Leakage Current Sensor Using Self-Powered Radio Transmission

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Solution Overview

Problem

Existing devices for measuring leakage currents in high- and medium-voltage systems are often unsuitable and expensive, requiring complex installation at earth potential, and are not cost-effective or reliable for monitoring leakage currents caused by moisture and contamination on insulators.

Innovation Solution

A compact, cost-effective device with first and second electrodes connected to an energy storage device and a radio module that charges and sends a radio signal when the energy storage voltage reaches a predetermined threshold, allowing for the measurement of leakage currents without additional energy supply, using RFID technology and a discharge resistor to adjust sensitivity and prevent false triggering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional current measuring devices are used to measure leakage currents, then measurement capability is achieved, but device size becomes too large and installation cost increases

Engineering Contradiction:
Improveleakage current measurement capabilityVSAvoiddevice size and installation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The measuring device uses the leakage current itself as the power source for the radio module, eliminating the need for separate power supply circuits, batteries, or external power connections. The energy storage device accumulates energy from the leakage current to power the radio module for transmitting measurement data.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts only the essential measurement and transmission functions from conventional complex measuring devices, implementing a minimalistic design with electrodes, energy storage device, and radio module that can be easily attached to insulators without complex installation.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If conventional measuring devices are placed at ground potential, then power supply requirements are simplified, but long-term placement and monitoring capability are limited

Engineering Contradiction:
Improvepower supply requirementVSAvoidlong-term monitoring capability
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The device autonomously harvests energy from the leakage current flowing through the insulator to charge the energy storage device, which in turn powers the radio module for transmitting measurement data. This self-powered operation enables long-term monitoring without external power supply or ground potential connection.

Inventive Principle:
Principle #25Self-service

3Productivity

If the energy storage voltage threshold is set low, then radio signal transmission frequency increases, but false triggering and reliability decrease

Engineering Contradiction:
Improveradio signal transmission frequencyVSAvoidfalse triggering resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The device includes a logic unit that monitors the energy storage voltage and controls the radio module activation based on the voltage threshold condition, enabling intelligent decision-making about when to transmit data while preventing false triggering from transient voltage fluctuations.

Inventive Principle:
Principle #23Feedback

4Use of energy by moving object

If additional power supply and complex isolation systems are added, then energy availability is improved, but device complexity and cost increase

Engineering Contradiction:
Improveenergy availabilityVSAvoidpower supply and isolation system complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The measuring device harvests energy directly from the leakage current flowing through the insulator using an energy storage device (capacitor), eliminating the need for external power supplies, batteries, or complex isolation systems. The leaked energy that would otherwise be wasted is converted into useful power for the radio module.

Inventive Principle:
Principle #25Self-service

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 device provides reliable and cost-effective measurement of leakage currents, allowing for monitoring of stress on insulators and detection of voltage issues, without the need for complex energy supply or additional isolation, and can be easily attached to components at various potentials.

Implementation Method 1

an energy storage device connected to the electrodes in such a way that it can be charged by means of the leakage current

Methodology Applied
Scientific EffectEnergy storage: Capacitance

Implementation Method 2

a radio module connected to the energy storage device and configured to transmit a radio signal when the energy storage voltage reaches or exceeds a predetermined voltage threshold

Methodology Applied
Scientific EffectRadio signal transmission: Electromagnetic Induction

Data Source

PatentEP3867651B1Measuring device, electrical system having a measuring device and method for measuring a leakage current
Publication Date: 2024.02.21 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP3867651B1 patent drawingFigure 1~2
  • EP3867651B1 patent drawingFigure 3~4
  • EP3867651B1 patent drawingFigure 5

AI summary

The invention relates to a device (20) for measuring a leakage current. The invention is characterized in that the device comprises a first and a second electrode (E1, E2) to be placed in a leakage current path, an energy store (C), which is connected to the electrodes in such a way that the energy store can be charged by means of the leakage current, and a radio module (22), which is connected to the energy store and is configured to transmit a radio signal when an energy store voltage on the energy store reaches or exceeds a predetermined voltage threshold value. The invention further relates to an electrical system (1) having the device (20) according to the invention and to a method for measuring a leakage current.