scholarly journals Determination of the technical condition of electrical equipment in power supply systems

2021 ◽  
Vol 939 (1) ◽  
pp. 012014
Author(s):  
A Rakhmatov ◽  
N Rajabov ◽  
Kh Yakubova

Abstract This article describes the methods and means for determining the technical condition of electrical equipment in power supply systems, particularly in transformer substations. There are many ways to determine the technical condition of electrical equipment. However, their implementation requires complex and additional equipment and devices. In addition, these tests must be carried out when the power supply system is off. This will lead to a decrease in the quality of electrical energy. Determination of the technical condition of electrical equipment using thermal imagers is performed under the voltage and in operating modes, the measurement process does not affect the parameters of the power supply system. The results of research in energy enterprises of the Syrdarya region are presented.

2021 ◽  
Vol 25 (5) ◽  
pp. 568-585
Author(s):  
Yu. N. Bulatov

The paper determines the effect of proposed joint voltage and frequency predictive controllers for distributed generation (DG) plants on quality indicators characterizing the control process in different operating modes of power supply systems. The studies are conducted in the MatLab environment (Simulink and SimPowerSystems simulation packages) employing control engineering methods. It is proposed to design and adjust joint predictive controllers by determining the resonant frequency of oscillations for the master generator rotor. This approach provides better quality indicators of voltage and frequency control in power supply systems while maintaining the same settings for the controllers of DG plants. With an additional load in an isolated power supply system, the maximum voltage sag is found to be 1.75 times lower than for local predictive control and 3.5 times lower as compared to the use of conventional controllers. For the specified mode, predictive controllers enable a threefold reduction in the transient time between rotor rotational speeds in a synchronous generator. In the start mode of a powerful electric motor, the predictive controllers of synchronous generators in the power supply system enable a 1.5 times reduction in voltage sag, with a 1.4 times reduction in overvoltage following its start. In the case of a short-term three phase short-circuit, joint predictive controllers allow a 1.5 times decrease in transient time and a 2.3 times decrease in the overshoot of power line frequency as compared to local control. In addition, frequency oscillation in the power system is also reduced. Similar effects are observed in other operating modes of the considered power supply systems equipped with DG plants. The performed dynamic simulation confirms the effectiveness of using joint voltage and frequency predictive controllers for DG plants, which consists in a positive impact on the quality of processes involved in controlling the parameters of power supply systems in various operating modes.


2019 ◽  
Vol 114 ◽  
pp. 04006
Author(s):  
Bui Ngoc Hung ◽  
Lidiia I. Kovernikova

Coal mining is one of the important economic sectors in Vietnam. Power supply systems of coal mines and open-cuts are complex. They have multiple levels of voltages and different types of loads. New electrical equipment usually works alongside with the equipment that is obsolete and worn-out. Power supply systems of industrial areas of Vietnam where coal is mined are characterized by the low power quality. In Vietnam the indices which characterize the distortion of both voltage and current waveforms have standard values. The article presents the findings upon the analysis of a power supply system of a coal open-cut in Vietnam and the electrical equipment of the coal sorting plant along with the results of the experimental studies of power quality indices and the non-sinusoidal mode parameters. The measurement analysis has shown that the indices of the 5-th and 7-th harmonics of voltage were over the limits. There are interharmonics in voltages and currents. The article analyzes the characteristics of active filters. It is possible to improve the power quality by using an active filter which generates both reactive power to increase the load power factor and harmonic and interharmonic currents to reduce the degree of voltage and current waveform distortion.


2021 ◽  
Vol 3 (1) ◽  
pp. 054-057
Author(s):  
Yu. N. KONDRASHOVA ◽  
◽  
I. V. NOVIKOV ◽  
A. M. MARKIN ◽  
◽  
...  

The paper analyzes damage along overhead and cable power lines. The calculation of the main indicators of reliability is carried out to predict the value of the actual resource of the main high-voltage electrical equipment for the shops of the production metallurgical line. The calculations were performed for the existing circuit using the software package [1]. The performed analysis of the obtained results of the developed algorithm and methods for calculating reliability indicators made it possible to assess the technical condition of overhead and cable lines subject to intense aging in terms of voltage levels and to estimate the number of outages at nodal substations.


2020 ◽  
Vol 216 ◽  
pp. 01162
Author(s):  
Raxmatillo Karimov ◽  
Maxsud Bobojanov

The article discusses the results of comparison and analysis of voltage stabilizing devices and contactless relays in the power supply system. Based on the analysis, the time variation of the voltage in the capacitive circuit is shown. Based on the results of the study, it was found that the determination of the actual value of the capacitive voltage by controlling the thyristor of the “charge-discharge” process of the capacitance makes it possible to determine the time delay of the contactless switching device when the capacitor reaches the saturation point.


Author(s):  
Yaroslav Bederak ◽  
Viktor Taradai ◽  
Hanna Kyselova ◽  
Vladlen Kyselov

The publication presents the most common and promising models and schemes for replacing the power supply system of industrial enterprises, and an example of their use in practice for power supply to sewage treatment plants of a chemical enterprise. Various types of models are considered (in tabular form, in the form of an electrical replacement circuit or in the form of a finite-state machine), as well as a logical-probabilistic approach to the representation of the power supply system. The use of automation systems in power supply systems of industrial enterprises can reduce the total number of accidents, prevent their development, reduce the time of disconnections of electrical installations and downtime of mechanisms, and also allows to transfer to work without constant maintenance a significant number of electrical installations of substations, which, in turn, leads to a reduction in the number of service personnel, increase labor productivity and reduce maintenance costs. One of the main tasks on the way to automating the power supply system of enterprises is to present it in the form of a model. The list of replacement models and schemes that can be used to represent the power supply system of enterprises is quite large, and choosing the appropriate model, for that best meets the requirements of the final goal is quite a complex scientific task. The purpose of this article is to analyze the most common and promising models and schemes for replacing the power supply system and provide recommendations on their application in practice for power supply to sewage treatment plants of a chemical enterprise. Presenting the power supply system in the form of a table allows you to simplify and visually perform certification of electrical equipment, identify problem and weak points in the power supply system of industrial enterprises. Such a table proves that a large amount of electrical equipment at lower levels depends on a single electrical device at higher levels. The representation of the power supply system in the form of a three-phase symmetric replacement circuit can be used to calculate short-circuit currents in symmetric and unbalanced modes in the MatLab program and similar. Using the model of the power supply system in the form of a finite-state machine allows you to visually check the reliability of power supply to consumers, simplify the design of the power supply system of an industrial enterprise, select the state of switching devices in the power supply system and take into account the advantages and disadvantages of each state. It is advisable to use the methods discussed in this article to represent the power supply system (in tabular form, in the form of a finite-state machine or a three-phase symmetric replacement scheme) and their further application and use in automated power supply systems of industrial enterprises. The logical-probabilistic method allows us to consider the issue of power supply reliability based on the theory of logical algebra.


2009 ◽  
Vol 46 (6) ◽  
pp. 16-26 ◽  
Author(s):  
S. Guseva ◽  
N. Skobeleva ◽  
N. Breners ◽  
O. Borscevskis

Determination of Service Areas of Urban Transformer Substations and Distribution Using Geometrical Templates In the work, a general and theoretically substantiated approach is proposed for the arrangement and determination of service areas for the future transformer substations (TSs). The modelling of TS service area has been performed, with geometrical templates designed to arrange TSs in the city building territory. The sizes of templates have been obtained depending on the TS capacity and load density in TS service area. The geometrical templates are to help in TS arrangement in view of rational use of the city territory and to re-arrange the existing stations for the reconstruction time. As a result, the urban power supply system will develop not chaotically but in a purposeful manner.


Author(s):  
Oleg Arsent'ev ◽  
Evgeniy Krylov

the questions of the organization of power supply system with control elements to reduce the impact of peak loads on the operation of electrical equipment and reduce energy costs


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