Method and device for preventing acceleration protection misoperation after distance

The invention discloses a method and device for preventing acceleration protection misoperation after distance, and belongs to the technical field of power system relay protection. The method comprises the following steps: analyzing a current fundamental wave amplitude, a current second harmonic amplitude and a voltage amplitude of each phase circuit of a power line; calculating an impedance value of the power line by using the current fundamental wave amplitude and the voltage amplitude, and comparing the impedance value with a preset impedance threshold value; when the impedance value is smaller than a preset impedance threshold value, the second harmonic amplitude of the current is continuously monitored within a first preset duration, and whether harmonic locking operation is started or not is judged according to a preset criterion; and when the harmonic locking operation is not started within the first preset duration, determining that the power line has a fault, and accelerating the protection action af