A method of analyzing unsymmetrical faults on six-phase power systems

The use of six-phase (and other higher order phase) systems for power transmission was proposed as an alternative for using electrical rights-of-way more effectively and efficiently. One of the important items in applying the six-phase alternative in transmission planning is the design of an adequate protective scheme. This requires a detailed and realistic fault analysis. The 23 significant fault types (symmetrical or asymmetrical) that can occur in six-phase power systems are analyzed. The theory of three-phase symmetrical components is used to develop a method for such analysis. The validity of the proposed method is checked by application to a simple system under a single line-to-ground fault, and three line-to-ground, five line-to-ground, and six line-to-ground faults. The advantage of the method is its applicability to all significant faults that occur on six-phase power systems