Measurement of Magnetic Properties of Electrical Steels At High Flux Densities Using An Improved Single Sheet Tester

Fundamental knowledge of the magnetic properties of electrical steels isessential to design a reliable and efficient transformer. It also helps predict thetransformer performance under extreme operating conditions such as the high fluxdensity scenario. However, the current relevant IEC standards on methods ofmeasurement of electrical steels? magnetic properties only cover the flux densities up to 1.80 Tesla, and indeed those methods are unable to measure the steel characteristics when approaching deep saturation. In this paper, an improved single sheet tester (SST) with magnetic flux waveform control is introduced to measure the AC magnetic properties of electrical steels at high flux densities up to their nominal saturation magnetization. It utilizes the B-coil instead of the standard SST secondary winding to measure the flux density, which largely reduces the error caused by the air flux when the steel is in saturation. The performance of this improved SST is verified by measuring magnetic properties of high-permeability grain-oriented (HGO) 3% silicon steel at 50 Hz up to 2.0 T.The necessity of using H-coil in saturation is also investigated and discussed here. The improved SST would then contribute to a better understanding of the electrical steel behaviours in deep saturation.

[1]  J. Sievert,et al.  Determination of AC magnetic power loss of electrical steel sheet: Present status and trends , 1984 .

[2]  S. L. Burgwin.  A Method of Magnetic Testing for Sheet Material , 1936 .

[3]  G. Bertotti,et al.  Connection between microstructure and magnetic properties of soft magnetic materials , 2008 .

[4]  Z. D. Wang,et al.  Electrical steels and power transformer cores in deep saturation , 2012, 2012 IEEE International Conference on Condition Monitoring and Diagnosis.

[5]  L. Bolduc.  GIC observations and studies in the Hydro-Quebec power system , 2002 .

[6]  Takaaki Yamamoto,et al.  Single sheet tester for measuring core losses and permeabilities in a silicon steel sheet , 1974 .

[7]  T. Meydan,et al.  Use of novel adaptive digital feedback for magnetic measurements under controlled magnetizing conditions , 2005, IEEE Transactions on Magnetics.

[8]  F. Brailsford,et al.  Iron losses at high magnetic flux densities in electrical sheet steels , 1955 .

[9]  Qing-Chang Qu.  Precise magnetic properties measurement on electrical sheet steels under deep saturation , 1984 .

[10]  J. D. Lavers,et al.  Prediction of core losses for high flux densities and distorted flux waveforms , 1976 .

[11]  Bertrand Poulin,et al.  Transformer Design Principles: With Applications to Core-Form Power Transformers , 2001 .

[12]  P. Pillay,et al.  An improved formula for lamination core loss calculations in machines operating with high frequency and high flux density excitation , 2002, Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344).

[13]  Carlo Stefano Ragusa,et al.  Magnetic losses at high flux densities in nonoriented Fe–Si alloys , 2008 .

[14]  J.G. Kappenman,et al.  Geomagnetic Storms and Their Impact on Power Systems , 1996, IEEE Power Engineering Review.

[15]  J. McFarlane,et al.  The control of flux waveforms in iron testing by the application of feedback amplifier techniques , 1958 .

[16]  J. Sievert.  The measurement of magnetic properties of electrical sheet steel survey on methods and situation of standards , 2000 .

[17]  N. Takahashi,et al.  Development of Measurement System of Magnetic Properties at High Flux Density Using Novel Single-Sheet Tester , 2009, IEEE Transactions on Magnetics.

[18]  Z.D. Wang,et al.  2-D Finite-Element Electromagnetic Analysis of an Autotransformer Experiencing Ferroresonance , 2009, IEEE Transactions on Power Delivery.