Applied Mechanics and Materials Vol. 793

Abstract: This paper presents a voltage stability assessment based approach to determine the congested line with optimal sizing and location. FVSI, a voltage stability index is chosen as the indicator for congested line identification, while particle swarm optimization technique (PSO) is used for optimal location and sizing of FACTs devices installation. Congested line is identified by increasing the reactive load at chosen load buses until they reach the maximum loadability level. PSO is applied for identifying the optimal location and sizing of FACTs devices as the compensating device. Results obtained from the implementation on IEEE 30 Bus RTS revealed that the proposed technique can manage the congestion subject to various disturbances.

Abstract: Presence of harmonic current brings adverse impacts on electrical system. Among others, it can derate rated ampacity of conductors. In a perfectly balanced 3-phase system, harmonics existence gives rise to harmonic-rich neutral current. In this paper, two alternative methods are compared with a technique from standard. Results show that the alternative methods are comparable with method from a standard.

Abstract: This paper presents the behavior of 33kV polymer insulator under nominal voltage and impulse by means of lightning activities. The electrical performance of the insulator is translated to electric field under uniform weather conditions which comprises of air humidity and contamination. ANSYS Maxwell modeling software is used to simulate the structure of the polymer insulator based on the real existing insulator’s dimension. The trend of electric field increase is discussed in detail.

Abstract: Electrical Power System protection is required to protectboth the user and the system equipment itself fromany fault, hence electrical power system is not allowed to operate without any protection devices installed. Power System fault is defined as the undesirable condition that occurs in the power system. Some of these undesirable conditions are short circuit, current leakage, ground faultand over-under voltage. With the increasing loads, voltages and short-circuit duty in power plant, over voltage protection has become more important today. Here, the component that had been used is PIC 16F877a microcontroller to control the whole system and especially on the circuit breakers as well as the LCT display unit is used to display the voltage level and type of generator that used to serve the load. Sensors are used to measure both thevoltage and the load. The controlled digital signal from PIC microcontroller is converted by using the digital analog converter to control the whole circuit. Thus a device called protective relay is created to meet this requirement. The protective relay is mostlyoften coupled with circuit breaker in a way that it can isolate the abnormal condition in the system.

Abstract: Under current scenario of regulation on the safety and environment, biodegradable oils are gaining interest as dielectric insulating fluid in transformers. There are different types of biodegradable oils that are currently examined and among them are Palm Oil (PO) and Coconut Oil (CO). It is important to carry out extensive examination on these oils at laboratory level since the failure in-service could be costly. Among the important studies are the AC breakdown strength properties under the influence of particles. In this paper, a study is carried out to examine the influence of particles on the AC breakdown voltage of POand CO. The PO used in this study is Refined Bleached and Deodorized (RBDPO) Olein type. Two types of particles are used for the investigations which are cellulose and copper particles.Four different weights of particles are added on each of the samples and tested with the AC breakdown tester at a gap distance of 1 mm using VDE electrodes. It was found that copper particles have more significant effect on the AC breakdown strength of RBDPO and CO than cellulose particles.

Abstract: Micro-grid system is an integrated energy system as it consists of distributed energy resources (DERs) and multiple electrical loads operating in parallel or islanded grid. The primary objective of this project is to examine whether Micro-grid implementation can reduce the cost of energy. It can be determined through the modelling bus bar system; 26-Bus Test System. This application can be divided into three aspects which are modelling, simulation and analysis. The power system analysis was conducted under two conditions, steady state condition and contingencies condition using two different methods which are optimal power flow and economic dispatch. Newton-Raphson algorithm was introduced during the power flow analysis. The optimal power flow and economic dispatch for total generation cost was obtained through PowerWorld software simulation.

Abstract: . In this paper, the electric fields due to a Malaysian transmission line was considered and the values of electric fields at different distances with respect to power line were evaluated and the evaluated fields were compared with the corresponding acceptable ranges of fields and the results were discussed accordingly. Moreover, the values of fields under different ground conditions were estimated and the results were discussed.

Abstract: One of the major concerns for the interconnection of distributed generation (DG) to distribution network is the technical issues associated from the connection. In the conventional distribution network, the power flow is uni-directional, from centralizes power plants to transmission and then to distribution before it supplied to the customer. However, with the anticipated amount of DG connected at distribution network, power flow is no longer uni-directional. Due to this fact, it is crucial to perform power system study to ensure the system stability is not deteriorating. This paper discusses the dynamic analysis to examine the electromechanical transient responses of the DG unit under various system faults and contingency situations. This contents presented in this paper can facilitate DG developers, consultants, contractor and utility engineer in planning for the new connection of DG to the distribution network.

Abstract: The voltage will be induced in the pipeline due to an electromagnetic field effect generated by the parallel transmission tower. This will bring up the negative effect to the pipeline, transmission tower and people get contracts with the pipeline. A study has been carried out to determine the electromagnetic field (EMF) distribution of parallel transmission line and pipeline due to AC currents and lightning faults. Only a few of previous study focus on lightning faults. The lightning faults data for transmission line and pipeline still insufficient nowadays. A mitigation system has been developed to minimize the induced voltage on pipeline due to the electromagnetic field of energized transmission line. ANSYS Maxwell software is used for modeling. The range of induced voltage obtained is within the acceptable level of the IEEE 80-2000 standards.

Abstract: This article investigates the characteristics of cap and pin glass insulator and its enhancement due to contamination particles or elements by means of laboratory experiments. The insulator surface is simulated for dry conditions as well as its changes under wet conditions. To find the influence of the contamination layers on the leakage current and voltage distribution, various levels of the ESDD of the insulators were applied in the study. Additionally, experimental results show that the higher contamination level of insulator may have lower breakdown voltage especially in wet condition.