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.

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 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.

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