Muzamir Isa
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Preferred name
Muzamir Isa
Official Name
Muzamir, Isa
Alternative Name
Isa, M.
Isa, Muzamir Bin
Isa, Muzamir
Isa, Muzamir A.M.
Bin Isa, Muzamir
Main Affiliation
Scopus Author ID
16642710600
Researcher ID
G-4076-2017

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  • Publication
    Influence of PD source and AE sensor distance towards arrival time of propagation wave in power transformer
    ( 2020-01-07)
    Khairul Nadiah Khalid
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Baharuddin Ismail
    ;
    Muzamir Isa
    ;
    Afifah Shuhada Rosmi
    ;
    Wooi Chin Leong
    ;
    Yii C.C.
    Partial discharge (PD) often begins with cracks or gas-filled voids in solid insulation or with gaseous bubbles in liquid insulation. These presences can degrade the quality of insulator. PD detection can identify these cracks at high voltage equipment such as power cables and power transformer at the early stage. One of PD detection methods is acoustic emission (AE) detection. PD produces an ultrasonic signal that can be captured by an AE sensor. The signal captured is then analysed by capturing the time of the receiving signal onto the sensor. The information related to time can be used for allocating the PD for maintenance purpose. This paper shows the influence of the distance between PD source and the AE sensor towards the arrival time of propagation wave in power transformer. In this study, the four placements of sensors were analysed by having three possible PD sources to represent the variety of distances between the PD source and the sensor. The simulated signal is generated by MATLAB and the arrival time is captured using time of arrival (TOA) method. The time captured and the distance between the PD source and arrival time showed that the relationship is proportional to one another.
  • Publication
    Modelling of piezoelectric sensor based on ZnO material for partial discharge detection on power transformer
    ( 2020-01-01)
    Akashah N.A.
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Afifah Shuhada Rosmi
    ;
    Muzamir Isa
    ;
    Baharuddin Ismail
    ;
    Kamarol M.
    ;
    Roslizan N.D.
    ;
    Khairul Nadiah Khalid
    Detection of partial discharge (PD) in early stages able to reduce the risk of decommissioning of high voltage (HV) equipment. However, the conventional method for PD detection are not suitable for on-site measurement due to electrical disturbance. One of the method in detecting PD signal is piezoelectric based acoustic emission (AE) sensors. In this project, an AE sensor is modelled to obtain a PD signal in the range of 10 – 300 kHz occurred in HV transformer and been found out by simulation and analytical approach. Two models of a piezoelectric sensor with different types of cantilever and different dimension variation starting from 4 mm to 15 mm are designed in the Finite element Method (FEM) in order to investigate the resonant frequency which is matched to the range of AE detection. Zinc oxide (ZnO) as a piezoelectric material is proposed in this project due to its high piezoelectric coupling and environmentally friendly compared to the others material which is harmful. Based on the simulation result, ZnO piezoelectric sensor with the length of 5 mm and thickness of 0.451 mm generates 0.0537 mV electrical potentials under the resonant frequency of 155.30 kHz which is in the range of AE detection technique.
  • Publication
    The magnetic flux density of various geometries of Rogowski Coil for overvoltage measurements
    ( 2020-01-01)
    Ayob Nazmy Nanyan
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Muzamir Isa
    ;
    Afifah Shuhada Rosmi
    ;
    Ahmad Zaidi Abdullah
    ;
    Baharuddin Ismail
    ;
    Haziah Abdul Hamid
    Overvoltage phenomenon is the common problem that always occurs in the power system and can cause the electrical system network breakdown, and in some cases, it may explode. The frequent overvoltage also can affect and degrade the lifespan of the electrical power system components and network. Thus, the overvoltage sensor is needed to overcome this problem matter. The Rogowski coil (RC) is one of an inductive coil group, and it is suitable for measuring the alternating current (AC) and transient currents or overvoltage. This paper demonstrated the effect of RC magnetic flux density, B with difference cross-section, geometries sizing and the number of turns by using Finite Element Method (FEM). Commonly, there are three types of RC widely used; rectangular, circular and oval. Each of these cross-sections has different characteristics in term of performance. The results have shown that the rectangular cross-section is better than oval and circular cross-section based on the number of magnetic flux density.
  • Publication
    Hilbert fractal UHF sensor based on partial discharge detection signal for on-line condition monitoring in power transformer
    ( 2020-01-01)
    Roslizan N.D.
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Afifah Shuhada Rosmi
    ;
    Baharuddin Ismail
    ;
    Muzamir Isa
    ;
    Akashah N.A.
    ;
    Mukhtaruddin A.
    PD detection is an effective method of inspecting insulation defects and identifying potential faults in a power transformer. Electromagnetic waves generated due to PD can be detected by ultrahigh-frequency (UHF) sensor in the frequency band greater than 300 MHz. However, the size and the frequency bandwidth of a UHF sensor for PD detection are the concern for practical installation inside a transformer. High sensitivity and wide bandwidth of sensors are needed in order to detect the PD signal in an early stage. This paper presents an array 4th order Hilbert fractal UHF sensor for PD detection inside a power transformer. This UHF sensor was modeled to capture PD signal in a range of frequencies between 300 MHz to 3 GHz. The sensor is designed by using CST software where the transmission lines combined 2 sensors become 1 output by setting the dimension of 100 x 200 mm for length and width with FR4 epoxy substrate of thickness 1.6 mm. Based on the simulation result, the proposed sensor is obtained a PD signal measurement with a reflection coefficient below-10 dB with VSWR ≤5. The advantages of this sensor have a wide bandwidth, high sensitivity and suitable size for easy installation. Thus, this sensor has been qualified as UHF PD detection in the power transformer.
  • Publication
    A review: Partial discharge detection using acoustic sensor on high voltage transformer
    ( 2020-01-07)
    Akashah N.A.
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Afifah Shuhada Rosmi
    ;
    Muzamir Isa
    ;
    Norfadilah Rosle
    ;
    Baharuddin Ismail
    ;
    Wooi Chin Leong
    Partial discharge (PD) is an electrical discharge which is one of the most critical breakdown factor that is affecting the electrical equipment. The loss of the power will affect consumers and system operation. High voltage (HV) transformer is one of the equipment's subjected to phenomena PD. In this paper reviews an application of acoustic methods in transformer and piezoelectric sensors application on PD detection in HV transformer. Based on this review, the new design in acoustic sensor is required in order to improve the sensitivity and bandwidth for PD detection at HV transformer. The valuable parameter such as materials, size, and PD frequency range were discussed in this paper and can be used for early stage on designing new acoustic sensor. This detection method given some benefits on preventing the power electrical system from breakdown.
  • Publication
    UHF Sensors for On-line Partial Discharge Detection on Power Transformer: Hilbert fractal, Moore Fractal and Peano fractal
    ( 2020-12-11)
    Abd Jalil M.A.
    ;
    Afifah Shuhada Rosmi
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Muzamir Isa
    ;
    Roslizan N.D.
    ;
    Leow W.Z.
    ;
    Mohd Aminudin Jamlos
    Partial discharge (PD) is the causes of the fault to occur in high voltage equipment due to the breakdown of the insulation system happen on equipment, even old equipment or new equipment. The PD in transformer oil is one of the significant causes of insulation failure and a breakdown. Hence, a sensor is needed to continuously monitor and detect the PD at an early stage on the power transformer. An antenna is one of the sensors that can be used to detect PD based on ultra-high frequency (UHF) method. However, the size of the antenna is the main problem to be installed in the transformer tank. Thus, three types of antenna which are Moore, Hilbert and Peano fractal with the dimension of 10 X 10 cm is designed to operate in UHF range 0.3 GHz to 3 GHz to be able to detect the frequency of partial discharge signal generated by electromagnetic waves. The performance of the proposed antennas in terms of return loss, Voltage Standing Wave Ratio (VSWR) and radiation pattern are analysed and compared for PD detection on the power transformer. Based on the result, the fourth-order of Hilbert fractal antenna was found to be the best antenna for PD detection in power transformer at working frequency range from 0.72 GHz to 2.77 GHz. This antenna also has low threshold of return loss at-36.2 dB for the resonant frequency at 1.67 GHz and the value of VSWR is near to one which is 1.03. Lastly, the radiation pattern of this antenna is almost in hemisphere shape and the gain variation of all frequencies are nearly stable compared to the other types of antenna.
  • Publication
    Partial discharge signal measurement based on stand-alone and hybrid detection technique for power transformer
    ( 2020-01-01)
    Jalil M.A.A.
    ;
    Afifah Shuhada Rosmi
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Muzamir Isa
    ;
    Auni W.N.
    ;
    Ahmad Zaidi Abdullah
    ;
    Aizam M.T.
    Partial discharge (PD) is a phenomenon that causes failures in high voltage (HV) components due to the degradation of insulation. Before an interruption or fault occurs, early detection of insulation degradation is essential. However, the long-term effect of PD will lead to the failure of the power system. This is important to control and diagnose the health of the HV power equipment such as power transformer. The main issue when measuring PD is the accuracy and sensitivity of the PD detection technique. This paper consists of two parts which are classification of the PD detection technique and hybrid detection technique. In this paper, an overview of the detection technique for power transformer including optical detection, chemical detection, electrical detection, electromagnetic detection, acoustic emission detection and hybrid detection technique is presented. The hybrid detection technique is based on combining two or more stand-alone detection technique. Based on this review, the hybrid detection technique showed that the advantages of performance in terms of sensitivity and accuracy for detecting the PD in power transformer.
  • Publication
    Selective harmonic elimination pulse width modulation for five-phase cascaded multilevel inverter using non-notch and notch switching technique
    ( 2020-01-01)
    Walter M.S.M.A.
    ;
    Baharuddin Ismail
    ;
    Muhammad Zaid Aihsan
    ;
    Siti Khodijah Mazalan
    ;
    Bimazlim M.A.S.
    ;
    Muzamir Isa
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Sengodan T.
    As in this era, the conversion of DC power to AC power is a necessity in the power system in order to make useful of renewable energy. The most commonly used switching mechanism is known as inverter or multilevel inverter. However, this switching may cause harmonics. Harmonics usually occur in a power system due to distortion, which can cause a lot of unwanted problems. It could appear either in voltage or in current waveforms. Minimization of Total Harmonic Distortion (THD) is necessary in order to maintain a good power system. This paper introduces selective harmonic elimination pulse width modulation for five-phase cascaded multilevel inverter. The proposed switching technique for five-phase cascaded multilevel inverter used in this research is non-notch and notch switching technique. Particle Swarm Optimization (PSO) algorithm was used as an optimization technique to find switching angles for non-notch and notch switching techniques. In addition, the simulation of a seven-level five-phase cascaded multilevel inverter for both switching operations is carried out in the PSIM environment. The results show that the non-notch switching was able to eliminate lower order harmonics up to the 7th harmonic. In addition, the notch switching technique managed to eliminate lower order harmonics up to the 21st harmonic for 3/3/3 switching distribution.
  • Publication
    Performance analysis of a modified reduce component count multilevel inverter
    ( 2020-01-07)
    Siti Khodijah Mazalan
    ;
    Baharuddin Ismail
    ;
    Muzamir Isa
    ;
    Muhammad Syahril Bahari
    ;
    Mohamad Nur Khairul Hafizi Rohani
    Reducing component in circuitry is desirable in many innovations. In multilevel inverter (MLI) perspective, the increasing of switching devices for a higher-level output will significantly increase power losses, thus affected the output harmonic distortion. In this paper, an extended and simplified three-phase reduce component count multilevel inverter (RCCMLI) structure adapted from S. S. Lee, Cascaded Compact-Module Multilevel Inverter (CCM-MLI) is demonstrated and analysed. Symmetrical reduce component structure with H-bridge inverter is considered in this work. For simplification purpose, the current path conduction for reverse current is not demonstrated in this paper. A simulation-based result is presented to observe the performance of RCCMLI with regards to its output voltage harmonic content. Related predetermined parameter values are included in this report. Particularly, this paper verified the aforementioned RCCMLI, but in higher level and three-phase application, which will further improve the pseudo-sinusoidal inverter output as it eliminates the triplens harmonic component compare to single-phase environment. As for the lower order odd harmonics elimination, computational algorithm namely Particle Swarm Optimization (PSO) has been implemented in the RCCMLI control strategy. In comparison to the traditional Cascaded H bridge (CHB), this work finds that employing the switching angle optimization in the proposed RCCMLI produce comparable improvement in minimizing the output voltage harmonic and able to bring the output quality closer to comply with IEEE 519 distortion limit with fewer components and compact size inverter.