The factory/distribution medium voltage switchgear is the power supply hub for the auxiliary equipment/power supply system of the whole plant. In the event of an internal fault, the ability to quickly remove the fault is critical to the safe operation of the plant/distribution system. However, according to the current protection scheme, there are several problems:
1) The medium voltage busbar is not equipped with any special protection; it is taken care of by the relevant backup protection of the incoming switch;
2) The protection of the incoming line switch and the outgoing line switch need to cooperate with each other: the difference of the general quick-break protection delay is at least 300ms, or even 500ms;
3) The over-current protection is up to 1 – 2 seconds.
Therefore, any faults that occur on the medium voltage busbar of the plant/distribution system must be delayed at least. In other words, the protection of the existing factory medium voltage busbars in the first time can be a blank. However, with a little attention, it is not difficult to find that none of the many electrical equipment upstream or downstream of the medium voltage switch busbar is equipped with fast protection. In contrast, we may not have a good reason to explain that the safety reliability of medium voltage busbars should be slackened. In view of the important position of the medium voltage busbar, the delayed removal of any fault is a situation we are extremely reluctant to see. Because of various faults in the switchgear, the arc generated by the short-circuit current and its high temperature make the gas in the cabinet expand rapidly, which can reach the peak in a very short time, which seriously endangers the safety of people and equipment.
1) The entire set of action trips exits quickly;
2) Using overcurrent and arc as the criterion, the action is reliable;
3) Continuous comprehensive self-test function;
4) Flexible programming according to various types of wiring;
5) Easy and flexible installation.