Capacitive Sensor Corona Detection in Power Cabinets

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Solution Overview

Problem

Existing electrical systems in power distribution cabinets lack effective detection and prevention mechanisms for corona events, which can lead to destructive arc faults and pose hazards such as component damage and fire risks.

Innovation Solution

A corona detection system utilizing capacitive sensors and a controller to identify displacement currents and frequencies indicative of corona events, allowing for remedial power reduction in affected zones and simultaneous monitoring for arc faults through fiber optic cables and photodetectors to prevent electrical breakdown.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If corona detection and prevention mechanisms are implemented, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvecorona event detection capabilityVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electrical box is divided into multiple zones with capacitive sensors distributed throughout. Each sensor independently monitors its local zone for corona events, allowing the system to detect and isolate specific problem areas without requiring complex system-wide monitoring infrastructure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Capacitive sensors serve as intermediary devices that detect the electric field changes caused by corona events without direct physical contact with the high-voltage components. This indirect detection method simplifies the overall system architecture while maintaining high reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If power is reduced in affected zones to prevent arc faults, then safety is improved, but productivity decreases

Engineering Contradiction:
Improvearc fault preventionVSAvoidpower distribution efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system applies power management locally rather than globally. When a corona event is detected in one zone, only that specific zone experiences power reduction while other zones continue normal operation. This localized response maintains overall productivity while preventing arc faults in the affected area.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The controller continuously monitors capacitive sensor outputs and automatically adjusts power distribution in real-time based on detected corona events. This closed-loop feedback system ensures rapid response to prevent arc faults while minimizing impact on overall system productivity through selective zone isolation.

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

The system effectively detects and mitigates corona events, reducing the risk of arc faults and maintaining component functionality by isolating potentially hazardous zones, thereby ensuring safety and preventing damage.

Implementation Method 1

Capacitive sensors are located along interior walls of the electrical box, and provide an output indicative of displacement current in a region adjacent to the sensor

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Implementation Method 2

remedial actions can then be taken in response to the detected corona event to prevent more serious arc fault events

Methodology Applied
Scientific EffectPower reduction:

Implementation Method 3

simultaneous monitoring for arc faults through fiber optic cables and photodetectors

Methodology Applied
Scientific EffectOptical fiber transmission: Optical Fibre

Implementation Method 4

monitoring for arc faults through fiber optic cables and photodetectors

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP2860536B1Integrated corona fault detection
Publication Date: 2018.12.05 HAMILTON SUNDSTRAND CORP
  • EP2860536B1 patent drawingFigure 1
  • EP2860536B1 patent drawingFigure 2

AI summary

A power distribution cabinet (10) includes a housing having walls (12) that define an interior space for housing electric components. A capacitive sensor (24) is located on an interior surface of one or more of the walls (12). The capacitive sensor (24) includes a first conductive layer (28b) located proximate to the interior surface of the wall (12), a second conductive layer (28a) located distal from the interior surface of the wall (12), and a dielectric layer (30) located between the first and second conductive layers (28b,28a). First and second output terminals (32) are connected to the first and second conductive layers (28b,28a) of the capacitive sensor (24) to provide an output representative of displacement current within the power distribution cabinet (10).