High-precision clock synchronization method for 5G smart power grid

The invention discloses a high-precision clock synchronization method for a 5G smart power grid, and the method comprises the following steps: time difference measurement: obtaining the clock phase deviation of a master node and a slave node, and obtaining the clock frequency deviation and clock drift according to the clock phase difference; performing clock state filtering: performing filtering estimation according to the clock phase deviation, the clock frequency deviation and the clock drift; time difference feedback control: based on filtering estimation, outputting feedback control quantity of phase and frequency of a slave node clock through a PI controller; the FLL assists the PLL and outputs a target clock, and the FLL assists the PLL to output the target clock by using the feedback control quantity of the phase and the frequency of the slave node clock so as to keep synchronous with the master clock; clock synchronization errors are effectively restrained, nanosecond-level clock synchronization preci