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An approach for solving reactive power planning problems is presented, which is based on binary search techniques and the use of a special heuristic to obtain a discrete solution. Two versions were developed, one to run on conventional (sequential) computers and the other to run on a distributed memory (hypercube) machine. This latter parallel processing version employs an asynchronous programming model. Once the set of candidate buses has been defined, the program gives the location and size of the reactive sources needed (if any) in keeping with operating and security constraints. Keywords: Reactive Power Planning; Parallel Processing; Binary Search; Heuristic Methods

This paper describes the implementation of a Monte Carlo based short-circuit analysis package in a hypercube parallel computer. The program generates accurate estimates of short-circuit current probability distribution curves which can be used in a variety of planning and design studies. Both network modeling aspects, such as network reduced equivalencing and mutual coupling representation, as well as the impact of the sample sizes used in Monte Carlo simulations are fully analyzed and illustrated by numerical results obtained testing on real-world systems. These examples clearly illustrate how computational efficiency in parallel machines varies with the ratio of communication to computation (communication overhead) and of the load balancing among the parallel computer processors.

Observability analysis based exclusively on topological information may lead to systems whose state cannot be estimated by regular state estimation methods. This paper discusses some practical situations in which the presence of the so called discardable measurements may pass undetected by topological observability analysis. As a consequence, wrong results, or even convergence problems, may occur. A numerically based observability analysis procedure is suggested for handling such cases; the new technique is an extension of previously published work on numerical observability analysis. The technique is fully illustrated by small scale examples taken from a real-life system where difficulties with discardable measurements have been observed.