Vacuum Interrupter Resistive Layers for Arc Shield Potential Control
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Solution Overview
Problem
In vacuum interrupters, when alternating-current voltage (low frequency) is applied, the electric field applied to nonlinear resistors is less than the operating electric field, leading to biased floating potential of the arc shield and potential dielectric breakdown.
Innovation Solution
A vacuum interrupter design that includes both a linear resistive layer and a nonlinear resistive layer covering the periphery of the insulation container, with a resistivity relationship of R1 > R3 > R2, allowing for controlled floating potential of the arc shield without external voltage sharing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external voltage sharing elements (capacitor or resistor) are used to control floating potential, then dielectric breakdown is prevented, but the vacuum interrupter size increases
Solution Approach 1:
The voltage sharing function is merged with the insulation container structure itself by forming resistive layers directly on the container surface. This eliminates the need for separate external voltage sharing elements like capacitors or resistors, thereby preventing size increase while maintaining dielectric breakdown protection. The insulation container simultaneously serves as both the structural insulation barrier and the voltage sharing component.
Solution Approach 2:
The resistive layers act as an intermediary between the arc shield and the external environment, providing a controlled path for charge distribution. This intermediary layer enables floating potential control without requiring large external components, as the resistive layers themselves mediate the electrical interactions and maintain proper potential distribution across the vacuum interrupter structure.
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 design enables both size reduction and improved dielectric breakdown resistance in vacuum interrupters, effectively managing floating potential and preventing dielectric breakdown during application of either AC voltage (low frequency) or lightning impulse voltage (high frequency).
Implementation Method 1
a linear resistive layer and a nonlinear resistive layer are disposed so as to cover at least a part of a periphery of the insulation container, and a magnitude relationship of each resistivity is R1>R3>R2, where a resistivity of the nonlinear resistive layer less than an operating electric field is R1, a resistivity less than or equal to an impedance when a lightning impulse is applied is R2, and a resistivity of the linear resistive layer is R3
Data Source
AI summary
A vacuum interrupter according to the present disclosure is configured such that a linear resistive layer and a nonlinear resistive layer are disposed so as to cover at least a part of a periphery of an insulation container, and a magnitude relationship of each resistivity is R1>R3>R2, where a resistivity of the nonlinear resistive layer less than an operating electric field is R1, a resistivity less than or equal to an impedance when a lightning impulse is applied is R2, and a resistivity of the linear resistive layer is R3.