S. Sulaiman

Comparing simulation results and experimental measurements of electroluminescence phenomenon in dielectric materials

Under continuous application of high electrical stresses, the insulation system of an underground power cable is subjected to long-term degradation that can eventually cause premature breakdown of the cable. This is as a result of electronic charges being injected into the dielectric material when intense electric field is applied. These charges will then interact with polymer molecules; causing even more charges to accumulate within the vicinity of the material and thus further deterioration. The interaction of the charges can lead to the dissipation of energy in the form of photons; a process known as electroluminescence (EL). In addition to space charge probing, the measurement of EL has becoming increasingly prominent in understanding the mechanisms that contribute to the early electrical ageing of an insulating material. This paper attempts to simulate EL behaviour based on the underlying hypotheses of charge injection and bipolar recombination processes that take place within a polymer. A detailed comparison between the computation results and the experimental measurements carried out by different researchers will be discussed in order to evaluate the mechanisms responsible for this phenomenon.

Analysis of wave propagation in Time Domain Reflectometry circuit simulation model

Time Domain Reflectometry (TDR) has been commonly used for testing and diagnosis of faults along a transmission line. It involves the sending of an electrical pulse along a cable and using an oscilloscope to observe the reflected pulses. In this paper, the experimental set up based on Time Domain Reflectometry technique is developed using PSpice circuit simulation software. From the PSpice circuit simulation, the incident and reflected pulses at various nodes are obtained. In order to determine the wave propagation in a Test cable, the actual reflected pulse from the Test cable need to be evaluated. However, in practice the actual reflected pulses cannot be obtained directly from the Test cable but must be measured from the oscilloscope. Therefore, in this paper, the relationship between the actual reflected pulses from the Test cable to the reflected pulses measured from an oscilloscope is established by using the electrical circuit analysis and transmission line theory. Moreover, the characteristic impedance of the Test cable can be computed accurately from this relationship.

Wave propagation characteristics of polymeric underground cables

Knowledge on wave propagation characteristics of both ideal and degraded XLPE cables due to water treeing are the important basics to examine the healthiness of a cable through localization of faults due to water treeing in cables using time domain reflectometry (TDR) measurement technique. In this study, both ideal and degraded XLPE cables are modelled and simulated using MATLAB. The same program is also used to simulate four other cables in different geometries to investigate whether cable geometry influences the results. All results are compiled and compared to determine the wave propagation characteristics of water treeing in XLPE cables.

Analysis of high frequency wave propagation characteristics in medium voltage XLPE cable model

Wave propagation characteristics of underground medium voltage cables are usually determined using the theory of natural modes of propagation. There are three important parameters involved in wave propagation along a cable which are the length of the cable, load condition, and propagation characteristics of the cable. Indeed, the last parameter is the most difficult one to be determined and normally should be modeled. Propagation losses occur in XLPE power cables as pulses propagate through the cable. Since different types of cable have different component parameters, the wave propagation characteristics such as attenuation and propagation speed will also vary accordingly. As such, the wave propagation characteristics for different cable types with their cable geometry are studied and analyzed using a developed MATLAB simulation model.

Application of time domain reflectometry technique in detecting water tree degradation within polymeric-insulated cable

Polymeric-insulated power cables are often subjected to multiple sources of degradation. Generally, the main cause for electrical breakdown in this type of cable insulation is usually due to the microscopic impurities and defects located in the bulk, or even at the interfaces of the material. When the dielectric is subjected to a high electrical stress, imperfections such as protrusions, contaminants and microvoids, will all act as points where the electric field is enhanced; increasing the likelihood that degradation processes will be initiated. The intensification of electric field within the insulating material can cause localized discharge to occur continuously, and thus tree-like channels can be developed in the long-run. This paper attempts to investigate whether the existence of water tree region can be detected within polymeric-insulated cables, and the proposed method for the detection mechanism is the time domain reflectometry (TDR). When water trees are present within an insulation system, the characteristic impedance of the material also changes so this can cause reflection of signal propagating along the cable. It was found that there is a difference in TDR signals between un-degraded cable and water tree degraded cable. It is hoped that the difference in these time domain signals can actually assist in determining the location where the presence of water trees can be considered as significant.

Simulation modeling of polarization and depolarization current analysis for underground cable insulation

High voltages, when applied continuously to an underground cable, leads to the deterioration of its insulation. Gradual yet permanent changes are made to its dielectric properties, caused by electronic charges created within the insulation material; affecting its ability to withstand high electrical stresses. Over an extended period of time, this continual insulation degradation plays a major role in its eventual cable breakdown. Therefore the monitoring of insulation condition is essential to power utilities, to avoid costly disruptions. One of the techniques developed to assess the insulation condition of underground cables is the polarization and depolarization current (PDC) analysis. This technique, executed by measuring the insulations polarization and depolarization currents, is commonly used to assess degradation in the transformer insulation. However it can also be used to monitor the degradation within cable insulation to a certain degree. This paper attempts to describe how PDC can be used to determine the condition of cable insulation via simulation modeling, developed based on the PDC theory for an ideal cable. The simulation results are then compared with experimental PDC measurements to determine the severity of insulation degradation.

Comparing simulation modelling and measurement results of polarization/depolarization current analysis on various underground cable insulation systems

Continuous application of high voltages in an underground cable can cause slow deterioration of its insulation system. Electronic charges can be generated within the medium of the material and this can lead to permanent change of its dielectric properties to withstand high electrical stresses. The long-term degradation of underground cable insulation plays an important role in its eventual breakdown event. One of the ways to assess the insulation condition of an underground cable is by measuring its polarization and depolarization currents (PDC). This technique has been widely used in assessing the performance of transformer insulation system, but can also be used to monitor the degradation within a cable to some extent. The paper aims to describe thoroughly the principle mechanism of PDC and how it can be used to monitor the condition of cable insulation. A simulation model has been developed based on theoretical conjectures of PDC in an ideal cable. The simulation results were then compared with PDC experimental measurements using new unused cables. In addition to this, simulated PDC currents for cables that are subjected to various degrees of degradation were also analyzed in order to deduce severity categorization for replacement exercise of in-service cables. By comparing the simulated data with the experimental results, it is hoped that a clearer understanding on the PDC mechanisms within underground cable insulation can be achieved.

Verification of MATLAB/Simulink Power Cable Modelling with Experimental Analysis

Received Mar 3, 2018 Revised Apr 11, 2018 Accepted Apr 21, 2018 Paintball has gained a huge popularity in Malaysia with growing number of tournaments organized nationwide. Currently, Ideal Pro Event, one of the paintball organizer found difficulties to pair a suitable opponent to against one another in a tournament. This is largely due to the manual matchmaking method that only randomly matches one team with another. Consequently, it is crucial to ensure a balanced tournament bracket where eventual winners and losers not facing one another in the very first round. This study proposes an intelligent matchmaking using Particle Swarm Optimization (PSO) and tournament management system for paintball organizers. PSO is a swarm intelligence algorithm that optimizes problems by gradually improving its current solutions, therefore countenancing the tournament bracket to be continually improved until the best is produced. Indirectly, through the development of the system, it is consider as an intelligence business idea since it able to save time and enhance the company productivity. This algorithm has been tested using 3 size of population; 100, 1000 and 10,000. As a result, the speed of convergence is consistent and has not been affected through big population.N. N. S. Abdul Rahman, N.M. Saad, A. R. Abdullah, M. R. M. Hassan, M. S. S. M. Basir, N. S. M. Noor 1,2,4,6Faculty of Electronic and Computer Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2,3Center for Robotics and Industrial Automation, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 3,5Faculty of Electrical Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, MalaysiaLight rail transit (LRT), or fast tram is urban public transport using rolling stock similar to a tramway, but operating at a higher capacity, and often on an exclusive right-of-way. Indonesia as one of developing countries has been developed the LRT in two cities of Indonesia, Palembang and Jakarta. There are opinions toward the development of LRT, negative and positive opinions. To reveal the level of LRT development acceptance, this research uses machine learning approach to analyze the data which is gathered through social media. By conducting this paper, the data is modeled and classified in order to analyze the social sentiment towards the LRT development.Mohamad, S., Nasir, F.M., Sunar, M.S., Isa, K., Hanifa, R.M., Shah, S.M., Ribuan, M.N., Ahmad, A. 1,4,6,7,8Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia, Johor, Malaysia 1,2,3UTM-IRDA Digital Media Centre, Media and Game Innovation Centre of Excellence, Universiti Teknologi Malaysia, Johor, Malaysia 1,2,3Faculty of Computing, Universiti Teknologi Malaysia, Johor, Malaysia 5Centre for Diploma Studies, Universiti Tun Hussein Onn Malaysia, Johor, Malaysia 6Research Centre for Applied Electromagnetics, Universiti Tun Hussein Onn Malaysia, Johor, MalaysiaReceived Jan 31, 2018 Revised Apr 21, 2018 Accepted Apr 30, 2018 Bluetooth is an emerging mobile ad-hoc network that accredits wireless communication to connect various short range devices. A single hop network called piconet is the basic communication topology of bluetooth which allows only eight active devices for communication among them seven are active slaves controlled by one master. Multiple piconets are interconnected through a common node, known as Relay, to form a massive network called as Scatternet. It is obvious that the performance of Scatternet scheduling is highly dependent and directly proportionate with the performance of the Relay node. In contrary, by reducing the number of Relays, it may lead to poor performance, since every Relay has to perform and support several piconet connections. The primary focus of this study is to observe the performance metrics that affects the inter-piconet scheduling since the Relay node’s role is like switch between multiple piconets. In this paper, we address and analyze the performance issues to be taken into consideration for efficient data flow in Scatternet based on Relay node.

Methods to estimate electric field stress ratios within water tree structures in polymeric cables

Water treeing is a phenomenon whereby the polymeric cable suffers serious degradation under combined stresses of electrical, thermal and chemical, thus shortening the lifespan of the cable. A high electrical field stress present at the tip of a water tree structure would degrade the surrounding healthy polymeric insulation, leading to electrical treeing and subsequent breakdown of the water tree affected polymeric cable. This paper aims at proposing methods to estimate the electric field stress ratios of water tree structures present in the insulation of water tree affected polymeric cables. The capacitances and lengths of water tree structures present the insulation were measured in water tree affected polymeric samples over a period. The measured data were then used in the proposed methodology to estimate the maximum electric field stress ratios present at the tips of the water tree structures, using electrostatic finite element software. A database of the electric field stress ratios was compiled and subsequently fed into the neural networks back propagation process. With the optimisation of weights in the neural networks back propagation process, an averaged error of less than 5% was found. This newly developed intelligent system provides a simple, time saving and practical way of obtaining electric field ratios.

FEM and ANN based Simulations to Study the Effect of Electrical Field Distribution on Water Tree Affected Polymeric Cables

Earlier researches have confirmed that polymeric cables suffer from serious water tree degradation under tree lengths in the affected polymeric cables are varied to assess their effect on the level of the electrical field distribution. The permittivity values within the water tree structures are varied accordingly to the lengths measured in water tree growths. The electrical field distribution waveforms arising out of the variation in water tree growths are plotted using FEM software and the results are analysed. Analysis shows that the electrical field distribution levels increases exponentially with the rise in water tree lengths. The results are then translated into electrical field ratios and fed to an ANN simulation. The simulation attempts to create a database for water tree degraded cables with two (2) categories of training inputs i.e. permittivity and water tree length, and a target output of electrical field ratio. The error in the ANN simulation is then marginalised to an error value of less than 1% using the back-propagation method for optimisation of weights.