Stray Loss
Konèar
PowerTransformers
Ltd.
A Joint Venture of
Siemens and Konèar
STRAY LOSSES
HOW TO REDUCE THEM AND WHY?
KPT-OIPT 013E, Published 02.2000.
Generally, there is a simplified understanding that the socalled load losses in a transformer (load losses, PL ) depend on the ohmic resistance of the windings. This is only partly true, as the losses arising from magnetic leakage flux in various metal parts of a transformer constitute a significant part of the total losses. This component of total losses is called stray (additional) loss (Ps ). In addition, experts distinguish between the stray losses in the windings (winding eddy loss: eddy-current loss in conductors, and circulating-current loss in parallel strands) and outside the windings (stray
2
1
magnetic shield on the tank
2
yoke clamping plate
3
core
The company Konèar Power Transformers (KPT) has been applying for over 25 years of a systematic approach in the research, control and continuous reduction of stray losses from magnetic leakage flux. Here are only several segments resulting from the complex and variegated activity,
i.e. achievements.As opposed to the ohmic losses I2R, the calculation of stray losses represents an exceptionally complex process, for which there is still no standardised method of determining them in the transformer calculation phase.The basis for the calculation of stray losses is the knowledge of the magnetic leakage field in a transformer. The main tool for solving this problem in KPT is a computer programme for the calculation of the magnetic leakage field in the transformer window, by means of which the magnetic field in a cylindrical coordinate system is determined at any point in or around the winding. Although stray losses, as a rule, are linked with the magnetic leakage field of windings, the high-current loops and their respective magnetic fields should not be neglected. Generally, stray losses
appear
PowerTransformers
Ltd.
A Joint Venture of
Siemens and Konèar
STRAY LOSSES
HOW TO REDUCE THEM AND WHY?
KPT-OIPT 013E, Published 02.2000.
Generally, there is a simplified understanding that the socalled load losses in a transformer (load losses, PL ) depend on the ohmic resistance of the windings. This is only partly true, as the losses arising from magnetic leakage flux in various metal parts of a transformer constitute a significant part of the total losses. This component of total losses is called stray (additional) loss (Ps ). In addition, experts distinguish between the stray losses in the windings (winding eddy loss: eddy-current loss in conductors, and circulating-current loss in parallel strands) and outside the windings (stray
2
1
magnetic shield on the tank
2
yoke clamping plate
3
core
The company Konèar Power Transformers (KPT) has been applying for over 25 years of a systematic approach in the research, control and continuous reduction of stray losses from magnetic leakage flux. Here are only several segments resulting from the complex and variegated activity,
i.e. achievements.As opposed to the ohmic losses I2R, the calculation of stray losses represents an exceptionally complex process, for which there is still no standardised method of determining them in the transformer calculation phase.The basis for the calculation of stray losses is the knowledge of the magnetic leakage field in a transformer. The main tool for solving this problem in KPT is a computer programme for the calculation of the magnetic leakage field in the transformer window, by means of which the magnetic field in a cylindrical coordinate system is determined at any point in or around the winding. Although stray losses, as a rule, are linked with the magnetic leakage field of windings, the high-current loops and their respective magnetic fields should not be neglected. Generally, stray losses
appear