Vacuum Interrupter Screen Seal for Higher Dielectric Strength
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Solution Overview
Problem
Existing medium-or high-voltage vacuum interrupters face challenges in withstanding higher voltages without increasing size, particularly due to dielectric stresses generated by the retaining flange of the protective screen.
Innovation Solution
The introduction of a semiconductor material seal surrounding the insulator, which is in electrical contact with the screen, eliminates the triple interface where dielectric stresses are highest, thereby increasing the dielectric strength of the vacuum interrupter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the screen is secured to the insulating jacket by clamping a retaining flange between two parts of the insulating jacket, then the screen is firmly fixed to protect contacts, but dielectric stresses are generated that reduce the voltage withstanding capability
Solution Approach 1:
A semiconductor ring is introduced as an intermediary component between the screen retaining flange and the insulating jacket. This ring acts as a mediator that provides electrical contact between the screen and the insulating jacket while eliminating the formation of a triple interface (insulator-screen-gas), thereby reducing dielectric stresses and improving voltage withstanding capability without compromising screen fixation reliability.
2Strength
If the vacuum interrupter size is increased to withstand higher voltages, then the dielectric strength is improved, but the device becomes larger and more bulky
Solution Approach 1:
The electrical parameters at the interface between insulating components are modified by introducing the semiconductor ring. This changes the electrical potential distribution and eliminates the triple interface configuration, thereby enhancing dielectric strength without requiring an increase in the physical dimensions of the interrupter.
3Device complexity
If a triple interface (insulator-screen-gas) is formed, then the structural configuration is simple, but dielectric stresses are concentrated reducing voltage withstanding capability
Solution Approach 1:
The semiconductor ring serves as an intermediary that eliminates the triple interface (insulator-screen-gas) by providing a controlled electrical connection between the screen and insulating jacket. This additional component prevents the concentration of dielectric stresses at a single triple interface point, thereby improving voltage withstanding capability.
Solution Approach 2:
The semiconductor ring creates equipotential regions by establishing controlled electrical contacts between components at different potentials. This reduces abrupt potential changes at interfaces and diminishes dielectric stress concentrations, allowing the system to withstand higher voltages without increasing size.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the dielectric strength of the vacuum interrupter, allowing it to handle higher voltages without size increase, or enabling smaller size for the same performance.
Implementation Method 1
a seal made of a semiconductor material surrounding the insulator, the seal being in electrical contact with the screen
Implementation Method 2
The semiconductor nature of the material of the seal makes it possible to contrive for the seal to be at the electrical potential of the screen in its entirety, thus allowing the seal to act as an electrical deflector weakening the electrical field in this area
Implementation Method 3
The contacts are placed in an insulating jacket forming a fluid-tight enclosure placed under vacuum
Implementation Method 4
The screen prevents any metal particles that become detached from the contacts during creation of an electrical arc from settling on the internal surface of the insulating jacket
Data Source
AI summary
A medium-or high-voltage vacuum interrupter, including: an insulator forming a receiving enclosure, the insulator being formed of two coaxial elements; two electrical contacts arranged inside the insulator and configured to be moved relative to one another between a closed position and an open position; and a screen radially surrounding the electrical contacts and configured to collect the metal particles emitted when an electric arc passes between the electrical contacts so as to protect the insulator from the metal particles emitted, wherein the screen includes a fixing flange clamped between the two elements of the insulator. The vacuum interrupter further includes a seal made of a semiconductor material surrounding the insulator, the seal being in electrical contact with the screen.