Short-Circuit Calculations for Multiline Switching and End Faults

In the short-circuit study of a network with mutually coupled lines, complications in calculation are introduced by the consideration of line removals, additions, impedance changes, and end faults. The modification of Z-bus terms to include these network changes is facilitated by the new algorithms presented in this paper. These new algorithms conform to a unified formulation for all the types of network changes mentioned, a feature that simplifies programming and reduces computer storage and processing time. In contrast with previously known algorithms, the new algorithms are simpler and are one-step procedures, i. e., the desired Z-bus modifications are obtained directly from original Z-bus and branch admittance data in one operation.