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.

The effects of load frequency control (LFC) of interconnected distribution power system in tie-line substation area load –frequency stability and the frequency respond at distribution generator (DG) are very important for interconnected control power system of tie-line area. The generating power system of solar farm and wind turbine which have interconnected distribution power system in tie-line substation area were tested using 3 simulation parameters: non-controller Automatic Voltage Regulator (AVR) and with Pl Controller. The results showed that there were 3 types of load and frequency changing in the interconnected area: load changed 0.02 p.u. had frequency of load changed 0.025 Hz and large disturbance. Comparisons of load-frequency to respond for steady state the time respond was 7.9 seconds for non-controller 5.4 seconds for AVR and 1.7 seconds for under controlled system at 0.1 p.u using Pl controller. Therefore the Pl controller has better efficiency than non-controller about 31 % and AVR about 16%. It can be concluded that the interconnected distribution power system in tie-line substation area controlling for storage for connected grid had better efficiency and optimization of generating power from renewable solar farm and wind turbine which have interconnected distribution power system in the nearby are balance of controlling of the original system.

The propose of this research present a comparative study of the Reliability Improvement of Electrical System for Electric Mass Rapid Transit Train which describes in term of the power supply efficiency including voltage imbalance that could indicate how much the electric power quality is being more or less. The electrical system to be used in the Mass Rapid Transit system has 4 types of connection between three (3) phases of Metropolitan Electricity Authority (MEA) transformer and station transformer which is Single phase V-Type Scott and Le- Blanc to be considered for the different transformer connections type could be carried out and resulted in the most unbalanced in power supply as well as properly solution for power supply mitigation of voltage imbalance. From foregoing the data analyst was discovered that a single phase connection could cause the most unbalance voltage but on the other hand Le-Blanc connection is the least unbalance which could be reduced the impact on the Mass Transit Train and increase the credibility of consumers in order to continuity implement service usage.