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.

Voltage drop is one of the power quality problems affecting power users. This happens due to the higher demand for electric power. Or a short circuit in the transmission system. This causes a voltage drop is one of the power quality problems affecting power users. This happens due to the higher demand for electric power. Or a short circuit in the transmission system. This results in drop in Solving of voltage drop problems in power distribution model with distributed generator were presented with MATLAB program by installing a generator in the distribution system. Therefore simulated a case study 5 case 1 simulation by not installing a generator at any bus case 2 simulation by installing a Generator at bus 1 case 3 Simulation by installing a Generator at bus 18 case 4 simulation by Generator installed at bus 33 and case 5 simulation by Generator installed at bus 13 17 21 31 to study the suitable location of generator installation to solve the problem of voltage drop.

This paper presents a mathematical simulation to compared to operations a small distributed photovoltaic power plant in the distribution system. Practices transmission of electric power by small distributed solar energy With the PVSyst and IEC 61724 mathematical modeling programs the main objective was to study the % performance ratio photovoltaic power plants 5.95 MWp connected in the distribution system of the Provincial Electricity Authority voltage level 22 kV. Therefore this paper is presented as a mathematical simulation compared to operations a small distributed photovoltaic power plant in a distribution system. The results of the study show that the operation of small distributed solar power plants increases the efficiency to be able to produce the maximum electricity and continuously. The system was able to produce the highest power of 8954.9 MWh/year and had an average annual efficiency ratio of 77.84% receiving the highest solar radiation intensity and the highest annual total energy output of approximately 1837 kWh/m2

Ground grid design of substation is very important. It will help prevent the danger caused by the fault which causes the high step voltage and high touch voltage and may cause the operator to die. It also helps prevent damage to equipment and increases reliability for power systems as well. Currently the Gas Insulated Substation (GIS) has been built a lot especially in areas with limited space because it takes less space than the Air Insulated Substation (AIS). In order to create a substation of the GIS model instead of the AIS model. In order to create the GIS instead of AIS including the improvement or maintenance of the substation it is necessary to build another small substation to supply electricity to replace electricity from the original substation. However there are two substation stations in the same area may cause an increase of high-slope ground potential between the ground grid systems of both substations. It will cause high step voltage and high touch voltage while the fault is diminished. Therefore before improvement or maintenance of substation the ground grid distance and the size of the newly constructed substation must be analyzed that what effect on step voltage and touch voltage generation. Including studying the effects of step voltage and touch voltage that will occur.

Design of grounding system to protect against lightning and fault is important for both safety and reliability especially for Metropolitan Electricity Authority (MEA) as mostly Metropolitan Electricity Authority operates on overhead networks. This thesis assesses lightning performance for 69 kV 115 kV overhead subtransmission lines 24 kV distribution line using case study from Metropolitan Electricity Authority. Because of the limitation of the right of way distribution feeders are regularly installed together with subtransmission lines in a single concrete pole. Overhead Ground Wire (OHGW) installed at top of the pole and grounding system in concrete pole protects fault current or direct lightning surge to ground. Metropolitan Electricity Authority has developed lightning protection based on an IEEE standard which uses international data for insulation coordination. As a result reliability of the system is lower than the designed value. This thesis suggests a methodology to improve the performance in order to increase the reliability of subtransmission and distribution lines feeding distribution substations. This thesis recommends installation of addition external ground wire on the outer surface of the concrete pole to reduce top pole voltage and back flashover rate or installation of bundle overhead ground wires to protect shielding failure. As all the case studies presented in the thesis which constitute this thesis are applied to existing systems of Metropolitan Electricity Authority it is expected that the proposed methodologies can be served as useful practical guidelines for lightning performance assessment subtransmission lines and distribution lines of Metropolitan Electricity Authority.