The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can ...The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can be widely used in not only concerning utilities but also manufacturers and research / certification institutes because of its many functions. The hardware architecture and software implementation of the simulator are described. The main features and functions of the simulator are also展开更多
This paper presented a scheme of relayed cellular mobile telecommunication network,which only employs fixed digital relays and not more than two-hop relay routes.Power saving potential of the network is deeply studied...This paper presented a scheme of relayed cellular mobile telecommunication network,which only employs fixed digital relays and not more than two-hop relay routes.Power saving potential of the network is deeply studied under the assumption of not occupying additional frequency bands(i.e.relays share the same frequency bands as used by the base stations).Theoretical analysis and simulation results have both shown that,with the same radio coverage requirement,the necessary effective transmission powers in such a relayed network have greatly decreased compared to conventional cellular network.展开更多
A new distribution principle of bus protection is presented.The protection system description,its design features,hardware structure,construction of data communication network are given.Dynamic simulation experiments ...A new distribution principle of bus protection is presented.The protection system description,its design features,hardware structure,construction of data communication network are given.Dynamic simulation experiments show its distinguishing advantages over traditional centralized principle.展开更多
This paper presents a coordination strategy of Load Frequency Control(LFC)and digital frequency protection for an islanded microgrid(MG)considering high penetration of Renewable Energy Sources(RESs).In such MGs,the re...This paper presents a coordination strategy of Load Frequency Control(LFC)and digital frequency protection for an islanded microgrid(MG)considering high penetration of Renewable Energy Sources(RESs).In such MGs,the reduction in system inertia due to integration of large amount of RESs causes undesirable influence on MG frequency stability,leading to weakening of the MG.Furthermore,sudden load events,and short circuits caused large frequency fluctuations,which threaten the system security and could lead to complete blackouts as well as damages to the system equipment.Therefore,maintaining the dynamic security in MGs is one of the important challenges,which considered in this paper using a specific design and various data conversion stages of a digital over/under frequency relay(OUFR).The proposed relay will cover both under and over frequency conditions in coordination with LFC operation to protect the MG against high frequency variations.To prove the response of the proposed coordination strategy,a small MG was investigated for the simulation.The proposed coordination method has been tested considering load change,high integration of RESs.Moreover,the sensitivity analysis of the presented technique was examined by varying the penetration level of RESs and reducing the system inertia.The results reveal the effectiveness of the proposed coordination to maintain the power system frequency stability and security.In addition,the superiority of the OUFR has been approved in terms of accuracy and speed response during high disturbances.展开更多
文摘The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can be widely used in not only concerning utilities but also manufacturers and research / certification institutes because of its many functions. The hardware architecture and software implementation of the simulator are described. The main features and functions of the simulator are also
基金National Science Fund for Creative ResearchGroups(No.60521002)Chinese NationalKey Technology R&D Program(No.2005BA908B02)Science Foundation ofShanghai Municipal Commission of Scienceand Technology,Chinese(No.05dz05802)
文摘This paper presented a scheme of relayed cellular mobile telecommunication network,which only employs fixed digital relays and not more than two-hop relay routes.Power saving potential of the network is deeply studied under the assumption of not occupying additional frequency bands(i.e.relays share the same frequency bands as used by the base stations).Theoretical analysis and simulation results have both shown that,with the same radio coverage requirement,the necessary effective transmission powers in such a relayed network have greatly decreased compared to conventional cellular network.
文摘A new distribution principle of bus protection is presented.The protection system description,its design features,hardware structure,construction of data communication network are given.Dynamic simulation experiments show its distinguishing advantages over traditional centralized principle.
基金This paper is funded by the higher ministry of education in Egypt.
文摘This paper presents a coordination strategy of Load Frequency Control(LFC)and digital frequency protection for an islanded microgrid(MG)considering high penetration of Renewable Energy Sources(RESs).In such MGs,the reduction in system inertia due to integration of large amount of RESs causes undesirable influence on MG frequency stability,leading to weakening of the MG.Furthermore,sudden load events,and short circuits caused large frequency fluctuations,which threaten the system security and could lead to complete blackouts as well as damages to the system equipment.Therefore,maintaining the dynamic security in MGs is one of the important challenges,which considered in this paper using a specific design and various data conversion stages of a digital over/under frequency relay(OUFR).The proposed relay will cover both under and over frequency conditions in coordination with LFC operation to protect the MG against high frequency variations.To prove the response of the proposed coordination strategy,a small MG was investigated for the simulation.The proposed coordination method has been tested considering load change,high integration of RESs.Moreover,the sensitivity analysis of the presented technique was examined by varying the penetration level of RESs and reducing the system inertia.The results reveal the effectiveness of the proposed coordination to maintain the power system frequency stability and security.In addition,the superiority of the OUFR has been approved in terms of accuracy and speed response during high disturbances.
