Vcb Outdoor High Voltage Vacuum Circuit Breaker In Substation 40.5KV

Vacuum Breakdown:

The major insulating media are atmospheric air, oil, paper and porcelain. These can withstand appreciable voltage but they are very small as compared to the withstand voltage of a gap in vacuum.

In the vacuum arc the neutral atoms, ions and electrons do not come from the medium in which the arc is drawn but they are obtained from the electrodes themselves by evaporating its surface material. Because of the large mean free path for the electrons, the dielectric strength of the vacuum is a thousand times more than when the gas is employed for arc interruption.

In the vacuum of range from 10–4 to 10–6 torr, the breakdown strength is independent of the gas density, but varies with gap length only. The actual value of breakdown voltage for a given gap depends upon the condition of electrode surfaces. Highly polished and thoroughly degassed electrodes have shown particularly high breakdown voltages. Contacts get roughened after use and thus the dielectric strength decreases which can be improved by applying successive high voltage impulse sparks.

This does not alter the arc roughened surfaces but removes the loosely adhering metal particles from the electrodes deposited there by the vapour blast during arcing. It has been found that for a vacuum of 10–6 torr some of the metals like silver, bismuth, copper etc. attain their maximum breakdown strength when the gap is slightly less than 3 mm. This property permits the use of short gaps in vacuum switches which results in simplifying the operating mechanism and increasing the speed of operation over conventional switches.

INTRODUCTION

Zhejiang Xinkou Power Equipment Co.,Ltd, is a high-tech enterprise specializing in developping, design, manufacture, sales, import and export of low voltage and high voltage electrical products.

Company main products: indoor and outdoor high voltage vacuum circuit breaker, load break switches, disconnecting switches, drop out fuse cutour, lightning arrester, etc. All products comply with the requirements of GB, IEC, ANSI and other international standard.

SERVICE

We have a very professional sales team which can offer you the best service and answer you very professional questions, so you can feel very comfortable before you buy machine from us. As is known to all of us, after-sale service is the most important to all industries. Our company has been trying our best to build a very professional and high-caliber after-sale service team which can solve all problems efficiently in the future.