SANTOS, W. C.; http://lattes.cnpq.br/0420215126997916; SANTOS, Wellinsílvio Costa dos.
Résumé:
High impedance faults (HIF) are serious and troubling disturbances in distribution systems
of electric power. Due to their fault current low levels, the main power system protection
devices are not able to diagnose them accurately. In this sense, HIF detection and location
methods have been the focus of many researches. Such methods are often validated with
the aid of computer simulations. The closer these models can reach the characteristics
found in real phenomenon, the more reliable will be the diagnostic algorithms based on
them. Thus, this paper presents a model of HIF which takes into account the main fault
currents characteristics of the disturbance, such as: low levels of overcurrent, asymmetry
between the half-cycles, nonlinearity, buildup, shoulder, and intermittence. The model is
based on actual HIF oscillographic data obtained in field tests. Simulations were performed
in ATP software and the model was implemented by using MODELS. At the end, it was
obtained a model that takes into account the type of contact surface, and simulates a larger
number of features than the evaluated models. With a specific model for each type of
surface, it was created a database composed of records with IEEE COMTRADE standard.
This pattern is used for most digital fault recorders (DFRs), qualimeters, and relays of the
electrical system, allowing, in this way, actual data to be inserted to the simulated database
without needing any kind of format conversion.