DIAS, A. D.; http://lattes.cnpq.br/8016439503561492; DIAS, André Dantas.
Abstract:
For many years, most of the measurement techniques applied to grounding grids were
only possible to be used in de-energized substations. However, in the recent decades,
several measurement techniques applicable to energized substations have been
developed, whose main goal is to perform measurements that provide a fast grid
evaluation, safely and without harming quality and continuity of power supply. In this
work, six substations grounding grids were studied. Several analysis techniques of
grounding grid conditions were applied in order to obtain more accurate and reliable
diagnosis. For this, were applied known techniques, such as: measurement of ground
resistivity, touch voltage and step voltage; and proposed techniques like: measurement
of grounding resistance in energized installations and measurement of surface
potentials, having their data treated and analyzed by a developed computational routine,
based on the Finite Difference Method (FDM). The results of grounding grids resistance
measurement, using the proposed method, were compared to results obtained through a
traditional measurement method (de-energized substation) as well as those obtained
through software simulation. Through the comparison of these results, the proposed
technique was validated. The developed computational routine was able to calculate and
display, through two-dimensional and three-dimensional graphics, the potentials
distribution on the ground surface. The graphic analysis of the surface potentials
through time allows monitoring and analysis of grounding grids conservation status.
The diagnosis obtained from the set of used measurement techniques proved to be
effective. Periodic measurements (semiannual) of grounding grids are recommended, in
order to monitor and analyze its aging over time.