Ahmed Abu Siada | Curtin University (original) (raw)

Papers by Ahmed Abu Siada

Designs, 2022

This paper presents a mechanism for active power sharing among multiple dispatchable and distribu... more This paper presents a mechanism for active power sharing among multiple dispatchable and distributed generation units within a micro grid comprising one or multiple interconnections with the main grid. Ideally, a micro grid should act as a constant load or a constant voltage source when connected to the main grid. However, to achieve ideal operation, natural load variations and the intermittency of renewable energy sources within the microgrid need to be adequately and timely compensated for by dispatchable power sources. While several control algorithms have been reported in the literature to achieve ideal microgrid operation, the majority of the proposed methods assumed a micro grid with a single interconnection to the main grid. In the real world, micro grids may have to maintain multiple live links with the main grid for several technical and operational reasons such as reliability, power-dispatch restriction, and operational limitations requirements. Therefore, a new method of ...

2017 1st International Conference on Electrical Materials and Power Equipment (ICEMPE), 2017

Dissolved gas analysis (DGA) is the most effective method to detect incipient faults in power tra... more Dissolved gas analysis (DGA) is the most effective method to detect incipient faults in power transformers. It uses the concentrations of various gases dissolved in the transformer oil due to decomposition of the oil and paper insulation. Gases such as hydrogen, methane, acetylene, ethylene, and ethane are generated as a results of oil decomposition, while carbon monoxide and carbon dioxide are generated due to the paper degradation. In the meantime, faults such as partial discharge, overheating, and arcing produce a range of gases. The concentrations of these gases can be used to identify faults and estimate their severity. Various techniques have been developed to interpret DGA results such the key gas method, Doernenburg, Rogers, IEC ratio-based methods, Duval triangles, and the latest Duval Pentagon methods. However, each of these techniques relies on the accumulated knowledge and experience of experts rather than quantitative scientific models, therefore different diagnoses may be reported for the same oil sample. Hence the accountability of the judgment is questionable if it only relies on one interpretation technique. This paper proposes the use of scoring point method to improve the accountability of DGA interpretation process. In this context, DGA results of several transformer oil samples are analyzed with four existing interpretation techniques; Doernenburg, Rogers, IEC, and Duval triangle methods from which a scoring index is developed for all fault types. Based on this analysis, each technique is assigned with specific weighting factor. The summation of scoring point times weightage represents the scoring index for particular faults. The proposed method is validated through DGA historical data of various transformers of pre-known health condition and life span. Results show that the proposed method can increase the accuracy of the DGA interpretation process.

Electronics, 2021

Dissolved gas analysis (DGA) is one of the regular routine tests accepted by worldwide utilities ... more Dissolved gas analysis (DGA) is one of the regular routine tests accepted by worldwide utilities to detect power transformer incipient faults. While the DGA measurement has fully matured since the development of offline and online sensors, interpretation of the DGA results still calls for advanced approaches to automate and standardize the process. Current industry practice relies on various interpretation techniques that are reported to be inconsistent and, in some cases, unreliable. This paper presents a new application for the advanced logistic regression algorithm to improve the reliability of the DGA interpretation process. In this regard, regularized logistic regression is used to improve the accuracy of the DGA interpretation process. Results reveal the superior features of the proposed logistic regression approach over the conventional and artificial intelligence techniques presented in the literature.

2019 2nd International Conference on High Voltage Engineering and Power Systems (ICHVEPS), 2019

Power transformer is one of the most important assets for any electricity utility. The overall po... more Power transformer is one of the most important assets for any electricity utility. The overall power transformer health condition can be assessed through the condition of its insulation system. Recent result of transformer oil measurements for parameters such as furan, dissolved gas analysis, water content, breakdown voltage, interfacial tension, acidity, and oil color scale are commonly used to assess the health condition of power transformers. Degradation rate of power transformer insulation system, especially paper insulation, reflects the transformer aging condition and can be used to estimate the useful remnant life of the asset. Unfortunately, continuous aging process of power transformer insulation system cannot be avoided due to the severe operating conditions that a transformer is operating on. So, it is very important to regularly monitor the condition of power transformer insulation to maintain its reliability. Historical data of transformer insulations are very substantial to define the history of power transformer health condition. This paper introduces two methods, first one to assess the degradation rate of power transformers insulation, and then estimate the insulation condition index based on historical data.

IEEE Transactions on Power Delivery, 2019

Frequency response analysis (FRA) has become a widely accepted technique by worldwide utilities t... more Frequency response analysis (FRA) has become a widely accepted technique by worldwide utilities to detect winding and core deformations within power transformers. The main drawback of this technique is its reliance on the personnel level of expertise more than standard or automated codes. To establish reliable FRA interpretation codes, accurate high frequency transformer model that can emulate the frequency characteristics of real transformers in a wide frequency range is essential. The model can be used to investigate the impact of various winding and core deformations on the transformer FRA signature. The transformer equivalent high frequency electric circuit parameters can be calculated based on design data, which are rarely available, especially for old transformers. As such, this paper presents an artificial intelligence technique to estimate these parameters from the transformer FRA signature. The robustness of the proposed technique is assessed through its application on three, 3-phase power transformers of different ratings, sizes, and winding structures to estimate their high frequency electric circuit parameters during normal and fault conditions. Results show that the proposed technique can estimate equivalent circuit parameters with high accuracy and helps interpret the FRA signature based on the numerical changes of these parameters. The main advantage of this approach is the physical meaning of the model parameters facilitates reliable identification of various faults and hence aids in establishing reliable interpretation codes for transformer FRA signatures.

IEEE Transactions on Power Electronics, 2018

This paper presents a novel three-phase DC-link multilevel inverter topology with reduced number ... more This paper presents a novel three-phase DC-link multilevel inverter topology with reduced number of input DC power supplies. The proposed inverter consists of series-connected half-bridge modules to generate the multilevel waveform and a simple H-bridge module, acting as a polarity generator. The inverter output voltage is transferred to the load through a threephase transformer, which facilitates a galvanic isolation between the inverter and the load. The proposed topology features many advantages when compared with the conventional multilevel inverters proposed in the literatures. These features include scalability, simple control, reduced number of DC voltage sources and less devices count. A simple sinusoidal pulse-width modulation technique is employed to control the proposed inverter. The performance of the inverter is evaluated under different loading conditions and a comparison with some existing topologies is also presented. The feasibility and effectiveness of the proposed inverter are confirmed through simulation and experimental studies using a scaled down low-voltage laboratory prototype.

8th Power Plant and Power System Control Symposium, 2012

This paper investigates different approaches to improve the power transfer capability (PTC) of tr... more This paper investigates different approaches to improve the power transfer capability (PTC) of transmission lines. Study was performed on the Eastern Gold Fields (EGF) area of the Western Power network in Western Australia where power transfer to this area is currently enhanced using four saturable reactor types static var Compensators (SR SVCs) installed in this region. These SR SVCs have reached to the end of operational life and they are scheduled for replacement by different dynamic reactive power devices such as Static Synchronous Compensators (STATCOMs) or Thyristor Controlled SVCs (TSVCs). Another proposed option to enhance the PTC to this area is by upgrading the 220 kV transmission line to 275 kV transmission line and / or using series capacitor compensation. This paper introduces technical and economical study for the aforementioned options and suggests a reliable and cost effective approach to improve the PTC to EGF area.

IEEE Transactions on Energy Conversion, 2021

Electronics

Dissolved gas analysis (DGA) is one of the regular routine tests accepted by worldwide utilities ... more Dissolved gas analysis (DGA) is one of the regular routine tests accepted by worldwide utilities to detect power transformer incipient faults. While the DGA measurement has fully matured since the development of offline and online sensors, interpretation of the DGA results still calls for advanced approaches to automate and standardize the process. Current industry practice relies on various interpretation techniques that are reported to be inconsistent and, in some cases, unreliable. This paper presents a new application for the advanced logistic regression algorithm to improve the reliability of the DGA interpretation process. In this regard, regularized logistic regression is used to improve the accuracy of the DGA interpretation process. Results reveal the superior features of the proposed logistic regression approach over the conventional and artificial intelligence techniques presented in the literature.

Iet Generation Transmission & Distribution, 2020

Current industry practice to identify fault location in transmission lines is based on visual ins... more Current industry practice to identify fault location in transmission lines is based on visual inspection, travelling waves, and line impedance measurement. Unfortunately, these techniques are only developed to detect the fault location upon its occurrence without the ability to predict abnormal events that usually precede major faults and issue a timely warning signal to avoid potential consequences for power line failures. Furthermore, the current fault locating techniques exhibit some drawbacks that limit their wide practical implementation. This includes cost, access to required data, and low accuracy when employed for specific power line topologies. This study is aimed at presenting and validating a new cost-effective technique based on the line voltage-current characteristics to predict and identify the location of various abnormal and fault events in real-time. By measuring the currents and voltages at both ends of the line, a unique line fingerprint can be identified. Any change in this fingerprint can be detected and analysed by a software installed in the control centre in real-time to identify the location, type, and level of the abnormal events or emerging faults. Robustness of the proposed technique is assessed through simulation analysis conducted on various case studies along with a practical case study.

IEEE Access, 2020

Tube electromagnetic bulging has been given much attention due to its superior advantages in the ... more Tube electromagnetic bulging has been given much attention due to its superior advantages in the field of light alloy processing. However, the conventional tube electromagnetic bulging process exhibits some critical issues that restrict its wide industrial applications. This includes non-uniform axial deformation and poor forming performance such as wall thickness thinning. This article proposes a cost-effective solution for such issues through simultaneous radial and axial electromagnetic force loading using an auxiliary driving coil. In this regard, the influence of the auxiliary coil geometrical parameters on the electromagnetic force distribution and tube forming performance is investigated using electromagnetic-structure coupling model of the bulging process. The robustness of the new proposed method is validated by comparing its electromagnetic force distribution and tube forming performance with the traditional cylindrical coil method, currently used by industry practice. Num...

Electronics

For technological, economic, and environmental reasons, renewable distributed generators (RDGs) h... more For technological, economic, and environmental reasons, renewable distributed generators (RDGs) have been extensively used in distribution networks. This paper presents an effective approach for technoeconomic analysis of optimal allocation of REDGs considering the uncertainties of the system. The primary issue with renewable-based distributed generators, especially wind and photovoltaic systems, is their intermittent characteristic that results in fluctuating output power and, hence, increasing power system uncertainty. Thus, it is essential to consider the uncertainty of such resources while selecting their optimal allocation within the grid. The main contribution of this study is to figure out the optimal size and location for RDGs in radial distribution systems while considering the uncertainty of load demand and RDG output power. A Monte Carlo simulation approach and a backward reduction algorithm were used to generate a reasonable number of scenarios to reflect the uncertainti...

Chemical engineering transactions, 2013

Dissolved gas analysis (DGA) of transformer oil is one of the most effective power transformer co... more Dissolved gas analysis (DGA) of transformer oil is one of the most effective power transformer condition monitoring tools which can be facilitated to determine transformer criticality ranking and hence identifying a suitable condition-based asset management decision. There are many interpretation techniques for DGA results however all the current techniques rely on personnel experience more than analytical formulation. As a result, the current techniques do not necessarily lead to the same conclusion for the same oil sample. A significant number of DGA results fall outside the proposed codes of the current based-ratio methods and cannot be diagnosed by these methods. Moreover, ratio methods fail to diagnose multiple fault conditions due to the mixing up of produced gases. To overcome these limitations, this paper introduces a fuzzy logic approach to aid in standardizing DGA interpretation techniques, identify transformer critical ranking and provide a suitable asset management decis...

International Energy Journal, 2005

This paper investigates the use of Superconducting Magnetic Energy Storage (SMES) unitto stabiliz... more This paper investigates the use of Superconducting Magnetic Energy Storage (SMES) unitto stabilize multi-mode torsional oscillations of Sub-Synchronous Resonance (SSR) oscillations ofa turbine-generator set at the same time to improve dynamic transient stability of the studied systemunder different operating conditions. Two-control algorithm are discussed, they are equal ?-modeand unequal ?-mode of the converter stations of the SMES unit. Results show that the designedcontroller provides proper damping to all oscillating modes a swing mode simultaneously.Eigenvalues analysis is used to show the effectiveness of the proposed controller in stabilizing allmodes of oscillations of the system under different operating conditions. The proposed controller issimple and easy to be implemented.

2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), 2020

Air-core transformer has advantages of no iron loss, no magnetic saturation, and compact in size,... more Air-core transformer has advantages of no iron loss, no magnetic saturation, and compact in size, which make them attractive to be studied for practical applications. In this paper, the H-formulation is used to numerically analyze the electromagnetic field and AC loss of the HTS air-core transformer and optimize the air gap.

The integration of renewable energy system into modern power grids has significantly increased du... more The integration of renewable energy system into modern power grids has significantly increased during the last decade. Solar and wind energy are the most popular renewable energy sources recently. Solar energy has reached about 17,3 GW in 2010 whilst about 340 TWh of wind energy source has been installed worldwide. In this paper, the overview of updated information regarding proposed storage energy systems for renewable energy is presented. It is useful information for practitioners in considering the possible options of storage energy technologies to be connected with renewable energy sources.

Designs, 2022

This paper presents a mechanism for active power sharing among multiple dispatchable and distribu... more This paper presents a mechanism for active power sharing among multiple dispatchable and distributed generation units within a micro grid comprising one or multiple interconnections with the main grid. Ideally, a micro grid should act as a constant load or a constant voltage source when connected to the main grid. However, to achieve ideal operation, natural load variations and the intermittency of renewable energy sources within the microgrid need to be adequately and timely compensated for by dispatchable power sources. While several control algorithms have been reported in the literature to achieve ideal microgrid operation, the majority of the proposed methods assumed a micro grid with a single interconnection to the main grid. In the real world, micro grids may have to maintain multiple live links with the main grid for several technical and operational reasons such as reliability, power-dispatch restriction, and operational limitations requirements. Therefore, a new method of ...

2017 1st International Conference on Electrical Materials and Power Equipment (ICEMPE), 2017

Dissolved gas analysis (DGA) is the most effective method to detect incipient faults in power tra... more Dissolved gas analysis (DGA) is the most effective method to detect incipient faults in power transformers. It uses the concentrations of various gases dissolved in the transformer oil due to decomposition of the oil and paper insulation. Gases such as hydrogen, methane, acetylene, ethylene, and ethane are generated as a results of oil decomposition, while carbon monoxide and carbon dioxide are generated due to the paper degradation. In the meantime, faults such as partial discharge, overheating, and arcing produce a range of gases. The concentrations of these gases can be used to identify faults and estimate their severity. Various techniques have been developed to interpret DGA results such the key gas method, Doernenburg, Rogers, IEC ratio-based methods, Duval triangles, and the latest Duval Pentagon methods. However, each of these techniques relies on the accumulated knowledge and experience of experts rather than quantitative scientific models, therefore different diagnoses may be reported for the same oil sample. Hence the accountability of the judgment is questionable if it only relies on one interpretation technique. This paper proposes the use of scoring point method to improve the accountability of DGA interpretation process. In this context, DGA results of several transformer oil samples are analyzed with four existing interpretation techniques; Doernenburg, Rogers, IEC, and Duval triangle methods from which a scoring index is developed for all fault types. Based on this analysis, each technique is assigned with specific weighting factor. The summation of scoring point times weightage represents the scoring index for particular faults. The proposed method is validated through DGA historical data of various transformers of pre-known health condition and life span. Results show that the proposed method can increase the accuracy of the DGA interpretation process.

Electronics, 2021

Dissolved gas analysis (DGA) is one of the regular routine tests accepted by worldwide utilities ... more Dissolved gas analysis (DGA) is one of the regular routine tests accepted by worldwide utilities to detect power transformer incipient faults. While the DGA measurement has fully matured since the development of offline and online sensors, interpretation of the DGA results still calls for advanced approaches to automate and standardize the process. Current industry practice relies on various interpretation techniques that are reported to be inconsistent and, in some cases, unreliable. This paper presents a new application for the advanced logistic regression algorithm to improve the reliability of the DGA interpretation process. In this regard, regularized logistic regression is used to improve the accuracy of the DGA interpretation process. Results reveal the superior features of the proposed logistic regression approach over the conventional and artificial intelligence techniques presented in the literature.

2019 2nd International Conference on High Voltage Engineering and Power Systems (ICHVEPS), 2019

Power transformer is one of the most important assets for any electricity utility. The overall po... more Power transformer is one of the most important assets for any electricity utility. The overall power transformer health condition can be assessed through the condition of its insulation system. Recent result of transformer oil measurements for parameters such as furan, dissolved gas analysis, water content, breakdown voltage, interfacial tension, acidity, and oil color scale are commonly used to assess the health condition of power transformers. Degradation rate of power transformer insulation system, especially paper insulation, reflects the transformer aging condition and can be used to estimate the useful remnant life of the asset. Unfortunately, continuous aging process of power transformer insulation system cannot be avoided due to the severe operating conditions that a transformer is operating on. So, it is very important to regularly monitor the condition of power transformer insulation to maintain its reliability. Historical data of transformer insulations are very substantial to define the history of power transformer health condition. This paper introduces two methods, first one to assess the degradation rate of power transformers insulation, and then estimate the insulation condition index based on historical data.

IEEE Transactions on Power Delivery, 2019

Frequency response analysis (FRA) has become a widely accepted technique by worldwide utilities t... more Frequency response analysis (FRA) has become a widely accepted technique by worldwide utilities to detect winding and core deformations within power transformers. The main drawback of this technique is its reliance on the personnel level of expertise more than standard or automated codes. To establish reliable FRA interpretation codes, accurate high frequency transformer model that can emulate the frequency characteristics of real transformers in a wide frequency range is essential. The model can be used to investigate the impact of various winding and core deformations on the transformer FRA signature. The transformer equivalent high frequency electric circuit parameters can be calculated based on design data, which are rarely available, especially for old transformers. As such, this paper presents an artificial intelligence technique to estimate these parameters from the transformer FRA signature. The robustness of the proposed technique is assessed through its application on three, 3-phase power transformers of different ratings, sizes, and winding structures to estimate their high frequency electric circuit parameters during normal and fault conditions. Results show that the proposed technique can estimate equivalent circuit parameters with high accuracy and helps interpret the FRA signature based on the numerical changes of these parameters. The main advantage of this approach is the physical meaning of the model parameters facilitates reliable identification of various faults and hence aids in establishing reliable interpretation codes for transformer FRA signatures.

IEEE Transactions on Power Electronics, 2018

This paper presents a novel three-phase DC-link multilevel inverter topology with reduced number ... more This paper presents a novel three-phase DC-link multilevel inverter topology with reduced number of input DC power supplies. The proposed inverter consists of series-connected half-bridge modules to generate the multilevel waveform and a simple H-bridge module, acting as a polarity generator. The inverter output voltage is transferred to the load through a threephase transformer, which facilitates a galvanic isolation between the inverter and the load. The proposed topology features many advantages when compared with the conventional multilevel inverters proposed in the literatures. These features include scalability, simple control, reduced number of DC voltage sources and less devices count. A simple sinusoidal pulse-width modulation technique is employed to control the proposed inverter. The performance of the inverter is evaluated under different loading conditions and a comparison with some existing topologies is also presented. The feasibility and effectiveness of the proposed inverter are confirmed through simulation and experimental studies using a scaled down low-voltage laboratory prototype.

8th Power Plant and Power System Control Symposium, 2012

This paper investigates different approaches to improve the power transfer capability (PTC) of tr... more This paper investigates different approaches to improve the power transfer capability (PTC) of transmission lines. Study was performed on the Eastern Gold Fields (EGF) area of the Western Power network in Western Australia where power transfer to this area is currently enhanced using four saturable reactor types static var Compensators (SR SVCs) installed in this region. These SR SVCs have reached to the end of operational life and they are scheduled for replacement by different dynamic reactive power devices such as Static Synchronous Compensators (STATCOMs) or Thyristor Controlled SVCs (TSVCs). Another proposed option to enhance the PTC to this area is by upgrading the 220 kV transmission line to 275 kV transmission line and / or using series capacitor compensation. This paper introduces technical and economical study for the aforementioned options and suggests a reliable and cost effective approach to improve the PTC to EGF area.

IEEE Transactions on Energy Conversion, 2021

Electronics

Dissolved gas analysis (DGA) is one of the regular routine tests accepted by worldwide utilities ... more Dissolved gas analysis (DGA) is one of the regular routine tests accepted by worldwide utilities to detect power transformer incipient faults. While the DGA measurement has fully matured since the development of offline and online sensors, interpretation of the DGA results still calls for advanced approaches to automate and standardize the process. Current industry practice relies on various interpretation techniques that are reported to be inconsistent and, in some cases, unreliable. This paper presents a new application for the advanced logistic regression algorithm to improve the reliability of the DGA interpretation process. In this regard, regularized logistic regression is used to improve the accuracy of the DGA interpretation process. Results reveal the superior features of the proposed logistic regression approach over the conventional and artificial intelligence techniques presented in the literature.

Iet Generation Transmission & Distribution, 2020

Current industry practice to identify fault location in transmission lines is based on visual ins... more Current industry practice to identify fault location in transmission lines is based on visual inspection, travelling waves, and line impedance measurement. Unfortunately, these techniques are only developed to detect the fault location upon its occurrence without the ability to predict abnormal events that usually precede major faults and issue a timely warning signal to avoid potential consequences for power line failures. Furthermore, the current fault locating techniques exhibit some drawbacks that limit their wide practical implementation. This includes cost, access to required data, and low accuracy when employed for specific power line topologies. This study is aimed at presenting and validating a new cost-effective technique based on the line voltage-current characteristics to predict and identify the location of various abnormal and fault events in real-time. By measuring the currents and voltages at both ends of the line, a unique line fingerprint can be identified. Any change in this fingerprint can be detected and analysed by a software installed in the control centre in real-time to identify the location, type, and level of the abnormal events or emerging faults. Robustness of the proposed technique is assessed through simulation analysis conducted on various case studies along with a practical case study.

IEEE Access, 2020

Tube electromagnetic bulging has been given much attention due to its superior advantages in the ... more Tube electromagnetic bulging has been given much attention due to its superior advantages in the field of light alloy processing. However, the conventional tube electromagnetic bulging process exhibits some critical issues that restrict its wide industrial applications. This includes non-uniform axial deformation and poor forming performance such as wall thickness thinning. This article proposes a cost-effective solution for such issues through simultaneous radial and axial electromagnetic force loading using an auxiliary driving coil. In this regard, the influence of the auxiliary coil geometrical parameters on the electromagnetic force distribution and tube forming performance is investigated using electromagnetic-structure coupling model of the bulging process. The robustness of the new proposed method is validated by comparing its electromagnetic force distribution and tube forming performance with the traditional cylindrical coil method, currently used by industry practice. Num...

Electronics

For technological, economic, and environmental reasons, renewable distributed generators (RDGs) h... more For technological, economic, and environmental reasons, renewable distributed generators (RDGs) have been extensively used in distribution networks. This paper presents an effective approach for technoeconomic analysis of optimal allocation of REDGs considering the uncertainties of the system. The primary issue with renewable-based distributed generators, especially wind and photovoltaic systems, is their intermittent characteristic that results in fluctuating output power and, hence, increasing power system uncertainty. Thus, it is essential to consider the uncertainty of such resources while selecting their optimal allocation within the grid. The main contribution of this study is to figure out the optimal size and location for RDGs in radial distribution systems while considering the uncertainty of load demand and RDG output power. A Monte Carlo simulation approach and a backward reduction algorithm were used to generate a reasonable number of scenarios to reflect the uncertainti...

Chemical engineering transactions, 2013

Dissolved gas analysis (DGA) of transformer oil is one of the most effective power transformer co... more Dissolved gas analysis (DGA) of transformer oil is one of the most effective power transformer condition monitoring tools which can be facilitated to determine transformer criticality ranking and hence identifying a suitable condition-based asset management decision. There are many interpretation techniques for DGA results however all the current techniques rely on personnel experience more than analytical formulation. As a result, the current techniques do not necessarily lead to the same conclusion for the same oil sample. A significant number of DGA results fall outside the proposed codes of the current based-ratio methods and cannot be diagnosed by these methods. Moreover, ratio methods fail to diagnose multiple fault conditions due to the mixing up of produced gases. To overcome these limitations, this paper introduces a fuzzy logic approach to aid in standardizing DGA interpretation techniques, identify transformer critical ranking and provide a suitable asset management decis...

International Energy Journal, 2005

This paper investigates the use of Superconducting Magnetic Energy Storage (SMES) unitto stabiliz... more This paper investigates the use of Superconducting Magnetic Energy Storage (SMES) unitto stabilize multi-mode torsional oscillations of Sub-Synchronous Resonance (SSR) oscillations ofa turbine-generator set at the same time to improve dynamic transient stability of the studied systemunder different operating conditions. Two-control algorithm are discussed, they are equal ?-modeand unequal ?-mode of the converter stations of the SMES unit. Results show that the designedcontroller provides proper damping to all oscillating modes a swing mode simultaneously.Eigenvalues analysis is used to show the effectiveness of the proposed controller in stabilizing allmodes of oscillations of the system under different operating conditions. The proposed controller issimple and easy to be implemented.

2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), 2020

Air-core transformer has advantages of no iron loss, no magnetic saturation, and compact in size,... more Air-core transformer has advantages of no iron loss, no magnetic saturation, and compact in size, which make them attractive to be studied for practical applications. In this paper, the H-formulation is used to numerically analyze the electromagnetic field and AC loss of the HTS air-core transformer and optimize the air gap.

The integration of renewable energy system into modern power grids has significantly increased du... more The integration of renewable energy system into modern power grids has significantly increased during the last decade. Solar and wind energy are the most popular renewable energy sources recently. Solar energy has reached about 17,3 GW in 2010 whilst about 340 TWh of wind energy source has been installed worldwide. In this paper, the overview of updated information regarding proposed storage energy systems for renewable energy is presented. It is useful information for practitioners in considering the possible options of storage energy technologies to be connected with renewable energy sources.