Non-destructive Dielectric Strength Testing of Liquid Insulators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for testing the dielectric strength of liquids, such as transformer oil, often lead to degradation or damage during the testing process, making them destructive and unsuitable for continued use.
Innovation Solution
A method and apparatus that gradually increase the electric field strength until charge transport commences, then limit and decrease it to prevent breakthrough, using short voltage pulses and a capacitor system to avoid damage, allowing for non-destructive testing and inline monitoring of dielectric strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage is increased from initial value until breakdown occurs to test dielectric strength, then measurement capability is achieved, but the liquid is degraded or damaged making it unusable
Solution Approach 1:
The patent applies periodic voltage pulses instead of continuous voltage increase. The testing generator delivers a series of voltage pulses with increasing amplitude, where each pulse duration is limited to prevent breakdown. This periodic action allows repeated measurements at different voltage levels without causing cumulative damage to the liquid, resolving the contradiction between achieving measurement precision and avoiding liquid degradation.
Solution Approach 2:
The patent uses partial action by applying voltage pulses that reach below the breakdown threshold. Instead of increasing voltage until complete breakdown occurs (excessive action), the method applies pulses that stop just before breakdown, using the charge transport phenomenon at sub-breakdown levels to assess dielectric strength. This partial action approach provides sufficient measurement information while preventing the harmful excessive voltage that would damage the liquid.
2Object-affected harmful factors
If voltage-dependent internal resistance is used to limit charge transport, then liquid protection is improved, but device complexity increases
Solution Approach 1:
The patent implements voltage-dependent internal resistance by changing the resistance parameter dynamically with voltage level. The testing generator's internal resistance increases as voltage increases, automatically limiting the charge transport at higher voltages. This parameter change approach provides liquid protection through a single integrated component rather than adding complex external control systems, thus improving liquid protection while minimizing device complexity.
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
Enables the non-destructive testing of dielectric strength, preventing damage to the liquid and allowing for continuous use, while detecting aging effects and maintaining the liquid's insulating properties.
Implementation Method 1
a capacitor (38) connected to the electrodes (16, 18). The controller (22) is configured to increase a voltage (U) applied to the electrodes (16, 18) until the current sensor (20) detects a charge transport (I>0) between the electrodes (16, 18)
Implementation Method 2
increasing a field strength of an electric field until a charge transport through the liquid commences
Implementation Method 3
a current sensor (20) configured to monitor a charge transport between the electrodes (16, 18). The controller (22) is configured to increase a voltage (U) applied to the electrodes (16, 18) until the current sensor (20) detects a charge transport (I>0) between the electrodes (16, 18)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a process for non-destructive testing of a dielectric strength of a liquid comprising increasing a field strength of an electric field until a charge transport through the liquid commences and limiting the charge transport through the liquid caused by the electric field by decreasing the field strength as the charge transport through the liquid commences.