Reliable electricity fuels economic development and our quality of life.

Three key prevention programs are improving reliability as Tucson Electric Power has reduced average customer outage times by more than 15 minutes over the past two years.

TEP tracks the duration of outages attributed to maintenance, equipment failure, weather and other factors with a metric called the System Average Interruption Duration Index, or SAIDI. After posting a SAIDI of 72 minutes in 2017, the company improved its scores in 2018 and 2019 to 50 and 55 minutes, respectively.

“Most utilities measure outages in hours, as opposed to minutes, so that just demonstrates how reliable our system really is,” said David Wagner, Director of Line Construction and Metering. “We continuously improve our system to make it better and to help us achieve these successful outcomes.”

The new programs include:

  • Visual inspections of all 109,000 poles in the distribution system. Teams are on a pace to evaluate every pole at least once every 18 months. If our experienced field inspectors see something out of place, they perform a closer inspection and submit a work order. Over the course of 225 inspection days, our staff corrected 77 items that otherwise could have contributed to an outage over time. “We really believe there’s value in this program to make sure our equipment is working optimally.”
  • Expanded replacement of wood poles with steel poles. In addition to the visual inspection, as well as the routine replacement of about 1,200 poles every year, teams are deployed to proactively test poles with a tool called a resistograph. Akin to a very thin drill bit, the tool measures the wood’s resistance and torque to check its strength. With a focus on older poles first, the number of replacements will be increased in each of the next five years.
  • Enhancing reliability of underground transformers and cables. To protect the safety of staff and improve reliability, we’re replacing the oldest transformers over the next decade.

Wagner said teams strive for excellence – constantly working to improve processes around the tracking and timely completion of priority work orders and analyzing data to detect outage trends.

“The effect is cumulative each year as time goes on and as these proactive reinforcements continue, so it is our hope to continue to meet or exceed our goals in decreasing the duration of outages.”

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