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Please use this identifier to cite or link to this item: http://www.lib.ncsu.edu/resolver/1840.16/1456

Title: Communication Challenges for the FREEDM system
Authors: Khanna, Mohit
Advisors: Dr Wenye Wang, Committee Chair
Dr. Subhashish Bhattacharya , Committee Member
Dr. Alex Dean, Committee Member
Keywords: Performance Evaluation
WiFi
Zigbee
DNP3
IEC61850
Smart Grids
FREEDM
Issue Date: 2-Dec-2009
Degree: M
Discipline: Computer Engineering
Abstract: The Future Renewable Electrical Energy Distribution and Management (FREEDM) Center's proposal to incorporate the renewable resources of energy as source of electricity into the existing power distribution system and allow for energy exchange between individ- ual sites, is a revolutionary idea which will help us meet the energy needs of the future in an environment friendly manner. The renewable resources of energy have certain characteris- tics which make such an integration very challenging. They are available in large amounts but not concentrated at an area and are intermittent in nature. Thus a lot of them need to be deployed along with storage resources in order to obtain a steady source of electricity resulting in a distributed energy generation environment. To maintain the stability of such an electricity distribution grid, it is essential to monitor and control each site from a central location using agents. These agents also need to communicate with each other to execute any protection scheme or for energy management to utilize any excess electricity at a site. Therefore, a reliable communication backbone becomes an essential platform which would allow such a communication to take place. Since FREEDM is intrinsically a complex sys- tem, the communication backbone must be a fault-tolerant in that distributed devices and elements may become faulty or fail. In this thesis, we investigate the challenges for such a communication backbone in a distributed energy generation and energy exchange environment within an electricity distribution system. We use the FREEDM system as a platform for our research. To our knowledge, a power system proposed by the FREEDM, does not exist, which makes our job more challenging. We need to identify the various communicating entities, communication scenarios and their timing requirements within the FREEDM system and propose a com- munication architecture which meets these criteria. We also need to identify the possible communication protocol standards which will be used for message exchange. In order to understand the communication needs of power system applications which would be used in the FREEDM system, we conduct a survey of the existing power system communication architectures (the SCADA and substation automation systems) and communication protocols (DNP3 and IEC 61850). Further we detail the various levels 2 of communication and communicating entities within the FREEDM system. We apply our understanding of existing substation automation systems to the FREEDM system and iden- tify the timing criticality and communication requirements for power system applications within the FREEDM system. In order to quantify the timing requirements and to iden- tify the various networking technologies which will be used to support the communication backbone of the FREEDM system, we set up a distributed communication testbed using ZigBee, WiFi and Ethernet communication technologies. A Web, SNMP{based monitoring tool set up by us, as a means to keep track of the distributed devices forming the testbed is also presented. We conclude the thesis by presenting the results of experiments performed by us on the testbed and presenting a road-map for our future work. This thesis, presents our ¯rst year e®orts towards setting up of a communication backbone for the FREEDM system and identifying the communication challenges. The reliability and security aspect of the communication backbone, will be taken up in our future work. Our preliminary results have provided a fundamental platform to study unique challenges in the future design and development of a reliable and secure FREEDM system.
URI: http://www.lib.ncsu.edu/resolver/1840.16/1456
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