Zaštita tronamotajnog energetskog transformatora zasnovana na faznoj komparaciji struja

2020 ◽  
Vol 22 (1-2) ◽  
pp. 36-43
Author(s):  
Jelisaveta Krstivojević ◽  
◽  
Zoran Stojanović ◽  
Milenko Đurić
Keyword(s):  
Power Transformer ◽  
Active Network ◽  
Test Results ◽  
Transformer Protection ◽  
Selective Protection ◽  
System Protection ◽  
Digital Phase ◽  
Passive Networks ◽  
Short Circuits ◽  
Index Terms

This paper presents a new algorithm for three-winding transformer protection against internal short circuits. The algorithm is based on the application of the digital phase comparison of currents measured at the primary, secondary and tertiary terminals of the power transformer. The applied digital phase comparison does not calculate the angle between the two currents compared in phase, but uses the method of integration of the product of two signals within one basic semi-period of the signals. In order to provide selective protection in the case where the power transformer has only one of its three windings connected to the active network and the other two windings feeding passive networks, an overcurrent function has been added to the digital phase comparator. The paper shows that the application of the new algorithm can successfully detect the internal faults of the three-winding transformer and ensure timely tripping of protection. The signals obtained by computer simulations were used to verify the operation of the proposed algorithm. The algorithm and test results are given in the paper. Index Terms- power system protection, power transformer, digital phase comparison, fault discrimination.

Rancang Bangun Piranti Lunak Pengolah Data Pasca Pengujian Terowongan Angin Kecepatan Rendah Indonesia

2016 ◽  
Vol 7 (2) ◽  
pp. 131-138
Author(s):  
Ivransa Zuhdi Pane
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Test Results ◽  
Effective Solution ◽  
Post Processing ◽  
Prototype Development ◽  
Design Activities ◽  
Index Terms ◽  
Test Objects ◽  
Processing Requirement

Data post-processing plays important roles in a wind tunnel test, especially in supporting the validation of the test results and further data analysis related to the design activities of the test objects. One effective solution to carry out the data post-processing in an automated productive manner, and thus eliminate the cumbersome conventional manual way, is building a software which is able to execute calculations and have abilities in presenting and analyzing the data in accordance with the post-processing requirement. Through several prototype development cycles, this work attempts to engineer and realize such software to enhance the overall wind tunnel test activities. Index Terms—software engineering, wind tunnel test, data post-processing, prototype, pseudocode

scholarly journals Recycling Heat Losses of an Oil-Immersed Transformer: Feasibility Study

2021 ◽  
Vol 21 (1) ◽  
pp. 48-54
Keyword(s):  
High Efficiency ◽  
Power Transformer ◽  
Heat Losses ◽  
Power Transformers ◽  
Passive Mode ◽  
Active Mode ◽  
Short Circuits ◽  
Definition Of ◽  
The Relationship ◽  
Novel Design

The paper investigates the feasibility of adding a liquid heater to an oil-immersed transformer. It proves that design the high efficiency of power transformers, losses due to idling and short circuits are substantial and are scattered in the environment as heat. The paper proposes a novel design that implements a liquid (coolant) heater to enable the unit not only to convert electricity, but also to generate heat. In order to analyze the feasibility of such heat recycling, the authors have developed an equivalent thermal circuit and a mathematical model thereof. Said heater can operate in two modes. In the passive mode, the coolant it contains only absorbs the heat emitted (lost) by the power transformer. In the active mode, it also receives the heat emitted due to the passage of electric current through the pipes of the heater. The paper further introduces the definition of heater efficiency. Studies have shown that up to 50 % of transformer heat losses can be recycled by heating the coolant in the heater. The paper presents the relationship between utilized heat and transformer losses, as well as heater efficiency as a function of coolant flow rate. The heater efficiency exceeds 90 % in the active mode.

scholarly journals ANALYSIS OF MONI SIS OF MONITORING OF THE A ORING OF THE AT-3 AUTOTRANSFORM TRANSFORMATOR IN T OR IN TashTES MODE

2019 ◽  
Vol 2019 (1) ◽  
pp. 209-217
Author(s):  
F Isakov
Keyword(s):  
Cooling System ◽  
Power Transformer ◽  
Short Circuit ◽  
Operation Mode ◽  
Wear And Tear ◽  
Basic Parameters ◽  
Short Circuits ◽  
One Year ◽  
Insulation Breakdown ◽  
Winding Insulation

The article considers the results of the analysis of autotransformers operation mode monitoring. The time diagram of active load current and oil temperature of autotransformer TashTES AT-3 is established and during one year changes of these variables and basic parameters of autotransformer were observed. Technical faults of the power transformer and high power autotransformer are established and methods of their elimination are determined. Damage of transformers and autotransformers with voltage of 110-500 kV of about 30% of the total number of outages which were accompanied by internal short-circuits and two main causes of damage were determined. The main causes of technological failures, which were not accompanied by internal short-circuits, are as follows: 20% of failures in operation of the onload tap-changer, 16% of oil leaks from the bushings, 13% of oil leaks and lowering of oil from the transformer due to violation of welded joints and rubber seals, 4% of engine damage to oil pumps of the cooling system, 3% of pressure increase in high-voltage hermetic bushings, 2% of film protection shell damage. The main reasons of technological violations accompanied by internal short-circuit in the transformer are as follows: breakdown of internal insulation of highvoltage bushings, insufficient short-circuit resistance, wear and tear of winding insulation, breakdown of insulation.

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