Applied Mechanics and Materials Vol. 793

Abstract: This paper discusses the effect of placing a power system stabilizer (PSS) at various generators for stability studies in a large power system. The damping control for the New-England 39-bus system was discussed. The effect of PSS in damping the electromechanical modes on different generator was studied. The PSS takes only a generator’s speed as input, and feeds it, after modification, to the voltage reference input of the generator’s excitation system. The results by placing a power system stabilizer on eight generators of the 39-bus system were found to be stable satisfactorily damped

Abstract: Plug-in Hybrid Electric Vehicles (PHEV) have a better future in term of providing sustainable mobility due to their high efficiency and low emission levels. However, the global penetration of PHEVs can create negative impacts if their charging activities are not scheduled and controlled. This paper presents the impact of PHEVs charging on the residential network in Malaysia under various charging scenarios. The simulation results shows there will be a significant voltage drop in the cable and increment in load profile due to additional load. In order to avoid any unwanted circumtances, several PHEV charging profiles are analysed and some potential solutions are suggested including controlling and resizing of the cable.

Abstract: In this paper, the analysis results of the imitative grounding systems consisting of 4 mesh grid with rods are presented by using the Finite Element Method (FEM) and field test. This combined grid with multiple rods configuration was installed by previous researchers [4] and the resistance value is obtained under steady state. The FEM simulations were conducted and the resistance value and electric field profile are obtained. Comparison study in terms of its resistance value is performed between FEM and at steady state, and further analysis of the grounding systems using FEM is presented and discussed in this paper.

Abstract: Multilevel inverters are one of the preferred inverter choices for solar photovoltaic (PV) applications. While these inverters are capable of producing AC staircase output voltage waveform, the total harmonic distortion (THD) of the output voltage waveform can become worse if the switching angle of each voltage level is not carefully chosen. In this paper, four switching angle arrangement techniques are presented and the switching angles generated by these techniques are applied to a new single-phase boost multilevel (SPBM) inverter. The performance of 3-, 5-, 7-, 9-and 11-level SPBM inverter having four different sets of switching angles derived using the aforementioned techniques have been evaluated and compared using PSIM software. Simulation results show that one of the techniques is able to produce an output voltage waveform with the lowest THD, whilst the other generates an output voltage waveform with the highest fundamental voltage component.

Abstract: This paper presents a new selective switching strategy for single phase SPWM Inverter that can reduce the power loss and total harmonic distortion. Power loss is always a command issue for inverter system. Power loss occurs during the switching of the inverter. This new selective switching strategy is modified from the typical switching strategy and has been proven to reduce the power loss and harmonics. This project had already been tested on direct power source and also from the solar PV module. This project is focusing on 100W inverter system.

Abstract: In developing country like Malaysia, the development of islands is mostly related to the electric power availability. Because there are many islands in Malaysia where the power grid is not available. As an island surrounded by sea, wave energy can be considered one of the environmental friendly power generating sources for island communities. But, high dependency on weather conditions is the main drawback of wave energy source. To overcome this drawback; wave energy device, energy storage devices and the electronic converters need to be integrated with each other. This study presents a battery storage standalone oscillating water column wave energy conversion system for island electrification in Malaysia

Abstract: This paper aims to analyzing and probing the influences of power system harmonics on a differential relay used for distribution transformer protection. The increased use of nonlinear devices in industry, commercial and residential areas can lead to a significant increase the level of harmonic distortion in the power system. This harmonic has the significant effects to the differential protection systems components such as current transformer (CT) and relay. The CT tends to saturate due to the presence of current harmonics in power system, so it will produce magnitude secondary current error and make the differential relay to miss operations. The harmonic distortion effects on the differential protection have been investigated through laboratory test. To determine the CT errors when operates under harmonic condition, the CT has been test with certain level of THD_i. The result of this testing was found that with increasing of the THDi, the magnitude of secondary current error increased and differential relay will operate at no fault conditions.

Abstract: The application of mineral oil in transformer is prominently act as and insulator and a coolant liquid. More often, petroleum based oil is used because most its elements are good to act as insulator such as excellent heat transfer and low in viscosity. Anyhow, the usage of mineral oil in transformer is possibly hazardous to the environment considering that it is poor biodegradable liquid where when a spill or leakage happens, it could pollute the environment surroundings. Moreover, it is known as a non-renewable energy sources, the world will be out of it someday near future. For this reason, a new option of transformer insulation liquid is studied. Vegetable oil is a fully biodegradable insulating liquid and for this paper, coconut oil is used as the insulator. In this paper, it concentrates on the performance of the transformer before and after virgin coconut oil is applied in a single-phase step down transformer that use the 220 V supply and 50 Hz frequency. Transformer is connected to 110V induction motor as load and has been test in two conditions, dry and after virgin coconut oil is applied. Comparison is made from both results and clearly shown a good improvement when virgin coconut oil is used as insulation oil.

Abstract: The important purpose of mineral oil in transformer is to be insulant and it is role of being a coolant. Petroleum based oil is commonly used because it has a good dielectric strength and cooling performance. However, the application of mineral oil brings negative impact to the environment such as oil spills, leakage, explosion and soon petroleum based oil will be running out for future generation used. Thus, vegetable oil is chosen as an alternative to replace mineral oil for transformer insulation liquid. Formerly, most of Malaysian researches were focusing on the properties of the vegetable oils rather than investigate the effect on the transformer performances after the vegetable oils are applied. Hence, this paper focuses on the performance of the transformer before and after vegetable oils are applied. For this paper, refined palm oil is used as insulation liquid for a single-phase step down transformer which use the 220 V supply and 50 Hz frequency. Transformer is connected to 110V induction motor as load and has been test in two conditions, dry and after palm oil is applied. Comparison is made from both results and clearly shown a good improvement when palm oil is used as insulation oil.

Abstract: This paper presents the design of linear permanent magnet generator for wave energy conversion using finite element analysis software. Four designs have been proposed which are simple, lightweight, portable and can produce 100 Watt electric power. Air-cored linear permanent magnet generator have been chosen and their electromagnetic characteristic were analyzed using finite element analysis. The determined electromagnetic analysis reveals that rectangular permanent magnet arrangement (Rect-PM) design gives efficient performance as compared to other designs.