An integrated technico-economical methodology for solving reactive power compensation problem

This paper provides a trade-off methodology for the solving reactive power compensation (RPC) problem. It is based on the full integration of two technical and economical aspects of the problem, that were previously considered either separately or combined as an objective function and its constraints. Minimization of the cost-economic function is based on the use of Y-matrix method. Voltage profile improvement is accomplished through a simplex algorithm based on the use of a sensitivity matrix (S). This paper proposes a modified computation of S in order to fit within the overall integration. The affinity of both technical and economical approaches, promotes this integration: both are based on linear programming techniques, coupled to the same load flow, and use similar Y and Z matrix components. The symmetry and sparsity characteristics of the Y matrix allow the reduction of the required mathematical calculations. This trade-off technique is tested on the IEEE 39-bus system. The modified simplex approach resulted in lower reactive power allocation while maintaining competitive voltage profile. Tests also showed that neither the technical nor the economical solution is complete by itself. A large scope of possible RPC allocations, is therefore provided to the decision maker to define his priorities and seek an 'optimal decision'.