Device and method for recording fault waveforms of power distribution lines

The invention discloses a device for recording fault waveforms of power distribution lines. The device comprises a DMA (direct memory access) module, a nonvolatile memory device and two annular cache regions. The invention further discloses a method for recording the fault waveforms. The device and the method have the advantages that acquired data can be temporarily stored in one annular cache region without intervention of a CPU (central processing unit) when power systems are free of faults or anomaly, so that memory spaces of the CPU can be effectively saved; the fault data can be pointed to the other newly developed annular cache region from the annular cache region when the lines have faults or abnormal running of the lines is detected, so that effective data can be prevented from being covered, and sufficient time can be reserved for the CPU to broadcast fault information; double caches can be switched over periodically, and accordingly complicated boundary data processing operation can be omitted.