The paper presents the application of IntervalMathematics as
a new method to, rigorously, address uncertainties associated
with designing substation earthing grid system. While several
methods exist to determine the important factors for personnel
safety in and around substations such as earth resistance,
touch, step and mesh potentials of substation earthing grid,
these methods usually require data which may be uncertain in
nature. To account for such uncertainties the interval
mathematics is developed with the integration of input
parameters’ uncertainties, in interval format, into the
governing standard expressions mentioned on IEEE STD 80-
2000. The effects of uncertain inputs within the proposedmodel
are examined for various assumed levels of overall
uncertainties. To assess the relative contribution of each
uncertain input, an interval sensitivity analysis is carried out.
While catering for uncertainties, the method also offers utilities
with alternatives for selecting the standard conductor size to be
used. Successful implementation of the proposed method is
described for the design and configuration arrangement of a
115/13 kV substation earthing rectangular grid with ground
rods system.