This research presents an Analysis of Voltage Sags on the Installation of Distributed Generation in the Distribution System. The computer program PSCAD/EMTDC (Power Systems Computer Aided Design / Electromagnetic Transient in DC system) version 4.2 is applied to provide electrical parameters for the modeling and simulation and to analyze the fault occurred which resulted in voltage sag. Test results from PSCAD/EMTDC show the values of voltage sag when 5 types of fault are occurred (Single Line to Ground Fault Double Line to Ground Fault Three Phase to Ground Fault Line to Line Fault and Three Phase Fault). For all cases the value of root mean square voltage before fault is 100% or 1.0 pu. It can be seen that for both radial line and closed circuit when DG are installed in the system the value of phase to ground RMS residual voltage and phase to phase RMS residual voltage at the bus of Bang-pa-in 2 substation are more than the values in case of the system without DG.

The fault in a power distribution system disturbs the power dispatch under normal conditions therefore decreases the quality of the electric power. The single line to ground fault is an asymmetric fault that may have a high percentage chance to happen. The kind of fault changes power and voltage dramatically. The size of the phase voltage decreases which affect the economic damage of the system. This paper presents an analysis of grounding systems to reduce voltage drop in a power distribution system by using the technical analysis system in case of one phase to ground fault. The objective is to minimize voltage drop for users using the simulation with single line to ground fault in distribution system voltage level at 22 kV PEA’s test system. The simulation utilizes the EMTDC-PSCAD program. The results show that the grounding method can reduce the voltage drop and reduce the damage of the economic system