Power fault recording technology has been widely used in power system management, recording the steady-state and event information of transmission, transmission and distribution links, capturing and recording the fault process, providing the basis for the overall research and evaluation of the operation reliability and stability of power supply system.

In the power system, it is necessary to find the faults and hidden dangers early, and quickly diagnose the nature and location of the faults, so as to quickly check the faults and avoid the expansion of the fault accidents and cause greater losses. So it is necessary to install fault recording device. The power fault recorder tracks and collects the instantaneous value and power frequency of input analog quantity such as voltage and current with the set frequency, calculates its effective value, active power, reactive power, total harmonic distortion rate and harmonic component, and stores the data. When a fault occurs and the monitoring value exceeds the specified value, start recording, quickly collect data, and restore it to waveform with waveform analysis software, so as to observe and analyze the data change rule and trend, quickly check the fault and prevent accidents. Therefore, the change of transformer should be determined according to the size of circuit voltage or current. The input of voltage and current are phase voltage and phase current. Generally, 32-96 channels of phase voltage or phase current can be monitored. The number of channels of voltage or current can be customized according to the needs. After the installation and commissioning, the number of channels of monitoring voltage or current can be determined randomly and cannot be changed.

The power fault recording device can monitor the switch state of 64-192 channels of switching value in real time, monitor the working state of circuit or equipment according to the opening and closing state of switch or relay contact, and judge the fault nature and fault location according to the action sequence of switch in fault state.