The analysis of power systems has in the past been directed mainly towards the solution of the fundamental problem of load-flow. Commercial computer programs, which were produced to deal initially with this steady-state problem, have become progressively more complex in order to cater for unbalanced and transient situations such as fault level, stability and harmonic penetration. Despite the sophistication of many of the available programs, there exists a class of problem for which they remain, as yet, unsuited.