Page 2: Teasing out the details >>
By Doug Houseman
When it comes to deploying Home Area Networks with the cooperation and assistance of utilities they worry about a number of issues. Do the devices meet the standard? Do they have the ability to operate in a fail safe manner? Can they perform repeated operations for years without causing issues? Do the devices work with our chosen meter? Is the standard tight enough that all the devices run the same way?
In the case of all but the last two questions, a manufacturer or a manufacturerâ€™s lab can do life testing and determine the answers. In the case of the last two, it takes a series of tests to make the determination.
Oncor decided that they needed to really understand the last two questions. In getting to these answers they produced one of the most useful documents for HAN testing that has been written so far and they created a path for manufacturers to submit HAN devices that answers the questions for SEP 1.0. That process and the lessons learned in doing this are being fed directly back into the SEP 1.x process and from there in the SEP 2.x process. In short, Oncor by making this document publicly available has set up an open process that is helping move the whole industry forward. SEP 1.0 is a very useful standard to the industry, and Oncor wants to make sure that 1.x and 2.x are both easier to deploy and operate.
Oncor, of course, chose the Landis+Gyr metering system and they use L+G in the initial testing of the HAN devices. Any manufacturer that wants to do testing with Oncor has to start by submitting their device to L+G for testing. L+G invested in a new set of test facilities to answer the question of whether the device works with the L+G meter and its supporting software. At the same time L+G does the testing that is required to determine if the device complies with the SEP 1.0 standard -- the standard adopted by Texas and used by Oncor.
This testing is the baseline that Oncor uses for the rest of the testing they do. That testing looks at how the device actually uses the SEP 1.0 standard and in what manner the required features are implemented. SEP 1.0 has enough wiggle room that a HAN device can either poll for information or wait for it to be pushed to the device. The behavior of one device versus the other device is part of what Oncor wants to know before they determine how that device will be supported in the field and how that device will operate with the Oncor L+G metering system. While this may not seem like a big deal, if every time a meter was polled by a device, the meter requested updated information from the head end, and a device polled every 10 seconds, millions of new messages per hour might be created from the overall system. So knowing the behavior of devices and knowing how to deal with that behavior operationally is critical to managing information flow and operational costs.
These operational impacts of the differences in the way devices operate within the standard are critical for deciding how to operate the Oncor metering system long term and what the capabilities of the system are. It is also helping Oncor determine what changes they would like to see in the SEP 1.x standard that will be deployed in Texas once it is complete and ready for deployment. Over time Oncor would like to see less operational variation in the devices being deployed so they are feeding information back into the standards process to clarify items that might not have been clear enough in the original version of the standard.
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