Siloxane Dielectric Voltage Divider for Stable Capacitance

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Solution Overview

Problem

Conventional voltage dividers, especially ohmic-capacitive types, face issues with capacitance drift due to moisture absorption and temperature fluctuations, leading to inaccurate voltage measurements over long periods, particularly in humid and temperature-varying environments.

Innovation Solution

A voltage dividing device utilizing a siloxane-based polymer dielectric with diffusion-inhibiting properties, which maintains a constant relative dielectric constant across various temperature and humidity conditions, ensuring stable capacitance and improved frequency transmission behavior, combined with a mechanically stable epoxy-based jacket for protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional dielectric materials (epoxy resin) are used in the voltage dividing device, then the device structure is simple and easy to manufacture, but the capacitance drifts over time due to moisture absorption and temperature fluctuations

Engineering Contradiction:
Improvecapacitance stabilityVSAvoiddielectric material selection
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the fundamental parameter of the dielectric material from conventional epoxy resin to siloxane-based polymer. This material substitution provides diffusion-inhibiting properties that prevent moisture penetration, thereby maintaining constant capacitance over long periods despite temperature and humidity variations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure combining siloxane-based polymer dielectric with specific capacitor element configurations. The siloxane polymer serves as the base material with embedded capacitor elements, creating a composite system that leverages the moisture-resistant properties of siloxane while maintaining the electrical functionality of the capacitor arrangement.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the capacitor arrangement is exposed to atmospheric humidity without protection, then the device structure remains simple, but water vapor diffusion into the dielectric causes significant capacitance drift

Engineering Contradiction:
Improvecapacitance constancyVSAvoidmoisture penetration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The siloxane-based polymer creates an inert environment within the voltage dividing device by preventing water vapor diffusion. The material's molecular structure acts as a barrier that blocks moisture penetration, effectively creating a protected internal environment that maintains stable electrical properties despite external humidity conditions.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent addresses the harmful effect of atmospheric humidity by selecting a dielectric material that naturally resists moisture absorption. The potential harm from environmental exposure is converted into a benefit where the siloxane polymer's inherent diffusion-inhibiting properties protect the capacitor elements, turning the challenge of humidity into an opportunity for enhanced reliability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Duration of action of stationary object

If epoxy resin is used as the dielectric material, then the manufacturing process is straightforward, but the dielectric absorbs moisture leading to changed capacitance over the lifetime of the voltage divider

Engineering Contradiction:
Improveoperational lifetimeVSAvoidvoltage measurement accuracy
Core Design Contradiction:
Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

The patent changes the dielectric material parameter from epoxy resin to siloxane-based polymer, which fundamentally alters the moisture absorption characteristics. This material substitution ensures that the capacitance remains constant over the operational lifetime, thereby maintaining voltage measurement accuracy throughout the device's service life.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

By using siloxane-based polymer, the patent eliminates the need for frequent calibration or replacement that would be required with moisture-absorbing materials like epoxy resin. The long-term stability provided by siloxane reduces the operational lifecycle costs and maintenance requirements, effectively creating a more durable solution.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Measurement precision

If the dielectric constant changes with temperature and humidity, then the device can adapt to environmental conditions, but the capacitance becomes unstable affecting measurement accuracy

Engineering Contradiction:
Improvevoltage measurement accuracyVSAvoiddielectric constant stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent selects a dielectric material (siloxane-based polymer) whose physical and chemical parameters remain stable across varying temperature and humidity conditions. The material's low dielectric loss and resistance to moisture absorption ensure that the dielectric constant remains constant, thereby maintaining accurate voltage measurements despite environmental fluctuations.

Inventive Principle:
Principle #35Parameter changes

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 provides a voltage dividing device with enhanced measurement accuracy and reliability by minimizing capacitance drift and preventing voltage flashovers, ensuring precise voltage measurement over decades, even in harsh environmental conditions.

Implementation Method 1

Siloxane-based polymers, especially solid siloxane polymers, also known as silicone polymers, exhibit diffusion-inhibiting properties. Such polymers as dielectrics are largely insensitive to water vapor diffusion

Methodology Applied
Scientific EffectDiffusion-inhibiting properties: Diffusion Barrier

Implementation Method 2

A major problem with such resistive-capacitive voltage dividers is that the capacitor's capacitance must remain as constant as possible over long periods of time

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

resistive voltage dividers operate with one or more electrical resistors

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP3821259B1Voltage-dividing device having a siloxane dielectric
Publication Date: 2024.01.03 GREENWOOD POWER GMBH
  • EP3821259B1 patent drawingFigure 1~2

AI summary

The invention relates to a voltage-dividing device (1), comprising a core region (2) having a capacitor assembly arranged in the core region (2) and an electrical resistor (3) arranged in the core region (2), a first electrode (4) of the capacitor assembly having a coupling part (5), a voltage-carrying element being able to be electrically connected to the voltage-dividing device (1) via the coupling part (5), and a second electrode (6) of the capacitor assembly having a grounding part (7), a ground being able to be electrically connected to the voltage-dividing device (1) via the grounding part (7), the first electrode (4) and the second electrode (6) being electrically connected by means of the electrical resistor (3), and the core region (2) comprising a dielectric, which comprises or consists of a siloxane-based polymer. The invention further relates to the arrangement of a voltage-dividing device on a connection part of a switchgear assembly of an electrical grid and to a method for producing the core region.