Abnormal phenomena and fault handling during capacitor operation

1.Leakage oil

Due to improper handling methods, the porcelain casing is lifted, causing cracks in the welded portion of the flange, or the force of tightening the nut during wiring is too large, causing damage to the welded joint of the porcelain sleeve and some defects in the manufacturing process of the product. The capacitor is leaking. At the same time, since the temperature changes drastically after the capacitor is put into operation, the internal pressure increases, which makes the oil leakage phenomenon more serious. In addition, due to long-term operation, the paint layer of the capacitor casing may be peeled off and the iron sheet is corroded, which is also a cause of leakage of oil in the capacitor during operation.

The consequence of leakage of the capacitor is that the impregnating agent is reduced, the upper part of the component is easily wetted and penetrated to damage the capacitor, so repairs must be made in time.

2. Shell expansion

Since the internal medium of the capacitor is freed by the voltage, the medium is decomposed to precipitate a gas or the dielectric is precipitated due to the breakdown of some components and the discharge of the pole to the outer casing. These gases will cause an increase in pressure in the sealed outer casing, thus causing the outer casing to expand. Therefore, expansion of the capacitor casing is a symptom of a capacitor failure or failure. If the capacitor casing is found to be inflated during the operation, measures should be taken in time. If the expansion is serious, the use should be stopped immediately to avoid accidents.

3. Capacitor explosion

When an inter-pole or pole-to-case breakdown occurs inside the capacitor, the capacitor bank operating in parallel with it will discharge it, at which point the capacitor may blast due to extreme energy. Since the inside of the low-voltage capacitor is generally equipped with a component protection fuse, such an accident occurs mostly in a high-voltage capacitor bank in which internal component protection is not installed. The consequences of capacitor blasting can jeopardize other electrical equipment and even cause a fire in the capacitor room (cabinet). In order to prevent the blasting accident of the capacitor, in addition to the requirement to strengthen the patrol inspection in operation, the most important time is to install the protection device of the internal components of the capacitor, so that the capacitor is cut off from the power grid in time before the explosion accident occurs.