Multiple fault analysis of delta-star transformer banks

Abstract

The paper briefly describes the recent method advocated by J.C. Neupauer in America for dealing with the simultaneous application of single-line-to-earth faults on opposite sides of a delta-star transformer bank, and proceeds to compare this method with matrix methods of attack based on the work of Kron. The comparison of the two methods of approach demonstrates the inherent advantages possessed by the matrix treatment.The classical method of solution involves a large amount of nonstandard computation, and necessitates the employment of technical staff throughout. On the other hand, a swift formulation of the problem in matrix terms permits the mechanical solution to be performed by automatic means, or alternatively, by clerical staff.Neupauer's method cannot be readily extended to the study of simultaneous dissymmetries other than earth faults; the application of matrix techniques, however, causes no further complication in principle, and conciseness is retained.This versatility is illustrated by applying the matrix methods to the case of the simultaneous application of an earth fault and a double-line-to-earth fault on opposite sides of the transformer bank.