High-voltage capacitors often appear problems

High-voltage capacitors are usually composed of a plurality of components combined, each of which is made of aluminum foil as an electrode, and a solid medium is placed between the electrodes and wound. The plate area of the component is large, and due to raw materials and manufacturing processes, it causes a series of problems at the beginning, which increases the hidden danger of the capacitor.

In the system caused by various factors such as overvoltage, overcurrent and surrounding high and low temperature, these weak points cause dielectric breakdown. Sparks are usually generated during breakdown, further expanding the range to form a multilayer short circuit or even a short circuit of the entire component. The voltage across the component in series with the breakdown component will increase, and the component group connected in parallel will be shorted, causing the voltage across the remaining series to rise, and the current through each component will follow. Increase. It will lead to rapid aging of various components and increase heat generation. At the same time, partial discharge of the edge of the plate will also occur under the action of a higher voltage. In addition, the discharge at the breakdown point causes the impregnating agent to release a large amount of gas. After a certain period of time, the other components of the entire series in series with the faulty component will be successively broken down, and a new series group will be shorted. The number of series groups is further reduced, the component voltage is further increased, the overcurrent phenomenon is more serious, the medium is further deteriorated, the temperature is further increased, the arc is further increased, the impregnating agent will further release the gas, and thus, the component damage is more and more. The casing expansion is getting more and more serious. In this case, the fuse and relay protection should be removed in time. If it cannot be removed, further breakdown will form a strong arc in the casing, and the inrush of other parallel capacitors and system energy will be short. During the time, the capacitor medium is rapidly aged, expanded, and the casing expands, and in severe cases, an explosion may occur. This kind of accident can't be eliminated by the user. It belongs to the early damage of the capacitor, and the cycle is usually about one year.