Smart grid system assists in transforming the traditional energy industry in terms of reliability, performance, and manageability through bi-directional information transfer between smart grid components. According to National Institute of Standards and Technology (NIST) conceptual model for smart grid, communication networks connect power system components that are divided into seven logical domains: Markets, Service Provider, Operations, Bulk Generation, Transmission, Distribution and Customer. Bi-directional communications offer many benefits including more visibility and control over power supply, source, price, quality and costs. Moreover, recent studies show that the power outage for an hour could cost billion dollars in industrialized countries. Thus, the choice of communication technology used in smart grid is highly critical to provide reliable and efficient bi-directional communications. However, current communication infrastructures and standards are incapable of meeting the strict requirements (such as delay, range, data rate, security, etc.) of smart grid systems. Thus the cognitive radio enabled dynamic spectrum access is a candidate technology that can be used to reduce the communication expenses by reusing the existing wireless infrastructures and wireless spectrum to improve overall performance of smart grid.
For instance, when ZigBee technology is used for Home Area Network (HAN) in smart grid, the maximum data rate that HAN can offer is 250Kbps. When this link is shared among (say) 25 networked home appliances in HAN, each device gets about 10Kpbs. However, when Wi-Fi channels (e.g., IEEE 802.11n with over 300 Mbps) are used (when available) by home appliances, data rate could be much higher (i.e., 12 Mbps which is over 1000 times faster than ZigBee for 25 HAN devices). Higher data rate implies lower delay in data transmission, which is one of the strict requirements of smart grid. Similar analysis can be found in Neighbourhood Area Networks and Wide Area Networks in smart grid. Thus, dynamic spectrum access offers better throughput and faster delivery of information in smart grid leading to enhanced overall performance. Furthermore, when dynamic spectrum access enabled communication is implemented in smart grid, devices can hop from a channel to the least interfered channel on the fly which results in jamming resistant communications in the smart grid.
