The insurer that issued the performance bond for a portion of the troubled Interstate-84 construction in Connecticut will pay $17.5 million to settle claims involving installation of defective drains. The payment from the insurer on behalf of the primary contractor for the project will allow the state to begin repairing the defective drains along a three-mile stretch of highway. Many of the defective drains lead nowhere or are clogged with debris, with others connected with substandard, cracked and leaking pipes. The state estimates that it will cost $27 million to repair them. Under the agreement, the state retains the right to sue the contractor for additional funds. The contractor has already been sued by its insurer, who accuses the firm of concealing funds and purchasing luxury cars with company resources.