Intertrip circuit avoiding self-excitation overvoltage of small hydro-generator

The invention relates to generators and provides an intertrip circuit avoiding self-excitation overvoltage of a small hydro-generator. The intertrip circuit comprises a long circuit input end, a main transformer, a generator outlet circuit breaker, a generator outlet disconnecting switch, a generator, a high voltage station transformer, a generator protecting module, an input end of the small hydro-generator, a first intertrip switch and a power input end. The long circuit input end is connected with the main transformer through a normally-closed contact of the first intertrip switch. One end is connected with the power input end and the other end is connected with one end of an outage coil of the first intertrip switch after the two ends of a normally-closed contact of the generator outlet circuit breaker and the two ends of a normally-closed contact of the generator outlet disconnecting switch are in parallel connection with the two ends of a normally-closed contact of the generator protecting module, the other end of the outage coil of the first intertrip switch is connected with the ground, and the disconnection duration of the first intertrip switch is smaller than that of the normally-closed contact of the generator outlet circuit breaker. The intertrip circuit is used for avoiding self-excitation overvoltage of the small hydro-generator.