One of two sets of hearings at which state utility regulators gather public input about Central Maine Power’s proposed transmission line project has been postponed.

Hearings at the Public Utilities Commission’s offices in Hallowell, originally set for Sept. 18-21, have been put off until sometime in late October or early November.

A pair of Public Witness hearings scheduled for Friday at 6 p.m. in Farmington and The Forks, however, will go on.

The PUC is one of the key agencies that must give approval for CMP to build a 145-mile high-voltage transmission line that would carry hydroelectric power from Quebec through Maine to Massachusetts. The $1 billion proposal has drawn widespread interest and already has generated more than 300 separate filings and a similar number of public comments in the case. Multiple requests for complex technical data, as well as confidential negotiations aimed at settling narrow aspects of the case, remain in play. For these and other reasons, the PUC concluded that it needed to delay next week’s hearings.

The impact of this delay is unclear.

CMP and its parent company, Avangrid, want to have all permits in hand to start construction by the end of 2019, and be in service by 2022. The PUC is set to deliberate the case on Nov. 27, which could produce a decision by year’s end. But with public hearings now being put off until later this fall, those timelines could change.

Parties in the case are reviewing their schedules to see when witnesses, lawyers and other experts are available, said Harry Lanphear, the PUC’s spokesman. He declined to speculate on whether a decision in the case would be pushed into the new year.

John Carroll, a spokesman for Avangrid/CMP, said the company is working to submit multiple documents requested in the case. The overall timeline for the project won’t be affected if the PUC case extends into 2019, he said.