Cable short circuit fault indicator 2DK fiber-optic, rotating illuminated sign

A fault indicator is an electromagnetic device that displays a fault sign (red card) when short-circuit current passes through it. Installing these fault indicators along distribution lines ensures that when a fault occurs, the short-circuit current triggers the fault indicator, causing the red card to appear. By inspecting the line, if all fault indicators from the power source to the fault point show the red card, while those beyond the fault point do not, the fault location can be determined between the last red card and the first non-red card point. Fault indicators typically include current and voltage detection, fault discrimination, fault indicator drive, fault status indication, signal output, and automatic delayed reset control. They are usually installed on overhead lines, overhead cables, or underground cables, as well as on busbars of switch cabinets, and detect voltage by sensing spatial electric field potential gradients and current by electromagnetic induction.

Cable-type fault indicator sensors and display (indication) sections are integrated into one unit, mechanically fixed on cable lines (busbars). They are typically installed on cable branch boxes, ring main units, switchgear, and other distribution equipment, consisting of three phase sequence fault indicators and one zero sequence fault indicator.