Insulating Oil Composition for Capacitors
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Solution Overview
Problem
Conventional electrically insulating oils used in capacitors swell polypropylene films at high temperatures, leading to dielectric breakdown, and existing solutions fail to maintain high dielectric breakdown voltage over a wide temperature range, especially in outdoor industrial equipment exposed to temperatures above 50°C.
Innovation Solution
An electrically insulating oil composition comprising 1,1-diphenylethane and benzyltoluene, with a para isomer proportion of 45% or more in benzyltoluene, combined with 0.01-1.0% epoxy compound and low chlorine content, to balance low-temperature performance and suppress swelling, maintaining high dielectric breakdown voltage from -50°C to 65°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrically insulating oils (benzyltoluene-based) are used to achieve high dielectric breakdown voltage, then the dielectric breakdown voltage is improved, but the polypropylene film swells at high temperatures causing dielectric breakdown
Solution Approach 1:
The patent changes the chemical composition parameters of the insulating oil by specifying precise proportions of o-xylene (5-20 mass%), m-xylene (20-40 mass%), p-xylene (30-60 mass%), and dibenzyltoluene (5-20 mass%). This parameter optimization reduces the oil's swelling effect on polypropylene films while maintaining high dielectric breakdown voltage, resolving the contradiction between insulation performance and film stability at high temperatures.
Solution Approach 2:
The patent creates a composite insulating oil system by combining multiple aromatic hydrocarbons (xylene isomers and dibenzyltoluene) in specific ratios. This composite composition achieves a balance between high dielectric breakdown voltage and reduced swelling effect on polypropylene films, preventing dielectric breakdown at elevated temperatures.
2Reliability
If polypropylene film is used as dielectric to improve capacitor performance, then the dielectric constant is improved, but the film extends defects and increases mechanical stress at high temperatures
Solution Approach 1:
The patent optimizes the insulating oil composition parameters to minimize swelling and reduce mechanical stress on the polypropylene film at high temperatures. By controlling the oil's chemical properties through specific component ratios, the film's mechanical integrity is preserved while maintaining high dielectric constant performance.
3Reliability
If electrically insulating oils with high aromatic content are used to achieve high dielectric breakdown voltage, then the withstand voltage characteristics are improved, but the oxidation stability deteriorates
Solution Approach 1:
The patent formulates a composite insulating oil using aromatic hydrocarbons (xylene isomers and dibenzyltoluene) that inherently provide both high dielectric breakdown voltage and good oxidation stability. The specific composition ratio creates a synergistic effect where the aromatic compounds deliver excellent withstand voltage characteristics while maintaining compositional stability against oxidation.
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 solution effectively maintains high dielectric breakdown voltage across a wide temperature range, reducing the likelihood of dielectric breakdown even at elevated temperatures for extended periods, thus enhancing the durability and performance of capacitors.
Implementation Method 1
Benzyltoluene has a high ratio of aromatic carbon in the molecule, has high hydrogen gas absorbency
Implementation Method 2
compounds constituting it are generally aromatic compounds, and therefore the insulating oil is a factor that swells the polypropylene film
Data Source
AI summary
It is an object to provide an electrically insulating oil composition that can maintain dielectric breakdown voltage high in a wide temperature range of −50° C. to 65° C., and can suppress a decrease in dielectric breakdown voltage even in the case of use at high temperature for a long time, and there is provided an electrically insulating oil composition comprising 1,1-diphenylethane and benzyltoluene, wherein the proportion of a para isomer in the benzyltoluene is 45% by mass or more based on a total amount of the benzyltoluene.