By R. Bruce Wright, CPCU

New technology offers the possibility of finding defects before they cause failures!

Everyone is aware of the major wildfire events that have erupted in past couple of years, particularly the California cases that were widely reported on the national news. In addition to these highly publicized events, as well as other widely reported line contact incidents, there have been numerous other wildfires over the last decade, several of which have involved fires in the service territories of utilities in this program, maybe even at yours. As a result of these widely publicized events, the general focus on utility power lines and the prevention of equipment failure has become even more intense than it was previously. Maintenance, inspection, and prevention seem to have risen to the level of a new “mantra” in every discussion of power line safety.  

Among the many challenges in maintaining a power distribution system, finding and replacing or fixing equipment before it fails has historically been one of the most difficult to solve. The cost of detailed inspections, the cost of replacing suspect, but not provably faulty, devices, the man-hours needed to get even the most cursory efforts done, have all lead to a reactive approach to failures, sending a crew out when the power goes off, or in the best case, when a circuit trips and resets. 

Most electric distribution system components last for decades, providing reliable  service. But, like all devices and materials, time takes its toll, and eventually, things fail. To provide continuous service, most utilities perform scheduled maintenance and tests on selected  components, such as oil spectrometer analysis on transformers, and infra-red surveys on other devices, keying in on those with relatively higher failure rates or failure consequences. Because of the sheer number of components in a distribution system and their diverse spread geographically, careful and detailed inspection of all of the components would require vast resources (read time and money), and generally is not done.

But now technology offers a new, proactive alternative, one that makes it possible to spot developing failures before they occur, and to take preventive action before an outage. In this way, utilities can keep their equipment up and working, and keep the power on, helping to avoid loss incidents along with the notoriety that would attend any new wildfires like those that have turned the publicity spotlight on power line operators.

The newsletter is not in the business of endorsing products, but it is intended to provide updates on safety and prevention techniques that are available to its readers. So far, only one company has been found that offers new DFA, or Distribution Fault Anticipation technology. What follows is some basic information on this technology with links to more detailed resources.  

While some equipment failures occur suddenly, such as when a tree falls and breaks a wire, other failures are frequently the last step in an extended process, which can begin to be seen as intermittent service problems such as flickering lights or repeated, self-clearing, over-current faults. These service issues can sometimes occur weeks or months apart, making it difficult to diagnose the root cause.

Now, new technology offers the possibility of a new monitoring approach for distribution circuits. As apparatus fail, they produce distinct electrical signatures, which can often be detected in voltage and current waveforms measured at a substation. Researchers at Texas A&M Engineering, in partnership with EPRI and over 20 distribution utilities, have developed new technology called Distribution Fault Anticipation (DFA), designed to automatically detect many common equipment failures, giving utilities the chance to fix problems before a sustained outage occurs.

DFA-Plus technology can usually be deployed using the infrastructure already available in many distribution substations, along with a 12-60V DC power input, backed by substation batteries and provided with internet connectivity. More details on DFA-Pluss can be found on the vendor’s site, at powersolutionsllc.us.

More information on the background of the methods used and on DFA research can be found in a presentation made by Dr. Jeffrey Wischkaemper, Texas A&M Engineering, at the i‐PCGRID Workshop 2019 in San Francisco, California in March of 2019. You can find the full presentation if you click Here.

(Both sites provided source material for this article.)