Switchgear Leakage Current Monitoring via Surface Electrodes

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Solution Overview

Problem

High voltage and medium voltage switchgear systems face challenges in monitoring leakage currents due to the complexity of differential measurements, high installation costs, and the inability to precisely localize failures, leading to a lack of effective leakage current monitoring in these systems.

Innovation Solution

A switchgear leakage current monitoring system comprising sensors with conducting layers or electrodes attached to insulating components, which acquire leakage current signals and transmit data to a monitoring unit, allowing for continuous monitoring and early warning of degradation, using either wired or wireless connections and powered by the measured leakage current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If differential leakage current sensors enclosing all conductors are used, then leakage current monitoring is achieved, but device size and cost increase significantly

Engineering Contradiction:
Improveleakage current monitoring capabilityVSAvoidsensor size and cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the monitoring system into multiple individual sensors, each attached to a specific insulating component rather than using one large differential sensor. This segmentation allows monitoring of leakage currents at the component level while avoiding the need for large enclosing sensors around all conductors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces conducting layers or electrodes as intermediaries attached to insulating components. These intermediaries enable leakage current detection without requiring direct contact with high-voltage conductors or large enclosing sensors, thus reducing device complexity while maintaining monitoring capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If accurate current sensors are used for individual phase current measurement, then leakage current detection precision is improved, but cost and device complexity increase

Engineering Contradiction:
Improveleakage current detection accuracyVSAvoidsensor cost and accuracy requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The conducting layers or electrodes serve as intermediaries that collect leakage currents from insulating components. These intermediaries enable measurement with simpler, less expensive sensors because they directly capture the leakage current at the source rather than requiring precise measurement of individual phase currents and complex differential calculations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the leakage current measurement function from the complex differential measurement of phase currents and implements it separately at each insulating component using simple conducting layers and dedicated sensors. This extraction simplifies the measurement requirement while improving precision for leakage current specifically.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If direct measurement of leakage currents in the grounding system is attempted, then comprehensive leakage detection is achieved, but installation feasibility decreases due to current spreading and small current densities

Engineering Contradiction:
Improveleakage current detection coverageVSAvoidinstallation feasibility
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by attaching conducting layers or electrodes to insulating components before the leakage current spreads into the grounding system. This allows capture of the leakage current at its origin where current density is higher, making measurement feasible with simple sensors and avoiding the problems of current spreading and small current densities in the grounding system.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The conducting layers or electrodes on insulating components serve as intermediaries that intercept leakage currents before they enter the grounding system. This intermediary approach enables practical measurement without requiring access to or encirclement of the grounding system, thus maintaining installation feasibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables continuous monitoring of leakage currents on insulating components, preventing catastrophic failures by providing early warnings and facilitating predictive maintenance, reducing installation costs and complexity through efficient data transmission and power sourcing.

Implementation Method 1

Each sensor (14, 16, 17) comprises at least one conducting layer or electrode (14) attached to or integrated on at least one surface of at least one insulating component (11)

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

A measurement unit (44) is configured to provide one or more measurement data relating to the at least one leakage current signal

Methodology Applied
Scientific EffectSignal conversion:

Data Source

PatentEP3929607B1Switchgear leakage current monitoring system for a high voltage or medium voltage switchgear
Publication Date: 2024.08.14 ABB (SCHWEIZ) AG
  • EP3929607B1 patent drawingFigure 1
  • EP3929607B1 patent drawingFigure 2~3
  • EP3929607B1 patent drawingFigure 4~5

AI summary

The present invention relates to a switchgear leakage current monitoring system (1) for a high voltage or medium voltage switchgear, comprising at least one sensor (14, 16, 17), and a leakage current monitoring unit (22). The at least one sensor comprises at least one conducting layer or electrode (14), wherein each sensor comprises a conducting layer or electrode. The at least one conducting layer or electrode is attached or integrated on at least one surface of at least one insulating component (11) of a high voltage or medium voltage switchgear. Each insulating component has a conducting layer or electrode attached or integrated on its surface. The at least one sensor is configured to acquire at least one leakage current signal. Each sensor is configured to acquire a leakage current signal on a surface of the insulating component to which its corresponding conducting layer or electrode is attached or integrated. The at least sensor has at least one data connection (24) to the leakage current monitoring unit. The leakage current monitoring unit is configured to be provided with at least one measurement data relating to the at least one leakage current signal via the at least one data connection.