Nonlinear Resistive Layer for High Voltage Electric Field Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric field control devices are damaged when used for high voltage DC applications above a certain limit, due to combined stress of nominal DC voltages and transient voltages, leading to harmful electric field concentrations and stress.
Innovation Solution
A device with a nonlinear resistive layer, an insulating layer, and a semi-conducting or conducting layer, arranged in a tapered geometry to form a triple point, which reduces resistive losses and allows for higher voltage usage without damage, by controlling electric fields and distributing stress effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resistive layer with linear current-voltage characteristic is used for field control, then the device can be manufactured with simple materials, but the device gets damaged at high DC voltages above a certain limit due to combined stress of nominal DC voltages and transient voltages
Solution Approach 1:
The patent changes the electrical parameter of the resistive layer from linear to nonlinear current-voltage characteristic. This nonlinear characteristic allows the material to dynamically adjust its resistance based on the applied voltage, providing better field control under combined DC and transient voltage stress, thereby preventing device damage at high voltages.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers with different electrical characteristics: a resistive layer with nonlinear current-voltage characteristic, an insulating layer, and a semi-conducting or conducting layer. This composite material approach allows each layer to contribute its specific properties for comprehensive field control and stress distribution, enhancing overall device reliability at high voltages.
2Strength
If the insulating layer extends to the end of the resistive layer, then the geometric field control is maximized, but harmful charges build up and cause high stresses upon rapid voltage changes
Solution Approach 1:
The patent extracts the insulating layer from extending to the full length of the resistive layer, creating a deliberate gap or reduced coverage zone. This extraction prevents the insulating layer from creating a continuous path that would trap charges during rapid voltage changes, while still maintaining sufficient geometric field control in the critical regions where the insulating layer is present.
3Adaptability or versatility
If standard field control devices are used for DC voltages above the material limit, then higher voltage applications are enabled, but the device will be damaged due to extraordinary stress from superposition of space charge resistive and capacitive field distributions
Solution Approach 1:
The patent uses a composite multi-layer structure where each material is selected for its specific electrical properties. The resistive layer with nonlinear characteristic handles the DC voltage component, while the insulating and semi-conducting/conducting layers manage the transient voltage components. This composite approach enables the device to withstand higher DC voltages without damage by distributing and controlling the combined stress from both DC and transient fields.
Solution Approach 2:
The patent changes the electrical parameters of the resistive layer to exhibit nonlinear current-voltage characteristics, which allows the material to adapt its resistance dynamically. This parameter change enables the device to handle higher voltage levels by preventing excessive current and heat generation that would otherwise occur with linear materials under combined DC and transient stress conditions.
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
The device effectively lowers electric fields in critical locations, increases breakdown strength, and reduces dissipated power, enabling safe operation at higher voltages while being cost-efficient.
Implementation Method 1
a resistive layer having a nonlinear current-voltage characteristic adapted for electrical field controlling purposes
Implementation Method 2
The electric potential between the live part and ground is distributed by means of a material with a suitable resistance forming the resistive layer
Implementation Method 3
For transients additionally the permittivity needs to be taken into account
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A device for controlling an electric field at a high voltage component comprises an inner deflector (4) to be electrically connected to a live high voltage part (1) of the high voltage component; a resistive layer (5) adapted for field controlling purposes, to be arranged along the high voltage component, and which at one position is to be electrically connected to the live high voltage part (1) of the high voltage component and at one end is adapted to be electrically connected to a grounded part of the high voltage component, the resistive layer having a nonlinear current-voltage characteristics; an insulating layer (6) arranged on the resistive layer and extending at least from the one position towards the one end of the resistive layer while ending without reaching the one end of the resistive layer; and a semi-conducting or conducting layer (7) arranged on the insulating layer and extending at least from the one position towards the one end of the resistive layer and past the end of the insulating layer, thereby defining an outer triple point at the intersection of the resistive layer, the insulating layer, and the semi-conducting or conducting layer. The resistive layer has first, second, and third adjacent sections as seen from the one position towards the one end, wherein a portion of the first section extends below the inner deflector.