Cable Terminal Voltage Sensor Shielding for Accurate HV Measurement

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Solution Overview

Problem

Existing voltage sensors in medium and high voltage equipment are susceptible to parasitic capacitances and external influences, leading to inaccurate voltage measurements due to their susceptibility to electrical fields and environmental conditions such as rain or humidity, which can cause errors in voltage level measurements and increase partial discharge levels.

Innovation Solution

The integration of shielding electrodes with a resistive voltage divider in a cable connection terminal, where the shielding electrodes are conically shaped with a larger opening diameter at the low voltage side and a smaller opening diameter at the high voltage side, providing integral shielding within the terminal housing to minimize external field effects and enhance dielectric withstand.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If voltage sensors are placed in medium or high voltage equipment, then voltage measurement function is achieved, but measurement accuracy deteriorates due to parasitic capacitances and external electrical field influences

Engineering Contradiction:
Improvevoltage measurement accuracyVSAvoidparasitic capacitances and external field influences
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces shielding electrodes as intermediary elements between the voltage sensor and the external electrical field environment. These shielding electrodes act as a mediator that blocks or reduces the harmful influence of external electrical fields and parasitic capacitances on the voltage measurement, thereby improving measurement accuracy without compromising the sensor's functionality in high voltage equipment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If shielding electrodes are added to reduce external field influences, then measurement accuracy improves, but device complexity increases

Engineering Contradiction:
Improvevoltage measurement accuracyVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the shielding electrodes with the existing terminal housing structure, integrating the shielding function into the housing itself rather than adding separate shielding components. This combining approach reduces overall device complexity while still providing the necessary electrical field shielding to improve voltage measurement accuracy.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If integral shielding is implemented in terminal housing, then susceptibility to external fields reduces, but manufacturing complexity increases

Engineering Contradiction:
Improvesusceptibility to external fieldsVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent employs conical shielding electrodes with specific geometric parameters (cone angle, height, positioning) that are optimized to provide effective electrical field shielding. By carefully controlling these geometric parameters, the design achieves reduced susceptibility to external fields while maintaining compatibility with standard manufacturing processes for terminal housings.

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

This configuration significantly improves the accuracy of voltage measurements by reducing parasitic capacitances and phase errors, allowing for more reliable protection and measurement under various operating conditions, even in challenging environmental conditions.

Implementation Method 1

the voltage sensor has a resistive voltage divider

Methodology Applied
Scientific EffectResistive voltage division: Electrical Resistance

Implementation Method 2

shielding electrodes are conically shaped with a larger opening diameter at the low voltage side and a smaller opening diameter at the high voltage side, providing integral shielding within the terminal housing to minimize external field effects

Methodology Applied
Scientific EffectElectrical shielding: Electrical Resistance

Data Source

PatentEP2696206B1Medium or high voltage arrangement with cable connection terminal
Publication Date: 2023.11.01 ABB (SCHWEIZ) AG
  • EP2696206B1 patent drawingFigure 1
  • EP2696206B1 patent drawingFigure 2
  • EP2696206B1 patent drawingFigure 3

AI summary

The invention relates to a medium or high voltage arrangement with cable connection terminal and voltage sensor, wherein the voltage sensor has a resistive voltage divider (3, 5) and shielding electrodes (10, 11). In order to enhance the accuracy of voltage measurement at medium or high voltage pole parts, the voltage sensor is applied as a voltage sensor module, which is integrated in the a further cable connection terminal, and that the shielding electrodes are integral part of the voltage sensor module or integral part of an insulating housing part of the terminal.