Fuzzy power flow: considerations and application to the planning and operation of a real power system

The deregulation of the electric sector has involved the restructuring and privatization of many power systems and consequently the electric markets are essentially competitive. Power quality, economy, reliability and security are some of the main issues of the current power systems. In order to meet those objectives some advanced analysis methods must be adopted. Thus, the conventional deterministic power flow program (PF) may be enhanced with the incorporation of uncertainties in the generation and loads. An extension of the PF is the fuzzy power flow (FPF), which may be used to obtain efficient and extended diagnostics of the power system operation for planning applications. The PF may not be able to foresee some extreme cases of operation that do not correspond with the maximum and minimum loading limits. In this paper the considerations for the application of the fuzzy power flow for the planning and operation of practical power systems are discussed. Special attention is given to the nonlinearity of the power flow problem taking into account uncertainty and the linking with a voltage stability function based on the use of eigenvalues and eigenvectors. All of these concepts have been implemented in the commercial grade interactive power flow program WINFLU that is an official tool in the Peruvian electrical sector. Tests results using a configuration of the Peruvian interconnected power system (SEIN) are included and they demonstrate the validity of the fuzzy concepts as applied to a more robust planning and operation of this power system.