Thanks to dIstrIbuted computing and communications, the smart grid will be able to deliver real-time information when and where it is needed. To implement such capabilities, the system must leverage two-way data communications systems that will manage both new applications and assets. In a white paper titled, "Developing a Communication Infrastructure for the Smart Grid," individuals from WireIE Holdings International and the University of Ontario Institute of Technology (UOIT) discuss a number of smart-grid applications. They also estimate the communication requirements of medium data-intensive smart-grid devices.
The authors of this paperV.K. Sood, D. Fischer, J.M. Eklund, and T. Brownnote that two-way communications will assist timely network realignment for more efficient power flow. Because the smart grid will cover all aspects of generation, transmission, distribution, and user networks as well as a large geographic territory, communication links will exist in a variety of formats including hardwired links, fiber-optic links, wireless systems, satellite systems, and terrestrial microwave links. The paper includes an evaluation of two potential smart-grid scenarios to evaluate their communication requirements: a sparsely populated rural environment or a densely populated, highly integrated meshed urban environment.
After assuming some basic conditions, such as the sampling of three voltages and three currents, the authors deduce that a basic data rate of 12 kb/s is required to broadcast raw data samples. Computed quantities like phase amplitude are likely to increase the bandwidth requirement to roughly 2 to 5 Mb/s. This data rate should be considered indicative of an application with a relatively low- to mediumdata- rate production.
In an example of a fault-detection system, the authors estimate that data throughput would be only on the order of tens of kilobytes per second for each distributed-generation unit. The maximum data latency for this application is very relaxedon the order of minutes. In contrast, system faults require continuous, high-rate monitoring on the order of millisecond sampling. They result in throughputs to 5 Mb/s latencies in the tens of milliseconds to allow for rapid fault detection. Five to six cycles (80 to 100 ms) is the accepted fault-detection time.
WireIE, 1 West Pearce St., Suite 505, Richmond Hill, ON, Canada L4B 3V2; (905) 882-4660, FaX: (905) 886- 1958, Internet: www.wireie.com. UOIT, 2000 Simcoe St. North, Oshawa, ON, Canada L1H 7K4; (905) 721-8668, FAX: (905) 721-3178, Internet: www.uoit.ca.
