BENTON — The Maine Public Utilities Commission has ordered an investigation into operations at a Central Maine Power Co. substation on Albion Road in hope of concluding a three-year dispute between the company and neighboring property owners about noise.

The commission is scheduled to have an initial conference in the case Thursday and ultimately could require the company to fix the cause of the loud noise.

A public advocate retained by CMP already has spent two years mediating the dispute, and a special land dispute team set up by the commission to deal with such cases decided the commission should take jurisdiction because it was outside the team’s scope.

Considering how long the issue has played out, commissioners want to reach a conclusion as soon as they can, Executive Director Harry Lanphear said Wednesday.

“We want to try to resolve the situation the best we can to address the concerns of the citizens,” Lanphear said. “We would really like to expedite this process and this proceeding as best we can.”

The dispute goes back to May 2013, just after CMP had finished building the substation as part of its $1.4 billion system upgrade called the Maine Power Reliability Program.

Immediately after the company energized the station, a handful of residents living near it reported it generated excessive noise, and they made 38 complaints about the station to CMP from the time it was powered on until October 2013, according to a chronology of the dispute attached to the commission order.

A voice mail left Wednesday afternoon for CMP spokeswoman Gail Rice was not returned immediately.

In a report to the commission’s land dispute team in February 2014, ombudsman Leah Sprague said residents living near the station — including Cherry Strohman; Sen. Scott Cyrway, R-Benton, who represents the area; and Doug and Sue Blaisdell — reported that loud, unpredictable noises, often late at night, prevented them from sleeping and had destroyed their quality of life in an otherwise quiet rural area.

Despite the complaints, CMP and Burns and McDonnell, the Missouri-based engineering firm managing the system upgrade, after several rounds of testing determined that sounds from the station were within the 45-decibel limit in Benton’s noise ordinance and the Maine Department of Environmental Protection noise standard, according to Sprague’s 2014 report. A noise reading at 45 decibels measures about halfway between the sound of a conversation at home and library noise.

Residents doubted those readings, stating the measurements were taken at a time when the station wasn’t generating excessive noise.

The commission’s land dispute team, set up to field complaints resulting from the CMP Maine Power Reliability Program, decided in 2014 the conflict was “not ripe for resolution,” according to a second referral Sprague filed with the commission last month.

In that report, Sprague noted that an independent noise test in fall 2014 “documented loud excursions in sound,” confirming residents’ accounts that the station noise could increase unpredictably and in the middle of the night.

Those results were confirmed by CMP and Burns and McDonnell in 2015 at the Albion Road location and another substation on Maguire Road in Kennebunk that was also the subject of noise complaints from neighbors, according to Sprague. The Maguire Road substation had been rebuilt and moved closer to neighbors as part of CMP’s upgrade, according to the commission.

In September, CMP started an in-depth investigation into what was causing the noise and determined it came from DC current flowing into the stations. The company came up with a possible way to block the current, but further analysis and testing meant the problem might not be fixed until October 2017 at the earliest, Sprague reported.

That timeline was not acceptable to the affected residents, who wanted CMP to make changes immediately, she said.

“These neighbors have been deprived of the quiet enjoyment of their homes for over two and a half years. The loud noises from the substation occur intermittently and unpredictably, typically in the middle of the night, and are loud enough and unpleasant enough to wake neighbors and render them unable to return to sleep,” Sprague wrote.

Sprague added that CMP “has indicated that commission approval will be required before any mitigation can be implemented.”

In its order, the PUC said the land dispute team decided it was not well-suited to address the issue because the complaints were outside the intended scope of the group, and the cost of solving the noise problem would “greatly exceed” the $200,000 threshold the team has to order mitigation.

“Finally, we also note that CMP has specifically stated that it will not carry out any mitigation efforts unless ordered to do so by the commission,” the order stated.

At least 17 parties have been notified of Thursday’s case conference, although Lanphear on Wednesday did not know how many people would attend.

Doug Blaisdell, reached at his automobile garage business on Wednesday, said he and his wife would be there.

“We just want the noise to disappear,” Blaisdell said, but he declined to comment further before talking with his lawyer.

Peter McGuire — 861-9239

[email protected]

Twitter: @PeteL_McGuire