Abstract:
This thesis presents the simulation model of a monopole for power transmission line 69 kV, single circuit type of Metropolitan Electricity Authority (MEA) witharrangement phase sequence conductor vertical and each phase have two strands bundle conductor by using ATP-EMTP Program. Parameter simulation of ground rod is divided into two cases; power frequency resistance and impulse impedance. Both of parametersare changed the length from 1.8metres to 2.4, 3, 4, 5 and 6 metres respectively and every length of ground rod had added number from 1 rod to 2, 3, 4 and 8 rods. The supply is generated 10/350 s lightning impulse current of 20 kA magnitudeon the top of monopole which is an overhead ground wire (OHGW).Then, the voltage on the top monopole have analysed for the system and overvoltage in the phase conductor.
The simulated results have shown that the surge impedance of monopole structure are 293.765 Ω and both amplitude of impedance model of ground rod are decreased when increase length or increase number of ground rod. An increasing of ground rod number will be give impedance of ground rod better than increasing of ground rod length. However, the installation of a suitable ground rod number is 4 rodsif the number of rod more than that it will affect to the stability of the system. Therefore, the installation of ground rod number is necessary to take into account of the political economy.