scholarly journals INVESTIGATION OF METHODS FOR MODELING THE OPERATION OF A VOLTAGE REGULATION SYSTEM OF A POWER TRANSFORMER WITH AN RPN DEVICE

2021 ◽  
pp. 27-31
Author(s):  
I. Lapteva ◽  
E. Karnakov
Keyword(s):  
Power Transformer ◽  
Voltage Regulation ◽  
Control Device ◽  
Power Transformers ◽  
Load Control ◽  
Regulation System ◽  
Electrical Networks ◽  
Modes Of Operation

The analysis of one of the important tasks arising in the process of automating the control of the modes of operation of electrical networks is given – maintaining the specified voltage levels on the busbars of substations. Centralized voltage regulation at substations provides for the widespread use of power transformers and autotransformers containing a load control device (RPN). A method for modeling the operation of a voltage regulation system of a power transformer with RPN devices is proposed.

scholarly journals Structure of many-level adaptive automatic voltage regulation system

2020 ◽  
Vol 178 ◽  
pp. 01068
Author(s):  
I.O. Golikov ◽  
A.V. Vinogradov ◽  
V.E. Bolshev ◽  
A.V. Vinogradova ◽  
M. Jasinski ◽  
...  
Keyword(s):  
Voltage Regulation ◽  
Electrical Network ◽  
Regulation System ◽  
Processing Unit ◽  
Electrical Networks ◽  
Structural Diagram ◽  
Voltage Level ◽  
Voltage Change ◽  
Tap Changer ◽  
Load Tap Changer

This article describes the features of voltage regulation in electrical networks of 35, 110, 220 kV. The structural diagram of the 35/10/0.4 kV network is presented. The paper also describes the adaptive automatic voltage regulation system which allows regulating the voltage taking into account the actual voltage values at the consumers’ inputs. The structural diagram of the adaptive automatic voltage regulation system in the 0.4 kV electrical network using a boost transformer as an additional means of voltage regulation is given. The system is based on voltage sensors installed in different parts of an eletcrical network sending information on voltage values to to the processing unit which generates a signal for voltage regulating supplied to the executive device and the working body whuch, in turn, change the on-load tap-changer position of a transformer. The paper justifies the need for the enhancement of the adaptive automatic voltage regulation system for different voltage classes wich allows controlling a voltage change at different power supply system levels and regulating voltage level in accordance with this change. For this problem the multi-level adaptive automatic voltage regulation systemis proposed. The system allows regulating the voltage not only in the 0.4 kV network but also in networks of higher voltage classes. The proposed system can be integrated into the structure of intelligent electrical networks.

scholarly journals Development of model of transient modes taking into account mutual inductance of scattering fields for implementation of digital twin of transformer

Vestnik IGEU ◽  
2021 ◽  
pp. 47-56
Author(s):  
I.S. Snit’ko ◽  
A.I. Tikhonov ◽  
A.V. Stulov ◽  
V.E. Mizonov
Keyword(s):  
Mathematical Models ◽  
Simulation Models ◽  
Mutual Inductance ◽  
Power Transformers ◽  
Electrical Networks ◽  
Production Environment ◽  
Modes Of Operation ◽  
Matlab Simulink ◽  
Leakage Inductance ◽  
Comparison Of The Results

Development of the refined mathematical models of power transformers (digital twins), which make it possible to calculate arbitrary modes of operation of these devices with high accuracy and increased speed is an urgent task. Currently, such problems are solved using simulation packages such as MatLab Simulink. One of the disadvantages of the existing simulation models of the transformer is the assumption that own leakage inductance of the windings is used. This assumption is not always acceptable. Thus, the purpose of this article is to develop models of transformers using matrices of mutual inductance of the scattering field. The finite element method is used to calculate the magnetic field in a 2D formulation, implemented by means of the EMLib library, as well as simulation methods with the MatLab Simulink package are applied. The authors have estimated the features and basic assumptions while developing refined mathematical models of power transformers of various designs (two- and three-winding). It makes possible to ensure the required accuracy when simulating transient and emergency modes of transformer operation. Field models have been developed to determine the own and mutual scattering inductance matrices. Simulation models of transformers of various designs with the use of winding leakage inductance matrices have been developed. The results of simulation of dynamic processes in a transformer in various modes are presented. Comparison of the results of the operation of models with matrices of mutual inductances and without them is carried out. The results of the research can be used during the design of power transformers in design companies and in production environment. It is also possible to use the developed models during operation of power transformers for the analysis of static and dynamic modes of operation of sections of electrical networks.

Adaptive Automatic Voltage Regulation in Rural 0.38 kV Electrical Networks

2019 ◽  
Vol 20 (3) ◽  
Author(s):  
Aleksandr Vinogradov ◽  
Alina Vinogradova ◽  
Igor Golikov ◽  
Vadim Bolshev
Keyword(s):  
Power Supply ◽  
Smart Grids ◽  
Voltage Regulation ◽  
Regulation System ◽  
Electrical Networks ◽  
New Approach ◽  
New Methods ◽  
Functional Capabilities ◽  
Processing Information ◽  
Technical Solutions

Abstract Development of smart grids for power supply to rural consumers assumes the creation of adaptive voltage regulation systems in 0.38 … 10 kV electrical networks as one of the directions. This paper considers a new approach to create an algorithm for controlling the technical means of regulation and voltage stabilization. The proposed adaptive voltage regulation system allows collecting and processing information on the actual voltage at the consumer inputs and automatically determine the voltage regulation coefficient. The developed mathematical model allows calculating the voltage regulation coefficient depending on the voltage at various points of the 0.38 kV electric network. In the paper there are also new methods of adaptive automatic voltage regulation in the 0.38 kV electrical networks and the requirements to the functional capabilities of this system. The article suggests technical solutions for the implementation of adaptive automatic voltage regulation system. The successful tests of experimental model of this system have been carried out.

On Developing the Theory of Resonant Processes in Power Transformer Windings. Part 1. Frequency Responses of a Circuit with Two PI Sections

2021 ◽  
pp. 49-55
Author(s):  
Vasily S. LARIN ◽  
Keyword(s):  
Equivalent Circuit ◽  
Power Transformer ◽  
Short Circuit ◽  
Natural Oscillation ◽  
Power Transformers ◽  
Equivalent Circuits ◽  
Electrical Networks ◽  
Frequency Responses ◽  
Voltage Resonance ◽  
Resonant Processes

The windings of power transformers are complex oscillatory circuits. Their natural oscillation frequencies range from a few to hundreds of kHz, and under unfavorable conditions they can coincide with the frequencies of transient voltage oscillations in electrical networks caused by switching operations and short circuit faults in cable lines. The development of electrical networks and the technical solutions that have come in wide use in recent years give rise to a situation in which the cases of damage to the insulation of power transformer windings resulting from resonant overvoltages are increasingly more frequently encountered during operation. An attempt is made in the article to develop the theory of resonant processes in the windings of power transformers. The frequency responses of voltages and currents in a simplified equivalent circuit of the power transformer winding are considered. Analytical expressions are obtained for the admittances of individual parts of equivalent circuits and the voltages at intermediate nodes, as well as expressions for the natural frequencies of the equivalent circuits considered. It is shown that the resonant growth of voltage in the transformer windings results from the voltage resonance caused by the presence of the winding’s own inductance and capacitance with respect to ground. By analyzing the frequency dependences of the admittances of equivalent circuit individual parts, the conditions and frequency ranges in which voltage resonance may occur are shown.

Analysis of voltage regulation devices.

2020 ◽  
Vol 23 (2) ◽  
pp. 44-47
Author(s):  
N. TIUTIUNNYK ◽  
◽  
G. SHEINA ◽  
Keyword(s):  
Power Supply ◽  
Flow Distribution ◽  
Voltage Regulation ◽  
Control Device ◽  
Electrical Network ◽  
Modes Of Operation ◽  
Electric Network ◽  
Electrical Systems ◽  
Reliability Of Operation ◽  
Operational Scheme

The paper considers an electrical substation with a voltage of 330/110/35 kV. Means of voltage regulation on the substation autotransformer are investigated. The paper considers the means of voltage regulation on autotransformers of the 330/110/35 kV substation to ensure uninterrupted power supply and the desired voltage level on the busbars of consumers. The choice of the optimal version of the on-load tap-changer of the autotransformer is shown. The electric network with voltage of 110 and 35 kV is considered. The power supply center is substation 330 kV. The connection between voltages is provided by three three-phase autotransformers of the ATDCTN200000/330/110 type. Autotransformers are used instead of three-winding transformers to reduce the cost of conductive material and increase transmission power, but unlike three-winding transformers, they have only one voltage control device - load control regulation. Steady-state and emergency modes are investigated. The PowerFactory program has created a network model, which is used to calculate the mode and evaluate the methods of voltage regulation. On the basis of calculations the point of economic flow distribution in which it is expedient to open a network in a normal mode, and on the switch to provide the device of automatic input of a reserve is defined. The principles of control of modes of operation of electrical systems are investigated: minimum costs for generation, transmission and consumption of electricity (technological losses), reliability of operation of electrical systems, quality of electricity. The purpose of this work is to substantiate the optimal operational scheme of the electrical network, the study of the modes of operation of the 330/110/35 kV network. The simulation of steady and emergency modes is performed in the work. The optimal operational scheme of the electric network is substantiated in order to improve the reliability of power supply and ensure the desired level of voltage on the busbars of consumers.

A Solid-State On-Load Tap Changer for the Power Transformers of 10—0.4 kV Distribution Networks

Vestnik MEI ◽  
2020 ◽  
Vol 6 (6) ◽  
pp. 82-90
Author(s):  
Dmitriy I. Panfilov ◽  
◽  
Mikhail G. Astashev ◽  
Aleksandr V. Gorchakov ◽  
◽  
...  
Keyword(s):  
Solid State ◽  
Physical Model ◽  
High Speed ◽  
Power Transformer ◽  
Voltage Control ◽  
Power Transformers ◽  
Control Algorithms ◽  
Load Voltage ◽  
Tap Changer ◽  
Load Tap Changer

The specific features relating to voltage control of power transformers at distribution network transformer substations are considered. An approach to implementing high-speed on-load voltage control of serially produced 10/0.4 kV power transformers by using a solid-state on-load tap changer (SOLTC) is presented. An example of the SOLTC circuit solution on the basis of thyristor switches is given. On-load voltage control algorithms for power transformers equipped with SOLTC that ensure high reliability and high-speed operation are proposed. The SOLTC performance and the operability of the suggested voltage control algorithms were studied by simulation in the Matlab/Simulink environment and by experiments on the SOLTC physical model. The structure and peculiarities of the used simulation Matlab model are described. The SOLTC physical model design and its parameters are presented. The results obtained from the simulating the SOLTC operation on the Matlab model and from the experiments on the SOLTS physical model jointly with a power transformer under different loads and with using different control algorithms are given. An analysis of the experimental study results has shown the soundness of the adopted technical solutions. It has been demonstrated that the use of an SOLTC ensures high-speed voltage control, high efficiency and reliability of its operation, and arcless switching of the power transformer regulating taps without load voltage and current interruption. By using the SOLTC operation algorithms it is possible to perform individual phase voltage regulation in a three-phase 0.4 kV distribution network. The possibility of integrating SOLTC control and diagnostic facilities into the structure of modern digital substations based on the digital interface according to the IEC 61850 standard is noted.

The Heating System of Agricultural Facilities Using Excess Heat Power Transformers

2020 ◽  
Vol 67 (1) ◽  
pp. 42-47
Author(s):  
Anatoliy I. Sopov ◽  
Aleksandr V. Vinogradov
Keyword(s):  
System Design ◽  
Heat Supply ◽  
Cooling System ◽  
Power Transformer ◽  
Electric Heating ◽  
Heating System ◽  
Power Transformers ◽  
Large Power ◽  
Excess Heat ◽  
Power Centers

In power transformers, energy losses in the form of heat are about 2 percent of their rated power, and in transformers of large power centers reach hundreds of kilowatts. Heat is dissipated into the environment and heats the street air. Therefore, there is a need to consume this thermal energy as a source of heat supply to nearby facilities. (Research purpose) To develop methods and means of using excess heat of power transformers with improvement of their cooling system design. (Materials and methods) The authors applied following methods: analysis, synthesis, comparison, monographic, mathematical and others. They analyzed various methods for consuming excess heat from power transformers. They identified suitable heat supply sources among power transformers and potential heat consumers. The authors studied the reasons for the formation of excess heat in power transformers and found ways to conserve this heat to increase the efficiency of its selection. (Results and discussion) The authors developed an improved power transformer cooling system design to combine the functions of voltage transformation and electric heating. They conducted experiments to verify the effectiveness of decisions made. A feasibility study was carried out on the implementation of the developed system using the example of the TMG-1000/10/0.4 power transformer. (Conclusions) The authors got a new way to use the excess heat of power transformers to heat the AIC facilities. It was determined that the improved design of the power transformer and its cooling system using the developed solutions made it possible to maximize the amount of heat taken off without quality loss of voltage transformation.

scholarly journals Predicting the influence of the non-sinusoidal network mode on power transformers

2019 ◽  
Vol 114 ◽  
pp. 04005
Author(s):  
Ngo Van Cuong ◽  
Lidiia I. Kovernikova
Keyword(s):  
Service Life ◽  
Electric Power ◽  
Power Quality ◽  
Electrical Equipment ◽  
Operating Conditions ◽  
Transformer Oil ◽  
Power Transformers ◽  
Electrical Network ◽  
Electrical Networks ◽  
Current Harmonics

The parameters of electrical network modes often do not meet the requirements of Russian GOST 32144-2013 and the guidelines of Vietnam. In the actual operating conditions while there is the non-sinusoidal mode in electrical networks voltage and current harmonics are present. Harmonics result in overheating and damage of power transformers since they cause additional active power losses. Additional losses lead to the additional heat release, accelerating the process of insulating paper, transformer oil and magnetic structure deterioration consequently shortening the service life of a power transformer. In this regard there arises a need to develop certain scientific methods that would help demonstrate that low power quality, for instance could lead to a decrease in the electrical equipment service life. Currently we see a development of automated systems for continuous monitoring of power quality indices and mode parameters of electrical networks. These systems could be supplemented by characteristics calculating programs that give out a warning upon detection of the adverse influence of voltage and current harmonics on various electrical equipment of both electric power providers and electric power consumers. A software program presented in the article may be used to predict the influence of voltage and current harmonics on power transformers.

Continuous Chopper-Based Voltage Regulation for Power Transformers

2007 ◽  
Vol 5 (3) ◽  
pp. 136-141 ◽  
Author(s):  
Octavio M Ruiz ◽  
Antonio Gomez
Keyword(s):  
Voltage Regulation ◽  
Power Transformers
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