Orange-based United Illuminating said this week that its various infrastructure investments dating back as far as 1996 have led to fewer and shorter outages for customers.
UI, which is now owned by Avangrid, said its average customer had a 54 percent chance of suffering a power outage of 5 minutes or longer during any year between 2012 and 2015, down from 67 percent during between 2006 and 2009.
In addition, outages typically lasted 92 minutes in the more recent period, down from 100 minutes in the prior period.
UI credited the improvement to an ongoing project that began in 1996 to replace 40-year-old substations. That effort is nearly completed, with just four substations remaining.
UI invested $15 million to shore up and protect coastal substations from flooding in the wake of major outages caused by Tropical Storm Irene in 2011 and Superstorm Sandy in 2012. The company said the loss of a substation can affect thousands of customers.
In 2013, UI wrapped a 12-year program to replace paper-insulated lead cable in its system, which it said caused 15 percent of outages in 2001, with rubber-coated cable.
In 2014, the utility began a more strict vegetation trimming program around overhead power lines.
