Mohd Wanik - Academia.edu (original) (raw)

Papers by Mohd Wanik

2017 IEEE Manchester PowerTech, 2017

This paper describe and present the study on online tap change (OLTC) operation in distribution n... more This paper describe and present the study on online tap change (OLTC) operation in distribution network in the case of utilizing reactive power capability of PV inverter. The conventional voltage control scheme and the effect of solar PV variation on the voltage profile in distribution network are discussed. Solar resources in the state of Qatar for different seasons and weather condition are presented. Real recorded solar irradiance in specific location in Qatar with 5 minutes interval is used for the simulation analysis. The simulation results shows that OLTC operation varies with different level and type of reactive power injection. Depending on the amount and type of reactive power, the operation of OLTC will either increase or decrease.

2019 IEEE PES GTD Grand International Conference and Exposition Asia (GTD Asia), Mar 1, 2019

This paper presents a hybrid AC/DC microgrid testbed which uses a mixture of emulators and indust... more This paper presents a hybrid AC/DC microgrid testbed which uses a mixture of emulators and industrial hardware to model a real-world environment for renewable energy systems at laboratory scale. The testbed description is detailed with reference to its components, system architecture and Human-Machine Interface (HMI). Testbed components include grid and PV emulators, programmable loads, and multiple power electronic converters connected in an AC/DC configuration. The system architecture is based on a hierarchical central control system implemented in LABVIEW, which integrates an intuitive HMI to enable supervisory control and data acquisition. It includes local and low-level control implementations for the PV emulator and programmable loads with the MPPT algorithm implemented at low power, using a single-stage inverter topology and Field Programmable Gate Arrays (FPGA). The proposed system offers a reconfigurable and flexible architecture with multiple communication protocols that enable the implementation of both high level to low-level microgrid control algorithms.

The aim of this paper is to evaluate grid-connected photovoltaic systems based on two kinds of ph... more The aim of this paper is to evaluate grid-connected photovoltaic systems based on two kinds of photovoltaic module technologies. This study presents a one-year evaluation of four grid-connected photovoltaic systems installed at the National Institute of Advanced Industrial Science and Technology, in Tsukuba in the northern Kantō region of Japan. Two grid-connected systems based on multi-crystalline: mc-Si and two other ones based on thin film technology namely copper indium selenium: CIS modules. The monitoring data have been collected for one year to make an evaluation of all possible changes in climate environment. The goal of this study is to define the characteristics, the behavior and the sensitivity of the grid-connected PV system to the environmental parameters. Various parameters were used for the outdoor performance evaluation of the four grid-connected PV systems; including performance ratio, temperature losses, final yield, reference yield, AC energy generated and system efficiency. It was found that the grid-connected PV systems based on mc-Si technology perform much better than the systems based on CIS. The annual average daily performance ratios of the systems based on mc-Si modules were found to be about 5.53% higher compared to those of the systems based on CIS module, and an annual average daily AC energy production about 42.85% higher than CIS.

This paper presents a study of resonance and its impact on harmonic distortion in a typical indus... more This paper presents a study of resonance and its impact on harmonic distortion in a typical industrial distribution system. The system utilised in the study is described and cases considered are detailed. The study is performed using frequency scan analysis with the aid of PSCAD and Matlab computer programs. The results, which visualize the impedance of the system at various

This paper describes a modeling of a Microgrid using real time simulation platform and presents t... more This paper describes a modeling of a Microgrid using real time simulation platform and presents the results of the simulation. The Microgrid under study consists of a Photovoltaic (PV) system as an example of an unreliable resource and a battery representing an energy storage. The modeling approach and the study analysis performed are described. The model and operation scenarios have successfully been simulated in real time using OPAL-RT OP5600 digital simulator. The operation of Microgrid in performing load leveling and voltage regulation in the local power system are demonstrated. The dynamic response of the Microgrid components are presented when subjected to sudden changes in solar irradiance. Battery energy storage is shown to be very effective in complementing and compensating the fluctuation of generated power from the PV. Microgrid is also shown very effective in regulating the voltage.

... Filtrr Tuned Bur CI LI Cz L2 Tppe Ea"c No (pF) (MH) (MH) SCE 5h 7tlD 442... more ... Filtrr Tuned Bur CI LI Cz L2 Tppe Ea"c No (pF) (MH) (MH) SCE 5h 7tlD 4421 0.0092 NIL NE SIT 9 3 7.0735 5.729 NIL NIL DTI: 5&&p 7&10 3586.34 0.0087 30954.5 0.0009 DTF 5h&? 3 0,0023 0.1297 0.0197 0.0014 TABLE 3. THD V AND I AFTER INSTALLATION STF AND DTF ...

International Journal of Electrical Power & Energy Systems, Sep 1, 2014

The Objective: This paper presents a method to identify the optimal location and size of DGs base... more The Objective: This paper presents a method to identify the optimal location and size of DGs based on the power stability index and particle swarm optimization (PSO) algorithm. Materials and methods: First, a novel maximum power stability index (MPSI) is derived from the wellestablished theorem of maximum power transfer. The MPSI is utilized as an objective function to determine the optimal DG locations. Next, a PSO-based model with randomized load is developed to optimize DG sizing in view of the system's real power losses. Results and Conclusion: Lastly, a IEEE 30-bus test system is employed in the simulation. The performance of proposed MPSI index are comparable with other voltage stability indices. The DG optimization model considering voltage stability and loss minimization provides better results compared to that obtained using only loss minimization approach.

This paper compares the impact of a middle-size Solar PV plant on the distribution network operat... more This paper compares the impact of a middle-size Solar PV plant on the distribution network operations of a neighbourhood power grid in two inverter technology scenarios: central and string inverters. As a case study, we focus on the integration of a 0.4 MWp PV plant with the Education City Housing Complex power grid in Doha, Qatar. The goal of the ensuing power system analysis is to assess the feasibility of the interconnection in question. The study utilizes the DIgSILENT PowerFactory simulator to assess the criteria that ensure a safe interconnection. The study indicates that the PV interconnection under analysis does not result in violations of the code of practice of a typical distribution network.

ABSTRACT This paper presents a simplified mathematical model of photovoltaic generation system wh... more ABSTRACT This paper presents a simplified mathematical model of photovoltaic generation system which can be used to perform various power system studies. First the relation between solar radiation and PV output is presented. Then the power electronics inverter control employed in PV system is described. Finally the performance of detail model and simplified model of PV system is compared and commented. The model is simplified by considering the technology and controller employed by grid connected PV generation system with a few assumptions on the electrical characteristic of the full model. The performance of simplified model is compared to the full model performances. Simplified model is found giving comparable results. The usage of this simplified model will reduce the complexity in modeling and will reduce substantially power system study time.

Turkish Journal of Electrical Engineering and Computer Sciences, 2013

Growing concerns over environmental impacts, improvement of the overall network conditions, and r... more Growing concerns over environmental impacts, improvement of the overall network conditions, and rebate programs offered by governments have led to an increase in the number of distributed generation (DG) units in commercial and domestic electric power production. However, a large number of DG units in a distribution system may sometimes contribute to high levels of harmonic distortion, even though the emission levels of the individual DG units comply with the harmonic standards. It is known that the nonoptimal size and nonoptimal placement of DG units may lead to high power losses, bad voltage profiles, and harmonic propagations. Therefore, this paper introduces a sensitivity analysis to determine the optimal location of DG units, as well as evolutionary programming and harmonic distribution load flow for determining the optimal size of DG units in radial distribution systems. A multiobjective function is created to minimize the total losses and average total harmonic distortion voltage (THD v) of the distribution system. The proposed methodology is tested with a 69-bus radial distribution system. The proposed optimal placement and sizing of the DG units is found to be robust and provides higher efficiency for the improvement of the voltage profile and the minimization of the losses and THD v .

This paper investigates PV induced voltage rise in a radial feeder through an effective circuit d... more This paper investigates PV induced voltage rise in a radial feeder through an effective circuit decoupling of real and reactive power and analytical equations. Two new parameters, equivalent voltage rise resistance and equivalent curtailment resistance, are introduced that allow a faster and accurate analysis of voltage rise, eliminating a need for complex computational calculations. Part of a distribution power network in Doha is simulated using Power Factory to evaluate the effectiveness of the proposed approach. Results obtained using the proposed equivalent resistances are compared to those obtained by simulations using Power Factory, showing a very good correlation and hence validating the accuracy of the proposed formula. The proposed approach greatly simplifies voltage rise and curtailment analyses, and only require basic feeder parameters.

2019 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe)

Power quality issues pose severe challenges in realizing large-scale photovoltaic (PV) integratio... more Power quality issues pose severe challenges in realizing large-scale photovoltaic (PV) integration into the low voltage (LV) networks, and therefore determining PV hosting capacity in such a network becomes a complex and important task. This paper investigates PV hosting capacity of a Qatar based radial rural farm/small scale industrial network. Typically, this kind of network experiences huge variation in local demand during different times of the summer days and nights, requiring the network to operate both in power export and import modes. These two modes require contradictory tap settings for the transformers with off-load tap changing (OfLTC) mechanism. If the tap setting is not optimized and other mitigation measures are not taken, the PV hosting capacity of LV buses in such networks can severely be limited. This problem worsens further if the transformer has already been set at either −1 or −2 in order to boost the downstream bus voltage. This paper proposes utilization of PV inverters, designed with capability of regulating its reactive power and power factor, for enhancing the PV hosting capacity. Simulation results show that the PV hosting capacity can, substantially, be increased with the proposed approach (up to 95%), compared to a traditional practice of deploying PV inverters designed to operate at unity power factor.

2004 IEEE Region 10 Conference TENCON 2004.

This paper presents a study on harmonic resonance and its impact on harmonic distortion level in ... more This paper presents a study on harmonic resonance and its impact on harmonic distortion level in a typical industrial distribution system. The system utilised in the study is described and the cases considered are detailed. The study is performed using the frequency scan analysis ...

This paper present brief description of a Microgrid development project currently in progress. In... more This paper present brief description of a Microgrid development project currently in progress. Initially, then Malaysian renewable energy policy is briefly highlighted. The objective of having Microgrid is discussed. The main components of Microgrid and the technique on how the Microgrid central controller was developed is also explained. The result from simulation study of Microgrid system in the project is presented to demonstrate the workability of the concept. The modeling and simulation is performed in DIgSILENT and MATLAB/SIMPOWERSYSTEM software. The simulation shows quite promising results. The Microgrid controller managed to control the voltage and frequency in both grid connected and islanding mode as well as maintained them within mandatory operational limit of respective operation code in Malaysia. An active power loss is also significantly reduced. Index Terms-Microgrid, renewable energy, distributed generation, coordinated voltage control. I. This research works is part of collaboration works between TNB Research Malaysia and Power System Research Group of Universiti Kebangsaan Malaysia. TNB (Tenaga Nasional Berhad) is a main electric utility company in Malaysia and a leading utility company in South East Asia with almost MYR 87 billion in assets. TNB Research is a research arm of TNB. The funding is mostly provided by TNB Research.

Przegląd Elektrotechniczny, 2013

Institution of Engineering and Technology eBooks, Aug 15, 2023

IAES International Journal of Artificial Intelligence (IJ-AI)

Dissolved gas analysis (DGA) is widely accepted as an effective method to detect incipient faults... more Dissolved gas analysis (DGA) is widely accepted as an effective method to detect incipient faults within power transformers. Gases such as hydrogen, methane, acetylene, ethylene and ethane are normally utilized to identify the transformer fault conditions. Several techniques have been developed to interpret DGA results such as the key gas method, Doernenburg, Rogers, IEC ratio-based methods, Duval Triangles, and the latest Duval Pentagon methods. However, each of these approaches depends on the experts' shared knowledge and experience rather than quantitative scientific methods, therefore different diagnoses may be reported for the same oil sample. To overcome these shortcomings, this paper proposed the use of decision tree method to interpret the transformer health condition based on DGA results. The proposed decision tree model employed three main fault gases; methane, acetylene, ethylene as inputs, and classified the transformer into eight fault conditions. The J48 algorithm ...

2022 IEEE 16th International Conference on Compatibility, Power Electronics, and Power Engineering (CPE-POWERENG)

Przegląd Elektrotechniczny, 2013

2017 IEEE Manchester PowerTech, 2017

This paper describe and present the study on online tap change (OLTC) operation in distribution n... more This paper describe and present the study on online tap change (OLTC) operation in distribution network in the case of utilizing reactive power capability of PV inverter. The conventional voltage control scheme and the effect of solar PV variation on the voltage profile in distribution network are discussed. Solar resources in the state of Qatar for different seasons and weather condition are presented. Real recorded solar irradiance in specific location in Qatar with 5 minutes interval is used for the simulation analysis. The simulation results shows that OLTC operation varies with different level and type of reactive power injection. Depending on the amount and type of reactive power, the operation of OLTC will either increase or decrease.

2019 IEEE PES GTD Grand International Conference and Exposition Asia (GTD Asia), Mar 1, 2019

This paper presents a hybrid AC/DC microgrid testbed which uses a mixture of emulators and indust... more This paper presents a hybrid AC/DC microgrid testbed which uses a mixture of emulators and industrial hardware to model a real-world environment for renewable energy systems at laboratory scale. The testbed description is detailed with reference to its components, system architecture and Human-Machine Interface (HMI). Testbed components include grid and PV emulators, programmable loads, and multiple power electronic converters connected in an AC/DC configuration. The system architecture is based on a hierarchical central control system implemented in LABVIEW, which integrates an intuitive HMI to enable supervisory control and data acquisition. It includes local and low-level control implementations for the PV emulator and programmable loads with the MPPT algorithm implemented at low power, using a single-stage inverter topology and Field Programmable Gate Arrays (FPGA). The proposed system offers a reconfigurable and flexible architecture with multiple communication protocols that enable the implementation of both high level to low-level microgrid control algorithms.

The aim of this paper is to evaluate grid-connected photovoltaic systems based on two kinds of ph... more The aim of this paper is to evaluate grid-connected photovoltaic systems based on two kinds of photovoltaic module technologies. This study presents a one-year evaluation of four grid-connected photovoltaic systems installed at the National Institute of Advanced Industrial Science and Technology, in Tsukuba in the northern Kantō region of Japan. Two grid-connected systems based on multi-crystalline: mc-Si and two other ones based on thin film technology namely copper indium selenium: CIS modules. The monitoring data have been collected for one year to make an evaluation of all possible changes in climate environment. The goal of this study is to define the characteristics, the behavior and the sensitivity of the grid-connected PV system to the environmental parameters. Various parameters were used for the outdoor performance evaluation of the four grid-connected PV systems; including performance ratio, temperature losses, final yield, reference yield, AC energy generated and system efficiency. It was found that the grid-connected PV systems based on mc-Si technology perform much better than the systems based on CIS. The annual average daily performance ratios of the systems based on mc-Si modules were found to be about 5.53% higher compared to those of the systems based on CIS module, and an annual average daily AC energy production about 42.85% higher than CIS.

This paper presents a study of resonance and its impact on harmonic distortion in a typical indus... more This paper presents a study of resonance and its impact on harmonic distortion in a typical industrial distribution system. The system utilised in the study is described and cases considered are detailed. The study is performed using frequency scan analysis with the aid of PSCAD and Matlab computer programs. The results, which visualize the impedance of the system at various

This paper describes a modeling of a Microgrid using real time simulation platform and presents t... more This paper describes a modeling of a Microgrid using real time simulation platform and presents the results of the simulation. The Microgrid under study consists of a Photovoltaic (PV) system as an example of an unreliable resource and a battery representing an energy storage. The modeling approach and the study analysis performed are described. The model and operation scenarios have successfully been simulated in real time using OPAL-RT OP5600 digital simulator. The operation of Microgrid in performing load leveling and voltage regulation in the local power system are demonstrated. The dynamic response of the Microgrid components are presented when subjected to sudden changes in solar irradiance. Battery energy storage is shown to be very effective in complementing and compensating the fluctuation of generated power from the PV. Microgrid is also shown very effective in regulating the voltage.

... Filtrr Tuned Bur CI LI Cz L2 Tppe Ea"c No (pF) (MH) (MH) SCE 5h 7tlD 442... more ... Filtrr Tuned Bur CI LI Cz L2 Tppe Ea"c No (pF) (MH) (MH) SCE 5h 7tlD 4421 0.0092 NIL NE SIT 9 3 7.0735 5.729 NIL NIL DTI: 5&&p 7&10 3586.34 0.0087 30954.5 0.0009 DTF 5h&? 3 0,0023 0.1297 0.0197 0.0014 TABLE 3. THD V AND I AFTER INSTALLATION STF AND DTF ...

International Journal of Electrical Power & Energy Systems, Sep 1, 2014

The Objective: This paper presents a method to identify the optimal location and size of DGs base... more The Objective: This paper presents a method to identify the optimal location and size of DGs based on the power stability index and particle swarm optimization (PSO) algorithm. Materials and methods: First, a novel maximum power stability index (MPSI) is derived from the wellestablished theorem of maximum power transfer. The MPSI is utilized as an objective function to determine the optimal DG locations. Next, a PSO-based model with randomized load is developed to optimize DG sizing in view of the system's real power losses. Results and Conclusion: Lastly, a IEEE 30-bus test system is employed in the simulation. The performance of proposed MPSI index are comparable with other voltage stability indices. The DG optimization model considering voltage stability and loss minimization provides better results compared to that obtained using only loss minimization approach.

This paper compares the impact of a middle-size Solar PV plant on the distribution network operat... more This paper compares the impact of a middle-size Solar PV plant on the distribution network operations of a neighbourhood power grid in two inverter technology scenarios: central and string inverters. As a case study, we focus on the integration of a 0.4 MWp PV plant with the Education City Housing Complex power grid in Doha, Qatar. The goal of the ensuing power system analysis is to assess the feasibility of the interconnection in question. The study utilizes the DIgSILENT PowerFactory simulator to assess the criteria that ensure a safe interconnection. The study indicates that the PV interconnection under analysis does not result in violations of the code of practice of a typical distribution network.

ABSTRACT This paper presents a simplified mathematical model of photovoltaic generation system wh... more ABSTRACT This paper presents a simplified mathematical model of photovoltaic generation system which can be used to perform various power system studies. First the relation between solar radiation and PV output is presented. Then the power electronics inverter control employed in PV system is described. Finally the performance of detail model and simplified model of PV system is compared and commented. The model is simplified by considering the technology and controller employed by grid connected PV generation system with a few assumptions on the electrical characteristic of the full model. The performance of simplified model is compared to the full model performances. Simplified model is found giving comparable results. The usage of this simplified model will reduce the complexity in modeling and will reduce substantially power system study time.

Turkish Journal of Electrical Engineering and Computer Sciences, 2013

Growing concerns over environmental impacts, improvement of the overall network conditions, and r... more Growing concerns over environmental impacts, improvement of the overall network conditions, and rebate programs offered by governments have led to an increase in the number of distributed generation (DG) units in commercial and domestic electric power production. However, a large number of DG units in a distribution system may sometimes contribute to high levels of harmonic distortion, even though the emission levels of the individual DG units comply with the harmonic standards. It is known that the nonoptimal size and nonoptimal placement of DG units may lead to high power losses, bad voltage profiles, and harmonic propagations. Therefore, this paper introduces a sensitivity analysis to determine the optimal location of DG units, as well as evolutionary programming and harmonic distribution load flow for determining the optimal size of DG units in radial distribution systems. A multiobjective function is created to minimize the total losses and average total harmonic distortion voltage (THD v) of the distribution system. The proposed methodology is tested with a 69-bus radial distribution system. The proposed optimal placement and sizing of the DG units is found to be robust and provides higher efficiency for the improvement of the voltage profile and the minimization of the losses and THD v .

This paper investigates PV induced voltage rise in a radial feeder through an effective circuit d... more This paper investigates PV induced voltage rise in a radial feeder through an effective circuit decoupling of real and reactive power and analytical equations. Two new parameters, equivalent voltage rise resistance and equivalent curtailment resistance, are introduced that allow a faster and accurate analysis of voltage rise, eliminating a need for complex computational calculations. Part of a distribution power network in Doha is simulated using Power Factory to evaluate the effectiveness of the proposed approach. Results obtained using the proposed equivalent resistances are compared to those obtained by simulations using Power Factory, showing a very good correlation and hence validating the accuracy of the proposed formula. The proposed approach greatly simplifies voltage rise and curtailment analyses, and only require basic feeder parameters.

2019 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe)

Power quality issues pose severe challenges in realizing large-scale photovoltaic (PV) integratio... more Power quality issues pose severe challenges in realizing large-scale photovoltaic (PV) integration into the low voltage (LV) networks, and therefore determining PV hosting capacity in such a network becomes a complex and important task. This paper investigates PV hosting capacity of a Qatar based radial rural farm/small scale industrial network. Typically, this kind of network experiences huge variation in local demand during different times of the summer days and nights, requiring the network to operate both in power export and import modes. These two modes require contradictory tap settings for the transformers with off-load tap changing (OfLTC) mechanism. If the tap setting is not optimized and other mitigation measures are not taken, the PV hosting capacity of LV buses in such networks can severely be limited. This problem worsens further if the transformer has already been set at either −1 or −2 in order to boost the downstream bus voltage. This paper proposes utilization of PV inverters, designed with capability of regulating its reactive power and power factor, for enhancing the PV hosting capacity. Simulation results show that the PV hosting capacity can, substantially, be increased with the proposed approach (up to 95%), compared to a traditional practice of deploying PV inverters designed to operate at unity power factor.

2004 IEEE Region 10 Conference TENCON 2004.

This paper presents a study on harmonic resonance and its impact on harmonic distortion level in ... more This paper presents a study on harmonic resonance and its impact on harmonic distortion level in a typical industrial distribution system. The system utilised in the study is described and the cases considered are detailed. The study is performed using the frequency scan analysis ...

This paper present brief description of a Microgrid development project currently in progress. In... more This paper present brief description of a Microgrid development project currently in progress. Initially, then Malaysian renewable energy policy is briefly highlighted. The objective of having Microgrid is discussed. The main components of Microgrid and the technique on how the Microgrid central controller was developed is also explained. The result from simulation study of Microgrid system in the project is presented to demonstrate the workability of the concept. The modeling and simulation is performed in DIgSILENT and MATLAB/SIMPOWERSYSTEM software. The simulation shows quite promising results. The Microgrid controller managed to control the voltage and frequency in both grid connected and islanding mode as well as maintained them within mandatory operational limit of respective operation code in Malaysia. An active power loss is also significantly reduced. Index Terms-Microgrid, renewable energy, distributed generation, coordinated voltage control. I. This research works is part of collaboration works between TNB Research Malaysia and Power System Research Group of Universiti Kebangsaan Malaysia. TNB (Tenaga Nasional Berhad) is a main electric utility company in Malaysia and a leading utility company in South East Asia with almost MYR 87 billion in assets. TNB Research is a research arm of TNB. The funding is mostly provided by TNB Research.

Przegląd Elektrotechniczny, 2013

Institution of Engineering and Technology eBooks, Aug 15, 2023

IAES International Journal of Artificial Intelligence (IJ-AI)

Dissolved gas analysis (DGA) is widely accepted as an effective method to detect incipient faults... more Dissolved gas analysis (DGA) is widely accepted as an effective method to detect incipient faults within power transformers. Gases such as hydrogen, methane, acetylene, ethylene and ethane are normally utilized to identify the transformer fault conditions. Several techniques have been developed to interpret DGA results such as the key gas method, Doernenburg, Rogers, IEC ratio-based methods, Duval Triangles, and the latest Duval Pentagon methods. However, each of these approaches depends on the experts' shared knowledge and experience rather than quantitative scientific methods, therefore different diagnoses may be reported for the same oil sample. To overcome these shortcomings, this paper proposed the use of decision tree method to interpret the transformer health condition based on DGA results. The proposed decision tree model employed three main fault gases; methane, acetylene, ethylene as inputs, and classified the transformer into eight fault conditions. The J48 algorithm ...

2022 IEEE 16th International Conference on Compatibility, Power Electronics, and Power Engineering (CPE-POWERENG)

Przegląd Elektrotechniczny, 2013