Electrical modeling of transformer connecting bars

Traditionally, connections in high-voltage, high-current, and low-frequency circuits are always considered as perfect short circuits, so to analyze their contribution to electrical performance of a structure is not considered necessary. We show here that, even for low-frequency structures, the electrical parasitic characteristics of cabling can lead to some unexpected performances. In particular, our study of outside connections of a 400 MVA transformer has shown current imbalances between the three phases and inside the phases. We achieved this by using a semianalytical method that is presented in this paper. Results show the need to model this part of the structure. This method has advantages over numerical techniques of calculation.

[1]  Automatic design of busbars considering electrical criteria , 2001, 2001 IEEE/PES Transmission and Distribution Conference and Exposition. Developing New Perspectives (Cat. No.01CH37294).

[2]  C. Hoer,et al.  Exact inductance equations for rectangular conductors with applications to more complicated geometries , 1965 .

[3]  Albert E. Ruehli,et al.  Inductance calculations in a complex integrated circuit environment , 1972 .

[4]  Edith Clavel,et al.  How to better know what happens inside a power multi chip module , 1997, PESC97. Record 28th Annual IEEE Power Electronics Specialists Conference. Formerly Power Conditioning Specialists Conference 1970-71. Power Processing and Electronic Specialists Conference 1972.

[5]  J. Roudet,et al.  Modeling of low inductive busbar connections , 1996 .

[6]  Fred C. Lee,et al.  Conducted EMI analysis of a boost PFC circuit , 1997, Proceedings of APEC 97 - Applied Power Electronics Conference.

[7]  Frederick Warren Grover,et al.  Inductance Calculations: Working Formulas and Tables , 1981 .

[8]  J. Roudet,et al.  Modeling of low inductive connections: the planar busbar structure , 1994, Proceedings of 1994 IEEE Industry Applications Society Annual Meeting.