Siti Rafidah Abdul Rahim
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Preferred name
Siti Rafidah Abdul Rahim
Official Name
Siti Rafidah, Abdul Rahim
Alternative Name
Abdul Rahim, Siti Rafidah
Rahim, S. R.
Rahim, S.R.A
Abdul Rahim, S.R.
Rahim, S.R. Abd
Main Affiliation
Scopus Author ID
11639107900
Researcher ID
E-5412-2011

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  • Publication
    Modified firefly algorithm-artificial neural network based technique for the prediction of time-current characteristic in directional overcurrent relay
    ( 2020-01-01)
    Muhamad Hatta Hussain
    ;
    Musirin I.
    ;
    Siti Rafidah Abdul Rahim
    ;
    Abidin A.F.
    This paper presents an integrated optimal predictor optimization technique termed as Modified Firefly Algorithm-Artificial Neural Network (MFA-ANN) for accurate prediction of Relay Operating Time (ROT). Directional Overcurrent Relays (DOCRs) coordination problem is formulated as Mixed Integer Linear Programming (MILP) problem. The developed techniques have been validated on the IEEE 8-bus systems using MATLAB. The simulation results obtained revealed that the proposed MFA-ANN model has shown the reduction in Root Mean Square Error (RMSE) values as compared with Particle Swarm Optimization-Artificial Neural Network (PSO-ANN) which improved the correlation coefficient of the relay operating time. The proposed MFA-ANN model managed to achieve 0% RMSE value.
  • Publication
    A Hybrid Optimization Approach for Power Loss Reduction and Voltage Profile Improvement in Distribution System
    ( 2022-01-01)
    Noor Najwa Husnaini Mohammad Husni
    ;
    Siti Rafidah Abdul Rahim
    ;
    Mohd Rafi Adzman
    In the past decades, the electrical power system is designed and developed to satisfy the owner demand that continuously appears in many variations. Hence, engineers have put their full effort to solve the problem associated with electrical power systems that come and might arise in the future. Therefore, distributed generation (DG) has been introduced to solve multiple electrical power system problems. The proposed methodology presented in this study focuses on minimizing network power losses, improving the voltage profile of system operation, and security constraints in a distribution. It is known that the location and capacity of DG play significant roles in the system losses in a distribution system. A hybrid metaheuristic nature-inspired algorithm is presented in this study for optimal location and sizing of multiple DG units. The best location and optimal sizing of DGs will be determined through Hybrid metaheuristic of Artificial Immune System Firefly Algorithm (AISFA). The designated technique will be tested into IEEE-69 test system using MATLAB software. For reducing the power losses, the simulation results have shown that bus 61 is the best location for reducing power losses and improving voltage profile in IEEE-69 test system in the preliminary result. By installing DG at bus 61, the real power losses improve about 89%, with a voltage profile improvement index up to 1.249099.
  • Publication
    Integrated clustering development using embedded meta evolutionary-firefly algorithm technique for DG planning
    ( 2020-12-01)
    Siti Rafidah Abdul Rahim
    ;
    Musirin I.
    ;
    Othman M.M.
    ;
    Muhamad Hatta Hussain
    ;
    Syahrul Ashikin Azmi
    Recent trend changes have created opportunities to achieve numerous technological innovations including the use of distributed generation (DG) to achieve different advantages. A precise evaluation of energy losses is expanding rapidly when DG is connected to the electricity sector due to developments such as increased competition and real time pricing. Nevertheless, non-optimal DG installation either in the form of DG locations and sizing will lead to possible under-compensation or over-compensation phenomena. The integrated clustering resulted from the pre-developed Embedded Meta Evolutionary Programming-Firefly Algorithm (EMEFA) has been used to ensure the optimum allocation and placement of DG. The study also considers the different types of DG. The aim of the technique is to consider the computational time of the optimization process for DG planning in achieving the minimal total loss. Two test systems have been used as test specimens to achieve the efficacy of the proposed technique. In this study, the techniques proposed were used to establish the DG size and the appropriate place for DG planning. The results for total losses and minimum voltage for the system were recorded from the simulation. The result in this study will be compared with the ranking identification technique to ensure the capability of this technique. The power system planner can adopt the suitable sizes and locations from the obtained result for the planning of utility in term of economic and geographical consideration.
  • Publication
    Grid integration of multiple PV inverters with reduced number of interfacing transformers— A dedicated controller for elimination of DC current injection
    ( 2023-03-01)
    Syahrul Ashikin Azmi
    ;
    Adam G.P.
    ;
    Williams B.W.
    ;
    Rahim N.A.
    ;
    Siti Rafidah Abdul Rahim
    The injection of dc current offset into ac networks may impacted the lifespan of the distribution system equipment including isolation transformers and measurement devices and in serious event may cause equipment's malfunction. This paper intents to eliminate dc current offsets in the output currents using a combinational of proportional-integral (PI) and proportional resonance (PR) controls embedded in one inverter unit. Resultant output currents of this method are sinusoidal and clean from dc offset before entering the point of common coupling. This method gives advantages for transformerless option for group of interfacing inverters in the medium-scale solar farm or in arrangement of inverters restricted in a small locale. Moreover, the use of expensive and high-accuracy measurement sensor nor complex transformer can be omitted, whilst indirectly give positive impact to the operational cost of the farm. The simulation verifications proved the usefulness of the proposed method by introducing varying unknown dc offset levels in the phase currents, and a dedicated dc offset suppressor inverter able to successfully eliminate the dc offset to zero. The validity of the proposed method is demonstrated in simulation using MATLAB/Simulink.
  • Publication
    Optimal Integration of Active and Reactive Power DGs in Distribution Network via a Novel Multi-Objective Intelligent Technique
    ( 2024-01-01)
    Azlina Abdullah
    ;
    Ismail Musirin
    ;
    Muhammad Murthada Othman
    ;
    Siti Rafidah Abdul Rahim
    ;
    Sharifah Azwa Shaaya
    ;
    Senthil Kumar A.V.
    This work introduces a novel approach called the Multi-Objective Integrated Immune Moth Flame Evolutionary Programming (MO-IIMFEP) algorithm. This algorithm aims to determine the optimal sizes and positions for Type III distributed generators (DGs) that generate both active and reactive power. The objectives involve reducing overall losses in the distribution system while adhering to voltage restrictions and taking into account the cost limitations connected with the installation of DG. MO-IIMFEP overcomes the constraints of traditional Evolutionary Programming (EP) and Moth Flame Optimization (MFO), particularly in effectively handling local optima. Fuzzy logic is employed in MO-IIMFEP to determine the best solution to compromise conflicting goals, as obtained from the non-dominated Pareto solutions. The efficacy of MOIIMFEP in identifying optimal solutions for multi-objective problems is demonstrated through comprehensive assessments conducted on the 118-Bus Radial Distribution Systems (RDS), comparing it against MO-EP and MO-MFO. The results underscore the strategic benefits of DG installation in sustaining voltage levels, reducing power losses, and minimizing total operating costs for power suppliers.
  • Publication
    Comparative Evaluation of Three-Phase Inverter Topologies Based on Voltage Boosting Features
    ( 2023-01-01)
    Yee C.S.
    ;
    Syahrul Ashikin Azmi
    ;
    Hwai L.J.
    ;
    Mohammad Faridun Naim Tajuddin
    ;
    Zahari M.Z.A.
    ;
    Siti Rafidah Abdul Rahim
    Voltage source inverter (VSI) is commonly used in industrial due to its stable operation and low cost. However, VSI needs to operate with an extra converter stage which is a DC-DC converter for voltage boosting purposes. In contrast, current source inverter (CSI) inherits voltage boosting features may become an alternative option to VSI. Yet, there were minimal research on CSI that dedicates to the voltage boosting features. This research focuses on comparing the voltage boosting features of CSI and VSI in both open-loop and closed-loop conditions. The performance of VSI and CSI are simulated using MATLAB/Simulink. Under open-loop operation, CSI produces a voltage boosting capability at approximately 55% higher than VSI. Yet, CSI suffers high THD percentage as compared to VSI for the same switching frequency. This high THD shortcoming can be easily resolved by using a simple CL filter. For closed-loop operation, VSI and CSI with voltage-controlled synchronous frame PI control systems are proven to have good reference tracking and harmonic rejection and are suitable to be implemented for household applications or for a standalone system. Interestingly, CSI closed-loop system can achieve a wider range of output due to the voltage boosting capability and provide a better quality of output waveform as compared to VSI.
  • Publication
    Comparative Study of Power System Security Assessment using Deterministic and Probabilistic Methods
    ( 2023-01-01)
    Aminudin N.
    ;
    Musirin I.
    ;
    Salimin R.H.
    ;
    Yusoh M.A.T.M.
    ;
    Siti Rafidah Abdul Rahim
    ;
    Yusof Y.
    Escalating electricity demand has forced the power system to operate very close to its security margin. Any unpredictable occurrence of a contingency would exacerbate the condition and threaten power system security. Thus, it is of utmost importance for the system operator to evaluate the actual system health accurately to avoid voltage collapse incidents and to evade overly conservative protection. This paper presents a risk-based security assessment (RBSA) in power system operation that quantifies the degree of risk faced by the system in its proximity to voltage stability violations due to transmission line outages that occur in the system. The risk value is calculated by considering the closeness of the system condition to the point of instability, which is also regarded as severity, as well as the likelihood of the contingency to occur. In the research, the performance of RBSA is compared with the traditional deterministic method in assessing power system conditions. The IEEE 30 bus system is engaged as the test system, and the simulation is done using MATLAB software.
  • 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.
  • Publication
    A hybrid multi-objective Evolutionary Programming-Firefly Algorithm for different type of Distributed Generation in distribution system
    ( 2022-12-01)
    Noor Najwa Husnaini Mohammad Husni
    ;
    Siti Rafidah Abdul Rahim
    ;
    Mohd Rafi Adzman
    ;
    Hussain M.H.
    ;
    Musirin I.
    ;
    Syahrul Ashikin Azmi
    With the rise in electricity demand, various additional sources of generation, known as Distributed Generation (DG), have been introduced to boost the performance of power systems. A hybrid multi-objective Evolutionary Programming-Firefly Algorithm (MOEPFA) technique is presented in this study for solving multi-objective power system problems which are minimizing total active and reactive power losses and improving voltage profile while considering the cost of energy losses. This MOEPFA is developed by embedding Firefly Algorithm (FA) features into the conventional EP method. The analysis in this study considered DG with 4 different scenarios. Scenario 1 is the base case or without DG, scenario 2 is for DG with injected active power, scenario 3 is for DG injected with reactive power only and scenario 4 is for DG injected with both active and reactive power. The IEEE 69-bus test system is applied to validate the suggested technique.
  • Publication
    An automatic irrigation system for plants using fuzzy logic controller considering volumetric water content
    ( 2020-01-07)
    Rahim S.
    ;
    Muhamad Hatta Hussain
    ;
    Siti Rafidah Abdul Rahim
    ;
    Hashim N.
    ;
    Halim H.A.
    An automatic irrigation system have an important role in today agriculture sector. Currently, automatic irrigation systems which can irrigate and supply plants with desired level and amount of water required for normal plant growth are not available. Furthermore, the classical method using on-off controller is inefficient due to results in loss of energy and productivity. Thus, an efficient automatic irrigation system with fuzzy logic controller is proposed to estimate the amount of water level using the irrigation model, soil type and type of plant. This paper presents a solution for irrigation system for plants using fuzzy logic controller using MATLAB Simulink. To indicate the effectiveness of the proposed method, on-off controller method is also applied for validation purpose.