PMU and power distribution network fault positioning method based on PMU

The invention discloses a PMU and a power distribution network fault positioning method based on the PMU. The method comprises the following steps: flexibly changing corresponding temporarily stored bit quantities of a plurality of logic links according to the bit quantity of a message receiving a fault value; adding more than one of the temporary memories corresponding to the plurality of logic links according to a preset increment if a message that the logic link generates a blocking and losing fault value is monitored; if a target temporary storage block with a preset critical amount, which is higher than the highest bit amount KB of the message with the fault value, the bit amount of the target temporary storage block is changed into the highest bit amount KB of the message with the fault value, and if the target temporary storage block does not have the highest bit amount KB of the message with the fault value, the processing is not executed; through regular interception, whether the message state of blo