nasser ali | Constructor University Bremen gGmbH (original) (raw)
Papers by nasser ali
The unified protocols are unified in application interface, models, and seamless. They generate o... more The unified protocols are unified in application interface, models, and seamless. They generate one standard protocol, one world called IEC 61850. IEC 61850 integrate the security, interoperability, modelling, mapping to a substation, and reliability. Presently, the more expensive fiber based Ethernet LAN is the most prevalent technology for medium and low voltage distribution substations. To circumvent this problem Wireless Local Area Network (WLAN) has been investigated for its suitability for applications that are compliant to IEC 61850: automation and metering; control and monitoring; and over-current protection. In this paper the IEEE 802.11n WLAN is studied when used in various IEC 61850 supported applications for substation automation. It also discusses the benefits of using GOOSE message to protect and control applications and the use of IEC 61850.
International Journal of Electrical Power & Energy Systems, 2018
Smart grid system protection can be divided into wide area network, WAN, and substation area prot... more Smart grid system protection can be divided into wide area network, WAN, and substation area protections. The IEC 61850 Ed.1 standard contains models for SV and GOOSE messages that can be used in intra-substation protection. This paper investigates the WAN and substation area protections based on a travelling wave with IEC 61850 that have not been used in a product since 2016. The high sampling frequency for processing the travelling wave may block the communications channel and reduce security. In order to address this problem, an approach is proposed that is based on using real-time travelling wave signal packing with lossless compression and travelling wave feature extraction. The performance of these techniques has been tested using an OPNET modeler, while their validity has been tested through computer simulation. The application of WLAN based on transient travelling wave for real-time protection has also been investigated. The lower sampling, or transformed, data can be used for the applications of transient waves in digital substations. The comparison protection based on travelling wave between the Ethernet and second-generation WLAN results has also been discussed. An IED design is proposed for fast tripping that can be used in WAN protection based on the travelling wave. This work paves the way for other research to start developing fast protection systems based on travelling wave with IEC 61850.
2015 3rd International Renewable and Sustainable Energy Conference (IRSEC), 2015
Electric Power Systems Research, 2016
Fast protection of distribution substation based on traveling wave is becoming a reality today. T... more Fast protection of distribution substation based on traveling wave is becoming a reality today. The transient traveling wave is mostly used in protection to determine the faulted line and the fault location. The advantages of signal of traveling wave includes immunity to system oscillation, transition resistance, CT saturation, and neutral point operation modes. In this article, a detailed study for analyzing the performance of using WLAN for real time protection based on the transient traveling wave. The high sampling frequency needed for traveling wave causes blockage in communication in the process bus. Now a packing of multi samples with suitable compression techniques in Merging Unit (MU), or using feature extraction with Hilbert-Huang transform with WLAN compliance with IEC 61850 has been tested. Further, this article presents the modeling and simulation of a WLAN communication network for an automation system using the precepts of IEC 61850, which is currently becoming a trend in Substation Automation System (SAS) specification. This article also investigates the impact of impulsive and interface noise on WLAN performance. Finally, the article advocates the wide application of traveling waves in the digital substations based on the IEC 61850 protocol.
2011 64th Annual Conference for Protective Relay Engineers, 2011
This paper is a tutorial in Ethernet communications and architectures. The defacto LAN standard t... more This paper is a tutorial in Ethernet communications and architectures. The defacto LAN standard throughout the world is Ethernet and the worldwide investment into this technology dwarfs that of investment into any other LAN standard. Speed, fiber support, multiple services and protocol support, and the emergence and usage of the IEC61850 protocol have resulted in an increase in the installation of Ethernet within substations and industrial facilities. There are many practical aspects associated with the application of Ethernet within the substation and industrial facility. This paper will address Ethernet fundamentals and will attempt to cover the most common elements of an Ethernet architecture from media selection, requirements for protective relaying systems, managed Ethernet Switch functions and terminology relevant to the protection relay engineer (such as VLAN, RSTP and QoS), network topology (ring, star, mesh, redundancy) and high speed recovery of redundant ring networks. Architectures for different applications will be reviewed, such as SCADA and GOOSE messaging. The intent of this paper is to educate the non-IT person, such as the protective relay engineer, on Ethernet fundamentals that are important to protective relaying applications.
Journal of Electrical Systems and Information Technology, 2014
Applied Mechanics and Materials, 2012
The process of hiding the information like text, binary image, audio etc. into another signal sou... more The process of hiding the information like text, binary image, audio etc. into another signal source like image, audio etc. is called watermarking. The approach involved in watermarking the binary image signal in the wavelet domain of the audio signal was implemented using MATLAB. In this paper, we propose a Discrete Wavelet Transform low frequency to high frequency. Besides, the high frequency spectrum is less sensitive to human ear. That is the reason why the high frequency component is usually discarded in the compression process. Therefore, information to be hidden can be embedded into the low frequency component to against the compression attack. The characteristic of this scheme is that the user can not only use the DAW to embed the text file in to the audio but also binary image. In this paper we embeds copyright information into audio files as a proof of their ownership, we propose an effective, robust, and an inaudible audio watermarking algorithm. The effectiveness of the ...
The development of a computational platform of a communication network for an automation system u... more The development of a computational platform of a communication network for an automation system using the precepts of IEC 61850 has become a great trend in substation automation systems (SASs) research. Recent developments in wireless communication technologies, especially the IEEE802.11 have enabled cost-effective remote control systems with a capability of monitoring, control and protection in the real-time operating conditions of substations. The message delay and throughput in substation automation while using the WLAN and smart grid must satisfy the standard requirements specified in the IEC 61850-5. In this paper, the end-to-end (ETE) delay of IEC 61850-based messages and operating time of the over current protection using the WLAN-based communication network has been evaluated using Opnet Modeler Edition 18.0.
International Journal of Computer Applications, 2014
Kalman filter estimates the state of a dynamic system, even if the precise form of the system is ... more Kalman filter estimates the state of a dynamic system, even if the precise form of the system is unknown. The filter is very powerful in the sense that it supports estimations of past and even future states. The description of the standard Kalman filter and its algorithms with the two main steps, the prediction step and the correction step. Furthermore the extended Kalman filter is discussed, which represents the conversion of the Kalman filter to nonlinear systems. Finally these filter was tested on aircraft tracking, and sinus wave using MATLAB.
As the initial scope of supporting communications inside substation automation systems, IEC 61850... more As the initial scope of supporting communications inside substation automation systems, IEC 61850 was defined to be mapped on Ethernet as the layer 2 communication network technology. It is because the Ethernet is the dominant technology for the Local area network – LAN and it brings significant advantages of high bandwidth and low latency especially with the use of optics fibers at the physical layer. Consequently, Ethernet is very appropriate for the substation indoor LAN with applications that require high bandwidth e.g. measurements and time-critical functions such as protection services. However, when IEC 61850 is extended to support large-scale communication networks between substations, control the centers to substations and DERs; Ethernet is no longer a good solution. The rapid emergence of DERs, the increasing amount of electric vehicles and smart meters reveal the shortcomings of Ethernet which rest in its high set-up cost and scalability problem following the use of cable...
Journal of Electrical Systems and Information Technology, 2014
This paper, studies the comparative performance of a traditional and Concatenated coding schemes ... more This paper, studies the comparative performance of a traditional and Concatenated coding schemes for transmission of digital data over a mobile communication channel. Traditional codes are effective for reliable transmission of information over hostile channel when the errors caused by the channel are statistically independent. This is the case for AWGN channel. However, some channels exhibits bursty error characteristics, one example is the mobile communication channel, such a case a concatenated block code is more effective to deal with such type of errors. Results presented in this paper prove that concatenated code has better performance than traditional code which is Reed-Solomon code and hence suggested for mobile communication.
The past decade has witnessed substantial progress towards the application of low-rate speech cod... more The past decade has witnessed substantial progress towards the application of low-rate speech coders to civilian and military communications as well as computer-related voice applications. Central to this progress has been the development of new speech coders capable of producing high-quality speech at low data rates. Most of these coders incorporate mechanisms to represent the spectral properties of speech, provide for speech waveform matching, and optimize the coder's performance for the human ear. A number of these coders have already been adopted in national and international cellular telephony standards. In mobile communication systems, service providers are continuously met with the challenge of accommodating more users within a limited allocated bandwidth. For this reason, manufactures and service providers are continuously in search of low bit-rate speech coders that deliver toll-quality speech. In this paper the simulated low bit rate vocoder (LPC) using MATLAB was implemented. The result obtained from LPC was compared with other implemented voice compression using wavelet transform. From the results we see that the performance of wavelet transform was better than LPC.
Abstract The Heat Process Trainer PT326 (Feedback UK) model is obtained by using two different te... more Abstract The Heat Process Trainer PT326 (Feedback UK) model is obtained by using two different techniques one by the Ziegler-Nichols approximating method and the other with the system identification method. The Data acquisition card EC641 I/O PT326 is developed ...
In this paper, the non-uniform discrete Fourier transform (NDFT) is utilized to randomly select s... more In this paper, the non-uniform discrete Fourier transform (NDFT) is utilized to randomly select sampling points in frequency domain, which could make the embedding points private. Furthermore, to improve security two different chaotic maps is used. One chaotic map is used to choose the NDFT domain embedding points for making them unpredictable; the other is used to encrypt the watermark
This paper is a tutorial in Ethernet communications and architectures. The defacto LAN standard t... more This paper is a tutorial in Ethernet communications and architectures. The defacto LAN standard throughout the world is Ethernet and the worldwide investment into this technology dwarfs that of investment into any other LAN standard. Speed, fiber support, multiple services and protocol support, and the emergence and usage of the IEC61850 protocol have resulted in an increase in the installation of Ethernet within substations and industrial facilities.
The unified protocols are unified in application interface, models, and seamless. They generate o... more The unified protocols are unified in application interface, models, and seamless. They generate one standard protocol, one world called IEC 61850. IEC 61850 integrate the security, interoperability, modelling, mapping to a substation, and reliability. Presently, the more expensive fiber based Ethernet LAN is the most prevalent technology for medium and low voltage distribution substations. To circumvent this problem Wireless Local Area Network (WLAN) has been investigated for its suitability for applications that are compliant to IEC 61850: automation and metering; control and monitoring; and over-current protection. In this paper the IEEE 802.11n WLAN is studied when used in various IEC 61850 supported applications for substation automation. It also discusses the benefits of using GOOSE message to protect and control applications and the use of IEC 61850.
International Journal of Electrical Power & Energy Systems, 2018
Smart grid system protection can be divided into wide area network, WAN, and substation area prot... more Smart grid system protection can be divided into wide area network, WAN, and substation area protections. The IEC 61850 Ed.1 standard contains models for SV and GOOSE messages that can be used in intra-substation protection. This paper investigates the WAN and substation area protections based on a travelling wave with IEC 61850 that have not been used in a product since 2016. The high sampling frequency for processing the travelling wave may block the communications channel and reduce security. In order to address this problem, an approach is proposed that is based on using real-time travelling wave signal packing with lossless compression and travelling wave feature extraction. The performance of these techniques has been tested using an OPNET modeler, while their validity has been tested through computer simulation. The application of WLAN based on transient travelling wave for real-time protection has also been investigated. The lower sampling, or transformed, data can be used for the applications of transient waves in digital substations. The comparison protection based on travelling wave between the Ethernet and second-generation WLAN results has also been discussed. An IED design is proposed for fast tripping that can be used in WAN protection based on the travelling wave. This work paves the way for other research to start developing fast protection systems based on travelling wave with IEC 61850.
2015 3rd International Renewable and Sustainable Energy Conference (IRSEC), 2015
Electric Power Systems Research, 2016
Fast protection of distribution substation based on traveling wave is becoming a reality today. T... more Fast protection of distribution substation based on traveling wave is becoming a reality today. The transient traveling wave is mostly used in protection to determine the faulted line and the fault location. The advantages of signal of traveling wave includes immunity to system oscillation, transition resistance, CT saturation, and neutral point operation modes. In this article, a detailed study for analyzing the performance of using WLAN for real time protection based on the transient traveling wave. The high sampling frequency needed for traveling wave causes blockage in communication in the process bus. Now a packing of multi samples with suitable compression techniques in Merging Unit (MU), or using feature extraction with Hilbert-Huang transform with WLAN compliance with IEC 61850 has been tested. Further, this article presents the modeling and simulation of a WLAN communication network for an automation system using the precepts of IEC 61850, which is currently becoming a trend in Substation Automation System (SAS) specification. This article also investigates the impact of impulsive and interface noise on WLAN performance. Finally, the article advocates the wide application of traveling waves in the digital substations based on the IEC 61850 protocol.
2011 64th Annual Conference for Protective Relay Engineers, 2011
This paper is a tutorial in Ethernet communications and architectures. The defacto LAN standard t... more This paper is a tutorial in Ethernet communications and architectures. The defacto LAN standard throughout the world is Ethernet and the worldwide investment into this technology dwarfs that of investment into any other LAN standard. Speed, fiber support, multiple services and protocol support, and the emergence and usage of the IEC61850 protocol have resulted in an increase in the installation of Ethernet within substations and industrial facilities. There are many practical aspects associated with the application of Ethernet within the substation and industrial facility. This paper will address Ethernet fundamentals and will attempt to cover the most common elements of an Ethernet architecture from media selection, requirements for protective relaying systems, managed Ethernet Switch functions and terminology relevant to the protection relay engineer (such as VLAN, RSTP and QoS), network topology (ring, star, mesh, redundancy) and high speed recovery of redundant ring networks. Architectures for different applications will be reviewed, such as SCADA and GOOSE messaging. The intent of this paper is to educate the non-IT person, such as the protective relay engineer, on Ethernet fundamentals that are important to protective relaying applications.
Journal of Electrical Systems and Information Technology, 2014
Applied Mechanics and Materials, 2012
The process of hiding the information like text, binary image, audio etc. into another signal sou... more The process of hiding the information like text, binary image, audio etc. into another signal source like image, audio etc. is called watermarking. The approach involved in watermarking the binary image signal in the wavelet domain of the audio signal was implemented using MATLAB. In this paper, we propose a Discrete Wavelet Transform low frequency to high frequency. Besides, the high frequency spectrum is less sensitive to human ear. That is the reason why the high frequency component is usually discarded in the compression process. Therefore, information to be hidden can be embedded into the low frequency component to against the compression attack. The characteristic of this scheme is that the user can not only use the DAW to embed the text file in to the audio but also binary image. In this paper we embeds copyright information into audio files as a proof of their ownership, we propose an effective, robust, and an inaudible audio watermarking algorithm. The effectiveness of the ...
The development of a computational platform of a communication network for an automation system u... more The development of a computational platform of a communication network for an automation system using the precepts of IEC 61850 has become a great trend in substation automation systems (SASs) research. Recent developments in wireless communication technologies, especially the IEEE802.11 have enabled cost-effective remote control systems with a capability of monitoring, control and protection in the real-time operating conditions of substations. The message delay and throughput in substation automation while using the WLAN and smart grid must satisfy the standard requirements specified in the IEC 61850-5. In this paper, the end-to-end (ETE) delay of IEC 61850-based messages and operating time of the over current protection using the WLAN-based communication network has been evaluated using Opnet Modeler Edition 18.0.
International Journal of Computer Applications, 2014
Kalman filter estimates the state of a dynamic system, even if the precise form of the system is ... more Kalman filter estimates the state of a dynamic system, even if the precise form of the system is unknown. The filter is very powerful in the sense that it supports estimations of past and even future states. The description of the standard Kalman filter and its algorithms with the two main steps, the prediction step and the correction step. Furthermore the extended Kalman filter is discussed, which represents the conversion of the Kalman filter to nonlinear systems. Finally these filter was tested on aircraft tracking, and sinus wave using MATLAB.
As the initial scope of supporting communications inside substation automation systems, IEC 61850... more As the initial scope of supporting communications inside substation automation systems, IEC 61850 was defined to be mapped on Ethernet as the layer 2 communication network technology. It is because the Ethernet is the dominant technology for the Local area network – LAN and it brings significant advantages of high bandwidth and low latency especially with the use of optics fibers at the physical layer. Consequently, Ethernet is very appropriate for the substation indoor LAN with applications that require high bandwidth e.g. measurements and time-critical functions such as protection services. However, when IEC 61850 is extended to support large-scale communication networks between substations, control the centers to substations and DERs; Ethernet is no longer a good solution. The rapid emergence of DERs, the increasing amount of electric vehicles and smart meters reveal the shortcomings of Ethernet which rest in its high set-up cost and scalability problem following the use of cable...
Journal of Electrical Systems and Information Technology, 2014
This paper, studies the comparative performance of a traditional and Concatenated coding schemes ... more This paper, studies the comparative performance of a traditional and Concatenated coding schemes for transmission of digital data over a mobile communication channel. Traditional codes are effective for reliable transmission of information over hostile channel when the errors caused by the channel are statistically independent. This is the case for AWGN channel. However, some channels exhibits bursty error characteristics, one example is the mobile communication channel, such a case a concatenated block code is more effective to deal with such type of errors. Results presented in this paper prove that concatenated code has better performance than traditional code which is Reed-Solomon code and hence suggested for mobile communication.
The past decade has witnessed substantial progress towards the application of low-rate speech cod... more The past decade has witnessed substantial progress towards the application of low-rate speech coders to civilian and military communications as well as computer-related voice applications. Central to this progress has been the development of new speech coders capable of producing high-quality speech at low data rates. Most of these coders incorporate mechanisms to represent the spectral properties of speech, provide for speech waveform matching, and optimize the coder's performance for the human ear. A number of these coders have already been adopted in national and international cellular telephony standards. In mobile communication systems, service providers are continuously met with the challenge of accommodating more users within a limited allocated bandwidth. For this reason, manufactures and service providers are continuously in search of low bit-rate speech coders that deliver toll-quality speech. In this paper the simulated low bit rate vocoder (LPC) using MATLAB was implemented. The result obtained from LPC was compared with other implemented voice compression using wavelet transform. From the results we see that the performance of wavelet transform was better than LPC.
Abstract The Heat Process Trainer PT326 (Feedback UK) model is obtained by using two different te... more Abstract The Heat Process Trainer PT326 (Feedback UK) model is obtained by using two different techniques one by the Ziegler-Nichols approximating method and the other with the system identification method. The Data acquisition card EC641 I/O PT326 is developed ...
In this paper, the non-uniform discrete Fourier transform (NDFT) is utilized to randomly select s... more In this paper, the non-uniform discrete Fourier transform (NDFT) is utilized to randomly select sampling points in frequency domain, which could make the embedding points private. Furthermore, to improve security two different chaotic maps is used. One chaotic map is used to choose the NDFT domain embedding points for making them unpredictable; the other is used to encrypt the watermark
This paper is a tutorial in Ethernet communications and architectures. The defacto LAN standard t... more This paper is a tutorial in Ethernet communications and architectures. The defacto LAN standard throughout the world is Ethernet and the worldwide investment into this technology dwarfs that of investment into any other LAN standard. Speed, fiber support, multiple services and protocol support, and the emergence and usage of the IEC61850 protocol have resulted in an increase in the installation of Ethernet within substations and industrial facilities.