This paper describes a system for estimating load curves at Low Voltage Substations. The system is built by the aggregation of individual Fuzzy Inference Systems of the Takagi-Sugeno type. The model was developed from actual measurements forming a base of raw data of consumer behavior. This database allowed one to build large test and training sets of simulated LV substations, which led to the development of the Fuzzy System. The results are compared in terms of accuracy with the ones obtained with a previous Artificial Neural Network approach, with better performance.

A numerical computation of lowfrequency electromagnetic field near power apparatus and systems that may be used for analysis of O C C U~~~~O M~ and general public low *ency electromagnetic field exposure is described in this paper. The computation is based upon the integral equation approach and the usage of the method of moments for solving such equations. The charge that causes the irrotational component of electric field is c a t c u l a k i ' h m known potentials of wires. The rotational component of electromagnetic field is calculated from a priori known line-currents taking into account the influence of the induced eddy currents in earth. The application of the computation is illusirated by the analysis o f the occupational electromagnetic field exposure in a 400 kV substation at 50 Hz.

The article presents a numerical solution for the distribution of the electromagnetic and thermal fi elds of an air-core transformer using the fi nite element method. The distribution of the magnetic fi eld is determined for the dynamic steady state and magnetic nonlinear core characteristics. The model presented facilitates the establishment of criteria for optimizing transformer operation under various load conditions, environments as well as in the case of failures. Thus, the transformer can operate at maximum capacity while, at the same time, the probability of faults due to overheating is reduced to a minimum.

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