Traditional arc protection methods mainly rely on overcurrent protection devices, such as differential relay circuit breakers and fuses, to cut off the circuit by detecting the magnitude and duration of the fault current, thereby limiting the duration of the arc fault. When using traditional time-grading or lock-based protection coordination principles, traditional protection systems may not be able to provide fast enough substation fault protection. In addition, high-impedance grounding faults may cause arc faults to last longer and release more arc energy.

Differential relay protection is also a traditional arc fault protection method. Taking differential relays as an example, when an arc fault occurs within the protection range of differential protection, if the current generated by the arc fault is large enough, resulting in an imbalance of current flowing into and out of the device exceeding the action threshold of the differential relay, the differential protection can also operate to cut off the fault, thereby limiting the duration and energy of the arc to a certain extent. However, additional CTs need to be installed using this arc protection method, and it is not sensitive enough to low-amplitude arc faults.