scholarly journals Intelligent condition monitoring and diagnosis of a power transformer: on-load tap changer (OLTC) and main winding

2019 ◽  
Author(s):  
Junhyuck Seo
Vestnik MEI ◽  
2020 ◽  
Vol 6 (6) ◽  
pp. 82-90
Author(s):  
Dmitriy I. Panfilov ◽  
◽  
Mikhail G. Astashev ◽  
Aleksandr V. Gorchakov ◽  
◽  
...  

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.


Author(s):  
Maximilian Wiesmüller ◽  
Beate Glaser ◽  
Franz Fuchs ◽  
Oliver Sterz

Purpose – The purpose of this paper is to report on the simulation of an on-load tap-changer (OLTC) in a power transformer. During design and test of the electrical insulation the influence of the environment on the OLTC is normally neglected. The authors investigate how large these influences are. Design/methodology/approach – The environment of the OLTC is taken into account by modeling tap leads in detail as well as transformer windings. The electric fields are computed and resulting breakdown voltages are estimated by using the streamer criterion. The results are compared to the ones of an OLTC without transformer and leads. Findings – For the investigated typical example the influence of the transformer and the tap leads on the internal OLTC insulation is small enough to neglect them during design optimization and test procedures. Originality/value – New is the execution of a finite element simulation and breakdown evaluation of such a complex geometric structure as the complete system consisting of OLTC combined with tap leads and windings. Furthermore, standard design and test procedures used by OLTC manufacturers are justified.


2020 ◽  
Vol 220 ◽  
pp. 01056
Author(s):  
T.V. Tabachnikova ◽  
L.V. Shvetskova ◽  
A.V. Yumalin

The introduction of “smart grids” technologies poses the problems of multi-criteria determination of the optimum voltage in the main substation of the object under study. In this study the busbar sections of the field substation of the oil and gas company is considered as the main substation. This paper studies regulation of voltage level in an electrical network using on-load tap changer (OLTC) of a power transformer for field substation of an oil and gas enterprise. Considered are approaches for voltage regulation taking into account the development of smart grid technologies. The authors have developed a universal method for determining the optimal voltage level on the busbar sections of a field substation, which allows for selection of the optimum voltage in accordance with certain parameters: loss of active, reactive power, voltage, electricity consumption, specific consumption or efficiency factor of artificial oil lift. The actual daily graphs of consumption of active, reactive power and voltage level at one of the field substations of PJSC Tatneft were studied. The operation mode of on-load tap-changer drive of the field transformer was modeled, taking into account the calculated optimal values of voltage and the dead zone. The paper presents the results of study of automatic voltage regulation on busbar sections of a field substation, taking into account the constraints for tap changer switches of a power transformer.


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