When one or more transmission lines are added to an existing transmission system, the intensity of the fault currents flowing along the ground wires near the substations may exceed the ground wire thermal limit. In such cases, it is generally preferred to improve the existing ground wire conductivity by replacing say a steel groundwire with an ACSR ground wire along the first spans near the substation. Generally, this procedure requires that the transmission line be de-energized, what may sometimes be considered unacceptable. This paper deals with optional procedures which can be implemented in the first line kilometers near the substations keeping the existing lines energized. Such procedures include sectionalizing of groundwires, use of continuous counterpoise and use of additional overhead ground wires installed below the conductors. This paper introduces also a technique known as "tower foot resistance adjustment", which complements the corrective effects of the aforementioned procedures. >
[1]
S. T. Sobral,et al.
A proposal for ground measurement techniques in substations fed exclusively by power cables
,
1988
.
[2]
L. Levey.
Calculation of Ground Fault Currents Using an Equivalent Circuit and a Simplified Ladder Network
,
1982,
IEEE Power Engineering Review.
[3]
D. Mukhedkar,et al.
Dimensioning of nearby substations interconnected ground system
,
1988
.
[4]
S. T. Sobral,et al.
Ground potential rise characteristics of urban step-down substations fed by power cables-a practical example
,
1988
.
[5]
Janos Endrenyi,et al.
Analysis of Transmission Tower Potentials During Ground Faults
,
1967
.
[6]
S. T. Sobral,et al.
Grounding measurements at the Itaipu generating complex using the 'extended Eleck method'
,
1988
.