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 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 Increasing the parameters of electrical distribution networks of town districts with low load density

2020 ◽  
Vol 1 (57) ◽  
pp. 28-32
Author(s):  
V. Perepecheny
Keyword(s):  
Power Supply ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Parameter Distribution ◽  
Electrical Networks ◽  
Supply Networks ◽  
Transformer Substation ◽  
Low Load ◽  
The Impact ◽  
Selection Of

This article presents the results of research on the parameters of electrical networks with a voltage of 6 (10) and 0.38 kV in relation to capital investments. The analysis of existing methods of estimation of parameters before designing for power supply networks in a small town with low load density is carried out. In modern conditions, in the distribution of electrical networks is of paramount importance the introduction of energy-saving schemes and parameters of power supply systems. One of the main ways to implement them is to increase the efficiency of 6-10 / 0.38 kV networks. In the actual design of electrical networks, economic proportionality can not always be maintained for various reasons: the impact of technical constraints, the discreteness of the rated power of transformers and cable crossing scales, a significant deviation of individual capacities of consumers from the average value. In that case there is an increase in the reduced costs. A methodology for determining the optimal power of transformer substations and optimal sections of 0.38 kV power transmission lines is proposed, taking into account the probable nature of the applied load. When assembling the power supply circuit for the optimal form of parameters, voltage, principles of voltage regulation and reactive power compensation. Decisions of this kind are substantiated by technical and economic comparisons of a series of technically acceptable variants of power supply networks. An important measure that facilitates the selection of the most economical option is the assessment of the proposed project, which relates to the selection of the optimal capacity of transformer substation (TS) networks using calculation formulas. The aim of the research was to improve the existing methods on the basis of separate accounting of the reliability coefficient of 0.38 kV and 6-10 kV network. Key words - electric power supply network, network parameters, transformer substation, load density, line wire section, specific load, unit costs, optimum parameter, distribution networks, electric energy.

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 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.

scholarly journals Influence of low-voltage electrical switching and protecting devices and parameters of electrical equipment on electricity losses in workshop power supply networks

2021 ◽  
Vol 23 (3) ◽  
pp. 3-13
Author(s):  
E. Yu. Abdullazyanov ◽  
E. I. Gracheva ◽  
A. N. Gorlov ◽  
Z. M. Shakurova ◽  
A. G. Logacheva
Keyword(s):  
Power Supply ◽  
Low Voltage ◽  
Electrical Equipment ◽  
Load Factor ◽  
Equivalent Resistance ◽  
Circuit Breakers ◽  
Supply Networks ◽  
Factors Affecting ◽  
Daily Schedule ◽  
Active Power Losses

THE PURPOSE. To develop an algorithm for estimating electricity losses, taking into account the influencing factors in the main circuits of shop power supply. To study the influence of the main parameters of electrical equipment on the equivalent resistance of the distribution busbar. METHODS. We use element-by-element methods for calculating active power losses using equivalent resistance on the example of a section of the main circuit of the shop network. Factors affecting the equivalent busbar resistance, such as the root-mean-square load factor, the load graph shape factor, the resistance of the contact connections of switching devices, and the ambient temperature, are investigated. RESULTS. The values of the resistances of the branch lines from the busbar are calculated taking into account the heating of the conductors and the resistances of the circuit breakers and magnetic starters installed on the line during the element-by-element calculation. The relations in the value of the equivalent resistance of the busbar to the values of the resistances of the contact connections of low-voltage electrical devices installed on the branch lines from the busbar, the values of the resistances of the branch lines taking into account heating, the value of the resistance of the busbar and the values of the resistance due to the heating of the busbar are revealed. CONCLUSIONS. The share of each of the studied parameters in the value of the equivalent resistance of the busbar is determined. The value of the relative error in determining the equivalent resistance of the busbar depending on the number of connected electric receivers and taking into account the studied parameters is calculated. The estimation of the value of the electricity losses of the section of the main scheme of the shop network was carried out in accordance with the daily schedule of the load of consumers.

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 Technical and Economic Assessment of Local Power Supply Systems for Agro-Industrial Production in the Digital Economy

2021 ◽  
Vol 37 ◽  
pp. 00132
Author(s):  
Vladimir T. Vodyannikov ◽  
Elena V. Кhudyakova ◽  
Marat M. Nizamutdinov ◽  
Asiyа K. Subaeva ◽  
Ilnur N. Safiullin
Keyword(s):  
Power Supply ◽  
Agricultural Production ◽  
Energy Supply ◽  
Capital Investment ◽  
Low Voltage ◽  
Local Power ◽  
Electrical Networks ◽  
Long Distance ◽  
The Cost ◽  
Central Station

Energy and energy supply development determines the rate of production intensification, including agricultural production. The current state of rural power supply is characterized by a high degree of deterioration of electrical equipment, long distance overhead power lines, low reliability of low-voltage electrical networks, and a higher accident rate. With an aim of ensuring food security and export orientation of the industry for the next 5 years, it is necessary to implement a set of measures to improve the efficiency of energy supply to agricultural production. This task will be hampered by a constant rise in prices and tariffs for energy resources. Thus, over the last 20 years, energy costs have increased from 3-5 % to 30-40 % in agricultural production. The specific capital investment (per 1 kW of power) and the cost of 1 kWh of electricity were reported to depend on a type of local energy source and its capacity. The paper proposes a method for marking out the economic boundaries of the effective use of local power supply arrangements to replace a standard central station. A power gen-set supplying energy to an agricultural holding is capable of operating in two modes subsequent upon utility (central station) electricity – autonomous and parallel. The authors compared the cost of electrical and thermal energy produced by the power gen-set and tariffs for these types of energy. Calculations have shown that it is advisable for an agricultural holding to have a local power supply system being a power gen-set based on gas engine-generators.

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 PROPERTIES OF THE REACTIVE POWER OF THE ASYNCHRONOUS MACHINE AS A LOAD OF THE ELECTRIC NETWORK

2021 ◽  
Vol 2 (37) ◽  
pp. 28-33
Author(s):  
O. Klyuyev ◽  
E. Khmelnitsky
Keyword(s):  
Power Supply ◽  
Reactive Power ◽  
Supply Voltage ◽  
Power Supply Unit ◽  
Minimum Point ◽  
Electrical Network ◽  
Electrical Networks ◽  
Asynchronous Machines ◽  
Load Unit ◽  
Main Consumer

It is known that the voltage mode of the electrical network is associated with the balance of reactive power and directly affects the operation of production equipment. A typical static characteristic of a power supply unit in terms of reactive power, obtained for a load composition characteristic of electrical networks, is an extreme function with a minimum point. It is the presence of a minimum point in the dependence of reactive power on voltage that makes it possible to develop this type of instability as a voltage avalanche. This mode is especially dangerous for industrial units with abruptly variable loads, which can create significant fluctuations in the supply voltage, which significantly affects the operation of powerful asynchronous motors. Therefore, the issues of the relationship between the parameters mode of the electrical network and the properties of electrical loads are always important, especially asynchronous machines as the main consumer of electricity, which largely determines the properties of the generalized reactive power curve of the entire load unit. Literary sources do not explain in detail why the curve of the dependence of the reactive power of the power supply unit on voltage has a minimum. The article sets out this issue in sufficient detail for asynchronous machines as the main consumer of reactive power in electrical networks. The task is to obtain the dependence of the reactive power of an induction machine with a squirrel-cage rotor on the voltage of the supply network, as well as to determine the criteria for controlling reactive power flows in order to inadmissibly reduce the voltage in the load unit. As a result, based on the system of equations of an asynchronous machine, the dependence of its reactive power on the supply voltage of the network was derived. The mathematical properties of this function are investigated with a physical justification of its unimodality and the presence of a minimum point. The obtained expressions make it possible to determine the magnitude of the control action on the high-speed reactive power compensation devices to stabilize the voltage level in the power supply unit.

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