BEIJING, May 14 (Reuters) - China's state planner revised a rule on electricity market operations on Tuesday, according to a government document.

The rule, which takes effect on July 1, tasks electricity market operators with carrying out market monitoring and risk prevention, according to an explanatory note on the website of the National Development and Reform Commission.

It also calls on electricity trading bodies to set up a market registration system. (Reporting by Colleen Howe; Editing by Christopher Cushing)