The faults in a power distribution system do not only impact to power outage directly. They also cause voltage sag problem spread over the system. A single-line to ground fault is about 70% of the overhead system faults. The magnitude and duration of voltage sag causes the economic damage of the system. This paper presents an analysis of the different systems grounding to mitigate the voltage sag 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 by the computer program. The results show that the grounding method can mitigate the voltage sag and reduce the damage of the economic system.

This thesis offers the design of the impulse generator 1.2 / 50 μs which applies for studying and generating the lightning impulse to test the endurance of the electricity transmission line. Moreover this study analyses the factors which affects the impulse waveform by using Orcad program. The parts of prototype device can find in the general market. After the efficiency test of the electricity transmission line the result shown that the device should have the high capability to endure the temporarily high impulse. This minimizes the dangerous from the electricity system.

This article presents how the analysis an insulation of high voltage transformer bushing. The purpose is to analysis the moisture in the bushing to evaluate the approach for maintenance. The analysis rely on the principle of the Polarization and Depolarization Current (PDC) technique which is a technique for analyzing the insulation of high voltage equipment to test high voltage transformer bushing for a case study. This method is performed by energize 1000 Vdc into a bushing in period of time and then switch off the circuit for discharge current. Finally we calculate the moisture of main insulation of high volt bushing as well compare with standard moisture of criteria. The method is useful of preventive maintenance plane of high volt bushing and reduce the failure in the power system.

The purpose of this research is to facilitate technology of limiting excess electricity from the source before supplying to the electrical appliances. The distribution of electricity by Metropolitan Electricity Authority (MEA) frequently exceeds the needs of households and factories due to the fact that the voltage has to be enough to send electricity to users who are located further at the end of the voltage grid lines. Most electrical appliances are designed to perform at optimum voltage of 220 Volt. The voltage optimization system controls the incoming voltage to fit the optimum voltage of electrical appliances which will reduce the overheating phenomenon and thus lengthen the lives of electrical appliances. It can save 8-14% of total energy being consumed and potentially reduce CO2 emission. This analysis system can be used for industries in the range of small to large companies. From the development of remote monitoring using a control via internet or 3G/4LTE the voltage optimization system showed practical power saving results of the reduced power usage and lengthen the lives of electrical appliances; that leads to reduction of emerging electricity resource eradication of natural resources increase the chance of marketing competition and energy sustainable

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.