This thesis presents improving power quality in power distribution system with integration of photovoltaic energy distributed generation having objectives to improve power quality in distribution system model of voltage sag and voltage swell in distribution system model of power loss in distribution system application of mathematical model model of power generation by using solar energy and distributed generation connection technique simulation. In this thesis the power flow was tested with Newton-Raphson algorithm joining with mathematical model. The case study was done by reduction of power loss in distribution system by using techniques of connection of distributed generation joining with model of distribution system 33 bus. The case study about improvement of voltage sag and voltage swell in distribution system used connection techniques of distributed generation joining with model of distribution system 69 bus. The study found that technique of connection of distributed generation that was presented could reduce power loss and showed the percentage of improvement of voltage sag and voltage swell in distribution system especially voltage sag case according to IEEE 1159-1995 standard. This thesis showed that severity level of voltage sag depended on the size and duration of each distribution system model situation by photovoltaic energy distributed generation can reduce voltage sag.

Rail transport is a type of transportation that strongly influences economic due to its ability to transport a large number of passengers and products per trip relying on diesel-electric engines. The objectives of this thesis were set to investigate and develop the electrical performance tracking system of long-distance diesel electric locomotives and compare the electrical performance measured by the diesel electric locomotive performance tracking system and measured from the measuring instrument at Diesel Engine Maintenance Station in Bang Sue. The electric diesel locomotive no. 4513 (Cummins KTA50-L) was selected as the study subject of the experimentation. The results showed that the power loss of the diesel electric locomotive from the conversion of alternating current to direct current was inversely proportional to the engine speed. The power losses between the low and high engine speeds were equal to 77.11 and 2.49 percent respectively. The above data reflects the limitation of diesel electric engine performance and should lead to the construction of a database for making decision on the right engine selection suitable for the towing load of the locomotive.