Mohd Rafi Adzman
Thumbnail Image
Preferred name
Mohd Rafi Adzman
Official Name
Mohd Rafi , Adzman
Alternative Name
Adzman, M. R.
Adzman, Mohd Rafi Bin
Adzman, Mohd Rafi
Main Affiliation
Scopus Author ID
16833392100
Researcher ID
AAF-8313-2019
F-8971-2017

Research Output

Filters

30
Reset filters

Settings
Now showing 1 - 10 of 30
  • Publication
    Differential equation fault location algorithm with harmonic effects in power system
    ( 2023-06)
    Izatti Md. Amin
    ;
    Mohd Rafi Adzman
    ;
    Haziah Abdul Hamid
    ;
    Muhd Hafizi Idris
    ;
    Melaty binti Amirruddin
    ;
    Omar Aliman
    About 80% of faults in the power system distribution are earth faults. Studies to find effective methods to identify and locate faults in distribution networks are still relevant, in addition to the presence of harmonic signals that distort waves and create deviations in the power system that can cause many problems to the protection relay. This study focuses on a single line-to-ground (SLG) fault location algorithm in a power system distribution network based on fundamental frequency measured using the differential equation method. The developed algorithm considers the presence of harmonics components in the simulation network. In this study, several filters were tested to obtain the lowest fault location error to reduce the effect of harmonic components on the developed fault location algorithm. The network model is simulated using the alternate transients program (ATP)Draw simulation program. Several fault scenarios have been implemented during the simulation, such as fault resistance, fault distance, and fault inception angle. The final results show that the proposed algorithm can estimate the fault distance successfully with an acceptable fault location error. Based on the simulation results, the differential equation continuous wavelet technique (CWT) filter-based algorithm produced an accurate fault location result with a mean average error (MAE) of less than 5%.
  • Publication
    Merekabentuk pengesan discas permukaan di dalam ''Inclined-Plane Test" dengan menggunakan kaedah optik
    ( 2007)
    Muzamir Isa
    ;
    Baharuddin Ismail
    ;
    Ismail Daut
    ;
    Che Mat Hadzer
    ;
    Faizah Abu Bakar
    ;
    Mohd Rafi Adzman
    Laporan ini bertujuan untuk memberikan seberapa maklumat tentang ciri-ciri aktiviti discas permukaan secara khustmrya dan aktiviti discas sejara secara umumnya serta peringkat-peringkat proses merekabentuk alat pengesan terhadap aktiviti ini menggunakan kaedah optikal ia meliputi kaji selidik dalam teori-teori tentang kejadian discas permukaan, kriteria-kriterianya dan proses bagaimana ia boleh dikesan oleh sesuatu alat pengesan. Objektif utama projek ini dijalankan adalah untuk merekacipta satu alat pengesan yang menggunakan kaedah optik bagi mengesan dan mengenalpasti kejadian aktiviti discas permukaan pada peralatan elektrik terutamanya pada peralatan voltan tinggi. Adalah diharapkan agar alat pengesan yang dihasil daripada projek ini akan dapat digunakan bagi kegunaan untuk mengesan dan seterusnya mengenalpasti lokasi dimana telah berlakunya aktiviti discas permukaan.
  • Publication
    Diagnostics of oil filled cable terminations
    ( 2006)
    Mohd Rafi Adzman
    ;
    Muzamir Isa
    ;
    Baharuddin Ismail
    ;
    Matti Lehtonen
    ;
    Petri Hyvonen
    Cable termination is one of the important components in the electrical power system. A failure of it can cause a long interruption, costly repair and loss of revenue. An existing oil filled cable termination such as rubber tube and porcelain type of cable termination require an observation and preventive maintenance in order to prevent an enormous electrical system failure in future. One of the defects ot this type of oil filled cable termination is lack of insulation oil inside it. The worst case if it becomes totally empty and at the same time there is no approach taht can help detect it. This paper presents the work carried out to find any possible method that can be used to detect a drying out of oil impregnated paper tape cable terminations. Futhermore, the diagnosis has to be used without destroying the terminations. Two diagnosis methods, infrared (IR) thermography and X-ray imaging are reviewed and the diagnosis result is presented. By comparison of two diagnosis method in this work, the X-ray imaging method is the best approach to observe and detect a drying out of paper tape oil impregnated cable terminations.
  • Publication
    Cost of energy losses analysis using a hybrid evolutionary programming-firefly algorithm for distributed generation installation
    ( 2022)
    Noor Najwa Husnaini Mohammad Husni
    ;
    Siti Rafidah Abdul Rahim
    ;
    Mohd Rafi Adzman
    ;
    Muhammad Hatta Hussain
    ;
    Ismail Musirin
    This paper presents the Hybrid Evolutionary Programming-Firefly Algorithm (EPFA) technique for the cost of energy losses analysis of distributed generation (DG). In this study, EPFA is developed to determine the optimal size of DG while considering the system’s energy losses. EPFA is developed based on embedded Firefly Algorithm (FA) properties into the classical EP technique. The objective of this study was to reduce the cost of energy losses while increasing the voltage profile and minimizing distribution system losses between the different operational strategies and types of DG. In this study, the analysis was done by considering DG type 1 and DG type 2. The proposed technique was tested using the IEEE 69-bus test system. In terms of economic concerns, power system planners can use the information acquired for utility planning to determine the right location and capacity of DG. Finally, the proposed method can determine the appropriate DG sizing while reducing the cost of energy losses and total losses in the system, based on the simulation results.
  • Publication
    Optimal design of photovoltaic power plant using hybrid optimisation: A case of South Algeria
    ( 2020-06-01)
    Zidane Tekai Eddine Khalil
    ;
    Mohd Rafi Adzman
    ;
    Mohammad Faridun Naim Tajuddin
    ;
    Samila Mat Zali
    ;
    Durusu, Ali
    ;
    Mekhilef, Saad
    Considering the recent drop (up to 86%) in photovoltaic (PV) module prices from 2010 to 2017, many countries have shown interest in investing in PV plants to meet their energy demand. In this study, a detailed design methodology is presented to achieve high benefits with low installation, maintenance and operation costs of PV plants. This procedure includes in detail the semi-hourly average time meteorological data from the location to maximise the accuracy and detailed characteristics of different PV modules and inverters. The minimum levelised cost of energy (LCOE) and maximum annual energy are the objective functions in this proposed procedure, whereas the design variables are the number of series and parallel PV modules, the number of PV module lines per row, tilt angle and orientation, inter-row space, PV module type, and inverter structure. The design problem was solved using a recent hybrid algorithm, namely, the grey wolf optimiser-sine cosine algorithm. The high performance for LCOE-based design optimisation in economic terms with lower installation, maintenance and operation costs than that resulting from the use of maximum annual energy objective function by 12%. Moreover, sensitivity analysis showed that the PV plant performance can be improved by decreasing the PV module annual reduction coefficient.
  • Publication
    Identifiability Evaluation of Crucial Parameters for Grid Connected Photovoltaic Power Plants Design Optimization
    ( 2021-01-01)
    Tekai Eddine Khalil Zidane
    ;
    Mohd Rafi Adzman
    ;
    Mohammad Faridun Naim Tajuddin
    ;
    Samila Mat Zali
    ;
    Ali Durusu
    ;
    Saad Mekhilef
    ;
    Chun-Lien Su
    ;
    Yacine Terriche
    ;
    Joseph M. Guerrero
    This paper aims to assess the impact of different key factors on the optimized design and performance of grid connected photovoltaic (PV) power plants, as such key factors can lead to re-design the PV plant and affect its optimum performance. The impact on the optimized design and performance of the PV plant is achieved by considering each factor individually. A comprehensive analysis is conducted on nine factors such as; three objectives are predefined, five recent optimization approaches, three different locations around the world, changes in solar irradiance, ambient temperature, and wind speed levels, variation in the available area, PV module type and inverters size. The performance of the PV plant is evaluated for each factor based on five performance parameters such as; energy yield, sizing ratio, performance ratio, ground cover ratio, and energy losses. The results show that the geographic location, a change in meteorological conditions levels, and an increase or decrease in the available area require the re-design of the PV plant. A change in inverter size and PV module type has a significant impact on the configuration of the PV plant leading to an increase in the cost of energy. The predefined objectives and proposed optimization methods can affect the PV plant design by producing completely different structures. Furthermore, most PV plant performance parameters are significantly changed due to the variation of these factors. The results also show the environmental benefit of the PV plant and the great potential to avoid green-house gas emissions from the atmosphere.
  • Publication
    Root cause analysis on manufacturing defects in brass oxygen valves
    ( 2023-05-01)
    Wan Mohd Haqqi Wan Ahmad
    ;
    Shaiful Rizam Shamsudin
    ;
    Salleh S.H.M.
    ;
    Mohd Rafi Adzman
    ;
    Rajaselan Wardan
    ;
    Mahalaksmi Gunasilan
    Brass valves are widely used in oxygen gas cylinder systems to regulate pressure and ensure safe operation. The production methods for brass valves include hot forging (700 °C), stress-relieving (300 °C), shot blasting, machining, and selective chrome plating on the external surface. Pneumatic testing at 400 bar has detected more than 10 % of the product production was found to have signs of leakage, and the most severe was when there were visible hairline cracks on the inner wall. Therefore, several tests to investigate valve failure were conducted to identify the root cause of the failure using a series of microscopic methods on the failed sample as well as the as-received brass billet. The study found that hairline cracks in brass valves were most likely caused by internal dross originating from the billet that was not properly removed during the casting process. The presence of dross in the billet manufacturing stage was identified as the primary reason for valve failure. Hot forging and other manufacturing techniques were found to be insufficient to eliminate the formation of dross, leading to a deterioration in the mechanical properties of the valves. In order to overcome this issue, flux can be added to the molten brass to help remove impurities and reduce the formation of dross. As a result, the mechanical properties of the final product deteriorated even though it had gone through the forging process.
  • Publication
    Failure investigation and analysis of locally manufactured turbine blade
    ( 2023-05-01)
    Mahalaksmi Gunasilan
    ;
    Shaiful Rizam Shamsudin
    ;
    Rajaselan Wardan
    ;
    Aleena Ramlee
    ;
    Wan Mohd Haqqi Wan Ahmad
    ;
    Mohd Rafi Adzman
    This study aims to identify the root cause of a turbine blade failure after only 36 hours of operation and recommends measures to prevent future failures. The analysis involved four samples, including an OEM sample, three fabricated samples with cracks and parts, including a kept sample for failure analysis. Microstructural analysis using Villella's reagent as an etchant, surface morphology, and micro-elemental analysis were conducted using the benchtop SEM & EDS. The hardness of the samples was tested using the Rockwell (HRC) method. The failed blade was made of AISI 422 grade stainless steel. It failed due to chipping that initiated cracks when it was tightly fastened, facilitated by internal stress and intermetallic particles in the microstructure. Instead of turbine blades made of hardened steel, the material was found to be slightly ductile and highly prone to compression before breaking when over-tightened during assembly. Inadequate heat treatment practices caused varied microstructural patterns, including the presence of intermetallic particles and significant hardness differences between the fabricated and OEM samples, leading to internal stress. In order to prevent future failures, there is a requirement to improve quality control measures during the fabrication process, particularly in the aspect of heat treatment practices.Thorough testing and analysis of the material microstructure may also be necessary to identify and eliminate potential sources of internal stress and intermetallic particles. Proper installation and fastening of turbine blades, regular inspection, and maintenance can also help identify early signs of failure and prevent catastrophic failures from occurring.
  • Publication
    Wireless IoT based overcurrent relay for transmission line protection
    ( 2021-10-29)
    Muhd Hafizi Idris
    ;
    Mohd Rafi Adzman
    ;
    Melaty Amirruddin
    ;
    Izatti Md Amin
    Typically, the relay must be wired from sensor terminals to relay terminals and from relay terminals to trip coils in the substation. This installation comes at a high cost to the utility since several relays are mounted in the substation to protect the transmission line, busbar, transformer, and other equipment. This article proposes a wireless Internet of Things (IoT) overcurrent relay that does not require the installation of wires to transmit measurements and signals from and to the relay. The relay scheme was developed using Matlab Simulink and the scheme model then was built and deployed into the Arduino Wi-Fi MKR 1010 which made the relay a standalone device. Simulink was also used to develop a transmission line system, and the simulation was performed in real-time. To exchange the data between transmission line and relay wirelessly, ThingSpeak platform was used as the cloud where the data are sent to and extracted from. From the real-time simulation, the relay successfully detected the set fault condition and sent the trip signal to open the circuit breaker. The result proves the feasibility of wireless relay to protect the power system. However, many other factors have to be considered and improved in the future to make wireless protection reliable and secure.
  • Publication
    Cost of Energy Losses for Distributed Generation Using Hybrid Evolutionary Programming-Firefly Algorithm
    ( 2021-12-01)
    Noor Najwa Husnaini Mohammad Husni
    ;
    Siti Rafidah Abdul Rahim
    ;
    Mohd Rafi Adzman
    ;
    Muhamad Hatta Hussain
    ;
    Musirin I.
    The cost of energy losses analysis for distributed generation (DG) is presented in this paper using a Hybrid Evolutionary Programming-Firefly Algorithm (EPFA). The proposed method was created to determine the optimal DG sizing in the distribution system while accounting for the system's energy losses. This study presents an investigation into hybrid optimization techniques for DG capabilities and optimal operating strategies in distribution systems. The objectives of this study were to reduce the cost of energy losses while increasing the voltage profile and minimize distribution system losses. In this study, the analysis was done by consider DG type I which is DG-PV. The suggested methodology was tested using the IEEE 69-bus test system, and the simulation was written in the MATLAB programming language. Power system planners can use appropriate location and sizing from the results obtained for utility planning in terms of economic considerations. From the simulation, the result shows the proposed method can identify the suitable sizing of DG while reduce cost of energy losses and total losses in the system.