scholarly journals Algorithms and models of power losses in circuit breakers installed in networks

Vestnik MGTU ◽  
2020 ◽  
Vol 23 (4) ◽  
pp. 345-353
Author(s):  
E. I. Gracheva ◽  
A. N. Gorlov ◽  
A. N. Alimova
Keyword(s):  
Power Supply ◽  
Low Voltage ◽  
Technical Condition ◽  
Active Power ◽  
Operating Conditions ◽  
Public Utility ◽  
Electrical Networks ◽  
Power Losses ◽  
Circuit Breakers ◽  
Technical Parameters

Determination of the main characteristics of the topology and technical condition of equipment underoperating conditions is necessary for analyzing and assessing power and electricity losses in intrashoplow-voltage industrial power supply networks. A comparative analysis of the technical characteristicsof automatic circuit breakers VA57-31 (KEAZ), NSX100 TM-D (Schneider Electric), DPX3 160 (Legrand), Tmax XT1 TMD (ABB) has shown that the main technical parameters of the machines are close in their values. At that it has been found out that automatic switches of the BA57-31 series have the lowest value of power losses per pole (7.5 W), whereas the automatic switches of the Tmax XT1 TMD series have the highest value (10 W). Thus, under the operating conditions of the equipment, the lowest value of power and electricity losses is characteristic of low-voltage electrical networks with installed circuit breakers of the BA57-31 series, and the highest value of losses is noted in in-shop systems with installed circuit breakers Tmax XT1 TMD. Using catalog data, the dependences of active power losses in circuit breakers on rated currents have been established; the algorithms have been developed and the obtained dependences have been modeled using approximating functions. The standard deviation of the compiled approximating functions has been calculated. Analytical expressions of the dynamics of power losses per pole have been determined as a function of the rated current. The graphical dependences of the investigated parameters of low-voltage equipment have been presented. The developed models are recommended to be used to increase the reliability of the assessment and refinement of the amount of active power and electricity losses in low-voltage electrical networks of industrial power supply systems, agrotechnical complexes, and enterprises of the public utility sector.

scholarly journals Influence of resistance of contact units of switching devices on the electric power losses in shop networks of low tension

2019 ◽  
Vol 124 ◽  
pp. 02013 ◽  
Author(s):  
D. D. Micu ◽  
I. V. Ivshin ◽  
E. I. Gracheva ◽  
O. V. Naumov ◽  
A. N. Gorlov
Keyword(s):  
Electric Power ◽  
Low Voltage ◽  
Technical Condition ◽  
Electrical Networks ◽  
Power Losses ◽  
Switching Device ◽  
Low Tension ◽  
Switching Equipment ◽  
Voltage Switching ◽  
Switching Devices

This paper presents calculation of resistance of tightening contact joints of switching devices. It allows considering the technical condition of low-voltage switching equipment and to specify energy emitted in the switching device in the mode of electrical networks operation is presented in the article.

REDUCTION OF ACTIVE POWER LOSSES IN LOW VOLTAGE NETWORKS WITH THE RECTIFIER LOAD

2017 ◽  
Vol 2017 (3) ◽  
pp. 65-70
Author(s):  
A.F. Zharkin ◽  
◽  
V.A. Novskyi ◽  
N.N. Kaplychnyi ◽  
A.V. Kozlov ◽  
...  
Keyword(s):  
Low Voltage ◽  
Active Power ◽  
Power Losses ◽  
Active Power Losses

scholarly journals Development of Optimum Repair Schedule of Electrical Network Equipment to Improve the Reliability of its Functioning

2019 ◽  
pp. 4-11
Author(s):  
Sergey V. Belyaev ◽  
Aleksey V. Malafeev ◽  
Evgeniy Ya. Omelchenko
Keyword(s):  
Power Supply ◽  
Technical Condition ◽  
Electrical Network ◽  
Steady Increase ◽  
Electrical Networks ◽  
Number Of Factors ◽  
Network Equipment ◽  
Long Time ◽  
Planning Algorithm ◽  
Labor Resources

To ensure uninterrupted power supply to consumers, maintenance of the electrical networks in a working condition is today carried out through the use of a system of preventive maintenance. In the general case such a system allows building equipment repair schedules based on repair cycles for a long time predetermining the list of necessary material and labor resources in advance. However, in practice, the use of this system is rather difficult and not always effective. This is due to the need to change the repair schedule for emergency or urgent repairs taking into account the seasonality of work performed and the organizational structure of the production department of electrical networks and related departments as well as taking into account the specific features of the operation of specific equipment. Taking into account the current pace of development of electrical networks with a steady increase in the number of consumers (which also leads to a complication of the configuration of electrical networks) this is impossible without the use of appropriate mathematics and software that automates the planning processes for the maintenance and repair of electrical networks with a large number of factors. The minimum equipment downtime was taken as the main criterion for optimality, as a factor that largely determines the reliability of power supply. A planning algorithm has been developed that takes into account the ranking of works in order of importance, the possibility of their shift in time and the likely adjustment of the schedule based on the results of assessing the technical condition of the equipment. A method for minimizing the downtime of repair crews by using them in adjacent areas as well as a technique for identifying a set of equipment that may be under repair in the same period of time are proposed.

scholarly journals RESEARCH AND EVALUATION OF FUNCTIONAL PARAMETERS OF LOW VOLTAGE DEVICES

2018 ◽  
Vol 20 (5-6) ◽  
pp. 13-21
Author(s):  
E. Gracheva ◽  
A. Safin ◽  
R. Sadykov
Keyword(s):  
Contact Resistance ◽  
Low Voltage ◽  
Experimental Studies ◽  
Threshold Value ◽  
Probability Of Failure ◽  
Technical Condition ◽  
Operating Conditions ◽  
Switching Device ◽  
Predicting Performance ◽  
Complete Contact

To assess the operability and technical condition of low-voltage devices, it is proposed to use the resistance of contact connections. The probability of failure-free operation is proposed to be evaluated by the dependence of the resistance of the contact connections of the apparatus on the number of switching operations. As a result of wear, the initial value of the contact resistance of the switching device increases and reaches a critical value at which the switching device fails. Due to the fact that in the process of research there are both complete contact failures and short-term switching of only one time, the contact resistance is exceeded by the contact resistance of the threshold value. For magnetic starters, circuit breakers and contactors, based on the results of the experimental studies carried out, in order to achieve the critical resistance value of the apparatus, аn average of three times the initial resistance. At the same time, the quantitative characteristics of the functioning efficiency are determined by the methods of probability theory and mathematical statistics. The set of the obtained quantitative indicators allows to determine the actual level of reliability of contacting, and also extends the possibility of predicting performance ratings in the design.  In the present article, a method for the complex evaluation of the efficiency of low-voltage apparatus has been developed and the laws of the change in the resistance of contact connections and the probability of failure-free operation of low-voltage switching devices have been revealed, depending on the operating conditions.

scholarly journals Solution of the problem of optimum power distribution of individual compensating devices for a group of asynchronous motors for a stable operating mode and for a smoothly changing load

2020 ◽  
Vol 220 ◽  
pp. 01015
Author(s):  
E.V. Tumaeva ◽  
S.S . Kuzin ◽  
I.F. Aflyatunov ◽  
T.G. Makuseva
Keyword(s):  
Power Supply ◽  
Optimization Problem ◽  
Reactive Power ◽  
Active Power ◽  
Power Lines ◽  
Power Losses ◽  
Asynchronous Motors ◽  
Power Loss Reduction ◽  
Active Power Losses ◽  
Compensating Devices

Residential and industrial buildings with large territorial dimensions, have mainly radial power supply schemes, which feed a large number of small and medium capacity 0.4 kV induction motors. For their power supply copper or aluminum cables of small cross-section (with high active resistance) are used. Calculations of electricity losses in such lines show significant values. In order to reduce active power losses in 0.4 kV cable lines, the optimization problem of minimizing active power losses in the radial power supply circuit is solved by optimal distribution of reactive power of a given value between compensating devices. The single-line scheme of power supply of a group of pumps of technological installation of petrochemical production is considered, the mathematical model of the optimization problem on criterion of minimum of active losses in power lines from reactive power flow is made, which limitations are presented as a system of linear algebraic equations. Results of distribution of optimum values of reactive power between compensating devices of asynchronous motors at maintenance of the set tg φ are received. The quantitative estimation of active power loss reduction in power lines at use of capacitor units, which reactive power is optimally distributed, is given.

3D Thermal Analysis of a Power Supply Busbar Structure

2010 ◽  
Author(s):  
Adrian Plesca ◽  
Alina Scintee
Keyword(s):  
Thermal Analysis ◽  
Power Supply ◽  
Low Voltage ◽  
Circuit Breaker ◽  
Convective Heat Exchange ◽  
Point Of View ◽  
Circuit Breakers ◽  
Transient Thermal ◽  
Supply Systems ◽  
Electrical Apparatus

Busbar technology is more and more used to realize connections within power supply systems in answer to the need of compactness. The integrated problem on heat conduction and radiation-convective heat exchange describes the temperature regime in current conductors and current carrying busbars of power electrical apparatus such as circuit breakers or high breaking capacity fuses. Beside steady-state conditions, the transient thermal regime of busbar has an important influence upon whole power supply system from thermal behaviour point of view. Hence, a 3D thermal analysis of a power system including fuse, low voltage circuit breaker and busbars connections, using a specific software package based on Finite Element Method, has been done. From 3D thermal modelling and simulations, the thermal transient impedance for the busbar has been computed. This allows a better correlation between protection characteristics of the fuse and circuit breaker and busbar design.

scholarly journals Analysis of unbalanced load low-voltage electrical networks operating modes

2021 ◽  
Vol 295 ◽  
pp. 02005
Author(s):  
Igor Naumov ◽  
Sergey Podyachikh ◽  
Dmitri Ivanov ◽  
Alexander Tretyakov ◽  
Andrey Bastron
Keyword(s):  
Low Voltage ◽  
Residential Buildings ◽  
Electrical Energy ◽  
Operating Mode ◽  
Electrical Network ◽  
Electrical Networks ◽  
Power Losses ◽  
Voltage Unbalance ◽  
Operating Modes ◽  
Unbalanced Load

The article discusses distribution electrical networks 0.38 kV operating modes, feeding individual residential buildings. The electrical energy parameters measurement were certified RESURS-UF2M device carried out. The currents and voltages time diagrams based on the measurements made and using Matlab technologies were constructed. It is established that the level of phase currents unbalance is quite high and causes significant three-phase power supply system unbalance voltage accordingly. The power of quality indicators - calculations, characterizing voltage unbalance were made, which were based on the measurements and the computer program “Asymmetry” was used. As well as the additional power losses coefficient determining by the phase currents unbalance, were calculations. Time diagrams these indicators are constructed and their analysis were made. As a result, the power of quality is significantly reduced by unbalance power consumption in the studied electrical network were founded. At the same time, the additional power losses are significant increases. Specific recommendations for the normalization electrical network-operating mode are given.

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