Transformer Insulation Design Based on the Analysis of Impulse Voltage Distribution

2013 ◽  
pp. 438-455
Author(s):  
Jos A.M. Veens
Keyword(s):  
Power Transformer ◽  
Physical Structure ◽  
Active Part ◽  
Voltage Distribution ◽  
Large Power ◽  
The Core ◽  
Impulse Voltage ◽  
Transformer Type ◽  
Transient Voltages ◽  
Transformer Insulation

In this chapter, the calculation of transient voltages over and between winding parts of a large power transformer, and the influence on the design of the insulation is treated. The insulation is grouped into two types; minor insulation, which means the insulation within the windings, and major insulation, which means the insulation build-up between the windings and from the windings to grounded surfaces. For illustration purposes, the core form transformer type with circular windings around a quasi-circular core is assumed. The insulation system is assumed to be comprised of mineral insulating oil, oil-impregnated paper and pressboard. Other insulation media have different transient voltage withstand capabilities. The results of impulse voltage distribution calculations along and between the winding parts have to be checked against the withstand capabilities of the physical structure of the windings in a winding phase assembly. Attention is paid to major transformer components outside the winding set, like active part leads and cleats and various types of tap changers.

Power Transformer Constants Affecting its Impulse Voltage Distribution

1977 ◽  
Vol 14 (1) ◽  
pp. 53-63
Author(s):  
A. M. El-Arabaty ◽  
Ezzat A. A. Mansour ◽  
Osama A. M. Said
Keyword(s):  
Power Transformer ◽  
Power Transformers ◽  
Stress Distributions ◽  
Voltage Distribution ◽  
Impulse Voltage ◽  
The Difference ◽  
Theoretical Results

This work deals with the modification of the known calculating formulae for power transformer constants used for impulse voltage distribution, presents the effect of transformer constants and their modifications on impulse voltage and stress distributions in power transformers, and compares experimental and theoretical results considering measures taken to minimize the difference between them.

Influence of Active Part Stiffness on Radiated Sound Power Level in Power Transformers

2019 ◽  
Author(s):  
Cassiano C. Linhares ◽  
João S. Costa ◽  
Ricardo E. R. Teixeira ◽  
Cristiano P. Coutinho ◽  
Sérgio M. O. Tavares ◽  
...  
Keyword(s):  
Power Transformer ◽  
Power Level ◽  
Low Frequency ◽  
Dynamic Mechanical Properties ◽  
Active Part ◽  
Power Transformers ◽  
Radiated Noise ◽  
The Core ◽  
Stiffness Properties ◽  
Directional Component

Abstract Power transformers are associated with the radiation of unwanted noise in many circumstances due to its low frequency and relative high power, which reduction and mitigation is imperative. It is known that the main source of this noise are originated by the vibrations induced in the active part, namely the core, primarily due to electromagnetic forces and magnetomechanical effects. On the other hand, the laminated design of the core is indispensable in order to reduce the Foucault currents losses. Thus, in addition to the electrical requirements, the development of an appropriate model of the core dynamic behavior taking into account its segmented structure is urgent, in order to avoid resonances at any of the excitation frequencies. In the current proceeding, the influence of the core equivalent dynamic mechanical properties on a power transformer radiated noise was studied by performing a numerical parametric analysis. It was concluded that the active part stiffness properties, namely the directional component related to the out of lamination plane bending, ruled the vibroacoustic behavior of the transformer for the studied frequency range.

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.

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