Analysis of internal winding short circuit faults in power transformers using transient finite element method coupling with external circuit equations

Power transformers play an indispensable component in AC transmission systems. If the operating condition of a power transformer can be accurately predicted before the equipment is operated, it will help transformer manufacturers to design optimized power transformers. In the optimal design of the power transformer, the design value of the magnetic flux density in the core is important, and it affects the efficiency, cost, and life cycle. Therefore, this paper uses the software of ANSYS Maxwell to solve the instantaneous magnetic flux density distribution, core loss distribution, and total iron loss of the iron core based on the finite element method in the time domain. . In addition, a new external excitation equation is proposed. The new external excitation equation can improve the accuracy of the simulation results and reduce the simulation time. Finally, the three-phase five-limb transformer is developed, and actually measures the local magnetic flux density and total core loss to verify the feasibility of the proposed finite element method of model and simulation parameters.

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Simulation of a Superconductor Fault Current Limiter with finite element method using A-V-H formulation

10.48011/sbse.v1i1.2229 ◽

2020 ◽

Author(s):

Gabriel Dos Santos ◽

Flávio Goulart dos Reis Martins ◽

Bárbara Maria Oliveira Santos ◽

Daniel Henrique Nogueira Dias ◽

Guilherme Gonçalves Sotelo ◽

...

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Simulation Analysis ◽

Short Circuit ◽

Normal Operation ◽

Fault Current ◽

Fault Current Limiter ◽

Current Limiter ◽

H Formulation ◽

Element Method

Nowadays, the complexity of electrical power systems is increasing. Consequently, the occurrence and the amplitude of the fault current are rising. This fault currents harm the substations’ electrical equipment. Besides, the growth in the fault current level is forcing the change of the circuit breakers to others with a higher interruption capability. A proposal to solve this problem is the fault current limiter (FCL). This equipment has low impedance in the normal operation and high impedance in a short circuit moment. Superconductors are an advantageous choice of material in this case, because of their properties. In order to simulate this equipment, the 2-D Finite Element Method (FEM) has been used. In this paper, a novel FEM simulation analysis of the saturated core Superconductor Fault Current Limiter (SFCL) is proposed using the A-V-H formulation. The current distribution in the superconducting coil is observed. The results are compared to the limited fault current measurements and simulations available in the literature.

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Leakage flux and force calculation on power transformer windings under short-circuit: 2D and 3D models based on the theory of images and the finite element method compared to measurements

IEEE Transactions on Magnetics ◽

10.1109/20.312690 ◽

1994 ◽

Vol 30 (5) ◽

pp. 3487-3490 ◽

Cited By ~ 30

Author(s):

A.G. Kladas ◽

M.P. Papadopoulos ◽

J.A. Tegopoulos

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Power Transformer ◽

Short Circuit ◽

3D Models ◽

The Finite Element Method ◽

Leakage Flux ◽

2D And 3D ◽

Force Calculation ◽

Element Method

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An analysis of inter-bar currents on a polyphase cage induction motor

Sba Controle & Automação Sociedade Brasileira de Automatica ◽

10.1590/s0103-17592004000400011 ◽

2004 ◽

Vol 15 (4) ◽

pp. 476-484

Author(s):

Renato Carlson ◽

Cláudia A. da Silva ◽

Nelson Sadowski ◽

Michel Lajoie-Mazenc

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Induction Motor ◽

Induction Motors ◽

Short Circuit ◽

Fundamental Component ◽

Cage Induction Motor ◽

Element Method

This work uses a methodology based on 2D-Finite Element Method (FEM) and on the Circuits Theory (Independent Currents Method) to analyze the inter-bar currents on the rotor of cage induction motors. The Multi-Slice Technique is used to consider the skewing effect. Three conditions are considered: one inter-bar resistance, two inter-bar resistances and three inter-bar resistances. The results show the distribution of currents in the rotor bars, short-circuit rings and transversal resistances at a given time. The fundamental component of the inter-bar and surrounding bar currents are shown to help understanding the phenomenon.

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