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 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.

Experimental Study of Contact Joint Characteristics in Electrical Equipment

2016 ◽  
Vol 870 ◽  
pp. 276-281 ◽  
Author(s):  
V.V. Goman ◽  
S.A. Fedoreev
Keyword(s):  
Experimental Study ◽  
Protective Coating ◽  
Laboratory Tests ◽  
Electrical Equipment ◽  
Power Industry ◽  
Light Alloy ◽  
Equipment Operation ◽  
Operation Conditions ◽  
Joint Characteristics ◽  
Electric Equipment

The paper describes the method and results of laboratory tests with several types of demountable contact joints and operation tests at functional power industry facilities. The contacts without protective coating are compared with contacts with the protective light-alloy-based coating applied according to the authors’ technology. It is demonstrated that the technology is applicable in real electric equipment operation conditions.

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 Model and Algorithm of Electricity Consumption Management for Household Consumers in the Republic of Tajikistan

2020 ◽  
Vol 7 (4) ◽  
pp. 520-526
Author(s):  
Saidjon Sheralievich Tavarov ◽  
Alexander Ivanovich Sidorov ◽  
Yulia Vladimirovna Kalegina
Keyword(s):  
Power Consumption ◽  
Control Algorithm ◽  
Electricity Consumption ◽  
Electrical Network ◽  
Forecasting Model ◽  
Operating Parameters ◽  
Electrical Networks ◽  
Factors Affecting ◽  
The Republic ◽  
And Control

The article is devoted to solving the problem of increasing the energy efficiency of urban electrical networks based on identifying factors affecting power consumption. According to the established patterns, a forecasting model has been developed, on the basis of which seasonal schedules of electricity consumption by household consumers are proposed. To monitor and control the operating parameters of the urban electrical network, taking into account the functionality of smart electricity meters, a control algorithm is proposed based on the proposed seasonal power consumption schedules by household consumers and a schematic implementation using smart electricity meters.

Study on Protection Configuration of Power Supply in 220kV Electric Railway Traction Substation

2014 ◽  
Vol 1070-1072 ◽  
pp. 1035-1038
Author(s):  
Xian Li ◽  
Jin Li Yu ◽  
Xin Ju Guo ◽  
Yu Bin Mao
Keyword(s):  
Power Supply ◽  
Power Grid ◽  
Cost Effective ◽  
Traction Substation ◽  
Railway Traction ◽  
Electric Railway ◽  
The Relationship

This article focuses on the characteristics of power supply protection in the Electric railway traction substation and the relationship among the protection configuration, the power grid stability and the security of the main transformer in the traction station. This article analyses the plan of the protection configuration which is safe, reliable, and cost-effective. Also proposes a simplified and optimized scheme.

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.

scholarly journals About Flexibility Problem of Distribution Electrical Network

2019 ◽  
Vol 217 ◽  
pp. 01014
Author(s):  
Ilia Shushpanov ◽  
Konstantin Suslov
Keyword(s):  
Control Systems ◽  
Relay Protection ◽  
Weather Conditions ◽  
Electrical Network ◽  
Operating Parameters ◽  
Electrical Networks ◽  
Information Communication ◽  
Emergency Control ◽  
Measuring Devices ◽  
Short Circuits

Global electricity companies have embarked on a transition to digital microprocessor devices. Digitalization penetrates every aspect of power industry, whether it is power generation, transmission or distribution. Being the most widespread, the distribution electrical networks are nevertheless the least digitalized. Some issues about them are still insufficiently studied. These are the collection of necessary information, adaptation methods, and the effect of the unrecognizability of some short circuits. This can be explained by improper placement of devices, which causes lack of data, which, in turn, leads to the failure of relay protection and emergency control systems of distribution electrical networks to provide selectivity. The paper proposes algorithms for placing measuring devices so that the information will be collected properly. Placement of the devices will allow adjusting the operating parameters of the relay protection and emergency control systems depending on changes in external weather conditions and load fluctuations in the network. We propose a technique for control of distribution network, taking into account the type of damage in case of emergency in real time, and a technique for placement of measuring devices and creation of an information communication network.

scholarly journals Optimal feeder reconfiguration in distributed generation environment under time-varying loading condition

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Yanrenthung Odyuo ◽  
Dipu Sarkar ◽  
Lilika Sumi
Keyword(s):  
Graph Theory ◽  
Distributed Generation ◽  
Spanning Tree ◽  
Voltage Stability ◽  
Electrical Network ◽  
List Type ◽  
Network Reconfiguration ◽  
Time Varying ◽  
Electrical Networks ◽  
Tree Algorithm

Abstract The development and planning of optimal network reconfiguration strategies for electrical networks is greatly improved with proper application of graph theory techniques. This paper investigates the application of Kruskal's maximal spanning tree algorithm in finding the optimal radial networks for different loading scenarios from an interconnected meshed electrical network integrated with distributed generation (DG). The work is done with an objective to assess the prowess of Kruskal's algorithm to compute, obtain or derive an optimal radial network (optimal maximal spanning tree) that gives improved voltage stability and highest loss minimization from among all the possible radial networks obtainable from the DG-integrated mesh network for different time-varying loading scenarios. The proposed technique has been demonstrated on a multiple test systems considering time-varying load levels to investigate the performance and effectiveness of the suggested method. For interconnected electrical networks with the presence of distributed generation, it was found that application of Kruskal's algorithm quickly computes optimal radial configurations that gives the least amount of power losses and better voltage stability even under varying load conditions. Article Highlights Investigated network reconfiguration strategies for electrical networks with the presence of Distributed Generation for time-varying loading conditions. Investigated the application of graph theory techniques in electrical networks for developing and planning reconfiguration strategies. Applied Kruskal’s maximal spanning tree algorithm to obtain the optimal radial electrical networks for different loading scenarios from DG-integrated meshed electrical network.

Study of the influence of overvoltage on the quality of electricity in energy systems.

2020 ◽  
Vol 23 (2) ◽  
pp. 52-58
Author(s):  
S. SKRYPNYK ◽  
Keyword(s):  
Power Supply ◽  
Fire Hazard ◽  
Lightning Discharge ◽  
Quality Standard ◽  
Normal Operation ◽  
Electrical Network ◽  
Modern World ◽  
Electrical Networks ◽  
The World

Our world with its high technologies has long been deeply dependent on the quality of electricity supply. In most countries of the world there are national power grids that combine the entire set of generating capacity and loads. This network provides the operation of household appliances, lighting, heating, refrigeration, air conditioning and transport, as well as the functioning of the state apparatus, industry, finance, trade, health services and utilities across the country. Without this utility, namely electricity, the modern world simply could not live at its current pace. Sophisticated technological improvements are firmly rooted in our lives and workplaces, and with the advent of e-commerce began the process of continuous transformation of the way individuals interact with the rest of the world. But with the achievement of intelligent technologies, an uninterrupted power supply is required, the parameters of which exactly meet the established standards. These standards maintain our energy security and create a reliable power system, that is maintaining the system in a trouble-free state. Overvoltage is the deviation of the rated voltage from the value of the corresponding quality standard (frequency, sinusoidal voltage and compliance of harmonics). Overvoltage in terms of fire hazard is one of the most dangerous emergency modes of electrical equipment, which causes conditions that in most cases are sufficient for the occurrence of fire hazards (exceeding the allowable voltage leads to disruption of normal operation or possible ignition). Against the background of deteriorating engineering systems, increased power consumption and poor maintenance, power supply of electrical installations, the main causes of overvoltage in electrical networks are thunderstorms (atmospheric overvoltage), switching switches, uneven phase load in electrical networks, etc. The physical picture of internal overvoltage is due to oscillatory transients from the initial to the established voltage distributions in the conductive sections due to the different situation in the electrical circuit. In the conditions of operation of electric networks planned, mode or emergency situations are possible. Therefore, the ranges of overvoltage are determined by the range from several hundred volts to tens and hundreds of kilovolts, and depend on the types of overvoltage. Atmospheric overvoltage is considered to be one of the most dangerous types of emergency modes of operation of the electrical network. This overvoltage occurs as a result of lightning discharge during precipitation by concentrating electricity on the surface of the object, the introduction of potential through engineering networks and

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