The network delay of the periodic messages transmission in the network control system （NCS） based on Ethemet for plant automation （EPA） is analyzed from the theoretical and experimental perspective in this paper. ...The network delay of the periodic messages transmission in the network control system （NCS） based on Ethemet for plant automation （EPA） is analyzed from the theoretical and experimental perspective in this paper. The composition and the characteristics of the network delay of EPA periodic messages transmission in a subnet is studied through analyzing the information transmission regularity and EPA deterministic scheduling mechanism. On this basis, the queuing delay at communication schedule management entity （EPA _ CSME） that is the most important component of network delay is analyzed, during which the formulas for the queuing delay of periodic messages and other real time parameters are proposed. Furthermore, an experiment is developed to test each component of network delay of periodic messages transmission in a EPA subnet. According to the experimental and the theoretical analysis, the conclusion is drawn that the delay during which the periodic messages wait for the periodic messages transmission time slice is the main factor that causes considerable network delay, and improvement method is presented.展开更多
The electric power system is an ageing infrastructure and the need for making reinvestments is increasing. Strict economic regulation of the DSOs （distribution system operators）, forces them to search for more effic...The electric power system is an ageing infrastructure and the need for making reinvestments is increasing. Strict economic regulation of the DSOs （distribution system operators）, forces them to search for more efficient work processes and improved technical solutions. The main challenges for network companies today are implementing new technologies and become more efficient in every part of the asset management. The work processes must be optimized and the right projects must be prioritized for reinvestment. The purpose of this paper is to give insight into some of the challenges electric distribution companies are facing today. This paper is based on experiences from NTE Nett AS--an electric distribution company in the middle of Norway. The paper also describes some of the measures that have been done in NTE Nett and what people believe will be the situation in the future.展开更多
The funding gap of public infrastructure networks(roads, railways, ports, electricity, and energy lines)can be solved partly by introducing private capital for investments, i.e., public-private partnerships(PPP). This...The funding gap of public infrastructure networks(roads, railways, ports, electricity, and energy lines)can be solved partly by introducing private capital for investments, i.e., public-private partnerships(PPP). This paper introduces an integrated model of a PPP project and investigates its implications on PPP policies and strategies regarding appropriate project appraisal and selection. The model has different resolution levels, namely, project level,business ecosystem level, and market and societal levels.The integrated model suggests that investing in merely financially viable projects is insufficient to realize economically and socially sustainable and acceptable projects.展开更多
基金Supported by the National High Technology Research and Development Programme of China (No. 2006AA040301-4, 2007AA041301-6 2007AA041407).
文摘The network delay of the periodic messages transmission in the network control system （NCS） based on Ethemet for plant automation （EPA） is analyzed from the theoretical and experimental perspective in this paper. The composition and the characteristics of the network delay of EPA periodic messages transmission in a subnet is studied through analyzing the information transmission regularity and EPA deterministic scheduling mechanism. On this basis, the queuing delay at communication schedule management entity （EPA _ CSME） that is the most important component of network delay is analyzed, during which the formulas for the queuing delay of periodic messages and other real time parameters are proposed. Furthermore, an experiment is developed to test each component of network delay of periodic messages transmission in a EPA subnet. According to the experimental and the theoretical analysis, the conclusion is drawn that the delay during which the periodic messages wait for the periodic messages transmission time slice is the main factor that causes considerable network delay, and improvement method is presented.
文摘The electric power system is an ageing infrastructure and the need for making reinvestments is increasing. Strict economic regulation of the DSOs （distribution system operators）, forces them to search for more efficient work processes and improved technical solutions. The main challenges for network companies today are implementing new technologies and become more efficient in every part of the asset management. The work processes must be optimized and the right projects must be prioritized for reinvestment. The purpose of this paper is to give insight into some of the challenges electric distribution companies are facing today. This paper is based on experiences from NTE Nett AS--an electric distribution company in the middle of Norway. The paper also describes some of the measures that have been done in NTE Nett and what people believe will be the situation in the future.
文摘The funding gap of public infrastructure networks(roads, railways, ports, electricity, and energy lines)can be solved partly by introducing private capital for investments, i.e., public-private partnerships(PPP). This paper introduces an integrated model of a PPP project and investigates its implications on PPP policies and strategies regarding appropriate project appraisal and selection. The model has different resolution levels, namely, project level,business ecosystem level, and market and societal levels.The integrated model suggests that investing in merely financially viable projects is insufficient to realize economically and socially sustainable and acceptable projects.
