Fernando Augusto Moreira

Latency Techniques Applied to the Transient Simulation of Transmission Lines Using the Z-Line Model

This paper presents an efficient technique for the transient simulation of transmission lines using the Z-line model. It is based on circuit latency exploitation, i.e., the possibility of using different and simultaneous integration steps in the time domain simulation of electric networks. For latency exploitation the original network is subdivided in subnetworks and each one is simulated with a time step according to its own requirements. With this approach the limitations of the Z-line model can be overcome, making it very attractive as the model of choice for accurate simulation of transmission lines

Illegal connection location on distribution lines using traveling waves method

The connection of loads on a main power cable causes a transient signal that propagate along the lines near the speed of light. Such signal is usually named a ‘Travelling wave’. Several techniques make use of TW signals for fault location in transmission lines. Based on the regular and known load of a network section of 13.8kV with extension 15.55km, a method for locating illegal clandestine connections in distribution lines is proposed. A computer model was developed using the ATP / EMTP® (Alternative Transients Program / Electromagnetic Transients Program) software, simulating a three-phase circuit. An illegal connection was simulated and had its position properly identified by the method based on the electromagnetic transient generated by the connection.

Statistical analysis of the relationship between payment behavior variables and delinquency in electricity consumption

This paper seeks to identify, through statistical analysis, the main variables that explain the phenomenon of default on residential electricity customers in the state of Bahia-Brazil. Identification and analysis of these variables is of great importance for building and operating models to support decision-making in favor of fighting delinquency. Database of residential consumers of Electricity Company of Bahia State (Coelba) are used as a study case. The analysis uses the concept of the Pearson correlation coefficient and bivariate method of Principal Component Analysis.

Analysis and application of transformer models in the ATP program for the study of ferroresonance

Ferroresonance is a phenomenon of complex nature which should be carefully analyzed so that preventive measures could be taken before its appearance may cause damages to electric power installations. There are some configurations as well as winding connections in transformers that may lead to the appearance of ferroresonance. In particular, middle-voltage underground networks formed by insulated cables, supplying unloaded or slightly loaded transformers. In order to identify the phenomenon and the nature of overvoltages, simulation is normally performed in EMTP-type programs. The ATP (Alternative Transients Program) has been chosen in this work. Several transformer models have been implemented in ATP, in particular the SATURABLE, BCTRAN and Hybrid (XFMR) models. The XFMR has been recently implemented in ATP and is still not yet widely known by the scientific community. Several simulations are performed with these models for typical configurations of distribution networks.