Fire and explosion prevention of the hottest high

Fire and explosion prevention of high-voltage circuit breaker

(1) the breaking capacity only in the past 1 year does not meet the requirements. Due to poor design, the breaking capacity of the circuit breaker is too small; Due to the development of electricity and the increase of system short-circuit capacity, the breaking capacity of the original circuit breaker can not meet the requirements; The manufacturing quality of the circuit breaker is poor, which cannot meet the parameter requirements of the product brand. Due to the above reasons, when a short circuit occurs, the circuit breaker cannot cut off the short-circuit current, causing the circuit breaker to explode and catch fire

(2) the maintenance quality does not meet the requirements. If the opening and closing speed is changed at will during maintenance, the role played by plastic packaging can not be underestimated. However, it is flammable high molecular materials, and the arcing distance (the distance between the arc extinguishing chamber and the static contact) will reduce the breaking capacity of the circuit breaker

(3) improper operation and maintenance. If the circuit breaker has cut off the short-circuit current for many times, the maintenance is not arranged in time according to the regulations; After the automatic tripping of the circuit breaker, the operator repeatedly forced power transmission inaccurately, so that the circuit breaker was impacted by short-circuit current for many times. All these have reduced the current breaking capacity of the circuit breaker and caused the explosion and fire of the circuit breaker

(4) the operating oil level is too high. The operating oil level of the oil circuit breaker is too high, which reduces the buffer space above the oil level of the circuit breaker. When the oil circuit breaker disconnects the short-circuit current, due to the reduction of the buffer space, the high-pressure oil-gas mixture generated by cutting off the arc may rush out of the buffer space, such as the ferry construction industry, forming the fuel injection of the circuit breaker, and even cause a fire; In addition, due to the reduction of the buffer space, the pressure of the buffer space will increase after the high-pressure oil-gas mixture is discharged into the buffer space. If this pressure exceeds the limit strength of the buffer space container, the circuit breaker may explode

(5) the operating oil level is too low. The operating oil level of oil circuit breaker is too low, which affects its arc extinguishing performance. When cutting off the arc, due to the low oil level, the oil path of cooling the arc becomes shorter, and the cooling effect of the arc is poor, resulting in the extension of the arc breaking time or the difficulty of extinguishing the arc. As a result, the arc light may rush out of the oil surface and enter the buffer space, and the combustible gas decomposed by the arc also enters the buffer space to mix with the air. The mixed gas may cause combustion and explosion under the action of the arc; If the oil level is too low, the contact of the circuit breaker may not be immersed in oil, and the arc cannot be extinguished when the contact is disconnected, which will also produce combustion and explosion

(6) the insulating oil is impure. The oil in the oil circuit breaker has a large amount of free carbonization, aging, moisture ingress in the oil, and water ingress. Due to the impure oil, flashover occurs inside the circuit breaker and leads to explosion

(7) hydraulic pressure or air pressure is too low. For oil circuit breaker and gas arc extinguishing (air, SF6) circuit breaker with hydraulic operating mechanism, due to the low hydraulic pressure of the operating mechanism, slow opening and closing will be caused when the circuit breaker is opened and closed, and slow opening and closing will make the arc generated between contacts not easy to extinguish and cause the explosion of the circuit breaker; When the pressure of gas arc extinguishing medium of air circuit breaker and SF6 circuit breaker is too low, the arc extinguishing capacity of the circuit breaker will be reduced, and even the arc cannot be extinguished, resulting in the explosion of the circuit breaker. Therefore, the oil circuit breaker and gas arc extinguishing circuit breaker with hydraulic operating mechanism are equipped with hydraulic and gas pressure locking devices. When the hydraulic pressure and air pressure are excessively reduced, the circuit breaker will be locked in the original position