Transformer Failure Triggers Outage, Power Restored to 195,000 Customers and DIA Trains

A transformer failure at an Xcel Energy substation just before 3 p.m. Sunday triggered cascading equipment damage that left roughly 195,000 customers across the southeast Denver metro and surrounding counties without power, disrupted Denver International Airport operations and halted some transit and emergency communications.

Xcel Energy said the failure occurred at a substation near Jewell and Abilene in Aurora, and that the initial fault damaged other equipment and propagated outages to additional substations. KOAA reported Xcel’s update that power was restored to all customers by 5:47 p.m. and that the failed transformer was being replaced.

The outage swept through multiple utilities and jurisdictions. CORE Electric Co-op reported more than 44,000 customers without power in Arapahoe, Douglas and Elbert counties, and the Intermountain Rural Electric Association said thousands of IREA customers in Douglas County, including Parker, were affected. An Xcel outage map at one point showed more than 100,000 customers impacted; aggregated reporting from local outlets reconciled later to roughly or more than 195,000 customers overall.

Transportation impacts were immediate. Concourse trains at Denver International Airport were temporarily halted while airport crews worked to restore systems. DIA posted that “DEN operations are back to normal” and added, “We are still conducting our own investigation but it appears the occurrence was propagated by the current large power outages with Xcel Energy. We want to thank our passengers for their patience.” KKTV relayed airport guidance urging travelers that “Passengers should follow directions of airport employees.” Regional Transportation District service on the H Line and R Line was also impacted; RTD deployed shuttle buses and regular rail service resumed by Sunday evening.

Public safety communications felt the strain. Parker police reported emergency and non-emergency lines were down and that 911 calls were being forwarded to the Douglas County Sheriff’s Office until Parker’s lines were restored by 4:20 p.m. KOAA reported that Aurora 911 service was affected and later returned to normal. The Douglas County Sheriff’s Office had urged residents to call 911 only for emergencies as it received reports of large outages spanning Douglas, Elbert, Arapahoe and Denver.

Residents in Aurora described audible and physical effects during the failure. Aurora resident Charlie Anderson told 9NEWS, “It was that big, big like a sonic boom. It was like ‘boom!’ The whole house kind of shook. And since we live right on the corner, you could really feel it,” and added, “And then, about a half hour later, another one happened.” KOAA included a tweet from Denver7 reporter Maggie Bryan quoting Xcel: “NEW: Xcel Energy says a transformer failed at the company’s substation near Jewell/Abilene in Aurora and caused Sunday’s power outage across the Denver Metro. Xcel says the failure damaged equipment and caused an outage that cascaded to other substations.”

No injuries or fatalities tied to the outage were reported in the immediate aftermath. Utilities and airport officials said investigations were underway; Xcel’s replacement of the transformer and DIA’s internal review were cited as next steps. For Douglas County residents, the incident underscores the interconnected risk when major substation equipment fails - impacts ranged from household outages and traffic disruptions to temporary interruptions of critical services such as 911 and airport transit. Officials advise monitoring utility and public safety channels for official restoration records and follow-up findings from Xcel and DIA.