The N.C. Supreme Court has upheld a 5.5 percent rate increase state regulators awarded Duke Energy Progress in 2013. The court rejected state Attorney General Roy Cooper’s appeal of an order by the N.C. Utilities Commission approving the rate hike. Cooper had contended the order was “not supported by competent, material, and substantial evidence.” Cooper, who has also appealed a 5.1 percent Duke Energy Carolinas increase the commission approved in 2013, says he is disappointed by the court's…