The objective of this research is to study the development of eco cars using power-cutting mechanism technique of Transmission System. Two eco cars had been studied. The first car was conducted with the aim of developing transmission system and clutch system by changing from gear drive transmission system and chain drive mechanical clutch to belt and pulley transmission system by new designing the belt and pulley transmission system to have propeller shaft as the device to transmit power from the right to the left side with bearings to help reduce friction. Pulley system and clutch lever were installed in which the newly built clutch can be controlled by driver. The new model of transmission system is weight 0.7 kg which is lighter than the previous weight of 0.8 kg. Based on the first testing by participating in the 22nd Honda Eco Mileage Challenge at Chang International Circuit it was found that the system with belt tension at 1 kN resulted in good performance of transmission system and clutch system with fuel efficiency value at 626.157 km/L. After that the belt tension was adjusted and set up at 1.1 kN for 3 tests at Solar Track Thailand and it was found that the maximum fuel efficiency value was 1061.18 km/L at the speed of 34 km/hr. The second car was improved in transmission system suspension system steering system and also engine. The first trial was experimented on the 22nd racing event at the Chang International Circuit where this fuel efficient prototype car could run at 18 km. The result showed that it could have good mileage which was 275 km/L. After improvement the car was tested again for three times at the Solar Track Thailand circuit where it ran at 16 kilometers. The result revealed that the best saving was equivalent to 613 km/L at the speed of 30.6 km/hr.

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.

Most of Metropolitan Electricity Authority (MEA) electric power system is using overhead line. It is 94% in the system including subtransmission distribution and low voltage system. All of them were installed on concrete pole. At present many public facilities have been built such as Sky-Train. It causes more constrains for construction with concrete pole due to lack of right of way. MEA needs to using electrical monopole plays an important role. It’s easier than concrete pole for construction and it requires less construction area than concrete pole. The thesis evaluation of lightning performance in subtransmission line 69 kV study on MEA. Case lightning strike on overhead ground wire (OHGW) at pole top of electrical monopole with suspension insulator Focusing on three factors is pole top voltage critical current and back flashover rate (BFOR). ATP-EMTP software is used for simulation. The results show that BFOR is reduced by 79% on electrical monopole structure with suspension insulator compared with existing concrete pole. BFOR is also reduced by 33.17% on concrete pole with external ground wire. The results could be served as a guideline in subtransmission line design and improvement in MEA power system.

The objectives of this research were to develop of transmission line calculation program based on usage and frequency consisting of the two-wire transmission line twisted pair transmission line and coaxial transmission line. The program was developed in the form of graphical user interface in Malta. The developing and testing results found that the program was correctly capable to calculate capacity conductance inductance resistance and impedance for each transmission line usage and frequency. The results from the program with black box testing by five experts and twenty system users found the average and the standard deviation of results form computer experts were 4.04 and 0.36 respectively while those of results form the system users were 3.88 and 0.48 respectively. Conclusion it showed that the efficiency of the calculation program was a high level and can be used as a teaching and learning as well.

Electricity Generating Authority of Thailand (EGAT) encountered problems voltage swell from the changes of power system configuration high-voltage 115 kV substation name Lopburi2 to radial. Control Center closed capacitor bank caused the steel industry electric power plants and renewable energy solar tripped themselves out. As a result EGAT loosed of power produced of solar power plants. It also affected confidence in the systems power consumption. EGAT’s necessary to learn from this event. This research was simulation power system modeling of “High Voltage Substation Lopburi2” and grid connection both the system EGAT and PEA with EMTDC-PSCAD for analysis of the voltage swell caused by close capacitor bank at “Lopburi2” substation compared with actual events then calculated the voltage swell occurred at high voltage station linkage. Finally this research presents a method of reduction of their impact of close capacitor bank at “Loburi2” to avoid the voltage swell in the future.