
17-16 Electrical Variables
against the real HST measurements. Four dierent HST proles have been considered, each one associ-
ated with dierent operating conditions of the power transformer.
To approximate the HST variations described in a data set consisting of 870 quadruplets of the form
[Θ
TO
(k − 1), Θ
TO
(k − 2), I
L
(k − 1)|HST(k)], an FNN with 3D Gauss–Hermite basis functions has been
used, containing 64 nodes in its hidden layer. e spectral components of the HST signal for both the
fault-free and the under-fault operation of the power transformer have been shown in Figures 17.10a
through 17.13a. Note that aer a fault has taken place in