Jasronita Jasni

Parameter selection in particle swarm optimisation: a survey

Nowadays, particle swarm optimisation (PSO) is one of the most commonly used optimisation techniques. However, PSO parameters significantly affect its computational behaviour. That is, while it exposes desirable computational behaviour with some settings, it does not behave so by some other settings, so the way for setting them is of high importance. This paper explains and discusses thoroughly about various existent strategies for setting PSO parameters, provides some hints for its parameter setting and presents some proposals for future research on this area. There exists no other paper in literature that discusses the setting process for all PSO parameters. Using the guidelines of this paper can be strongly useful for researchers in optimisation-related fields.

Particle swarm optimisation for discrete optimisation problems: a review

In many optimisation problems, all or some of decision variables are discrete. Solving such problems are more challenging than those problems with pure continuous variables. Among various optimisation techniques, particle swarm optimisation (PSO) has demonstrated more promising performance in tackling discrete optimisation problems. In PSO, basic variants are merely applicable to continuous problems. So, appropriate strategies should be adopted for enabling them to be applicable to discrete problems. This paper analyses all strategies adopted in PSO for tackling discrete problems and discusses thoroughly about pros and cons of each strategy.

Suitability of Palm Based Oil as Dielectric Insulating Fluid in Transformers

Mineral oil has been widely used as dielectric insulating fluid in transformers due to its excellent performance in-service. However, there are few issues with mineral oil such as it has poor biodegradability and could contaminate the environment if a spillage occurs. With the increasing tight regulation on safety and environment, alternative fluids for mineral oil are currently being investigated and among the suitable candidate is the vegetable oil. There are different types of vegetable oils and one of them is the palm based oil. At the moment, extensive research works are carried out to examine its feasibility to be applied in transformers. This paper will review the previous research works that were carried out to examine the suitability of palm based oil as dielectric insulating fluid in transformers. The physical and chemical properties of palm based oil are studied based on viscosity, acidity, oxidation stability and flash point. Next, the electrical characteristics of palm based oil are examined based on AC breakdown voltage, relative permittivity, dissipation factor and partial discharge.

Approaches for FACTS optimization problem in power systems

This paper discusses thoroughly about different methods for solution of flexible AC transmission systems (FACTS) optimization problem in power systems. First, it explains the requirements of an ideal solution for FACTS optimization problem, then classifies the methods used by researchers in four main groups as classical methods, technical methods, heuristics and mixed methods, and discusses thoroughly about characteristics, advantages and disadvantages of each group of methods. Finally, some tips are offered for future research on this area.

Particle swarm optimisation applications in FACTS optimisation problem

FACTS optimisation is one of the most important and difficult problems in power systems. For solving this problem, so many different approaches have been proposed in the literature. Among them, particle swarm optimisation (PSO) has exposed so promising behavior. In this paper, applications of PSO in FACTS optimisation problem are explained and analysed from the viewpoint of the objectives, used basic PSO variant, PSO parameter selection, multi-objective handling, constraint handling and discrete variable handling. Eventually, some hints for future research is provided.

A fuzzy logic based controller for an indirect vector controlled three-phase induction motor

This paper presents the theory, design and simulation of a fuzzy logic based controller used for an indirect vector controlled three-phase induction motor. The analysis, design and simulation of the fuzzy logic controller for IVCIM drive system are carried out based on the fuzzy set theory. The FLC algorithm has been simulated on Simulink Toolbox in Matlab. The performance of the proposed FLC has been investigated and compared to the results obtained from the conventional PI controller based drive at different operating conditions such as sudden change in load. The simulation results demonstrate that the performance of the FLC is better than that for the conventional PI controller.

Recent statistics on lightning fatalities in Malaysia

It is a fact that Malaysia encounters more than 70% of power outages due to lightning and it is known as the “Crown of Lightning” in the world. The effects of lightning on electrical/communication networks and structures account for equipment damage, downtime/data losses and malfunctioning of control and automated systems that may cost the nation over RM 250 million and thousands of human injuries and deaths. Good statistics about death and injuries around the world are just beginning to be collected. This paper presents an update of the statistics on lightning fatalities in Malaysia and some comparisons with other countries around the world. In addition, a case study that accounts the geographical location, lightning detection data and distribution system layout will be presented.

Chemical enhancement materials for grounding purposes

It is an aim of this work in finding the best performed chemical enhancement material in order to provide the lowest impede path for fault currents to be dispersed into the earth in the shortest time possible. These fault currents are typically due to transients and they could be dangerous to the power system, equipment in it and the personnel involved with the system. Hence, it is desired that a grounding system is installed to provide such path to clear these fault currents from the power system in the manner that danger could be reduced. Such transients are generated by lightning, or switching action. Note that in this study, only lightning strike is considered. Lightning could create impulsive transient during its direct or indirect strikes to power system. This problem is normally prevented by installing a suitable grounding system to the power system. A grounding system will create a path for transient to be safely dispersed into the earth by providing lowest resistance path. This can be easily done using either natural or chemical enhancement materials. However, this work only reported the findings of having chemical enhancement materials in the vicinity of grounding system for protection against lightning. It is found that sodium chloride demonstrated the best performance in being enhancement material for earthing system on top of sodium thiosulphate, magnesium chloride, cuprum sulphate, and ammonium chloride.

Natural materials as grounding filler for lightning protection system

Grounding resistance could significantly reduce with the usage of grounding filler for grounding rod in lightning protection system. However, the cost of the normally used grounding fillers such as bentonite and other chemicals is the main drawback. Therefore, it is an aim of this study to determine the electrical properties and durability of natural grounding fillers as an alternative to bentonite. The 61.8% rule from the fall of potential method was used to obtain values of grounding resistance of the lightning protection system installed with natural grounding fillers such as bentonite, coconut coir peat, planting-clay soil and paddy dust. The measured grounding resistances were then compared with the grounding resistance of the reference grounding rod. Results revealed that natural materials especially planting-clay soil is the best alternative to replace bentonite as grounding filler because it gave the lowest grounding resistance values at the end of the experiment and had generally the highest percentage reduction in grounding resistance.

On the influence of inclined lightning channel on lightning induced voltage evaluation

This paper investigates the influence of inclined lightning channel on induced voltage on the line. The angle variations of inclined lightning channel may cause the voltage to be induced at different values for different points along the power line. This behaviour may affect the lines lightning performance if the peak of induced voltage is greater than the critical flashover voltage (CFO) of the line. This induced voltage is expected to be increased when the inclined angle with respect to the observation point is decreased. Appropriate method of induced voltage algorithm with respect to the incline lightning channel will be developed and compared with other method. The outcome of this study would be useful for the utility for their planning and selection of appropriate protection scheme for the line.