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FY15 NSRP ETP Panel Project
Safer Inspection of Medium Voltage Electrical Panels on Navy Ships - Final
NSRP ETP Panel Meeting Electrical Panel Meeting, Biloxi, MSMay 10, 2016
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Penn State Electro-Optics CenterThe Navy Manufacturing Technology Center of Excellence for Electro-Optics222 Northpointe Blvd.Freeport, PA 16229
Jeff CallenResearch and Development Engineer Electrical Engineering and Systems Engineering724-295-7000, ext. [email protected]
Matthew E. DiGioiaEngineering Project ManagerAssistant to ManTech Program Operations724-295-7000, ext. [email protected]
DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.
Presentation Outline1. Project Background
• Issue & Approach• Participants & Stakeholders• Technical Approach & Deliverables
2. Status• Testing Results• Project Completion
3. Summary Quad / End
4. Backups
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Background• Even under best practices, installation of shipboard switchboards results in loose connections and wiring
mistakes that lead to arc faults and other electrical maladies– Average of 8 arc faults per year throughout the navy fleet - all occurred in Switchboards and Load
Centers - cost Navy millions of dollars in downtime and repairs [NAVSEA, SUPSHIP Gulf Coast]
• Newer ships have electrical systems considered medium to high voltage– LHD, LHA, DDG-51(FLTIII), DDG-1000 = Medium, 4160 volt systems (CVN = High, 13,800 volt systems)
• Switchboard Inspections: during construction, builder’s trial, during sea trials, and again at regular maintenance intervals
– Current inspection methods: typically utilize Thermal IR imagers to investigate cabinets and comparatively identify ‘hotspots’; other investigation modes require close proximity interrogation
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Safer Inspection of Medium Voltage Electrical Panels on Navy Ships
Load Center
Temperature difference between phases
Photos from NSWC Philadelphia
Inspection Criteria• Inspection results are assessed against criteria previously established – the “Star Chart”
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Thermographic Inspection
Table 504-17-1 ELECTRICAL INSPECTION CRITERIA
Severity Code Temperature Rise (ΔT) Assessment and Action
**** 70 °C (126°F) and above Failure Imminent. Equipment should be secured immediately and not operated until repairs are complete
*** 40 °C (72 °F) to less than 70 °C (126 °F)
Failure Almost Certain. Equipment should be secured if operating conditions permit otherwise monitored until corrective action can be taken.
** 20 °C (36 °F) to less than 40 °C (72 °F)
Failure Possible. Corrective action should be taken as soon as feasible.
* 5 °C (9 °F) to less than 20 °C (36 °F)
Performance Degraded. Corrective action should be taken at next scheduled routine maintenance period or as schedule permits.
N/A Less than 5 °C (9 °F) No corrective action required; note for future reference
NOTE: The temperature rises or ΔT’s indicated above are the temperature differentials between the thermal anomaly (i.e., faulty connection or component) and the reference temperature. The reference temperature should be a similar, normal operating connection, component, or phase. Decision regarding repair priorities and order of maintenance should be determined by the magnitude of the temperature differential and the critical nature of the equipment or system involved.
From S9086-RJ-STM-010 NSTM Chapter 504 Pressure, Temperature and other Mechanical and Electromechanical Measuring Instruments. Revision 7. 1 September 2012
Issue• Current Inspection Practices: secure the area, full coverage Personal Protective Equipment (PPE) to image
inside open active panels, preferably while drawing a high load (at sea). Some facilities will not open panels for inspection on 4160V, even with PPE.• Violates OSHA regulations - requires Technical Warrant Holder (TWH) waiver requests
Approach• EOC’s initial analysis identified potential solutions for both “temporary” installations during testing as well
as “permanent” solutions compliant with Mil-Specs for shipboard operations• Leading candidate: IR transparent windows in panel covers enabling safe IR inspection without
opening cabinet– Inspections at any time using the same cameras and practices currently but without PPE or the
need to secure the area and deactivate and reactivate electrical panels.• Candidate solutions were vetted through NSRP Electrical Technologies Panel (ETP) presentations and
subsequent stakeholder interactions. • Other potential solutions with pros and cons of each were explored including a standalone gantry for
remote imaging, temperature sensitive paint, and RF interrogation of embedded temperature sensors
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Safer Inspection of Medium Voltage Electrical Panels on Navy Ships
With the support of this community, the approach was refined to focus on demonstration of temporary (or permanent) installation of panel covers with IR transparent windows enabling safe IR inspection without exposing personnel to energized electrical components
• New MIL-DTL-32483, dated 8 Nov. 2013, DETAIL SPECIFICATION SWITCHGEAR, POWER, HARD-MOUNTED, MEDIUM VOLTAGE, NAVAL SHIPBOARD, requires use of thermal imaging windows. Requirements currently under revision accounting for recommendations from this project.
• LHA 8 invokes MIL-DTL-32483 for 4160V Switchboards.
Lead Investigators
Jeff Callen Penn State Electro-Optics CenterResearch and Development Engineer,Electrical Engineering and Systems Engineering
Matthew E. DiGioia Penn State Electro-Optics CenterEngineering Project Manager, ManTechSensors, Robotics, and Automation
Sponsoring Shipyard
Jason Farmer Ingalls Shipbuilding (Pascagoula)Project Lead / Electrical Engineer IV
Government Stakeholder
Clay Smith SUPSHIP Gulf CoastEngineering
Project Technical Representative
Richard Deleo Newport News ShipbuildingEngineering Manager - Submarine Electrical
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Active Project Participants
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Integrated Project Team (IPT): Advisors and Other StakeholdersGovernment StakeholdersDave Mako NSWC Philadelphia Division, Code 427, Propulsion
& Power Systems [email protected]
Tom Connolly NSWC Philadelphia Division, Code 427, Propulsion& Power Systems
John Zabita NSWC Philadelphia Division, Code 511, Instrumentation & Sensors (IR Thermography)
Industry Advisors
Gary Weiss DRS Power & Control Technologies, Inc.Business Development Manager for Power Distribution and Power Conversion
John Ykema L3 SPD Electrical Systems, VP and CTO [email protected]
Other Interested Parties
George Rasich Life Cycle Engineering – Support Contractor for NSWC Philadelphia, Advanced Electrical Systems
Greg Stevens Bath Iron WorksElectrical Engineering
Dennis Neitzel AVO Training Institute, Inc.OSHA Authorized Maritime TrainerPrincipal Committee Member, NFPA 70E
Process and Means to Accomplishing Goals and Objectives (from SOW)
Review Shipbuilder/Government/Industry Requirements for IR PanelInspection and Current Inspection Practices [HII, SSGC & Penn StateEOC]
Determine Camera(s) and Window(s) to be Used [Penn State EOC Led]
Laboratory Tests of Cameras and Windows [Penn State EOC Led]
Devise Practical Implementation [Penn State EOC, HII & SSGC]
Plan and Prepare for Final Demonstration [Penn State EOC, HII & SSGC]
Develop Technology Transition Path Including Safety/Business Case[All]
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Technical Approach
Windows and CamerasIR Windows – Crystal vs. Polymer• Crystal Windows
– Pro: Vis and IR, no reinforcement grid. – Con: transmissivity possibly could degrade over time. Transmission cuts off midway through
long IR band• Polymer Windows
– Pro: no degradation, full IR band, some rectangular– Con: Need reinforcing grid, some will not pass vis light (need separate window)
Cameras and IR Windows• Cameras
– Fluke TI32 from Ingalls (Lab Testing)– FLIR T440 borrowed from FLIR (Lab Testing) - Same type as used by Navy– Fluke TI10 from Ingalls (Field Testing) – Similar to TI32, but with fewer features.– FLIR T300 from SSGC (Field Testing) – Similar to T440
• Windows– FLIR IRW-4S: 4” round crystal (matches LHA-8 spec) (Lab and Field)– Fluke CLirVu CV400: 4” round as a 2nd crystal window (Lab)– Exiscan XIR-A-4-H-X: 4” square polymer window (Lab)– IRISS VPT-100: 4” round as a second polymer window (Lab)– FLIR IRW-3C: 3” round crystal window (Field)
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Laboratory Tests – EquipmentCameras
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4” Windows (covers removed)
FLIR T440 Fluke TI32
FLIR IRW-4S Fluke CV400 IRISS VPT-100 Exiscan XIR-A-4-H-X
Laboratory Test Results - 1
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These tests established baseline on how windows affect measurements (accuracy, Field of View, Visible imaging, simulated fault testing) and provided insight on impacts to shipboard thermography inspections. Environmental tests on windows were outside project scope.
Test Conclusions:
1. Reasonably accurate temperature measurements can be made through IR windows provided attention is paid to emissivity and transmissivity settings in the camera.
2. Variations in emissivity and transmissivity will need to be minimized by developing uniform techniques and procedures to provide a useful comparison test, as is done presently with emissivity settings.
3. Windows allow wide enough field of view that number and placement of windows in the cabinet will be limited only by the internal obstructions and line of sight views.
Window HFOV VFOV Temp drop at extreme edge
Crystal (FLIR) 129° 127° 10%
Polymer (IRISS) 114° 115° 28%
Thermal Image of simulated fault
Laboratory Test Results - 2
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Test Conclusions (continued):
4. Polymer window reinforcement grids affect thermal measurements slightly, but also affect the field of view and make visible imaging difficult.
5. Rubber dust boots do affect the absolute thermal measurements. Hot spots will show up on the boot or cable, but it was not possible to quantify the differences properly. More study is needed.
6. Reflected glare indicates that for visible imaging in a closed cabinet, some other illumination source will be needed, either through the same window or through some opening.
DeliverableProof of Concept Demonstration
A demonstration of IR thermography through one or more IR windows installed in the door of a 4160Vswitchgear panel that is representative of the type of switchgear panels to be on LHA-8 and similarvessels.
Originally Targeted LHA-7 Sea Trial (trials scheduled for late Summer 2016 = outside PoP) Testing took place at DRS’ Milwaukee Facility, February 24 and 25, 2016:
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Thermography Demonstration in DRS’ prototype4160V switchgear panel and testing facility
– Energized with low voltage, high current to simulate properly operating panel
– IR thermography imaging done through IR windows mounted in panel cover with movable window and camera placement
– 4” and 3” crystal windows tested, as well as taking visible images into dark cabinet. Dust boot over one connection.
– Loosened one connection to show temperature rise that simulates a fault.
IR Windowonverticaltrack
DeliverableProof of Concept Demonstration
Field testing to a large extent confirmed the laboratory testing in a relevant cabinet.
– Additional Conclusions – Practical Implementation Issues.• Internal obstructions will be biggest challenge. Will affect number and placement of windows.• Larger windows are better than smaller. Hard to get simultaneous vis and IR images through 3” window• Fault condition is visible as hot spot through rubber boot but accurate temperature measurement is difficult.
Heating on cables emerging from beneath boot looks to be more reliable.• Illumination in dark cabinet for visible images may require auxiliary lighting source.
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Faulty connection (R) through window (no boot) Dust boot in place over faulty
connection. Hot spot on boot and hot cable below boot are
indicative of the fault
Visible image taken with auxiliary lighting adjacent to the camera and illuminating through
the window.
Conclusions - 1
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IR Windows are a commercial product sold for IR Thermography. Project examined the suitability of IR Windows for Navy ships
Conclusions:
1. IR thermography through windows can be accurately done to within 1-2 % provided camera emissivity and transmissivity are properly set. Procedures will need to be developed for determining best camera settings and determining action criteria (new “star chart”).
2. The field of view through the windows is sufficiently large to allow off angle viewing of most areas within electrical panels, but larger windows are better than smaller ones.
3. Crystal vs. Polymer Window Type
– Crystal windows have better field of view. Reinforcement grid on polymer window is a significant obstruction in visible imaging.
– Crystal windows meet commercial and Navy standards for vibration and shock (All windows meet IEC or IEEE arc flash standards)
– Crystal degradation over time due to absorption of moisture is not an issue – very small and does not affect a comparison test.
Conclusions - 2
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4. Practical implementation issues
– Window placement limited by internal obstructions rather than window field of view. – Dust boots do affect IR thermography. Quantitative measurements are difficult, but hot
spots and relative temperature differences are evident. Procedures will need to be developed to take this into account.
– Reflected glare off windows affects visible imaging (not IR) and will need to be accounted for in procedures to provide appropriate lighting for visible imaging with closed panels.
5. Project results indicate use of IR windows is viable for safer shipboard inspection of medium voltage electrical panels.
– Path to temporary/permanent installation being explored. Latest revisions of MIL-DTL-32483A and MIL-DTL-XX653 (specifications for medium voltage switchgear) are requiring IR windows and incorporating lessons learned from this project).
– Panel manufacturers will need to account for window line of sight in future designs.
– Exploring ideas on permanently installed temperature monitoring of panel connections.
Safer Inspection of Medium Voltage Electrical Panels on Navy Ships
Implementation: System: Medium & High Voltage Electrical Infrastructures
on Navy Platforms (LHD, LHA, CVN…)Site: LHA-8 SUPSHIP-GC (Future)Schedule: Mar 2016 = Demo Results with Transition Plan for
Temporary InstallationsStatus: Results being incorporated in MIL-DTL-32483A & XX653
Benefits / Payoff: • Reduced safety risk to personnel: enables safer practices within
existing inspection methods and procedures• Potential to provide inspection process cost savings • Applicable across multiple military domains & platforms with
Information shareable across shipbuilder industry
Sponsor: The National Shipbuilding Research Program2014 Electrical Technologies Panel Project
Objective: Develop safer, cost effective solution within existing thermographic inspection practices for onboard medium/high voltage electrical infrastructures: utilize IR transparent viewports in electrical panel covers to reduce risk for government and shipbuilders
Performing Activities: Jan 2015 – Jul 2016, $150K• Penn State Electro-Optics Center• Ingalls Shipbuilding • SUPSHIP Gulf Coast• Newport News Shipbuilding• Integrated Product Team Includes: NAVSEA (TWH Office), Naval
Surface Warfare Center – Philadelphia Division, OSHA Safety Trainer, Industry Product Supplier
Tasks/Achievements: Leverage the current state of the art in industry and the recently revised NFPA 70E criteria (National Electrical Code, “Standard for Electrical Safety in the Workplace”); emphasizes substantial risk reduction for workplace injuries and fatalities due to shock, electrocution, arc flash, and arc blast Review Shipbuilder/Government/Industry Requirements for IR
Panel Inspection and Current Inspection Practices Laboratory Experimentation with Cameras and Windows Plan and Execute Final Demonstration of Practical / Representative
scenario on a Navy ship Develop Technology Transition Path Including Safety/Business Case
Deliverables: Quarterly Reports: April, July, and October Proof of Concept Demonstration: representative IR thermographic
inspection using an IR window in closed electrical panel cover Final Project Report: Jun-16
Average of 8 arc faults per year throughout the navy fleet - all occurred in Switchboards and Load Centers – can result in serious injury and costs Navy millions of dollars in downtime and repairsCurrent Inspection Practices: secure the area, personnel don full coverage Personal Protective Equipment to image inside active
panels, preferably while drawing a high load such as during sea trials.
NOV15DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.
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BACKUPS
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Camera Compare
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Window CompareNo. LHA-8 Spec FLIR IRW Series FLIR IRW S* Exiscan XIR-A-
4-H-XExiscan XIR-A-3-H-X
Exiscan XIR-S-4-H-X
Fluke CLirVu Fluke CLKT IRISS VPFC IRISS VPT
1 Permanently attached cover Y Y Y Y Y Y N Y Y2 Single hole installation Y Y No, 8 bolts No, 8 bolts No, 8 bolts Y 3 self tap screws ?? ??3 standard hole punch install Y Y Saw or punch Saw or punch Saw or punch Y Y ?? ??4 Solid metal cover Y Y Y Y Y Probably Probably Y Y5 No tools to open window single
thumbscrewsingle thumbscrew
4 hex head captive screws
4 hex head captive screws
4 hex head captive screws
1/4 turn hand turn captive
Hex head screw Phillips screw Phillips screw
6 Broadband (vis and thermal) Y Y No, separate window for vis
No, separate window for vis
No, separate window for vis
Y Y Y Y
7 No obstructions, including reinforcing screens
Y Y Diamond reinforcing screen
Diamond reinforcing screen
Diamond reinforcing screen
Y Y Y Hex reinforcing screen
8 Rated to 250 °C 260 °C 260 °C 150 °C 150 °C 150 °C 232 °C & 260 °C intermittent
250 °C 200 °C 200 °C
9 Stainless Steel housing Anodized Alum. 316 Stainless Stl anodized Alum, pwdr coat
anodized Alum, pwdr coat
Stainless "high strength alloys"
Aluminum Nylon Nylon, SS cover
10 Pull out strength 3600 lbs. 2" 1450 lb. 3" 3650 lb.4" 3700 lb.
2" 1450 lb. 3" 3650 lb.4" 3700 lb.
No Spec No Spec No Spec No spec 1388 lb. No Spec No Spec
11 Rated low, med, high voltage Y Y Y Y Y Y Y ?? ??12 Meet UL 50V Y Y Y Y Y Y ? Y Y13 Meet UL50 Environ. Type 4/12 4/12 4/12 4 4 4 4/12 3/12 4 414 Meet KEMA (IEC 62271-200) Arc
flash 5kV, 63 kA 30 cycles 60 Hz.5 kV, 63 kA 30 cycles 60 Hz
5 kV, 63 kA 30 cycles 60 Hz
ANSI/IEEE C37 20.7
ANSI/IEEE C37 20.7
ANSI/IEEE C37 20.7
63 kA 30 cycles 60 Hz, meets C37 20.7
C37.20.7 50 kA for 30 cycles 60 Hz
?? C37.20.7 63 kA, 15 kV for 30 cycles 60 Hz
15 Meet TUV (IEC 60529) IP67 IP 67 IP 67 IP65 IP65 IP65 IP67 IP65 IP65 IP6516 Meet TUV (IEC 60068) 100 m/s2
vibration100 m/s2 100 m/s2 No Spec
vibration "unaffected"
No Spec vibration "unaffected"
No Spec vibration "unaffected"
IEC 60068-2-6 IEC 60068-2-6 ?? ??
17 Meet TUV (IEC ^0068-2-3) 15 day extreme humidity
Y Y Humidity & moisture "unaffected"
Humidity & moisture "unaffected"
Humidity & moisture "unaffected"
IEC 60068-2-3 IEC 60068-2-3 ?? ??
18 Optic Material Calcium Fluoride Calcium Fluoride Polymer Polymer Polymer Crystal Crystal Calcium Fluoride Polymer
Project Goals and ObjectivesThe suitability and the safety impact of using IR windows in electrical panels for
thermographic inspection of electrical connections on Navy ships will be determined
1. Develop safer, cost effective solutions with IR transparent viewports in electrical panelcovers to reduce risk for government and shipbuilder inspection of onboard medium/highvoltage electrical infrastructures• Comprehensive inspections accomplished with less risk and reduced labor• Eliminate or reduce the need for secured locations, personal protective equipment (PPE), and waiver
requests wrt OSHA standards
2. Develop and demonstrate a proof of concept solution that meets temporary (or permanent)installation requirements for the shipbuilder/government implementers• Demonstrate on a representative panel under real or simulated operating conditions
3. Establish the business/safety case and path to implementation for government andshipbuilder applications• Develop the business case and risk reduction benefits for shipbuilder construction and government
applications where inspection of electric switchboards, load centers, and transformers is necessary• Pursue industry support and buy-in with identification of vendors which can provide products that
meet temporary installation requirements• Explore the criteria and viability for permanent installations within MIL-DTL-32483 (RevA pending)
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Safer Inspection of Medium Voltage Electrical Panels on Navy Ships
Other Solution ConceptsIR Fibers for Blackbody Radiation [NNS via Deleo]
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IR Fibers for Blackbody Radiation 1. One potential avenue is to use IR fibers to transmit blackbody radiation to a high density FO
connector on the face of the panel. 2. Connector can then be “read” by a variety of methods. Can even develop a special tool to
automate scanning.3. This allows a high level of flexibility with regard to mapping the inside of a panel and
monitoring areas without a direct line of sight. 4. You can also easily accommodate a large number of measurements without a significant
impact to the panel face (just a connector and dust cap).Pro’s:
1. Non-conductive materials eliminate short circuit potential2. No EMI concerns3. Not a tactical concern (failure or loss doesn’t degrade performance of equipment)4. Flexible and can be added easily to a design with minimal risk to military qualifications5. Field installable6. Lends itself to automation in the future7. Simple installation. Fibers are not required to carry data so precision installation not an
issue. Large light loss acceptable. You only need enough to measure radiation frequency to determine temperature.
8. High quality FO conductors exist9. High quality (and Mil Spec) connectors exist (Mil-DTl-38999) at high densities (e.g. 64
conductors in small footprint)Con’s:
1. Not consistent with current inspection practices2. Expensive / impractical retrofit?
Other Solution ConceptsEmbedded Temperature Sensor & Camera [via Mako & Smith]
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FLIR AX8TMCombining thermal and visual cameras in a small, affordable package, the AX8 provides continuous temperature monitoring and alarming for uninterrupted condition monitoring of critical electrical and mechanical equipment.
1. The AX8 provides early detection of temperature-related issues in electrical and mechanical equipment, making it the ideal temperature sensor for continuous condition monitoring and hot spot detection for electrical cabinets, process and manufacturing settings, data centers, mass transit facilities, energy generation plants, and storage facilities.
2. Easy to install in electrical cabinets or other confined areas, the AX8 provides uninterrupted condition monitoring of critical electrical and mechanical equipment to help reduce unplanned downtime and prevent safety hazards.
3. Learn more about this powerful thermal sensor and camera, and its many practical applications: http://www1.flir.com/e/5392/automation-display--id-65816/xm2jz/892531353
Pro’s:1. Continuous condition monitoring – 24/72. Excellent solution for new construction (pending cost/safety benefit)
Con’s1. Not consistent with current inspection practices2. Expensive / impractical retrofit?
Pending Further Investigation
Results of Initial Trade Study
With the support of this community, the approach was refined such that this project focuses on demonstration of temporary (or permanent) installation of panel covers with IR transparent windows
enabling safe IR inspection without exposing personnel to energized electrical components
• EOC’s initial analysis identified preliminary requirements and potential solutions for both “temporary” installations acceptable before and during sea trials as well as “permanent” solutions which must be compliant with Mil-Specs for shipboard operations
• Leading candidate solution: temporary or permanent installation of panel covers with IR transparent windows enabling safe IR inspection without exposing personnel to active electrical components
– This would allow inspectors in the room to operate at any time before/during acceptance/sea trials without PPE, while utilizing the same cameras and practices currently used but without the cumbersome and costly need to secure the area and deactivate and reactivate electrical switchboards.
• Besides IR windows, potential solutions with pros and cons of each were identified including:– Curtain – RF interrogation of embedded temperature sensors– A standalone gantry for remote imaging– temperature sensitive paint
• Candidate solutions were vetted through NSRP Electrical Technologies Panel (ETP) presentations and subsequent stakeholder interactions
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Replace panel with a temporary panel that has IR transparent windows in it. 1. Windows would be small to keep costs down. 2. Multiple windows would supply the required angles and fields of view. 3. Small panels, some of each with windows, can be modular. 4. An entire panel might consist of 9 subpanels, of which 3 or 4 would have windows. 5. The subpanels would be reconfigured to match the best viewing angles for the switchboard that is being
inspected. 6. Some of the windows could be in angled conical mounts so as to direct the FOV somewhat off of normal. 7. Rotating conical mounts like this would allow this angle to be aimed in any direction. 8. The power would be shut off while the regular panel is removed and this temporary panel takes its place.
Power restored then inspection takes place same as the old inspection. 9. Temporary panel removed and taken to next switch panel. 10. Temporary panel can be reconfigured if necessary.
Pro’s:1. Allows inspectors in room, permitting inspection at any time, including underway2. Inspection can be done with same cameras and techniques used now.
Con’s:1. Requires temporary shutdown of panel while temporary panel installed or removed.2. Geometry dependent. Even with modular subpanels, might be difficult to get the best location and best angles
for meaningful test.3. Unclear whether one size will fit all. May need more than one set, or some adaptor to make it fit on different
size panels.
Other Issues / Determinations:1. Wide array of LWIR transparent windows materials: ideal would be one that has high visible (~ 80%) and IR
(>60%) transmission, large/standard size, and durability to withstand a flash event (not be blown out or melt). Cost implications
2. Could use separate IR/Vis windows unless it is possible to take the vis pictures after the inspection is over and the panel is shutdown for removal of our temporary panel
Initial Trade Study – Solution ConceptsPanel with IR Transparent Windows (Temporary or Permanent)
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Curtains (subset of Panel with IR Transparent Windows): Instead of panel with conical camera ports, create a curtain with a port in the middle.
1. Curtain would resist spark and flame, like welding curtains. 2. Can make it from same material as the flash protection suits. 3. Curtain could be sewn so as to form pyramidal or conical general shape. 4. Curtain flexible enough to allow camera to be moved around to exact position and
angle desired. If looking through camera lens, no window in curtain will be needed, just a hole to poke the camera through.
5. Camera may need lights for the visible pictures.
Pro’s:1. Simpler than panel2. More flexible in positioning camera3. No IR window needed4. Not very expensive
Con’s:1. Not sure welding curtain type cloth will be acceptable. (flash protection suit
material should be acceptable)2. May be unwieldy to move camera surrounded by thick curtain
Initial Trade Study – Solution ConceptsCurtains - Subset of Panel with IR Transparent Windows
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Temp Sensor w/RFID Interrogation 1. Researched commercially available: see below, “- Temp Sensor w/RFID Interrogation”2. Use a contact temperature sensor with RFID-like (wireless) interrogation.
Pro’s:1. No change to existing panels2. No camera required to inspect – documentation with auto logging of sensor serial
#/location 3. Gather data when convenient. Panels operated normally – no open panels, no personnel
safety issues.4. Geometry independent – camera same angles as with present inspection
Con’s1. Requires additional steps to add and remove sensors and create database of sensor
locations2. Unknowns/Issues:3. EMI interference with panel closed when trying to read? Unlikely but Need more research 4. Cost?5. Perhaps make a permanent installation?6. Variation: www.iriss.com has a product called Delta T Alert, which is a wireless device
you put on the door and it monitors temperature inside the cabinet vs. outside, and logs data at regular intervals. Can set up a network of these. Only measures entire cabinet temperature, but one testimonial credited it with alerting him to a phase unbalance in one of his cabinets. Perhaps part of the long term solution.
Initial Trade Study – Solution ConceptsTemp Sensor w/RFID Interrogation
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Standalone Gantry with PTU1. Build a man-high frame with a motorized X-Y gantry on it. On the gantry, mount the camera on a PTU. 2. Shut down the switchgear, remove the panels, set up the frame where a person would stand to do the inspection. 3. Gantry and PTU permit the camera to be placed anywhere a person would place it. Control everything remotely. 4. When inspection finished, shut down power remotely, replace panels and move on.
Pro’s:1. Can get all of the viewing angles that are currently available.2. Probably simplest to implement (X-Y and PTU do not need to be of any great precision)3. Costs are low, depending on the camera
Con:1. Need a camera that can be operated remotely2. Probably will be wired, so will need to see what safety issues there are running cables out of the room.3. Bulkiest of the potential solutions.4. Requires people to be out of room, so would be difficult to implement while underway.
Subset (Gantry with PTU inside panel box)1. Reproduce the XY gantry with PTU in a box that hangs on the switchgear in place of the regular front panel. Shut down
panel, remove front, replace with this box, re-energize and do inspection.
Pro:1. Panel is closed so inspection can be done with people in room and done at any time.2. Fairly low cost – XY gantry and PTU do not need to be of great precision
Con’s:1. Of necessity will have camera fairly close to panel. FOV and focus might be problematic that close Camera might be
bulky2. Difficult if panels are significantly different in size3. Projection from panel might be an issue.4. Need remotely operated camera
Initial Trade Study – Solution ConceptsRemote Operated Camera Gantry System
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Temperature Sensitive PaintThere are paints that change color depending on their temperature (thermochromic). There are both irreversible (which stay at the color they changed to at their highest temperature) and reversible (which change back to their original color when the temperature returns). In the case of irreversible, it is often a change in density of the same color, so the color darkens. They could be incorporated in the following manner:
Subset (Irreversible Thermochromic Paint)The paint can be applied on assembly or prior to inspection to the potential hotspots (terminals on cables, studs on panels). If desirable not to introduce paint to the components, pads can be constructed with the thermochromic paint on the top and an adhesive backing. Prior to inspection, these pads can be applied to the potential hotspots. After the panel is powered up, then shut down, the cabinet doors are opened and the colors on the pads examined. Those that were hotter will have darker or different color than their neighbors in the same circuit. Comparison color charts can be made up that can be held against the pad in the panel to judge a maximum temperature reached. Photos can be taken with visible light color camera.Pro’s:
1. No change to existing panels2. No camera required to inspect – documentation with a visible camera only3. Panels operated normally – no open panels, no personnel safety issues.4. Geometry independent – camera same angles as with present inspection
Con:1. Will change color only when absolute temperature exceeds threshold. A bad connection may not indicate at less than full current (lower temp).2. Requires additional steps to add and remove pads3. Temperature sensitivity may not have fine enough resolution to tell difference between a few °C. (ACTION) Need more research.4. Need to have the pads made up. 5. If paint applied directly, then would need to pass approval to be permanently installed inside the cabinet. Also, would need to be stripped off and
reapplied for each retest.6. Requires shutdown of panel both before (to install the pads) and after (to read the results)
Subset (Reversible Thermochromic Paint)The paint can be applied on assembly or prior to inspection to the potential hotspots, either directly, or via the pads described above. Panel replaced with temporary panel containing visible transmission windows. Inspection done while panel energized and color change is noted by comparing color of different phases of the same circuit. Done with visible camera for inspection or just documentation.Pro’s:
1. No camera required to inspect – documentation with a visible camera only2. Much more flexibility in obtaining appropriate visible windows than IR windows.3. Transmission much higher through visible windows (closer to 100 %). 4. Less geometry dependent – visible windows can be larger to cover more angles than IR
Con’s:1. Will change color only when absolute temperature exceeds threshold. A bad connection may not indicate at less than full current (lower temp).2. Requires additional steps to add and remove pads3. Temperature sensitivity may not have fine enough resolution to tell difference between a few °C. Need more research.4. Requires temporary shutdown of panel while temporary panel installed or removed. May not be able to open panel quickly enough to catch change
Initial Trade Study – Solution ConceptsTemperature Sensitive Paint
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Flexible Camera Head Through Louvers (borescope)1. IR camera with imaging head on gooseneck, probably (non-conductive) fiber optic. 2. Insert camera head through louvers in existing panel while switchpanel is energized. 3. Move camera head around via gooseneck, or attached to insulating rod or other manipulating device. 4. Move to different louvers to get best view.
Pro’s:1. No change in existing panels2. No requirement to shut panels off while equipment is installed or removed.3. Test can be done at any time, including while ship is underway
Con’s:1. Highly geometry dependent. Doubtful that all relevant views can be obtained through louvers. Unclear if
required manipulation can be done through louvers.2. Requires penetration of plane of panel – Potential safety issue, even if camera head is isolated
Embedded Camera Ports (Subset to Temporary Panel/Curtain)1. Instead of IR windows, have subpanels with camera ports, probably conical to the outside of the panel. 2. Camera goes at peak of cone, but has ability to be angled in pan and tilt. Inside of cone has mechanical
shutter. 3. Panel is installed in place of regular panel. All shutters are closed. 4. Camera is installed in one port, and then shutter is opened. 5. Camera angled for best view and test performed. Shutter closed and camera moved to next port.
Pro’s:1. Less expensive than multiple IR windows
Con’s:1. May not get all the angles needed with camera fixed at end of cone2. Possible mechanical challenge to allow PT at port while still protecting from HV discharge within
Initial Trade Study – Solution ConceptsOther Ideas Considered but Not Explored in Initial Trade Study
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