With the development and improvement of microcomputer technology and communication technology, China's current power system has introduced a large number of new power system fault recorders and substation integrated automation systems. A large amount of data is transmitted to the power grid dispatch center through the public telephone network (power carrier, microwave and other channels).Because the baud rate is unlikely to be too high, especially the transmission time will be very long, the fault wave device records the analog quantity and state quantity of the whole process of the system from before the fault to the normal working state is restored. Even if the IEEE COMTRADE binary recording format is used, the recording time will vary from a few seconds or tens of minutes.