A method for studying sequential faults on a three phase distribution transformer

"A method has been presented for studying sequential faults on opposite sides of a three-phase distribution transformer using the theory of symmetrical components and Alpha, Beta, and Zero components of three-phase systems. The effect of the faults on the distribution system has also been analyzed and improvements in the protection scheme suggested. The sequential faults occurred, one after the other, on the distribution system of the Central Electric Power Cooperative of Jefferson City in the state of Missouri resulting in a double unbalanced fault condition. The data used in the example problem has been supplied through the courtesy of the above Cooperative. The problem has been solved in three stages, namely, for a two line to ground fault, an open conductor and the resulting double fault conditions with grounded transformer as well as with the ungrounded transformer when the grounding wire of the transformer burns out"--Abstract, page ii.