformer oil and magnetic structure deterioration consequently shortening the service life of a power transformer. In this regard there arises a need to develop certain scientific methods that would help demonstrate that low power quality, for instance could lead to a decrease in the electrical equipment service life. Currently we see a development of automated systems for continuous monitoring of power quality indices and mode parameters of electrical networks. These systems could be supplemented by characteristics calculating programs that give out a warning upon detection of the adverse influence of voltage and current harmonics on various electrical equipment of both electric power providers and electric power consumers. A software program presented in the article may be used to predict the influence of voltage and current harmonics on power transformers.

scholarly journals Selection of C-Type Filters for Reactive Power Compensation and Filtration of Higher Harmonics Injected into the Transmission System by Arc Furnaces

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2330
Author(s):  
Andrzej Grzegorz Lange ◽  
Grzegorz Redlarski
Keyword(s):  
Reactive Power ◽  
Second Harmonic ◽  
Transmission System ◽  
Operating Conditions ◽  
Arc Furnace ◽  
Steel Mill ◽  
Nonlinear Loads ◽  
Higher Harmonics ◽  
Current Harmonics ◽  
Arc Furnaces

This article presents a method for selecting the elements of a C-type filter working with a conventional LC-type filter for compensating reactive power and filtering out higher harmonics generated by arc furnaces and ladle furnaces. The study was conducted in a steel mill supplied by a 110 kV transmission system, where higher harmonic currents and nonlinear loads were measured. A series of computer simulations were performed under various operating conditions, and an algorithm for selecting the parameters of a third-order C-type filter (for suppressing the second harmonic) and two second-order LC-type filters (for suppressing the third harmonic) was proposed. The filtering system was tested in an arc furnace with the highest rated power, and harmonics in the current spectrum were evaluated. The results of the measurements were used to analyze the effectiveness of the compensation system comprising two passive C-type and LC-type filters at different system configurations. C-type filters significantly influenced current harmonics. The influence of the changes in the number of arc furnace transformers on the true Root Mean Square (RMS) of the currents injected into the 110 kV transmission system and on the voltages of the 110 kV busbars was discussed.

scholarly journals Evaluation of the Influence of Non-sinusoidal Conditions on Power Transformers

2018 ◽  
Vol 58 ◽  
pp. 03012
Author(s):  
Lidiia Kovernikova ◽  
Ngo Van Cuong
Keyword(s):  
Cost Effective ◽  
Electrical Equipment ◽  
Power Transformers ◽  
Electrical Network ◽  
Operating Parameters ◽  
Electrical Networks ◽  
Equipment Operation ◽  
Traction Substation ◽  
Operation Conditions ◽  
Railway Traction

The electrical equipment operation is cost-effective and reliable when operating parameters of the electrical network correspond to the rated data of the equipment. The real operation conditions, however, differ from those required for electrical equipment, which negatively affects its efficiency. The non-sinusoidal conditions in electrical networks are currently very common. The paper provides an overview of the characteristics obtained from an analysis of publications, which are used to evaluate the effect of the non-sinusoidal conditions on power transformers. The results of the calculation of these characteristics for a transformer installed at a railway traction substation are presented. Parameters of the non-sinusoidal conditions are obtained as a result of measurements.

scholarly journals Procedure to Evaluate the Impact in Distribution Single Phase Transformers, Due to Massive Insertion of New Nonlinear Load, Which Changes Daily Demand Graphs

2019 ◽  
Author(s):  
Jorge Enrique Carrión González ◽  
Antonio Martínez García ◽  
Alfredo del Castillo Serpa ◽  
Marianela Carrión González ◽  
Rodolfo Pabel Merino ◽  
...  
Keyword(s):  
Power Systems ◽  
Single Phase ◽  
Phase Distribution ◽  
Nonlinear Load ◽  
Current Harmonics ◽  
Distribution Transformers ◽  
New Type ◽  
Nonlinear Devices ◽  
The Impact ◽  
Transmission And Distribution

Power Electronic development determines introduction of nonlinear devices in Electric Power Systems. Introduction of nonlinear devices increase current harmonics in Transmission and Distribution Power Systems. Distribution transformers and feeders increase power losses and their nominal parameters are reduced. Present work introduces a procedure to evaluate maximum permissible load in single phase distribution transformers with massive introduction of a new type of nonlinear load which changes daily demand graphs.

scholarly journals Current Harmonics Reduction In Microgrids Using Dual Interfacing Converters

2021 ◽  
Vol 12 (2) ◽  
pp. 1647-1654
Author(s):  
Venkatesh E , Et. al.
Keyword(s):  
Distributed Generation ◽  
Low Voltage ◽  
Supply Voltage ◽  
Control Technique ◽  
Test Results ◽  
Nonlinear Loads ◽  
Nonlinear Load ◽  
Current Harmonics ◽  
The Matrix ◽  
Over The Top

The Growing Installation of Distributed Generation (DG) units in low voltage conveyance frameworks has promoted the idea of nonlinear load symphonious current remuneration utilizing multi-utilitarian DG interfacing converters. In appropriation frameworks, the load has been an unexpected increment or diminishes and it resembles as nonlinear loads so the load draw non-sinusoidal flows from the AC mains and causes the load sounds and responsive power, and over the top impartial flows that give contamination in power frameworks. It is investigated in this paper that the pay of neighborhood load symphonious current utilizing a solitary DG interfacing converter may make the intensification of supply voltage sounds touchy loads, especially when the primary framework voltage is profoundly twisted. To address this impediment, in contrast to the activity of customary unified power quality conditioners (UPQC) with arrangement converter, another concurrent stock voltage and matrix current symphonious pay technique is proposed utilizing composed control of two shunt interfacing converters. Through the presentation of staggered control destinations, it is delineated that the proposed framework could ride through voltage unsettling influences and proceed with the power move between the nearby generation and the matrix, while an excellent voltage is kept up for the neighborhood loads. By utilizing this proposed regulator, the lattice voltage stage bolted circle and the identification of the load current and the stockpile voltage music are superfluous for both interfacing converters. In this manner, the computational load of interfacing converters can be fundamentally decreased. Mimicked and test results are caught to approve the exhibition of the proposed geography and the control technique.

scholarly journals Analysis of the influence of non-sinusoidal and unbalanced network modes on induction motors

2021 ◽  
Vol 289 ◽  
pp. 01002
Author(s):  
Ngo Van Cuong ◽  
Lidiia I. Kovernikova
Keyword(s):  
Power Systems ◽  
Power Quality ◽  
Induction Motors ◽  
Electrical Power ◽  
Electrical Energy ◽  
Operating Conditions ◽  
Premature Aging ◽  
Electrical Network ◽  
Electrical Networks ◽  
Electrical Power Systems

The parameters of electrical network modes do not correspond the requirements GOST 32144-2013 of Russian and the National technical regulation of Vietnam. In real operating conditions in electrical networks in non-sinusoidal and unbalanced modes there are harmonic components of voltages and currents as well as voltages and currents of negative sequence. They cause additional losses of active power, which leads to additional heating and causes premature aging of the insulation, and as the result, the reduction in the service life of induction motors. Currently, we see that the process of formation of intelligent electrical power systems is underway. Systems for continuous monitoring of power quality indices and parameters of electrical systems modes are being developed. These systems can be supplemented with programs for calculating characteristics that issue the warning when the unfavorable influence of the parameters of non-sinusoidal and unbalanced modes is detected on various electrical equipment of both electrical power systems and consumers of electrical energy. The paper provides an overview of the characteristics used to analyze, assess and predict the influence of poor power quality associated with non-sinusoidal and unbalanced of currents and voltages on induction motors. A computer program was developed to calculate these characteristics. The program was used to study the influence of non-sinusoidal and unbalanced modes on the induction motors of the coal sorting plant of the Vietnamese company “Cua Ong-Vinacomin”.

ELECTROMAGNETIC COMPATIBILITY OF LOW-POWER AUTONOMOUS POWER SUPPLY EQUIPMENT

2020 ◽  
Author(s):  
V.N. Delyagin ◽  
◽  
V.I. Bocharov ◽  
Keyword(s):  
Low Power ◽  
Power Supply ◽  
Electromagnetic Compatibility ◽  
Autonomous Systems ◽  
Electric Energy ◽  
Electrical Energy ◽  
Electrical Equipment ◽  
Electrical Network ◽  
Nonlinear Load ◽  
Harmonic Components

The article presents the results of research on the evaluation of electromagnetic compatibility of elements of the power supply system for Autonomous low-power consumers. The subject of the study is a quantitative assessment of the level of harmonic components of currents and voltages in systems: a permanent magnet generator-a DC-to-AC Converter-a consumer with a nonlinear load and interfering interaction of jointly working elements of this system. The level of harmonics of voltage and current in the local electrical network (farm), repeatedly (from 3 to 10 times) exceeds the regulatory requirements. The multiplicity of the increase in electrical energy losses (K-Factor) is from 5("pure" sine of the DC-AC Converter) to 20 (rectangular meander). When designing Autonomous systems, it is necessary to provide measures to reduce the loss of electrical energy, exit from standing electrical equipment and false triggering of electronic devices in the consumer of electric energy

scholarly journals Analysis of Internal Overvoltages in Transformer Windings during Transients in Electrical Networks

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2644 ◽  
Author(s):  
Jakub Furgał ◽  
Maciej Kuniewski ◽  
Piotr Pająk
Keyword(s):  
Power Systems ◽  
Electromagnetic Waves ◽  
Power Transformer ◽  
Electrical Power ◽  
Operating Conditions ◽  
Electromagnetic Transients ◽  
Electrical Network ◽  
Electrical Networks ◽  
Insulation Systems ◽  
The Impact

Due to the increasing requirements for the reliability of electrical power supply and associated apparatus, it is necessary to provide a detailed analysis of the overvoltage risk of power transformer insulation systems and equipment connected to their terminals. Exposure of transformer windings to overvoltages is the result of the propagation condition of electromagnetic waves in electrical networks and transformer windings. An analysis of transformer winding responses to transients in power systems is of particular importance, especially when protection against surges by typical overvoltage protection systems is applied. The analysis of internal overvoltages in transformers during a typical transient related to switching operations and selected failures is of great importance, particularly to assess the overvoltage exposure of insulation systems in operating conditions. The random nature of overvoltage phenomena in electrical networks implies the usage of computer simulations for the analysis of overvoltage exposures of electrical devices in operation. This article presents the analysis of the impact of transient phenomena in a model of a medium-voltage electrical network during switching operations and ground faults on overvoltages in the internal insulation systems of transformer windings. The basis of the analysis is simulations of overvoltages in the windings, made in the Electromagnetic Transients Program/Alternative Transients Program (EMTP/ATP) using a model with lumped parameters of transformer windings. The analysis covers the impact of the cable line length and the ground fault resistance value on internal overvoltage distributions.

Application of the Superposition Method for Fault Location in Medium Voltage Networks

2021 ◽  
pp. 38-44
Author(s):  
Aleksandr L. KULIKOV ◽  
◽  
Vladislav Yu. OSOKIN ◽  
Dmitriy I. BEZDUSHNYY ◽  
Anton A. LOSKUTOV ◽  
...  
Keyword(s):  
Fault Location ◽  
Operating Conditions ◽  
Electrical Network ◽  
Superposition Method ◽  
Electrical Networks ◽  
Medium Voltage ◽  
Arbitrary Configuration ◽  
Time Expenditures ◽  
Technical Solutions ◽  
High Degree

Medium-voltage networks are characterized by a long length and high degree of wear. Isolation of a failed network section requires significant time expenditures, a circumstance that makes accurate and fast determination of the fault location a topical problem. In view of specific features of emergency modes in medium voltage networks, the development of precise algorithms for fault location in the case of single and double ground faults involves certain difficulties. The arbitrary configuration of electrical networks, specific neutral grounding conditions, and lack of the possibility to perform multilateral measurements of emergency parameters complicate the development of universal fault location algorithms. In addition, technical solutions are as a rule limited by the need of using one-sided measurements of emergency mode parameters. The considered algorithms for calculating the distance to the fault location involve the use of emergency and normal electric network mode parameters. The proposed algorithms are based on using the superposition method and do not depend on the electrical network topology; they make it possible to decrease the influence of the current distribution pattern in lines with branches, as well as the influence of the load operating conditions on the accuracy of calculating the distance to fault location. The application of the proposed algorithms is justified by the results of simulation and makes it possible to calculate the distance to the fault location in networks with insulated neutral with high accuracy.

scholarly journals Research of higher harmonic components of voltage and current and their influence on the functioning of shipboard electrical equipment

2021 ◽  
pp. 34-43
Author(s):  
В.Ф. Белей ◽  
Г.А. Решетников ◽  
К.В. Коротких
Keyword(s):  
Experimental Studies ◽  
Electrical Energy ◽  
Electrical Equipment ◽  
Electrical Network ◽  
Electric Motors ◽  
Electrical Networks ◽  
Higher Harmonic ◽  
Harmonic Components ◽  
Quality Of Electrical Energy ◽  
Asynchronous Electric Motors

Одним из направлений научно-технического прогресса на объектах морской индустрии является широкое использование технологий, основанных на нелинейных элементах, что позволяет значительно снизить их массогабаритные показатели и расшить их функциональные возможности. Однако применение таких технологий приводит к ухудшению качества электрической энергии, в первую очередь за счет высших гармонических составляющих напряжения и тока. В статье показана природа высших гармонических, выполнен анализ разделов «Правил классификации и постройки морских судов. 2021», российских и ряда зарубежных стандартов в области качества электроэнергии, регламентирующих уровень высших гармонических составляющих напряжения и тока в электрических сетях и системах. В работе приведены результаты теоретических и экспериментальных исследований влияния высших гармонических составляющих на функционирование судового электрооборудования: асинхронных электродвигателей, силовых кабелей, трансформаторов, конденсаторных батарей и систем освещения. Определены выражения, позволяющие оценить это влияние. Показано, что в основном это влияние проявляется: в дополнительном нагреве электрооборудования за счет поверхностного эффекта; вибрации асинхронных электродвигателей при высоких значениях 5 и 7 гармоник напряжения судовой электрической сети. One of the areas of scientific and technological progress at the facilities of the marine industry is the widespread use of technologies based on nonlinear elements, which can significantly reduce their weight-size parameters and dimensions and expand their functional capabilities. However, the use of such technologies leads to a deterioration in the quality of electrical energy, primarily due to higher harmonic components of voltage and current. The article shows the nature of higher harmonics, analyzes the sections of the «Rules for the Classification and Construction of Sea-Going Vessels. 2021», Russian and a number of foreign standards in the field of electric power quality, regulating the level of higher harmonic components of voltage and current in electrical networks and systems. The paper presents the results of theoretical and experimental studies of the influence of higher harmonic components on the functioning of shipboard electrical equipment: asynchronous electric motors, power cables, transformers, capacitor banks and lighting systems. Formulas have been determined to assess this effect. It is shown that the influence is mainly manifested: in additional heating of electrical equipment due to the skin effect; vibrations of asynchronous electric motors at high values of 5th and 7th voltage harmonics of the ship's electrical network.

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