Afifah Shuhada Rosmi
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Afifah Shuhada Rosmi
Official Name
Afifah Shuhada, Rosmi
Alternative Name
Rosmi, Afifah Shuhada
Rosmi, Afifah Shuhada C
Rosmi, A. S.
Rosmi, A. S.C.
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Scopus Author ID
57193830914
Researcher ID
DNN-7471-2022

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  • Publication
    Comparison of Image Restoration using Median, Wiener, and Gaussian Filtering Techniques based on Electrical Tree
    ( 2021-01-01)
    Abdulah C.S.K.
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Baharuddin Ismail
    ;
    Isa M.A.M.
    ;
    Afifah Shuhada Rosmi
    ;
    Wan Azani Wan Mustafa
    Electrical treeing lead to a major cause of a breakdown in solid insulation. Thus reduced solid insulation performance by degrading the insulation. Hence, it is important to study the electrical treeing and learn the root cause of the treeing formation. In this paper, the performances of median, wiener, and gaussian filters in restoring noisy images are studied based on electrical tree images. The electrical tree colour images is being transform into grayscale images, noisy images using impulse noise (salt and pepper), and finally motion blur are applied. Even though, there are several number of filters available, this paper focus on median, wiener, gaussian, and combination of the filters. In the end, comparison between these filters is made to study the efficiency using PSNR, SNR, and MSE in graph form.
  • Publication
    Review of Edge-based Image Segmentation on Electrical Tree Classification in Cross-linked Polyethylene (XLPE) Insulation
    ( 2021-06-11)
    Mohd Annuar Mohd Isa
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Baharuddin Ismail
    ;
    Afifah Shuhada Rosmi
    ;
    Isa M.
    ;
    Wan Azani Wan Mustafa
    ;
    Kamarol M.
    ;
    Mansor N.S.
    ;
    Nazar N.S.M.
    Electrical trees are the degradation events most linked with partial discharge (PD) activity in cross-linked polyethylene (XLPE) insulation of high voltage (HV) cables. To investigate tree structures and forms, study of electrical tree structures for morphological analysis often carried out using optical microscopy. However, since the noise induced by the occlusion and illumination, as well as by non-uniform intensity either from optical device's setting or the non-standard readout procedure, causes the deterioration of the original microscopy images, resulting in critically loses of information pertaining the tree structures making it difficult to obtained accurate measurement. Image segmentation is one of the potential solutions as it is well-suited for extracting information or certain features from microscopy images. This paper provides review of several segmentation techniques applied on the classification of electrical tree image acquired through lab environment. The works can be separated into three stages. The first step includes the preparation of samples and collection of treeing images by means of real-time microscopy observations. The captured data would then be pre-processed to achieve image binarization. In the next step, image segmentation process is conducted using existing edge-based segmentation methods including Prewitt, Roberts, Canny and Kirsch's templates. Later, comparative analysis will be performed using IQA (image quality assessment) metrics of accuracy, sensitivity, specificity, false-positive-rate and the Matthews Correlation Coefficient (MCC) as the final step. Performance-wise indicates that Kirsch's template able to segment most of the treeing pixels with accuracy of 97.63%, 63% sensitivity, 98.18% specificity and 0.46 MCC while showing low pixels misclassification. This result provides better justification for the integration of the edge-based technique in developing image segmentation algorithm well-matched for the electrical tree analysis in the future.
  • Publication
    A Review: Partial Discharge Detection using UHF sensor on High Voltage Equipment
    ( 2020-01-07)
    Roslizan N.D.
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Wooi Chin Leong
    ;
    Isa M.
    ;
    Baharuddin Ismail
    ;
    Afifah Shuhada Rosmi
    ;
    Wan Azani Wan Mustafa
    Partial discharge (PD) is one of the most popular failure or breakdown that can happen at high voltage (HV) equipment. PD is the fault that causes the insulation breakdown occurred between two electrodes. It happened or occurred because of the improper insulation, ageing, environment effect and manufacturing defects. The loss of the power will affect consumer and system operation. One of the technique that can measure or detect the PD is by using ultra high frequency (UHF) method for HV equipment insulation condition monitoring and assessment. In this paper, the application of UHF method have been reviewed as the best method to detect PD in transformer, GIS and cable. The UHF method for every electrical equipment is described in order to detect the PD and the laboratory result shows that this method can be considered as suitable technique. Based on this review, the new design in UHF sensor is required in order to improve the sensitivity and bandwidth for PD detection in HV equipment. The valuable parameter such as size and PD frequency range can be used for early stage of designing new the UHF sensor.
  • Publication
    Piezoelectric Sensor using PZT Material for Partial Discharge Detection on Power Transformer
    ( 2020-07-09)
    Alleef Abd Jalil M.
    ;
    Afifah Shuhada Rosmi
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Muzamir Isa
    ;
    Nurul Auni Wan Mohammad W.
    ;
    Zaidi Abdullah A.
    ;
    Wan Azani Wan Mustafa
    This paper presents an analysis of acoustic emission (AE) detection technique for partial discharge (PD) on power transformer using piezoelectric sensor. The AE PD detection technique using piezoelectric material is one of the popular method due to its low cost and compact size. A matching resonant frequency of AE sensor with PD signal which in range 10 kHz to 300 kHz is an important factor for this technique. An AE sensor that have a resonant frequency match with PD signal able to give an optimal performances. Therefore, a simulation on different dimensions of lead zirconate titanate (PZT) AE sensor using finite element method (FEM) is conducted in order to determine the performances in terms of resonant frequency, total displacement and generated voltage. The length of AE sensor is varied from 2 mm to 30 mm in order to reveal the influence of length dimension against generated voltage. Based on the obtained results, that 2 mm length of AE sensor able to generate voltage of 3.01 x10-5 mV at resonant frequency of 113.58 kHz which can be proposed toward PD detection on the power transformer.
  • Publication
    Electrical Tree Investigation on Solid Insulation for High Voltage Applications
    ( 2021-01-01)
    Abdulah C.S.K.
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Baharuddin Ismail
    ;
    Isa M.A.M.
    ;
    Afifah Shuhada Rosmi
    ;
    Wan Azani Wan Mustafa
    ;
    Kamarol M.
    Electrical treeing is a major cause of a breakdown in solid insulation cable. This phenomenon reduced aging by degrading the insulation, leading to failure in the high voltage materials. The most common experimental set-up in studying the electrical tree is using a needle electrode to initiate the treeing image. Different types of needle and insulation material had been studied from the previous experiment. This paper review the method used to investigate tree growth and its technique to capture the treeing image. Based on this review, several causes delay the treeing process in the needle embedded experiments. In contrast, 2D image processing is the most frequent image developed in the electrical tree on solid insulation.
      6  23
  • Publication
    Electrical Tree Image Segmentation Using Hybrid Multi Scale Line Tracking Algorithm
    ( 2023-01-01)
    Mohd Annuar Mohd Isa
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Baharuddin Ismail
    ;
    Jamil M.K.
    ;
    Muzamir Isa
    ;
    Afifah Shuhada Rosmi
    ;
    Mohd Aminudin Jamlos
    ;
    Wan Azani Wan Mustafa
    ;
    Nurulbariah Idris
    ;
    Mas’ud A.A.
    Electrical trees are an aging mechanism most associated with partial discharge (PD) activities in crosslinked polyethylene (XLPE) insulation of high-voltage (HV) cables. Characterization of electrical tree structures gained considerable attention from researchers since a deep understanding of the tree morphology is required to develop new insulation material. Two-dimensional (2D) optical microscopy is primarily used to examine tree structures and propagation shapes with image segmentation methods. However, since electrical trees can emerge in different shapes such as bush-type or branch-type, treeing images are complicated to segment due to manifestation of convoluted tree branches, leading to a high misclassification rate during segmentation. Therefore, this study proposed a new method for segmenting 2D electrical tree images based on the multi-scale line tracking algorithm (MSLTA) by integrating batch processing method. The proposed method, h-MSLTA aims to provide accurate segmentation of electrical tree images obtained over a period of tree propagation observation under optical microscopy. The initial phase involves XLPE sample preparation and treeing image acquisition under real-time microscopy observation. The treeing images are then sampled and binarized in pre-processing. In the next phase, segmentation of tree structures is performed using the h-MSLTA by utilizing batch processing in multiple instances of treeing duration. Finally, the comparative investigation has been conducted using standard performance assessment metrics, including accuracy, sensitivity, specificity, Dice coefficient and Matthew’s correlation coefficient (MCC). Based on segmentation performance evaluation against several established segmentation methods, h-MSLTA achieved better results of 95.43% accuracy, 97.28% specificity, 69.43% sensitivity rate with 23.38% and 24.16% average improvement in Dice coefficient and MCC score respectively over the original algorithm. In addition, h-MSLTA produced accurate measurement results of global tree parameters of length and width in comparison with the ground truth image. These results indicated that the proposed method had a solid performance in terms of segmenting electrical tree branches in 2D treeing images compared to other established techniques.
      1  17
  • Publication
    Investigation on partial discharge activities in cross-linked polyethene power cable using finite element analysis
    ( 2020-01-07)
    Isa M.A.M.
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Afifah Shuhada Rosmi
    ;
    Muzamir Isa
    ;
    Rosle N.
    ;
    Wan Azani Wan Mustafa
    ;
    Daniel I.N.
    ;
    Roslan M.A.
    The nationwide usage of cross-linked polyethylene (XLPE) for medium to high voltage distribution networks are practically common due to its excellent electrical, thermal and mechanical properties and widely installed through existing network of cable line in Malaysia. However, cable exposures to harsh climates coupled with inadvertent damage throughout installation or transportation are influencing the presence of voids inside the insulation leading to the initiation of partial discharges (PD) in the cable line. Therefore, this study is important to investigate the activities of PD due to the manifestation of voids in XLPE cable and how it affects the physical, electrical and mechanical characteristics of the cable. Analysis has been performed using Finite Element Analysis (FEA) tool to simulate the PD activities in a 2D model of a three (3) core-XLPE insulated armoured sheathed cable (500 mm2, 11 kV) with several placements of voids. The varied placement and radius of voids is very crucial in order to achieve comprehensive analysis. From the obtained result, it has been established that closest the void to the core yielded higher electric field potential. Additionally, it is verified from the simulation that the larger the size of void, the higher the electric field potential consequently increasing the current density inside the void. This simulation and analysis is quite important to provide better insight pertaining to the behaviour of PD in correspond to the presence of voids which will accelerate ageing failure in insulation framework of the XLPE cable.
      12  1
  • Publication
    Review Study of Image De-Noising on Digital Image Processing and Applications
    ( 2023-03-01)
    Abdulah C.S.K.
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Baharuddin Ismail
    ;
    Mohd Annuar Mohd Isa
    ;
    Afifah Shuhada Rosmi
    ;
    Wan Azani Wan Mustafa
    ;
    Ahmad Zaidi Abdullah
    ;
    Wan Nor Munirah Ariffin
    ;
    Jamil M.K.M.
    This paper reviews several studies of image de-noising on digital image processing and applications. Noisy images contain different noise that exist either due to environment or electronic interferences. Ergo, de-noising is crucial to eliminate the noise that disturb data collecting process. The impact of de-noising on image processing can result for accurate and precise data collected from the image. Additionally, de-noising process required several crucial steps that help to enhance knowledge on digital image and its application. Hence, study and understanding de-noising can improve multiple aspect such as image quality, data sensitivity and specificity, accuracy of the collected data, and increase the percentage of each parameter.
      1
  • Publication
    Modelling of Piezoelectric Sensor with Different Materials Approach for Partial Discharge Detection on Power Transformer: PZT-5H, ZnO and AlN
    ( 2020-07-09)
    Akashah N.A.
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Afifah Shuhada Rosmi
    ;
    Muzamir Isa
    ;
    Baharuddin Ismail
    ;
    Khalid K.N.
    ;
    Wan Azani Wan Mustafa
    ;
    Wooi Chin Leong
    The acoustic emission (AE) technique is one of the unconventional methods of partial discharges (PDs) detection. It plays a most important role in oil-filled power transformers diagnostics because it enables the detection and online monitoring of PDs as well compared to the conventional method for PDs detection which are not suitable for on-site measurement due to electrical disturbance. In this paper, the acoustic based on piezoelectric sensor by different material is modelled in order to be able to obtain PDs signal occurred in power transformers. Modelling of a piezoelectric sensor with different material which is PZT-5H, ZnO, and AlN is approached in order to investigate the performance of resonant frequency, electric potential, and the performance in processing in order to match the range of AE detection. Piezoelectric materials have become very useful in processing devices because of their electrical-mechanical mutuality. Study was performed on frequency target of PDs should be higher and in the range of 10 kHz -300 kHz in order to prevent the power transformer from failure or breakdown and it has been found out by proven from analytical and simulation result by using the Finite Element Method (FEM). Based on this information, acoustic sensor is analyses with different types of cantilever beam and piezoelectric material and different length dimension of the beam in order to analyses the performance between them. Based on the result, the piezoelectric material that be chosen in this project is ZnO due to its high piezoelectric coupling and environmental friendly is used in order to support green technology compared to others material discussed which is harmful even though produced high performance. This detection method gave some improvement in monitoring system PD activities in the transformer's tank.
      1  10