Diagnosis of a turn-to-turn short circuit in power transformers by means of zero sequence current analysis

2004 ◽  
Vol 69 (2-3) ◽  
pp. 321-329 ◽  
Author(s):  
Guzmán Dı́az González ◽  
Javier Gómez-Aleixandre Fernández ◽  
Pablo Arboleya Arboleya
Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3266
Author(s):  
Antonio Roniel Marques de Sousa ◽  
Marcus Vinicius Alves Nunes ◽  
Wellington da Silva Fonseca ◽  
Ramon Cristian Fernandes Araujo ◽  
Diorge de Souza Lima

The main equipment responsible for connection and transmission of electric power from generating centers to consumers are power transformers. This type of equipment is subject to various types of faults that can affect its components, in some cases also compromising its operation and, consequently, the electric power supply. Thus, in this paper, electromagnetic, thermal, and structural analysis of power transformers was carried out with the objective of providing the operator with information on the ideal moment for performing predictive maintenance, avoiding unplanned shutdowns. For this, computational simulations were performed using the finite element method (FEM) and, from that, the different transformer operation ways, nominal currents, inrush current, and short-circuit current were analyzed. In this perspective, analyses of the effects that thermal expansion, axial forces, and radial forces exerted were carried out, contributing to possible defects in this type of equipment. As a study object, simulations were carried out on a 50 MVA single-phase transformer. It is important to emphasize that the simulations were validated with real data of measurements and with results presented in the current literature.


2014 ◽  
Vol 8 (2) ◽  
pp. 250-260 ◽  
Author(s):  
Bashir Mahdi Ebrahimi ◽  
Saeed Saffari ◽  
Jawad Faiz ◽  
Alireza Fereidunian

Author(s):  
Antonio R. M. Sousa ◽  
Wellington Da S. Fonseca ◽  
Marcus V. A. Nunes ◽  
Ramon C. F. Araujo ◽  
Diorge de S. Lima

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 691 ◽  
Author(s):  
Ju-Yong Kim ◽  
Ho-Sung Kim ◽  
Ju-Won Baek ◽  
Dong-Keun Jeong

Low-voltage direct current (LVDC) distribution has attracted attention due to increased DC loads, the popularization of electric vehicles, energy storage systems (ESS), and renewable energy sources such as photovoltaic (PV). This paper studies a ±750 V bipolar DC distribution system and applies a 3-level neutral-point clamped (NPC) AC/DC converter for LVDC distribution. However, the 3-level NPC converter is fundamental in the neutral-point (NP) imbalance problem. This paper discusses the NP balance control method using zero-sequence voltage among various solutions to solve NP imbalance. However, since the zero-sequence voltage for NP balance control is limited, the NP voltage cannot be controlled to be balanced when extreme load differences occur. To maintain microgrid stability with bipolar LVDC distribution, it is necessary to control the NP voltage balance, even in an imbalance of extreme load. In addition, due to the bipolar LVDC distribution, the pole where a short-circuit condition occurs limits the short current until the circuit breaker operates, and a pole without a short-circuit condition must supply a stable voltage. Since the conventional 3-level NPC AC/DC converter alone cannot satisfy both functions, an additional DC/DC converter is proposed, analyzed, and verified. This paper is about a 3-level NPC AC/DC converter system for LVDC distribution. It can be used for the imbalance and short-circuit condition in bipolar LVDC distribution through the prototype of the 300 kW 3-level NPC AC/DC converter system and experimented and verified in various conditions.


2020 ◽  
Vol 35 (2) ◽  
pp. 1048-1057
Author(s):  
Haytham Saeed ◽  
Mariana Kamel ◽  
Abdelrahman Karrar ◽  
Ahmed H. Eltom ◽  
Mark Bowman

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