A self-healing capacitor element with linear temperature additional protection

Abstract

The invention provides a self-healing capacitor element with linear temperature supplementary protection. The self-healing capacitor element comprises a shell, wherein the shell is internally provided with a cylinder in a closed manner, the cylinder is formed by wrapping at least two layers of metallized films on a hollow pipe, electrodes are lead out from two ends of the cylinder, the hollow pipe is internally provided with a linear temperature-sensing electric wire which is lead out from the hollow pipe and is connected with an external detection circuit, and the detection circuit is connected with an actuating mechanism so as to disconnect or isolate a capacitor. When the internal temperature of the capacitor element rises to an operating value of the temperature-sensing electric wire due to a fault, the temperature-sensing electric wire is shorted and unrecoverable, an adjunct circuit additionally arranged at the outside detects the shorted condition of the temperature-sensing electric wire and triggers an automatic protection device, for example, a contactor of the capacitor is triggered to be opened so as to isolate the capacitor before first or burst.

Description

technical field [0001] The invention relates to the field of self-healing power capacitor manufacturing, in particular to a self-healing capacitor element with linear temperature additional protection. Background technique [0002] The manufacture of the self-healing capacitor is a cylinder formed by winding a metallized film, and metal particles are attached to both ends to form a pole plate. When a capacitor fails, it is possible to isolate the capacitor from the grid or the operating system, and the internal fault of the capacitor is generally self-healing. Self-healing means that when the insulating film breaks down, a short-circuit current is generated between the metal layers. The heat generated by this large current will evaporate the metal coating around the breakdown point, thus isolating the original short-circuit fault point and restoring the insulation performance. If the breakdown continues to extend or self-heals in multiple places, the plastic film begins to ...

AI Technical Summary

Problems solved by technology

If the breakdown continues to extend or self-heals in multiple places, the plastic film begins to heat up, the gasification of the metal layer increases the internal pressure of the component, and the electrical short circuit also heats up the capacitor, which in turn increases the overall temperature and the internal pressure of the capacitor. As a result, the insulation performance of the plastic film will be reduced, and the damage cycle will be accelerated. Finally, the high temperature will melt the insulating plastic film and the insulating medium will fail. If the capacitor is not isolated at this time, the capacitor may catch fire or burst and burn the capacitor.

When the self-healing capacitor works stably, its working temperature and working current are constant values. When it fails, due to excessive self-healing, the internal temperature of the capacitor element will increase, the internal pressure will increase, and it may also be damaged. Generate a large short-circuit current

Most self-healing capacitors use an integral pressure protection device. The disadvantage is that the failure of an internal capacitor element may cause the failure of the entire capacitor, which has a great impact on the power system.

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