Pittsburgh, PA, U.S.A. --- (METERING.COM) --- June 16, 2010
High voltage broadband over powerline (BPL) bandwidth, security, and latency are all expected to support the most demanding combination of smart grid applications, and hence it is very likely that BPL could accelerate the transmission smart grid, according to a recent report from the United States National Energy Technology Laboratory (NETL).

The report describes two pilot HV BPL projects. In the first, a proof of concept, smart grid application company Amperion and American Electric Power (AEP) tested a short 46 kV line in West Virginia. The results indicated that digital relaying and supervisory control and data acquisition (SCADA) could likely be supported using BPL on HV lines.

Subsequently, working together, the NETL and Amperion tested BPL over a 69 kV, 5-mile line connecting three AEP stations. Reliable communications at over 10 megabits/second, with typical latency of about 5 milliseconds, were achieved, and distances included approximately 4 miles without repeating and more than 5 miles with just one repeater – all complying with FCC emission limits.

These results strongly indicate that high speed, digital communications over HV transmission lines can be a viable alternative to traditional optical communication approaches, and at a small fraction of the cost, says the report. Additionally, circuit deployment times would be days rather than months.

The transmission smart grid will require broadband, low latency, secure connectivity between all transmission stations and from these stations to their control centers, the report points out. With such a platform in place, faster and more reliable control, protection, and grid status information becomes possible. Synchrophasor measurements, combined with advanced digital protection will allow cycle-by-cycle system assessment and response. More powerful central computers will interact with these remote subsystems to create faster simulations and to convey grid conditions instantaneously to system operators in new, more easily understood ways. Power electronic-enabled devices, such as flexible AC transmission systems (FACTS), HV DC, and bulk storage, will respond in milliseconds to signals issued either centrally or locally.

To accommodate confidently the full range of transmission smart grid applications available today would require installing optical communications between stations and to control centers. While an excellent solution, it is both costly, of the order of tens of billions of dollars, and time consuming, with a deployment time of a decade or more.

The report says the test results strongly indicate that high speed, digital communications over HV transmission lines can be a viable alternative to traditional optical communication approaches, and at a small fraction of the cost. Additionally, circuit deployment times would be days rather than months.

In the next steps of testing, Amperion and AEP are now trying to advance the technology further, by raising the applicable voltage to 138 kV and extending the repeater-less distance. In addition, HV BPL’s compatibility with today’s most advanced commercial digital protection, monitoring, and control products is being tested. These results should be available in late 2010.

The report was prepared by Booz Allen Hamilton, Inc. and Renz Consulting LLC.

Background White Paper: The Transmission Smart Grid Imperative