We all know that the shorter the fault process of the power system, the better, the shorter the fault time, the less damage to the equipment, and the more favorable to the safe and stable operation of the power grid. All kinds of fault information of power system must be recorded by special fault recorder.

The starting of fault recorder mainly uses the electrical quantity with obvious fault characteristics to start the recorder. The general starting quantity includes the starting quantity of current and voltage mutation, the starting quantity of current and voltage out of limit, the starting quantity of frequency variation and the starting quantity of switching value.

In order to facilitate the fault analysis, the recording data generally includes the part before the fault and the whole process of the fault. The instantaneous waveform reflecting the change of current and voltage and the switching value reflecting the change of potential are drawn with a unified time scale. The output department includes brief analysis report, important fault information data and waveform of the whole process of fault. The amplitude and number of output waveform can be set when displaying and printing as required.

Because the fault recorder graph reflects the whole process before and during the fault, reading the recorder graph can also understand the whole process of the fault. In the recorder graph, we can see the current, voltage amplitude and phase, fault nature, fault duration, protection, switch action time and other information during the fault process.