Abnormal phenomena and processing methods of capacitors in operation - News - Global IC Trade Starts Here Free Products

Photocoupler

Abnormalities and accidents are:

(1) Leakage oil. Damage to the flange or weld during installation and overhaul, or defects in manufacturing and corrosion of the outer casing during long-term operation may cause leakage of oil. Leakage of oil may reduce the impregnating agent, making the component susceptible to moisture and causing local breakdown.

(2) The casing expands. Capacitor internal faults (overvoltage, discharge to the casing, breakdown of components, etc.) can cause the medium to decompose the gas, causing the internal pressure of the casing to increase and causing the casing to expand. In this case, measures or power outages should be taken immediately to avoid accidents.

(3) Capacitor explosion. In a high-voltage capacitor bank without internal component protection, when a capacitor breaks between poles or poles, the capacitor bank in parallel with it will discharge it. When the discharge energy is not available, the capacitor may explode. Other equipment may cause malfunction or even fire after the explosion. In addition to strengthening the patrol inspection during operation, it is better to install the capacitor internal component protection device.

(4) The temperature rise is too high. Overvoltage, overload, dielectric aging (increased dielectric loss), and poor capacitor cooling conditions of the capacitor bank may cause the temperature rise to be too high, which may affect the service life or even breakdown. The ambient temperature must be closely monitored and controlled during operation, or cooling measures should be taken to control the temperature within the allowable range. If it cannot be controlled, it should be powered off.

(5) The surface of the porcelain insulation flashes. The cause of flashover on the surface of porcelain insulation is: surface contamination, environmental pollution, bad weather (such as rain, snow) and overvoltage will cause surface flashover to cause capacitor damage or trip. Protective measures are taken in dirty areas.

(6) Abnormal sound. An abnormal sound (“Zizi” or “咕咕” sound) during operation indicates that there is a partial discharge phenomenon inside or outside. In this case, stop the operation immediately and look for the faulty capacitor.

In handling capacitor accidents, operators should pay attention to the following:

(1) Power outage. The capacitor breaker and disconnector must be removed or the fuse removed.

(2) Discharge. Although the capacitor bank has self-discharged internally, there is still residual charge, which must be manually discharged. The grounding terminal must be grounded first. Then discharge several times until there is no spark and sound.

(3) Protective equipment (such as insulated gloves) must be used during operation, and the short-circuit line should be used to connect the discharge between the two poles (because there may still be residual charge between the poles).