Two Measurements Of Vacuum Level In Vacuum Interrupters And Complementary Analysis

Vacuum switches have been widely used in electric power system and other industrial fields. Vaccum interrupters are important parts of vaccum switches.The vacuum degree in vacuum interrupters will have the direct effect upon the performance of vacuum switches. Internal pressure estimation of vacuum interrupters is an important approach to ensure the operating quality.There are many methods testing and detecting the vacuum degree,and they are divided into the offline detection and online detection.The methods are different with the different situations.Every method is applied to specific situation and need differential conditions.The dissertation investigated two methods of impulse magnet controlled discharge and shielding case potential detection.After analysing and comparing the two methods, design complementarity.Impulse magnet controlled discharge is a method based on the motion theory of charged particles in the orthogonal electromagnetic field and the structure of vaccum interrupters. The vaccum degree in the vaccum interrupters can be obtained according to the relationship between the detected discharge current and vaccum degree.C-type electromagnetic coil has been designed to produce transverse magnetic field.The magnetic induction result in stable discharge current in method of impulse magnet controlled discharge by ANSYS analysis and calculation. The range of impulse magnet controlled discharge is 10-1～10-4Pa.Shielding case potential detection is a method based on the structure of interrupters and the principle of partial discharge. The dissertation investigated the change mechanism of the potential on shielding when the vacuum degree descended, analyse the discharge emergence in the interrupters when the vacuum degree descended to a certain value.A equivalent circuit model of the potential changing on shielding also had been given, and the relationships between alternating potential, direct potential on shielding and the vacuum degree are founded separately.Apply complementary thinkings to vacuum detections, combine and contrast the characteristics of the two methods impulse magnet controlled discharge and shielding case potential detection, and design the complementary of two methods.