scholarly journals Influence of Harmonics on the Working Efficiency of a 6/1.2 kV Transformer in a Pit Mine

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Xuan Cuong NGO ◽  
Nhu Y DO
Keyword(s):  
Power Supply ◽  
Underground Mining ◽  
Electrical Equipment ◽  
Underground Mine ◽  
Electrical Networks ◽  
Electric Networks ◽  
Design Specifications ◽  
Sinusoidal Currents ◽  
Working Efficiency ◽  
A Current

Explosion-proof transformers 6/1.2 kV is important electrical equipment responsible forsupplying electricity in underground mine electrical networks. A failure of this transformer will cause aninterruption in the power supply and loss of safety in underground mining. Usually, explosion-prooftransformers in underground mine electrical networks are designed and manufactured to work with idealparameters such as sinusoidal currents, and the network structure is symmetrical. However, today inunderground mine electric networks, many power electronics are connected to the network, such asinverters and soft starters. As a result, a current flowing through the transformer is non-sinusoidal,overloading the transformer even by working with the design specifications. This paper studies theinfluence of harmonics on the working efficiency of a 6/1.2 kV transformer in a pit mine. Research resultssuggest reasonable solutions for transformer operation to ensure longevity and not cause damage to thetransformer.

scholarly journals ELECTRIC SUPPLY OF UNDERGROUND CONSUMERS OF DEEP ENERGY-INTENSIVE MINES

2018 ◽  
pp. 25-46
Author(s):  
F. P. Shkrabets
Keyword(s):  
Power Supply ◽  
Supply Voltage ◽  
Maximum Load ◽  
Electrical Equipment ◽  
Transport Systems ◽  
Local Power ◽  
Electrical Networks ◽  
Electric Networks ◽  
Supply Networks ◽  
Technical And Economic Indicators

The increase in the capacity of cleaning and construction vehicles for highcapacity and energy-intensive mines calls for an increase in the  supply voltage of cleaning and tunneling combines, as well as  transport systems: from a voltage of 660 V switched to 1140 V, and  now to 3300 V. This allows improving technical and economic  indicators for clearing and access areas, as well as improving the reliability of local Power Supply Systems (PSS). However, this  trend prevents the supply of underground electric networks with a  voltage of 6 kV, in connection with which the problem arises of  increasing the voltage of supply networks. To date, it has become  possible to apply the 10 kV voltage to the operation, which is most  acceptable for the use of electrical equipment for electrical networks  and protection devices. Leading educational, research and design  organizations were engaged in research on this issue. An analysis of the results of the research showed that switching to 10 kV voltage is  justified and timely. At the same time, 35 kV voltage is not removed  from the agenda, which is technically feasible and economically  justified, but there are problems with the safety of its operation in  underground workings, which requires appropriate refinement. This  level of voltage will improve the quality of electricity.Conclusions: 1. Application of 35 kV voltage in the underground power supply system of coal and ore mines is advisable at a depth of more than 1000 m with a maximum load of at least 1000 kVA at the  level of the stem cables.2. Application of 35 kV voltage in underground electrical networks will allow to significantly improve the quality indicators of voltage,  reliability, and economy of the system due to the current unloading  of the most important element of SES, such as stem cables.3. Analysis of the main parameters and characteristics of electrical mine electrical equipment gives reason to believe that it allows  implementing a trend of 35 kV deep input to deep horizons of mines  (mines) and placement of 35/6 kV substations on working horizons.

scholarly journals Method for determining the maximum load of consumers in city power supply systems

2019 ◽  
Vol 139 ◽  
pp. 01078 ◽  
Author(s):  
A.G. Saidkhodjaev ◽  
A.M. Najimova ◽  
A.K. Bijanov
Keyword(s):  
Power Supply ◽  
Maximum Load ◽  
High Accuracy ◽  
New Method ◽  
Electrical Networks ◽  
Electric Networks ◽  
Reliable Determination ◽  
Supply Systems

In this article, we propose a new method for determining the maximum load of electric consumers in urban electric networks, which differs from existing methods in more accurate and reliable determination of the maximum loads. Based on the determination of the maximum loads of the objects of urban electrical networks, it is concluded that the proposed methods are determined by high accuracy and minor errors.

scholarly journals Substantiation of the choice of the replacement scheme of line for mathematical modeling of 20 kV power supplies.

2021 ◽  
Vol 24 (1) ◽  
pp. 69-72
Author(s):  
SKRYPNYK S. ◽  
Keyword(s):  
Power Systems ◽  
Transmission Lines ◽  
Power Supply ◽  
Electrical Equipment ◽  
Distribution Networks ◽  
Power Line ◽  
Power Lines ◽  
Electrical Networks ◽  
Overhead Lines ◽  
Replacement Scheme

In the current global economic crisis and acute shortage of energy resources, increasing importance is attached to energy saving measures, economical and careful consumption of raw materials, materials, electricity and heat, environmental safety of industrial production. During the reconstruction of existing power supply systems of industrial enterprises, modern progressive solutions should be considered and implemented, morally and physically obsolete electrical equipment should be replaced, namely the introduction of new electrical equipment for transition from 6/10 kV to 20 kV in Ukrainian power systems. It is also necessary to pay attention to the improvement of power supply circuits and distribution networks, the implementation of complex automation of complex technological processes, rational compensation of reactive power at all levels of power supply systems. In the power system, the main transport link is the power line. Power lines (transmission lines) are long conductors suspended at a safe distance from the ground overhead lines (overhead lines) or cable lines (overhead lines) in which conductors are insulated from each other and from the environment and protected by insulation and armor electricity. Power lines are the most massive elements of the power supply system, they connect the individual nodes of its circuit. Longitudinal and transverse parameters are distinguished in alternative schemes. The load current flows through the longitudinal parameters, voltage is applied to the transverse ones. The replacement circuit of the electrical network consists of replacement circuits of the following elements: power lines, transformers, reactors, capacitors, loads, power sources. Calculating the steady-state modes of power systems, the substitution schemes of the elements are given in a single-line design, because the parameters of all phases are symmetrical. In local and local electrical networks with a relatively short length and low rated voltage, the conduction currents are small compared to load currents. Therefore, in typical electrical calculations of these networks, the capacitive conductivity of the lines is not taken into account. However, for these networks, the accounting of capacitive conductivities is necessary when considering some modes, the existence of which in itself is due only to the presence of capacitive conductivities. For example, the mode of single-phase ground fault in a network with isolated or compensated neutral or analysis of the modes of operation of neutrals of electrical networks of different voltage classes cannot be performed without taking into account the capacitive conductivity of these networks. When switching the power system of Ukraine to the nominal voltage of 20 kV, it should be taken into account that the transmission line will be replaced in the sections of both the overhead power line and cable power line, namely 35, 10, 6 kV. The replacement scheme must describe all the characteristics and properties of the elements of cable and overhead lines in accordance with real conditions. Thus, it is not expedient to use simplified substitution circuits that neglect energy parameters and properties of conductors to study the parameters of transmission lines. The use of a complete "P" -shaped scheme for the analysis of the parameters of transmission lines and transmission lines for a voltage of 20 kV is the basis of mathematical modeling of the transmission system in the distribution networks of our country.

scholarly journals Methodology for managing equipment repairs in oilfield electrical networks

2020 ◽  
pp. 139-155
Author(s):  
Vladimir Levin ◽  
◽  
Nikolay Guzhov ◽  
Natalya Chernenko ◽  
Ammar Yahya ◽  
...  
Keyword(s):  
Power Supply ◽  
Risk Function ◽  
Electrical Equipment ◽  
Distribution Networks ◽  
Condition Index ◽  
Technical Condition ◽  
Technical Diagnostics ◽  
Electrical Networks ◽  
Destructive Testing ◽  
Risk Event

An innovative methodology for managing repairs in distribution networks and power supply systems for oilfield facilities is proposed in this paper. The methodology makes it possible to select optimal solutions in accordance with the priority management goal by formalizing a risk-based model for planning maintenance and repair (M&R) of electrical equipment with a "condition-based maintenance" strategy. One of the main options in the complex of M&R management tasks is an adaptive model of the technological map for the repairs of power facilities, formed in compliance with a number of key principles. The developed model allows you to optimize the volume and complexity of repairs of electrical equipment of a certain type based on the minimum composition of technological operations necessary to eliminate the identified defects. Detection of defects in electrical equipment is achieved by using methods of technical diagnostics and non-destructive testing. In this case, each of the defects is recorded in the defect statement for the object, with the determination of the degree of criticality and fixing a specific type of corrective action. Optimal prioritization of electrical equipment repairs is performed in accordance with the minimum risk function under current restrictions on reliability (an equipment technical condition index) and available resources (total maintenance costs). The originality of the implementation of a key risk event – a power supply failure of an oilfield facility provides calculating the probability and severity of the consequences of an electrical equipment failure taking into account its technical condition and features of the power supply scheme. The given example illustrates the effectiveness of the proposed approach and emphasizes the validity of optimal decisions. The key components of the developed methodology have found practical application in the conditions of real operation of the equipment of oilfield facilities.

scholarly journals Analysis of the Causes of Emergency Shutdowns on Electric Networks

2021 ◽  
Vol 2096 (1) ◽  
pp. 012130
Author(s):  
M N Polkovskaya ◽  
M A Yakupova
Keyword(s):  
Power Supply ◽  
Negative Impact ◽  
Climatic Factors ◽  
External Factors ◽  
Economic Losses ◽  
Equipment Failure ◽  
Electrical Networks ◽  
Electric Networks ◽  
Overhead Lines ◽  
Equipment Failures

Abstract The paper analyses the causes of emergency outages on electric networks according to the data of the Pravoberezhny district of Irkutsk for 2008-2017, according to which 82% of failures of elements of the electric network are caused by breakdowns and equipment failure; 9% are due to the influence of external factors; 5% occurred due to natural and climatic reasons, 4% – due to other circumstances. The largest number of outages due to operational reasons occurs due to damage to cable and overhead lines. Accidents caused by the influence of external factors are mainly associated with the negative impact of people, animals and birds. Equipment failures related to natural and climatic factors are mainly due to wind or thunderstorms. Other circumstances, as a rule, include staff errors and unidentified reasons. Calculations of undersupply of electricity and economic losses caused by interruptions in power supply were made. It should be noted that in order to reduce the number of equipment failures, it is necessary to carry out timely maintenance and reconstruction of various elements of electrical networks.

scholarly journals RATIONALE FOR THE REASONABILITY OF REPLACING ELECTRICAL EQUIPMENT IN SUBSTATIONS 110/35/10

2020 ◽  
Author(s):  
Ya. Ovsepian
Keyword(s):  
Cost Effectiveness ◽  
Power Supply ◽  
System Performance ◽  
Electrical Equipment ◽  
Electricity Supply ◽  
Extreme Conditions ◽  
Electrical Networks ◽  
Effectiveness Analysis ◽  
Electricity Power

To ensure the reliability and quality of the electricity supply, the utilities are required to renovate the substations, in a part of the replacement of electrical equipment. This largely determines the investment of big amounts of capital in the object, which is designed. The reliability of the power supply is ensured by suitable electrical appliances, in according to electricity power in usual and extreme conditions. Installation of electrical networks leads to higher material losses. Therefore, a detailed cost-effectiveness analysis and system performance of all electricity supplies should be checked and made during the design.

On damage rate of overhead power transmission lines in power supply systems

2021 ◽  
Vol 14 (2) ◽  
pp. 92-99
Author(s):  
I. V. Naumov ◽  
D. N. Karamov
Keyword(s):  
Transmission Lines ◽  
Power Supply ◽  
Power Transmission ◽  
Distribution Networks ◽  
Power Transmission Lines ◽  
Electrical Networks ◽  
Electric Networks ◽  
Operating Personnel ◽  
Damage Rate ◽  
Overhead Power Transmission Lines

The purpose of the article is to analyze the damage rate of overhead power transmission lines (OPL) in medium-voltage electrical distribution networks of the Irkutsk region. The established International Indices that determine the level of reliability of the functioning of electric networks are considered, and information on the compliance of the condition of electric networks in Russia with these indices is analyzed. Analytical information on the damage rate of elements of these networks and their causes in Europe, America, and Russia is presented. The emphasis is placed on the fact that the most common damage is characteristic of overhead power lines, especially 6–10 kV lines. As an object of research, two branches of the Irkutsk electric grid company (IEC) were taken, one of which provides electricity to rural consumers, the other — mainly to consumers residing in the territory of the city Irkutsk. The characteristics of these electric networks, their territorial location and basic technical data are presented. To conduct analytical monitoring of the level of reliability of overhead power transmission lines, logs of disconnection of the Eastern and Southern electric networks of the IEC over a long-term period were used. On the basis of this information, tables of failures and their consequences in the studied electrical networks were compiled for monthly average data over the period under examination for various causes of damage. To plot time diagrams of the parameters under examination, computer programs were compiled in the Matlab system, the use of which made it possible to obtain visualization of changes in failures for various reasons for the electrical networks under consideration. The information on the time of power supply interruptions in these networks, as well as the amount of electricity underutilized by consumers during these interruptions and its cost are analyzed. It is shown that in the electric networks under consideration, most of the power failures are related to the territorial dispersion of these networks, and the low level of equipment controls and insufficient qualification of operating personnel, as evidenced by the significant number of failures for unknown reasons. Besides, a significant part of the failures is due to damage to the overhead line wires, switching equipment and the effect of wind load. Recommendations for improving the condition of power transmission lines and a number of measures aimed at improving the level of reliability of power supply are presented.

scholarly journals DEVELOPMENT PROSPECTS OF EXTERNAL POWER SUPPLY ELECTRICAL NETWORKS OF TRACTION SUBSTATIONS

2020 ◽  
Vol 1 (154) ◽  
pp. 8-15
Author(s):  
I. Domanskyi ◽  
О. Kozlova
Keyword(s):  
Power Supply ◽  
Electrical Equipment ◽  
Energy Losses ◽  
Electric Transport ◽  
Electrical Networks ◽  
Traction Substations ◽  
External Power ◽  
Traction Power Supply ◽  
Traction Power ◽  
External Power Supply

In the paper on the basis of the analysis of classical power schemes traction substations of railways and urban electric transport conceptual directions of development of electric networks of external power supply of traction substations in the conditions of market economy and normative requirements of the electric power industry of Ukraine are developed, which allow to provide energy saving modes of their operation. Based on system analysis of domestic and foreign traction power supply systems of railways and electric transport of large cities, the concept of their development is substantiated and proposed by increasing the supply voltage of traction substations and minimizing capacity upflows and energy losses, which provides resource and energy savings. It is suggested that the investment programs of the structures that are part of Corporation «Ukrzaliznytsia» and the municipal services be synchronized according to their technological indicators, as well as according to the criteria of energy efficiency and quality of energy supply with similar investment programs of external energy. For reduction of energy losses, it is proposed: realization of rational schedule of train movement and deep high voltage inputs with the prospect of transition to own 110 kV distribution networks, modernization and equipping of modern rolling stock electrical equipment and infrastructure of the main and perspective directions of the railways. The need to expand tram and trolleybus lines and modernize power supply devices in terms of resource conservation requires new technologies for the design, construction and operation of the facilities of municipal enterprise «Miskelektrotransservice». Such technologies have been implemented by the «DAK-Energetika» enterprise in the manufacture of modern electrical equipment of municipal enterprise «Miskelektrotransservice» TS. The most important tasks are the improvement of stationary and mobile substations and other linear facilities of traction power supply by completing functional modular blocks with modern switchgear with digital relay protection and diagnostics of traction networks; local and remote control of switchgear devices, as well as switch diagnostics and self-diagnosis. Keywords: external power supply, traction substations, electrical networks, power systems operation modes.

Application of the 20 kV Voltage Class in the Electric Power Supply Systems of Modern Megalopolises

Vestnik MEI ◽  
2020 ◽  
Vol 5 (5) ◽  
pp. 83-88
Author(s):  
Mikhail Yu. Lvov ◽  
◽  
Dmitriy Yu. Kamnev ◽  
Keyword(s):  
Power Supply ◽  
Electricity Consumption ◽  
Technical Condition ◽  
Electrical Networks ◽  
Electric Networks ◽  
Electric Power Supply ◽  
Limited Bandwidth ◽  
Electrical Loads ◽  
Cable Lines ◽  
High Level

Megacities are characterized by a high level of energy consumption, a significant density of electrical loads and increased requirements for the reliability of power supply to consumers. Traditionally in the USSR and further in Russia, voltage classes of 6 and 10 kV are used for urban distribution electric networks. The increasing density of electric load and electricity consumption does not allow in extremely cramped conditions of developing cities to provide electricity through existing cable lines with a voltage of 6-10 kV due to their limited bandwidth and lack of reliability. The technical condition of the equipment and cable lines in the 6-10 kV supply networks has significant physical and moral deterioration. Existing networks have insufficient redundancy and have practically exhausted their ability to connect new consumers. These circumstances required a decision to switch to a voltage class of 20 kV, which is a strategic direction for the development of medium voltage electrical networks in Moscow. According to this decision, since the 2000s, electric networks with a voltage of 20 kV have been actively developing in Russia and in Moscow. This article analyzes the implemented approaches to the use of an electric network of 20 kV in megacities of different countries.

Study of the operation of an artificial neural network that works in the electric network in order to prevent emergency conditions.

2020 ◽  
Vol 14 (1) ◽  
pp. 48-54
Author(s):  
D. Ostrenko ◽  
Keyword(s):  
Neural Networks ◽  
Learning Algorithm ◽  
Electricity Consumption ◽  
Electrical Energy ◽  
Energy System ◽  
Electrical Networks ◽  
Electric Networks ◽  
Electric Network ◽  
Time Dynamics ◽  
Emergency Situations

Emergency modes in electrical networks, arising for various reasons, lead to a break in the transmission of electrical energy on the way from the generating facility to the consumer. In most cases, such time breaks are unacceptable (the degree depends on the class of the consumer). Therefore, an effective solution is to both deal with the consequences, use emergency input of the reserve, and prevent these emergency situations by predicting events in the electric network. After analyzing the source [1], it was concluded that there are several methods for performing the forecast of emergency situations in electric networks. It can be: technical analysis, operational data processing (or online analytical processing), nonlinear regression methods. However, it is neural networks that have received the greatest application for solving these tasks. In this paper, we analyze existing neural networks used to predict processes in electrical systems, analyze the learning algorithm, and propose a new method for using neural networks to predict in electrical networks. Prognostication in electrical engineering plays a key role in shaping the balance of electricity in the grid, influencing the choice of mode parameters and estimated electrical loads. The balance of generation of electricity is the basis of technological stability of the energy system, its violation affects the quality of electricity (there are frequency and voltage jumps in the network), which reduces the efficiency of the equipment. Also, the correct forecast allows to ensure the optimal load distribution between the objects of the grid. According to the experience of [2], different methods are usually used for forecasting electricity consumption and building customer profiles, usually based on the analysis of the time dynamics of electricity consumption and its factors, the identification of statistical relationships between features and the construction of models.

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