3D Stray Field Analysis of Transformer Cores Considering DC-bias

• Autorzy: Mulasalihovic E. , Pfutzner H. , Zanolin P.

Warianty tytułu

PL

Analiza 3D pola rozproszonego rdzenia transformatora podmagnesowanego polem stałym

• Języki publikacji: EN

Abstrakty

EN

The paper presents experimental analyses of stray field configurations of a 3-phase/3-limb model transformer core. Core-tank interactions are roughly simulated arranging a steel plate above the core. The paper considers also DC-bias, caused e.g. by geomagnetically induced currents (GICs). For the determination of stray field distributions B(x,y,z,t) an automatic scanning system was applied, based on the 3D Hall sensor method. A sensor with four needle contacts was used for non-destructive 2D analyses of local distributions of eddy current fields E(x,y,t) as arising at the upper and lower surface of the simulated tank material. The results reveal strong increases of stray field through weak bias if arising in a nonbalanced way. In the tank simulation plate, mainly cross-sectional eddy currents are generated, flowing perpendicular to the limbs as a rough tendency. Bias yields very strong enhancements of eddy current losses. Above the tank simulation, a considerably strong rest stray field arises. As a rough tendency, it is directed from one yoke to the other one, however, with complex reconstructions as a function of time. The novel methodology promises to complement traditionally performed numerical analyses in a effective way.

PL

Przedstawiono analizę pola rozproszonego w trzyfazowym modelu rdzenia transformatora podmagnesowanego polem DC. Źródłem takiego pola mogą być na przykład pola geomagnetyczne. Zastosowano automatyczny system skanera wykorzystującego czujnika Halla. Do analizy pola elektrycznego od prądów wirowych wykorzystano czujniki igłowe. Badania wykazały znaczący wpływ podmagnesowania. Zbiornik symulowano przy użyciu płytki stalowej. Podmagnesowanie znacząco zwiększało też straty od prądów wirowych.

Słowa kluczowe

EN

transformer cores; stray field; eddy current field; dc-magnetization; geomagnetically induced currents; GICs; electrical technology; electrical power engineering

PL

rdzeń transformatora; prądy wirowe; podmagnesowanie; elektrotechnika; elektroenergetyka

• Wydawca: Wydawnictwo SIGMA-NOT
• Czasopismo: Przegląd Elektrotechniczny
• Rocznik: 2011
• Tom: R. 87, nr 9b
• Strony: 57--60
• Opis fizyczny: Bibliogr. 6 poz., rys., tab., wykr.

Twórcy

autor

Mulasalihovic E.

autor

Pfutzner H.

autor

Zanolin P.

• Vienna University of Technology, Institute of Electrodynamics Microwave and Circuit Engineering, Gusshausstr. 27, A-1040 Vienna, Austria,

Bibliografia

• [1] Guidelines for limiting exposure to time-varying electric, magnetic and electromagnetic fields (up to 300 GHz) International Commission on Non-Ionizing Radiation Protection. Health Phys. 54 (1998), 115-123
• [2] Molinski T.S., Why utilities respect geomagnetically induced currents, J.Atm. & Solar-Terrestr. Phys. 64 (2002), 1765-1778
• [3] S.Lu, Y.Liu, FEM analysis of DC saturation to assess transformer susceptibility to geomagnetically induced currents, IEEE Trans.Power Deliv. 8 (1993), 1367
• [4] E. Mulasalihovic, H. Pfützner, P. Zanolin, Complete surfaceanalysis of model transformer core considering dc-magnetization components, El.Rev.(Prz.Elektrot.) 85 (2009), 43-46
• [5] Pfützner H., Krismanic G., The needle method for induction tests - sources of error, IEEE Trans.Nagn.40 (2004),1610-1616
• [6] G.Krismanic, E.Leiss, S.Barsoum, H.Pfützner, Automatic scanning system for the determination of local loss distributions in magnetic cores, J.Magn.Magn.Mater. 254-255 (2003), 60-63