Monthly Archives: August 2010

Smart Grid Communication Network Technologies

Below is a literature review, which is defined on Wikipedia as:

A literature review is a body of text that aims to review the critical points of current knowledge including substantive findings as well as theoretical and methodological contributions to a particular topic. Literature reviews are secondary sources, and as such, do not report any new or original experimental work.

This literature review is written for an audience that has a technical background, so many technical terms may not be explained or defined.  I hope you enjoy this literature review, and please feel free to leave comments.

Selected Review of Literature: Smart Grid Communication Network

Given the increased emphasis on energy efficiency, the current electrical grid is in need of a robust communication network.  The communication infrastructure will rely on three technologies: 4G wireless communications, fiber optics, and/or broadband over power lines (BPL) to reliably transmit low latency data at speeds of 2-to-5 Mbps per device (Sood, Fischer, Eklund, & Brown, 2009).  The smart grid will need to be able to handle two-way communication in order to share energy-related data amongst utilities and end-users (Aggarwal, Kunta, & Verma, 2010).  This communication system must handle large amounts of continual two-way data transmission from all electricity users, devices, and sensors in order to provide proper usage feedback to both the end-user and to the utility (Aggarwal, et al., 2010).  This paper will look at the three competing technologies, and some of the pluses and minuses of each.

Broadband Over Power Lines

Broadband over power line technology uses the electrical grid to transfer data on top of the AC power already being transferred through the power lines.  This allows utilities to build a communications network on top of the already existing infrastructure, i.e. the power lines (Srinivasa Prasanna, et al., 2009).  BPL typically has limited bandwidth because the current power grid infrastructure was not designed to transfer data, but according to Schneider, speeds of 5Mbps are achievable in distances less than 1 kilometer.  Increasing this distance will reduce the speeds that BPL can achieve, but using additional equipment can help alleviate that issue (2009).  BPL typically uses the 1-34 MHZ frequency range instead of AC’s 60HZ to transfer data (Tsiropoulos, Sarafi & Cottis, 2009).  According to Anderson, the estimated installation cost of BPL is $1000 per home, but offers the capability to reach any home with electrical service (2010).

Fiber Optics

Fiber optics are able to handle large amounts of data at much faster speeds than any of the other communication technologies discussed in this paper.  Utilities typically have the right away along their transmission lines, so this makes laying fiber optic cable relatively easy.  Fiber optic cables have the ability for transfer speeds of several hundred Gbps.  Since such high data rates are possible it makes fiber optics an expandable and relatively future-proof communication technology (Aggarwal, et al., 2010).  Another strong reason to pick fiber optics is the fact that there are many fiber optic cables already available.  This gives utilities the option of leasing current fiber optic infrastructure to help reduce costs and time to market (Sood, et al., 2009). With so many positive points one might wonder why other technologies are being considered for the smart grid communication system.  One thing to take in consideration is that fiber optics may not always be the most feasible solution in certain areas.  This could be due to location, cost, or regulatory restrictions.

4G Wireless

Since 4G wireless technologies are starting to be deployed nationwide, this gives utilities another great alternative to the other two communication technologies.  Wimax 4G is estimated to cost roughly $440 per home to install and is currently seeing transfer speeds between 3-to-6 Mbps per connection (Anderson, 2010).  With a lower cost per home than BPL and a higher transfer speed than BPL, this makes 4G a very attractive option for utilities where 4G service is available.  Wimax 4G also offers very low latency times (~10ms), so the smart grid can communicate with devices rather quickly (Sood, et al., 2009).  Although fiber optics have a much lower latency time (~5 µs per kilometer), Wimax 4G latency is still within current smart grid requirements (Sood, et al., 2009).  The ability to communicate to devices quickly is very important, especially if a breaker is in need of being kicked as fast as possible.  Another quality of Wimax is its closed loop power control features.  These features allow each device linked to the Wimax network to have its own power control settings, and this minimizes the power consumption of the Wimax radio equipment (Sood, et al., 2009).  The single biggest issue that Wimax 4G has is its ability to communicate with devices inside buildings and other radio frequency dead areas.  Another major problem is that 4G wireless communications do not provide coverage everywhere a home would be located.

Conclusion

Due to the high cost of implementing a smart grid communication network it must be built with adequate capacity for future growth.  Utilities will need to plan their systems for increased usage during emergency situations, and for a lifespan of roughly 20 years (Wenpeng, Sharp, & Lancashire, 2010).  It is unlikely that any one-communication technology will reign supreme.  It is much more likely that we will see hybrid systems that implement several or all of these technologies for varying circumstances (Tsiropoulos, et al, 2009).

References

Aggarwal, A., Kunta, S., Verma, P.K. (2010). A proposed communications infrastructure for the smart grid. Innovative Smart Grid Technologies (ISGT) (1-5). Gaithersburg, MD. doi: 10.1109/ISGT.2010.5434764

Anderson, M. (2010). WiMax for smart grids. Spectrum, IEEE 47(7), 14-14. doi:10.1109/MSPEC.2010.5490999

Schneider, D. (2009). Is this the moment for broadband over power lines?. Spectrum, IEEE 46(7), 17-17.

Sood, V.K., Fischer, D., Eklund, J.M., Brown, T. (2009). Developing a communication infrastructure for the Smart Grid. Electrical Power & Energy Conference (EPEC) (1-7). doi: 10.1109/EPEC.2009.5420809

Srinivasa Prasanna, G.N., Lakshmi, A., Sumanth, S., Simha, V., Bapat, J., Koomullil, G. (2009). Data communication over the smart grid,” Power Line Communications and Its Applications. IEEE International Symposium (273-279). doi: 10.1109/ISPLC.2009.4913442

Tsiropoulos, G.I., Sarafi, A.M., Cottis, P.G. (2009) Wireless-broadband over power lines networks: A promising broadband solution in rural areas.  PowerTech, 2009 IEEE Bucharest (1-6). Bucharest, Romania:IEEE. doi: 10.1109/PTC.2009.5282200

Wenpeng Luan, Sharp, Duncan, Lancashire, Sol. (2010). Smart grid communication network capacity planning for power utilities. Transmission and Distribution Conference and Exposition (1-4). IEEE. doi: 10.1109/TDC.2010.5484223