A water and power district east of San Diego is suing the University of California over records related to a legal opinion that supports Gov. Jerry Brown’s plan to expand the state power grid across the western United States. The lawsuit, filed last week in Alameda County, said university officials refused to turn over documents that three law professors relied on to produce the study. The opinion was commissioned in March by the California Independent System Operator, or CAISO, the government nonprofit that manages most of the the grid.