ST. PAUL — State regulators have approved the final leg of a high-voltage power line through southeastern Minnesota.

The Minnesota Public Utilities Commission voted 4-0 Thursday to approve the nearly 90-mile route from Hampton, in Dakota County, to La Crosse, Wis. The agency also approved a shorter, lower-voltage line from near Pine Island to Rochester.

The CapX2020 project will add more than 700 miles of new transmission lines and strengthen the regional power grid. Some parts of the $1.9 billion upgrade already are completed and the rest are expected to be finished by 2015.

Minneapolis-based Xcel Energy Inc. and two other power companies are prime sponsors.

Two connecting segments of the CapX2020 project, near Fargo, N.D., and La Crosse, still need approval from regulators in those states.