Singlephase ground is an accident that often occurs in low voltage distribution systems of chemical company, this paper analyzes whether the high voltage side of the transformer over current protection can play a role in the lowvoltage side ground fault protection by calculating, then analyzes how to set ground protection at the low voltage circuit breaker of the total line and the branch line, discusses how to achieve rapidly removal of singlephase ground current with useing ground fault protection in each electrical circuit breakers to. Finally, at low total incoming circuit breaker and feeder breakers cancel out the trunk ground fault protection, and the use of the circuit breaker when the general conclusion of each load circuit breaker ground current is greater than the instantaneous current.