The magnetizing current as a tool for on-line transformer core diagnostics

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Project abstract

The no-load current of a power transformer can give a lot of information about the state of the core. Changes and problems in the core will give different characteristic signatures in the no-load current, and these signatures are in many cases quite pronounced. However, the complex interaction between the electrical and magnetic circuits of a three-phase transformer makes the behavior of a healthy transformer very difficult to predict, and it is therefore difficult to diagnose a transformer unless it can be compared to an identical unit, or to an earlier measurement of the same unit. To deal with this, this project focuses on developing more advanced simulations and diagnostic techniques.

Summary of work

2015-2016: An existing transformer simulation model has been improved by introducing hysteresis, and by implementing a more detailed core geometry. In order to improve the accuracy, a new approximation of the static hysteresis curve of has been developed for the most common grade of tranformer steel.

2015: Measurements have been performed on a 1 MVA transformer, and simple faults were introduced in the core in order to study the changes in the no-load current caused by those faults.

Two power transformers in operation are being studied in order to determine if they have a change or problem in their cores.

Event log

2014: The technique for measuring the magnetization of full-size single-phase power transformers was presented at the 13th International Workshop on 1&2-Dimensional Magnetic Measurement and Testing in Torino, Italy.

2016: The simulation method was presented at the Advances in Magnetics conference in Bormio, Italy.

2016: The static-hysteresis approximation technique was presented at the Joint European Magnetics Symposia in Glasgow, UK

2016: The method for finding and diagnosing faults was presented at the 14th International Workshop on 1&2-Dimensional Magnetic Measurement and Testing in Tianjin, China.

Project reference-group

Niclas Schönborg,  Svenska kraftnät
Eskil Agneholm,  Ellevio
Kurt Gramm,  ABB Power Grids
Bengt Jönsson,  ABB Power Grids
Torbjörn Wass,  ABB Corporate Research
Göran Engdahl,  KTH

Publications by this researcher

See alternatively the researcher's full DiVA list of publications, with options for sorting.
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Magnetizing Currents in Power Transformers : Measurements, Simulations, and Diagnostic Methods
Claes Carrander.
2017,   Thesis (PhD), KTH Royal Institute of Technology, TRITA-EE 2017:042

A semi-empirical approximation of static hysteresis for high flux densities in highly grain-oriented silicon iron
Claes Carrander,   Göran Engdahl.
2017,   8th Joint European Magnetic Symposia, JEMS 2016, Glasgow, United Kingdom, 21 August 2016 through 26 August 2016

An application of the time-step topological model for three-phase transformer no-load current calculation considering hysteresis
Claes Carrander,   Seyedali Mousavi,   Göran Engdahl.
2017,   Journal of Magnetism and Magnetic Materials, vol. 423

On methods of measuring magnetic properties of power transformers
Claes Carrander.
2015,   Thesis (Licentiate), Kungliga Tekniska högskolan, TRITA-EE 2015:013

Magnetizing current measurements on full scale power transformers
Claes Carrander,   Göran Engdahl.
2015,   International journal of applied electromagnetics and mechanics, vol. 48(2-3)

Comprehensive Study on Magnetization Current Harmonics of Power Transformers due to GICs
Seyedali Mousavi,   Göran Engdahl,   Claes Carrander.
2013,   International Conference on Power Systems Transients (IPST2013) in Vancouver, Canada July 18-20, 2013

Electromagnetic transients due to interaction between power transformers and network during a GIC attack
Seyedali Mousavi,   Göran Engdahl,   Claes Carrander.
2013,   Cigre2013

Publication list last updated from DiVA on 2024-01-10 15:21.

Page started: 2015-09-01
Last generated: 2024-01-10