The invention relates to the technical field of 
power grid monitoring, and particularly discloses a 
clock synchronization abnormity monitoring method and device and a computer readable storage medium. The method comprises the following steps: acquiring a 
voltage sag waveform monitored by each 
power quality monitoring device in a 
power grid; screening out homologous 
voltage sag waveforms from the 
voltage sag waveforms, wherein the homologous 
voltage sag waveforms are waveforms corresponding to voltage sags caused by transient disturbance events of the same 
power grid; and based on the 
voltage sag starting time of each homologous 
voltage sag waveform, determining whether clocks among the corresponding 
power quality detection devices are synchronous and abnormal. Compared with the prior art, the method does not need to compare a large amount of historical data, does not need to depend on manual detection, can achieve the automatic detection of the 
clock synchronization 
abnormality according to the waveform data recorded by the 
power quality monitoring equipment in real time, is good in real-time performance and reliability, is high in monitoring efficiency, and is high in intelligent degree.