SACO —  The Maine Turnpike will be subject to 20-minute closures in the overnight hours this week because of power line construction.

The closures will take place between 10 p.m. and 5 a.m. beginning tonight. They are expected to continue through Saturday.

Central Maine Power will be installing electrical conductors near the utility’s new substation on Industrial Park Road and in the transmission corridor near Jenkins Road in Saco.

The installation of the conductors is one of the last steps in the Saco Bay Transmission Reinforcement project. The work will allow Central Maine Power to energize the new substation later this month.

The company began construction last fall on the $30 million project to improve capacity and reliability of the transmission system for Saco, Old Orchard Beach, Scarborough and Biddeford. The project, which is expected to be completed in the fall, includes new substations in Saco and Old Orchard Beach and improvements to the network of transmission lines.