All kinds of arc effects produced by the huge energy released by arc short circuit will cause serious injury to the nearby workers. Therefore, arc protection can cut off arc short circuit fault within the arc withstand time standard of existing switchgear.
The induced voltage will damage the muscles and nerves of people. The high temperature gas produced by the arc burning will cause serious burns to the skin. The strong flash will hurt the eyes and cause temporary blindness together with the blasting sound. The blasting pressure shock wave will cause the falling of people working at heights, the flying of fragments will damage the human body. The blasting sound will cause the eardrum and viscera damage, and the arc will burn The toxic gas produced by burning will hurt people's respiratory system, etc.
It is worth mentioning that in addition to the obvious risk of electric shock death and physical shock, another risk that may be more sensitive is the thermal effect of electric arc on human beings. The reason why it is sensitive is that the fault arc produces a large proportion of radiant heat, which is invisible to the human eye. It may cause two and three degree burns to the skin, and it can cause serious and even fatal injuries to people.
In order to protect people from the fault arc in a large extent, on the one hand, the protection system should cut off the fault as fast as possible. For example, if the short-circuit current supplied to the arc point can be cut off at the beginning of the arc discharge stage, the energy released by the fault arc will be greatly reduced, thus greatly reducing the harm of the arc effect on people. On the other hand, when operating personnel are working near the switchgear, they can also provide corresponding protection by wearing appropriate personal protective equipment (protective gloves, protective coats, protective masks and goggles) through the assessment of the working conditions of the possible injury caused by the fault arc on the site. The purpose of using personal protective equipment is to provide workers with escape time in case of arc fault and reduce the burn degree of arc thermal effect, so as to increase the survival chance of accident victims.
The arc light protection system of smreap uses the arc light probe to monitor the arc light signal and cooperate with the over-current to judge the fault. The action time of the whole group is less than 1ms, and the tripping time of the circuit breaker is 35-60ms, which can effectively protect the switchgear. It is the arc light protection system with fast action at present and the feasible solution for the internal fault protection of the medium voltage switchgear.
