In-plane Flux Distribution in 45 T-joint of 3Phase Transformer Core with Staggered Yoke 10mm

Abstract

This paper describes the result of measurement of in-plane flux distribution on 100kFA 3phase distribution transformer assembled with 43 T-joint and mitred lap comer joint with stagger yoke of 10mm. The measurement involves the fundamental third and fifth harmonic of the easy and hard direction of flux density at each location measurement. The flux distributions have been measured using no load test by arrays of search coil in M5 (CGO) grades material of transformer core laminations. The localised flux density at the outer 43 Tjoint is 0,147T and rises to be 0,206T at the inner edges of 45 T-joint when the transformer cove energized 1.5 T 50Hz. Harmonic occurs mostly in the Tjoint where local regions are saturated and the flux deviates from the rolling direction. A small amount of flux deviation from the rolling direction occurs at the overlap, but no rotational flux is present in the joint. This paper describes the result of measurement of normal flux distribution on 100kVA 3phase distribution transformer assembled with 45 T-joint and mitred lap corner joint with staggered yoke of 10mm. The Investigation involves the variation of normal flux distribution In the core lamination. The normal flux distribution has been measured using me load test oy arrays of search coil The highest normal flux distribution occurs at the comer edge of the center limb that is 0.158T and lowest at upper edge of poke that is 0.092T. The average value of normal flux distribution is high at flux transfer region of the lamination. The flux transfer mechanism shows that two separate path flowing horizontally in the yoke before leaving the lamination to vertically adjacent layer and combine with the flux in that layer. Then, if will transfer back to origin region and extend through the center limb.