Retractable Sensor System for Switchgear Maintenance

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Solution Overview

Problem

Existing switchgear cabinets face challenges in accessing and maintaining sensors within inaccessible areas, such as the bus and cable compartments, leading to extended downtime and labor costs due to the need for disassembly and the risk of arcing faults posing hazards to personnel and equipment.

Innovation Solution

A retractable sensor system that allows sensors in the bus or cable compartments to be withdrawn and accessed from a user-friendly area within the equipment compartment, utilizing a rack and slider mechanism that forms a protective conduit and can be oriented to avoid obstacles, eliminating the need for additional wire length and tool usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sensors are fixedly mounted in the bus or cable compartment to detect arcing faults, then arc fault detection capability is improved, but accessibility for inspection, maintenance or replacement deteriorates

Engineering Contradiction:
Improvearc fault detection capabilityVSAvoidaccessibility for sensor maintenance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The sensor mounting system transitions from a fixed static configuration to a dynamic retractable one. The sensor can be pulled out along a guide mechanism from its operating position in the bus/cable compartment to a accessible position at the front of the cabinet, enabling maintenance without disassembly while maintaining reliable arc detection positioning during operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A guide mechanism and retractable assembly act as intermediaries between the sensor and the cabinet structure. This intermediary system provides both a stable mounting solution for arc detection and a controlled access path for maintenance, resolving the contradiction between fixed positioning and accessibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If sensors are located in inaccessible areas of the cabinet, then monitoring coverage is improved, but maintenance time and labor cost increase

Engineering Contradiction:
Improvemonitoring coverageVSAvoidmaintenance downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The retractable mechanism allows the sensor to dynamically transition between its monitoring position in the bus/cable compartment and a maintenance position at the front access panel. This eliminates the need for cabinet disassembly and component disconnection, reducing maintenance time while preserving optimal monitoring coverage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sensor system is segmented into a retractable mounting assembly that can be independently operated. The sensor itself remains in its optimal monitoring location during operation, but the mounting mechanism can be separately actuated to provide access, separating the monitoring function from the maintenance access requirement.

Inventive Principle:
Principle #1Segmentation

3Strength

If arc-resistant compartments with venting are used, then equipment protection is improved, but personnel safety risk remains due to hot gas release

Engineering Contradiction:
Improveequipment protection capabilityVSAvoidpersonnel exposure to hot gases
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The sensor is extracted from the hazardous environment inside the arc-resistant compartment and positioned at the front access panel when not in use. The retractable mechanism allows the sensor to be removed from the area where hot gases are released during arcing events, protecting both the sensor and personnel while maintaining monitoring capability when needed.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sensor positioning is made dynamic, allowing it to be retracted to a safe position away from the arc-resistant compartment during or after arcing events. This dynamic positioning reduces exposure to hot gases and associated harmful factors while maintaining the ability to detect and respond to arc faults.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3078247B1Retracting mechanism for sensing components in a switchgear cabinet
Publication Date: 2020.09.02 SCHNEIDER ELECTRIC USA INC
  • EP3078247B1 patent drawingFigure 1
  • EP3078247B1 patent drawingFigure 2
  • EP3078247B1 patent drawingFigure 3~5

AI summary

A switchgear cabinet (100) includes an equipment compartment (102), a bus compartment (104) and a cable compartment (106). The cabinet can employ a sensor(s) (190) to monitor conditions, such as arcing, in the bus or cable compartment. The cabinet also includes a retractable sensor system (150), which has a rack (160) and a slider (170). The rack is mounted in the cabinet, and the slider is configured to retain the sensor. The slider is movably engaged to the rack. The slider can slide in one direction toward a back of the bus or cable compartment to a racked-in position in which the sensor is located to sense arcing in the bus or cable compartment. The slider can slide in an opposite direction toward a front of the equipment compartment to a racked-out position in which the sensor is drawn into the equipment compartment.