Substation is the most vital part of electrical
power system that should be operated continually and safely.
Ground grid is installed to help detecting ground faults and
assure safety of persons. In this paper IEEE 80-2013 was
utilized to make optimum design of substation ground grid.
A new cost function was proposed which is based on the
effective factors that affect grid performance. These factors
include number of horizontal conductors, cross-sectional
area of these conductors, grid burial depth, number of
ground rods, length of each rod and surface material
thickness. MATLAB software was used to design, study and
analyze the whole parameters affecting the grid
performance. The study of each of the mentioned parameters
has been used to develop weight factors based on the effect of
each parameter upon the grounding grid performance
represented in grounding grid resistance, mesh voltage and
step voltage. These weight factors were used in conjunction
with the proposed cost function to aid the search for the
optimum design of the grid. Genetic Algorithm (GA) utilized
this function to minimize the cost of the grid and avoid over
designing. This study was carried out on Future substation
220/22 kV located in Egypt. Results show that the use of cost
function only is not sufficient to give a reasonable optimum
design and the use of weight factors gives better and more
realistic options for optimum design. |
