What is the reason for the crackling sound of the switch cabinet

Recently, there are many rainy days in southern China, especially in coastal areas. Several southern coastal power plants (discharge, photovoltaic, thermal power, etc.) feed back that their high-voltage switch cabinets often have crackling discharge sound, and every year in the plum rain season in summer, they will encounter the problem of wet discharge of high-voltage transmission and transformation equipment, especially in indoor switchgear. Through years of working experience, cyprey found that the reason why the switch cabinet has discharge phenomenon is that most parts of the switch cabinet are epoxy resin, belonging to hydrophilic material, so the switch cabinet with poor sealing performance (most of them are not good) will have crackling discharge sound in the cabinet during the plum rain season, which may lead to the risk of short-circuit explosion.



In recent years, the volume of switchgear products has been shrinking, and the insulation performance defects and faults have increased. The main performance is: the creepage distance and air gap are not enough, especially for the handcart cabinet. Now many manufacturers have not taken effective measures to ensure the insulation strength in order to shorten the cabinet size, greatly reduce the phase to phase and ground distance of circuit breaker and isolation plug installed in the cabinet; poor assembly technology, due to poor assembly quality, a single component in the switch cabinet can pass the withstand voltage test, but After assembly, the switch cabinet as a whole can not pass through; the contact capacity is insufficient or the contact is poor, when the contact capacity is insufficient or poor contact, the local temperature will rise and the insulation performance will decline, causing flashover to the ground or between phases; the condensation phenomenon is easy to damage the self-contained heater and can not work normally, and condensation phenomenon occurs in the switch cabinet, which reduces the insulation performance; the insulation performance of the supporting accessories is poor. In order to reduce the cost, some manufacturers use the accessories with low insulation level, which reduces the overall insulation performance of the switch cabinet, which easily leads to power safety accidents.