|
|
|
|
Get a HAN on the Situation – Controlling the Future
By Ron Chebra
|
|
|
A few weeks ago, in an unceremonious manner, a 40-year milestone was reached. On June 29, 1968, the Federal Communications Commission (FCC) ruled that the monopoly that the Bell system held on telephone equipment should be broken. In what has become known as the Carterphone Decision, this ruling opened the door for any telephone equipment provider to connect to the “Bell System.” Since then any number of “certified” devices that are manufactured and marketed from any number of sources can be connected to the standard telephone line. However, to ensure that these devices do not cause harm to the network, they must undergo a series of tests that are specified by the FCC.
Using this telephone system ruling parallel as precedent, utilities that are pursuing AMI or are in process of creating a communications infrastructure to support metering and Home Area Networks (HAN) traffic must have an active role in defining the characteristics that would be supported in their infrastructure. These would include establishing a service level delivery requirements that must be properly evaluated and characterized. While bandwidth and speed are important, considerations must include security, latency and transparency and monitoring metrics to ensure growth of these services as anticipated are properly managed.
In last month’s article on Home Area Networks (HAN) the concepts of the Utility HAN (uHAN) and Consumer HAN (cHAN) were explored, as well as the overlapping area of these two networks that form the Joint HAN (jHAN). While there may be some challenges establishing the bridge or gateway system that would manage the interflow and interoperability of these networks, there still needs to be significant work to establish the rules within each of these respective networks.
On the consumer side, the growing proliferation of WiFi in the home has been fostered by standards such as 802.11(b), 802.11 (g) or even 802.11 (n) that are governed by the Institute of Electrical and Electronic Engineers (IEEE). It is through the standards accreditation and monitoring that devices manufactured by any number of vendors are able to interoperate and cohabitate without harm to other devices on the network.
While there is a plethora of other HANs in use today, many of these have experienced varying levels of adoption. These include X-10, Home Plug, Z-wave, Home Plug Command and Control, 6LoWPAN. However, there is great interest in ZigBee as the emerging Home Automation and Sensor control network that would be directly linked to utility AMI systems.
Recently, the ZigBee Alliance released the Smart Energy Profile Specification Revision 14 on May 29, 2008. This comprehensive document covers a number of devices including the traditional uHAN devices shown in the following table extracted from this specification:
|
|
|
|
|
|
This specification has established an extensive set of common message types that are generic across all devices. These include basic messaging, identification, key establishment. Optional common data clusters would include alarms, power consumption, reporting, commissioning.
Each of the devices identified above has a defined set of mandatory and option data clusters. Typically these messages are small in size.
Of particular interest is the Energy Service Portal, which is defined in the specification. This is excerpted below:
“The Energy Service Portal connects the energy supply company communication network to the metering and energy management devices within the home. It routes messages to and from the relevant end points. It may be installed within a meter, thermostat, or In-Premise Display, or may be a standalone device, and it will contain another non-ZigBee communication module (e.g. power-line carrier, RF, GPRS, broadband Internet connection).”
As noted the specification gives a number of options for this service, including, but not limited to the meter end device. The metering device is defined:
“The Metering end device is a meter (electricity, gas, water, heat, etc.) that is fitted with a ZigBee device. Depending on what is being metered, the device may be capable of immediate (requested) reads or it will autonomously send readings periodically. A Metering end device may also be capable of communicating certain status indicators (e.g. battery low, tamper detected).”
For many implementations, the meter will serve as both the service portal and the metering device.
One of the key cluster types that the meter will need to optionally support is complex metering and the tunneling capability which, as of yet undefined in the specification.
|
|
|
|
|
|
Because of the lack of specificity surrounding this cluster type, one of the most difficult challenges facing utilities may be trying to determine the extent and impact that this requirement may have on the overall LAN data requirements of the AMI system.
While it is anticipated that the Smart Energy Tunneling will be used for load profile reporting, power quality management and C&I metering. The flexibility that now exists in residential meters is soon approaching the functionality of many current C&I meters.
Therefore, it essential that utilities need to take an active part in ensuring that devices, such as metering devices, energy service portals and uHAN devices properly communicate in harmony, and that they individually and collectively do not cause harm to the AMI network utilities are now deploying.
|
|
|
Download the July 2008 Issue
Use the link below to download the PDF of the full issue of the July 2008 Automation Insight for the complete print versions of the articles.
|
|
|
|
[download] Automation Insight - July 2008 (.pdf 86 kb)
|
|
|
|
|
|
|
|
|
|
