MINNEAPOLIS (AP) - A Minnesota judge says Xcel Energy mismanaged a major renovation of a nuclear power plant in Monticello, finding the utility company at fault for $402 million in cost overruns.

The judge who headed a state investigation found Xcel misjudged the project's complexity, which more than doubled its cost.

The Minnesota Public Utilities Commission will decide how much Xcel will pay for the extra costs and how much will be passed on to customers. The judge in the investigation backed a recommendation from the state Commerce Department that Xcel should account for $71 million.

The commission is expected to vote in March on a proposed rate increase for 1.2 million Xcel customers. The president of Xcel's Minnesota regional unit says it's reviewing the judge's decision.