99.96 percent of smart meters accurate in Texas


Austin, TX, U.S.A. — (METERING.COM) — August 2, 2010 – Independent testing of smart meters in Texas has found that 99.96 percent were accurate by ANSI standards.

The testing, which was conducted by Navigant Consulting, was done on a total of 5,627 meters in use by the state’s transmission and distribution service providers Oncor, CenterPoint and AEP Texas. These included 2,400 new meters that had not yet been deployed, 2,706 meters that had been deployed and were removed for testing, and 521 meters that were tested in the field.

According to the tests, all but two (Oncor meters) were accurate to +/-2.0 percent – the requirement of the Texas Public Utility Commission (PUC). Further, all but a further three (two Oncor meters, one CenterPoint meter) were accurate to +/-0.5 percent – the performance standard expected by the three utility companies.

Oncor and AEP Texas are deploying Landis+Gyr Focus AXR-SD advanced meters to residential and commercial customers. As of June 30, 2010, the two companies had installed over 1 million and over 14,000 advanced meters respectively.

CenterPoint is installing Itron’s Centron advanced meters and as of June 30, had installed over 450,000 advanced meters.

The testing was called for by the PUC in March following a number of complaints about high bills and concerns over the accuracy of the new meters.

In its report Navigant Consulting says that its investigation focused primarily on evaluating the accuracy of the advanced meters deployed by the three companies and the reliability of the advanced metering systems and infrastructure at each. It also included efforts to address the reasons for the increased incidence of customer complaints and the perceived correlation of higher electric bills with the installation of the meters.

In addition to the testing of the 5,627 meters, the investigation included reviewing historical test results for accuracy on close to 1.1 million advanced meters and over 86,000 electromechanical meters, over 18,000 pages of hard copy documentation, and the electronic records at the three companies relating to approximately 850,000 residential advanced meters already deployed as well as up to 4 years of historical electric usage records for over 1.8 million residential customers with either advanced or electromechanical meters.

Navigant Consulting says that its opinion is that the vast majority of the advanced meters currently installed by the three companies are accurately measuring and recording electric usage, as well as communicating that information through the respective advanced metering systems for use in customer billing.

However, from the two Oncor meters that failed the PUC testing criteria, with one of these running fast and the other running slow, it also was possible to identify two discrete groups of advanced meters that were not performing at acceptable levels.

In the case of the meter running fast the problem was traced to the manual soldering of a component to the meter’s circuit board, which if poorly worked, could lead to the meter potentially running fast. Out of the 120,000 meters of this design type, which had been deployed in late 2008 and early 2009, approximately 439 meters were found to potentially exhibit the problem. These have now been replaced (except for one, for which Oncor is still working with the customer to remove it). In subsequent testing of 415 of these to date, 74 were found to be outside the +/-2.0 percent accuracy range, the majority running fast.

In addition further tests are being conducted by Landis+Gyr on a random sample of these meters, and Oncor has introduced a screening process to identify any others exhibiting similar problems.

In the case of the meter running slow the fault was traced to a failed current transformer. A group of 989 meters were identified as potentially exhibiting this issue and similarly have been removed from service. Of 839 of these that have been tested, 64 did not meet the test criteria, of which 43 had a failed CT. Oncor and Landis+Gyr are continuing to evaluate the potential root cause but a significant number also have evidence of potential tampering. Similarly a screening process has been introduced to identify these meters in service.

In its conclusions Navigant Consulting comments that as with any technology advanced meters will fail or cease to perform to acceptable standards for a variety of reasons, but there is a high probability that if it does so the meter will communicate an event or error code. As such the utility companies should be aggressively monitoring the information communicated by the advanced meters and correlating that to potential problems with the proper functioning of the meters, as well as whether the meter is effectively and consistently communicating with the utility as expected.

Further the utility companies should continue to develop, improve and monitor processes and controls surrounding the effective identification, analysis and prompt evaluation of either identified codes or meter communication problems that may be characteristic of larger errors or issues once advanced meters have been in service for some time

It is also recommended that that the utility companies should keep detailed records of meter types and firmware, and that a root cause analysis should be conducted on problem meters.