An arc fault is properly the most destructive fault senario that can happen within an electrical installation. Arcs develop when the insulation between conductors are broken down sufficiently to leave an ionized channel which can carry current. Insulation can be degraded for different reasons, e.g. conductive dust, moisture, cobwebs etc. If the switchboard is capable of supplying enough energy, a run-away reaction can occur, if this happens the current heats and ionizes more air, carrying even more current, heating up and eventually boiling the conductors. The following explosion will spray the cabinets with molten copper and tear it apart by the rise in pressure - this happens as the arc fault converts the full capacity of the power source to heat.
The damage can be so extensive that it will take days or even weeks to re-establish production. However, even more serious is the risk of personal injury. Arcs can and do kill people by explosions, shock waves, shrapnel, extreme heat etc. Arc protection is one way to lower the risk of disaster, even though it is not a replacement for personal protection (PPE equipment).
It is not generally possible to extinguish a developing arc, but the damage can be limited by cutting the power to the switchboard as soon as possible.
In case of an arc flash fault, the D1000 detects and generates a tripping pulse in less than 1 millisecond. This tripping pulse is taken to the circuit breaker(s) that controls the supply to the installation. The total arcing time is thus reduced to the mechanical opening time of the circuit breaker, which is typical around 30-100 milliseconds. If even shorter arcing time is required, the D1000 can control arc quenching devices as well as breakers, limiting the arc time to less than 2 ms.
The trip circuit is based on a solid state semiconductor switch (IGBT), which provides both fast reaction as well as drive capability for even the largest circuit breakers.