Remote asynchronous power frequency signal phase difference measurement method and system

The invention relates to a remote asynchronous power frequency signal phase difference measurement method and system. The power frequency signal phase difference measurement method comprises the steps that first phase difference between a first measured power frequency signal and a city power reference signal and second phase difference between a second measured power frequency signal and the city power reference signal are acquired, and phase difference between first and second measured power frequency signals is acquired through first and second phase difference. According to the invention, remote asynchronous phase difference measurement is realized; the problem of inconvenient tow wire construction, which is caused by long distance between two measured signals in engineering application, is solved; defects of long distance signal transmission distortion are avoided; the construction difficulty of the measurement system based on a phase difference technology in the fields of power device state monitoring, signal acquisition and analysis, communication, automatic control and the like is reduced; and the quality of the relevant measurement system and the effectiveness of state determination are improved.