Single-phase earth fault arc quenching judgment method for electric transmission line

The invention discloses a single-phase earth fault arc quenching judgment method for an electric transmission line. The single-phase earth fault arc quenching judgment method for the electric transmission line is characterized by comprising the steps that after a single-phase earth fault happens to the electric transmission line and relay protective action enables a fault phase breaker to achieve tripping, fault phase end voltage sampling is conducted on the electric transmission line to obtain a sampling value sequence, the last three high-order inter-harmonics total aberration rates with the frequency being higher than three of power frequency cyclic wave sampling value sub sequences in the current sampling current sequence are calculated, the last three high-order inter-harmonics total aberration rates are divided by three corresponding high-order inter-harmonics total aberration rates before the half power frequency period, and if obtained values are smaller than a preset threshold value, it is judged that arc quenching has already been achieved; otherwise, it is judged that arc quenching cannot be achieved and detection continues. The single-phase earth fault arc quenching judgment method for the electric transmission line has the advantages of being high in arc quenching judgment accuracy, easy to implement, capable of not being influenced by power grid integer subharmonic waves, short in response time and wide in applied range, thereby having great engineering practical value.