Current Transformer Peak Detection for Integrated Switchgear Sensing

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Solution Overview

Problem

Existing solutions for monitoring switchgear temperature and current require separate current sensors, increasing cost and complexity, and do not effectively integrate real-time current monitoring with temperature sensing.

Innovation Solution

An integrated sensing module that uses a current transformer to generate a secondary current signal, detecting its peak value during saturation to measure primary current, allowing simultaneous temperature and current sensing without additional sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate current sensor is added to measure real-time current while monitoring temperature, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvecurrent measurement precisionVSAvoidsensing module complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the current measurement function and temperature monitoring function into a single integrated sensing module. The current transformer not only provides power to the sensing module but also serves as the current sensing element, eliminating the need for separate current sensors and reducing overall device complexity while maintaining measurement precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The current transformer is designed to perform multiple functions: it generates power for the sensing module and simultaneously measures the real-time current. This multi-functional design reduces the number of components needed and simplifies the sensing module structure while achieving both power supply and measurement objectives.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If additional current sensor is mounted into switchgear to measure real-time current, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvecurrent measurement precisionVSAvoidassembly ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

By combining the current sensing function with the existing temperature monitoring module, the patent eliminates the need for separate current sensor installation. The integrated sensing module can be installed as a single unit, significantly simplifying the assembly process and improving ease of operation while maintaining accurate current measurement capabilities.

Inventive Principle:
Principle #5Merging (Combining)

3Use of energy by moving object

If current transformer operates in saturation state to generate power, then use of energy is improved, but measurement precision deteriorates

Engineering Contradiction:
Improvepower generation efficiencyVSAvoidcurrent measurement precision
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent detects the peak value of the secondary current signal during the saturation state of the current transformer. By capturing the peak value at the moment of saturation, the system can accurately determine the primary current before the transformer fully enters saturation, thus maintaining measurement precision while utilizing the energy available during saturation for power generation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the secondary current signal to detect the peak value during saturation. This feedback mechanism allows the system to continuously monitor and adjust measurements based on the saturation state, ensuring accurate current measurement while maximizing energy utilization for power generation.

Inventive Principle:
Principle #23Feedback

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

Simplifies the structure and assembly of the sensing module by integrating primary current and temperature sensing, enhancing monitoring reliability and ease of use by dynamically adjusting warning limits based on real-time current.

Implementation Method 1

a current transformer configured to receive a primary current from a bus bar to generate a secondary current

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

detect a peak value of the secondary current signal during a saturation of the current transformer

Methodology Applied
Scientific EffectMagnetic saturation: Magnetic Saturation

Data Source

PatentEP3997465B1Sensing apparatus and sensing method
Publication Date: 2025.09.03 ABB (SCHWEIZ) AG
  • EP3997465B1 patent drawingFigure 1A~1B
  • EP3997465B1 patent drawingFigure 2
  • EP3997465B1 patent drawingFigure 3~4

AI summary

A sensing apparatus and a sensing method are provided. The sensing apparatus (100) comprises a current sensing circuit (104) configured to sense a secondary current generated from a current transformer (102) to generate a secondary current signal representing the secondary current, the current transformer (102) being configured to receive a primary current from a bus bar to generate the secondary current for supplying a power to the sensing apparatus (100); and a controller (106) configured to detect a peak value of the secondary current signal during a saturation of the current transformer (102), and configured to measure the primary current based on the peak value of the secondary current signal by a look-up table.