Generator rotor ground protection method through voltage division by using resistor

The invention relates to a generator rotor ground protection method through voltage division by using resistors. The generator rotor ground protection method comprises a Ping-Pong-type generator rotor ground protection method through voltage division by using resistors and an injection-type generator rotor ground protection method through voltage division by using resistors. The generator rotor ground protection method is characterized in that exciting voltage which is input into a protection screen is reduced, whether a ground fault occurs on the lead of an exciting circuit or the lead of a measuring circuit is correctly judged through switching of different extraction resistors, and theoretical data is provided for troubleshooting of field fault points by calculating the ground resistance and the positions of two positioned points. Aiming at overcoming the defects existing in the traditional Ping-Pong-type and injection-type generator rotor ground protection methods and further improving the traditional Ping-Pong-type and injection-type generator rotor ground protection methods, by reducing the exciting voltage input into the protection screen, the requirement on the measurement accuracy of the ground resistance and the position of one point in the field is met.