Análise de defeitos em coordenadas de fase utilizando modelagem a quatro condutores e fluxo de potência continuado

Abstract

The effects of neutral wires and system grounding in most power flow and fault analysis methodologies are neglected or merged into phases using Kron’s reduction method. Thus, the neutral wire and ground currents and voltages remain unknown, restricting the analysis. This work presents a new formulation for fault analysis in the phase domain using three-phase, four-wire modeling, in which the neutral wires and grounding impedances explicitly represented. Unbalanced systems and loads, mutual impedances, dispersed generation, transformers with the most varied forms of grounding and connections are also represented in modeling. In additional, the loads can be represented as constant power, constant current, constant impedance or any combination among these models during the fault analysis. The solution methodology is based on the continuation power flow technique, where the fault impedances are continuation parameters. The proposed algorithm is of general usage and can be used to solve any kind of fault in transmission, subtransmissão, distribution and industrial systems. Several faults, simple and simultaneous, were conduct in academicals systems, IEEE distribution test feeders and real power systems. Simulation results show the efficiency of the proposed methodology for fault analysis, highlighting voltage sag studies.