ABSTRACT In the Asynchronous Transfer Mode (ATM) based Broadband Integrated Services Digital Netw... more ABSTRACT In the Asynchronous Transfer Mode (ATM) based Broadband Integrated Services Digital Network (B-ISDN) it is necessary to have a good insight into how the cell streams from various types of sources interact and modify each other and thereby introduce a cross influence of the network performance (NP) quality of service (QoS). Insight into this interaction is necessary for a proper dimensioning of networks and network elements. Since the cell streams have very complex stochastic properties, e.g. a large and irregular autocorrelation, an exact analysis is in the general case out of the question. The report presents an approximation where the number of cells in a buffer is expressed as a linear combination of the numbers of arrivals to the buffer up to that slot. Various approximating models of this type are discussed, and models are presented using the 'shift operator'. The linear expressions are fitted so that certain relations of the exact model will be satisfied. On this basis, an approach for deriving the correlation between the waiting times in two subsequent buffers is also outlined.
Due to large scale introduction of Distributed Energy Resources (DERs) in the next generation dis... more Due to large scale introduction of Distributed Energy Resources (DERs) in the next generation distribution grid, real time monitoring and control is increasingly needed to maintain a stable operation. In such scenario, monitoring systems and state estimation are key tools for getting reliable and accurate knowledge of the grid. These real time applications have strong requirements on communication latency, reliability and security. This paper presents a method, based on Stochastic Activity Network modeling, for analyzing the performance and dependability of advanced communication technologies, such as LTE and 5G, for supporting monitoring system applications. A novel software tool, based on Möbius linked to external libraries, is developed and employed to analyze the impact of communication failures on the state estimation of a distribution grid. The application of the tool and its capabilities are demonstrated through a case study. The approach is promising both with respect to strength as a modelling tool and the kind of results obtained.
The underlying network infrastructure faces challenges from addressing maintenance, security, per... more The underlying network infrastructure faces challenges from addressing maintenance, security, performance, and scalability to make the network more reliable and stable. Software-defined networking, blockchain, and network function virtualization were proposed and realized to address such issues in both academic and industry wise. This paper analyzes and summarizes works from implementing different categories of blockchains as an element or enabler of network functions to resolve the limitation. Blockchain as a network function has been proposed to give support to the underlying network infrastructure to provide services that have less lag, are more cost-effective, have better performance, guarantee security between participating parties, and protect the privacy of the users. This paper provides a review of recent work that makes use of blockchain to address such networking related challenges and the possible setbacks in the proposal.
2019 3rd International Conference on Smart Grid and Smart Cities (ICSGSC), 2019
The future trends for smart distribution grids will be increasingly characterized by more use of ... more The future trends for smart distribution grids will be increasingly characterized by more use of advanced communication technologies, like the function virtualization. The smart grid can benefit from virtualization and emerging standard ICT technologies such as 5G, to become more cost effective. However, stringent performance requirements must be met and higher reliability, robustness, flexibility and scalability must be provided. This paper discusses the usage of virtualzation concepts in 5G technology for protection function/application in distribution grid. A 5G based architecture using an edge computing infrastructure to hosting the control and protection applications is proposed. A stochastic activity network based model is used to analyze and compare the reliability of the proposed 5G based architecture with a functionally identical Ethernet based IEC 61850 architecture. The 5G architecture seems to result in a significant gain in availability provided that redundancy on the radio links is used to compensate the loss due to random fading processes.
ABSTRACT In the Asynchronous Transfer Mode (ATM) based Broadband Integrated Services Digital Netw... more ABSTRACT In the Asynchronous Transfer Mode (ATM) based Broadband Integrated Services Digital Network (B-ISDN) it is necessary to have a good insight into how the cell streams from various types of sources interact and modify each other and thereby introduce a cross influence of the network performance (NP) quality of service (QoS). Insight into this interaction is necessary for a proper dimensioning of networks and network elements. Since the cell streams have very complex stochastic properties, e.g. a large and irregular autocorrelation, an exact analysis is in the general case out of the question. The report presents an approximation where the number of cells in a buffer is expressed as a linear combination of the numbers of arrivals to the buffer up to that slot. Various approximating models of this type are discussed, and models are presented using the 'shift operator'. The linear expressions are fitted so that certain relations of the exact model will be satisfied. On this basis, an approach for deriving the correlation between the waiting times in two subsequent buffers is also outlined.
Due to large scale introduction of Distributed Energy Resources (DERs) in the next generation dis... more Due to large scale introduction of Distributed Energy Resources (DERs) in the next generation distribution grid, real time monitoring and control is increasingly needed to maintain a stable operation. In such scenario, monitoring systems and state estimation are key tools for getting reliable and accurate knowledge of the grid. These real time applications have strong requirements on communication latency, reliability and security. This paper presents a method, based on Stochastic Activity Network modeling, for analyzing the performance and dependability of advanced communication technologies, such as LTE and 5G, for supporting monitoring system applications. A novel software tool, based on Möbius linked to external libraries, is developed and employed to analyze the impact of communication failures on the state estimation of a distribution grid. The application of the tool and its capabilities are demonstrated through a case study. The approach is promising both with respect to strength as a modelling tool and the kind of results obtained.
The underlying network infrastructure faces challenges from addressing maintenance, security, per... more The underlying network infrastructure faces challenges from addressing maintenance, security, performance, and scalability to make the network more reliable and stable. Software-defined networking, blockchain, and network function virtualization were proposed and realized to address such issues in both academic and industry wise. This paper analyzes and summarizes works from implementing different categories of blockchains as an element or enabler of network functions to resolve the limitation. Blockchain as a network function has been proposed to give support to the underlying network infrastructure to provide services that have less lag, are more cost-effective, have better performance, guarantee security between participating parties, and protect the privacy of the users. This paper provides a review of recent work that makes use of blockchain to address such networking related challenges and the possible setbacks in the proposal.
2019 3rd International Conference on Smart Grid and Smart Cities (ICSGSC), 2019
The future trends for smart distribution grids will be increasingly characterized by more use of ... more The future trends for smart distribution grids will be increasingly characterized by more use of advanced communication technologies, like the function virtualization. The smart grid can benefit from virtualization and emerging standard ICT technologies such as 5G, to become more cost effective. However, stringent performance requirements must be met and higher reliability, robustness, flexibility and scalability must be provided. This paper discusses the usage of virtualzation concepts in 5G technology for protection function/application in distribution grid. A 5G based architecture using an edge computing infrastructure to hosting the control and protection applications is proposed. A stochastic activity network based model is used to analyze and compare the reliability of the proposed 5G based architecture with a functionally identical Ethernet based IEC 61850 architecture. The 5G architecture seems to result in a significant gain in availability provided that redundancy on the radio links is used to compensate the loss due to random fading processes.
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Papers by Bjarne Helvik