Rod-Structured Voltage Divider for Stable Capacitance Measurement

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Solution Overview

Problem

Ohmic-capacitive voltage dividers face challenges with capacitance stability over long periods due to temperature fluctuations, frequency changes, and moisture absorption, leading to measurement inaccuracies and potential voltage flashovers.

Innovation Solution

A voltage dividing device with finger-shaped or rod-shaped control elements for the capacitor electrodes, arranged concentrically, embedded in a siloxane-based polymer dielectric, which reduces detachment and cavity formation, maintaining constant capacitance and dielectric strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional transducers with ferromagnetic iron core are used for voltage measurement, then voltage measurement capability is achieved, but susceptibility to interference increases

Engineering Contradiction:
Improvevoltage measurement accuracyVSAvoidinterference susceptibility
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent removes the ferromagnetic iron core from the voltage divider design, extracting the source of magnetic interference while maintaining the voltage measurement function through an air-core or non-magnetic core structure, thereby resolving the contradiction between measurement capability and interference susceptibility

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If ohmic voltage dividers with electrical resistances are used, then voltage division function is achieved, but measurement accuracy deteriorates due to stray capacitances and parasitic capacitances

Engineering Contradiction:
Improvevoltage division functionalityVSAvoidmeasurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the electrical parameters of the voltage divider by incorporating capacitive elements with specifically designed capacitance values that compensate for and counteract the effects of stray and parasitic capacitances, thereby improving measurement accuracy while maintaining the voltage division function

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the capacitance of the capacitor is increased to reduce the influence of stray capacitances, then measurement accuracy is improved, but capacitance stability over time deteriorates due to detachment and cavity formation

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidcapacitance stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent segments the capacitor structure into multiple smaller capacitor elements arranged in parallel, which collectively provide the required total capacitance while reducing the stress and detachment risk on individual elements, thereby maintaining capacitance stability over time

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs composite material structures for the capacitor electrodes and dielectric layers, combining materials with complementary properties to enhance mechanical bonding, prevent detachment, and maintain stable capacitance characteristics over long operational periods

Inventive Principle:
Principle #40Composite materials

4Volume of moving object

If capacitor elements are arranged as two concentrically arranged annular capacitor elements, then compact structure is achieved, but detachment and cavity formation increase due to dielectric shrinkage and temperature fluctuations

Engineering Contradiction:
Improvedevice compactnessVSAvoidcapacitor element bonding reliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent introduces flexible compensating structures or thin film layers between the capacitor elements and dielectric that can accommodate thermal expansion and contraction, preventing detachment while maintaining the compact concentric arrangement

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent incorporates pre-designed compensating elements or stress-absorbing structures in the capacitor assembly that anticipate and cushion against the effects of dielectric shrinkage and temperature fluctuations, preventing detachment before it occurs

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 ensures stable capacitance and increased dielectric strength over the device's lifespan, minimizing measurement inaccuracies and voltage flashovers, enabling reliable and accurate voltage measurement across varying conditions.

Implementation Method 1

embedded in a siloxane-based polymer dielectric

Methodology Applied
Scientific EffectEmbedding:

Implementation Method 2

siloxane-based polymer dielectric

Methodology Applied
Scientific EffectDielectric: Dielectric

Implementation Method 3

electrically conductive, essentially finger-shaped or rod-shaped control elements

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 4

capacitor arrangement with constant capacitance

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 5

capacitive voltage dividers...If the capacitance of the capacitor is sufficiently large, the stray capacitances and parasitic capacitances mentioned above become negligibly small and the measurement accuracy is increased

Methodology Applied
Scientific EffectCapacitive voltage division:

Data Source

PatentEP3821260B1Voltage division device having a rod-like structure
Publication Date: 2023.12.27 GREENWOOD POWER GMBH
  • EP3821260B1 patent drawingFigure 1~2

AI summary

The invention relates to a voltage division 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), wherein a live element can be electrically conductively connected to the voltage division device (1) via the coupling part (5), a second electrode (6) of the capacitor assembly having a grounding part (7), wherein a grounding can be electrically conductively connected to the voltage division device (1) via the grounding part (7), wherein the first electrode (4) and the second electrode (6) are electrically conductively connected via the electrical resistor (3), and wherein the first electrode (4) and the second electrode (6) have multiple electrically conductive, substantially finger-shaped or rod-shaped modulation elements (9). The invention also relates to the arrangement of a voltage division device on a connection part of a switching system of a power network.