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Aging Electrical Systems Research Program

Aging Electrical Systems Research Program. Prepared for: EAPAS Aging Aircraft Workshop November 6, 2002. Robert A. Pappas · Federal Aviation Administration Manager, Aging Electrical Systems Research Program · AAR-480. Arc Fault Circuit Breaker. Outline. Background AFCB R&D

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Aging Electrical Systems Research Program

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  1. Aging Electrical Systems Research Program Prepared for: EAPAS Aging Aircraft Workshop November 6, 2002 Robert A. Pappas · Federal Aviation Administration Manager, Aging Electrical Systems Research Program ·AAR-480

  2. Arc Fault Circuit Breaker

  3. Outline • Background • AFCB R&D • Flight Test Program • AFCB Specification • Pros/Cons of AFCB Installation • AFCB Implementation Considerations & Operational Issues • Future arc fault R&D • Wrap-up / Q&A

  4. Arc Fault Circuit Breaker Background

  5. AFCB Purpose Mitigate the effects of electrical arcing on aircraft wiring.

  6. Background:Current Inspection Technology • Current inspection and surveillance methods for aircraft wiring are limited in effectiveness and periodic in frequency. • Arc fault circuit breakers provide continuous monitoring & protection.

  7. Background:Arc Faults • Present aircraft circuit breakers are designed to protect against over loads and short circuits. • Arcing faults draw less current than hard faults and are intermittent in duration. • Arcing faults can cause systems failures and fires.

  8. Background:Typical Arcing Fault Arc Voltage and Current Waveform of Arcing Fault at 10,000 Feet

  9. Background:Wire Degradation • Wiring insulation degradation increases with time do to a variety of factors such as: • Chaffing • Environmental stresses • Maintenance. • Degradation varies due to design, maintenance, and operational differences

  10. Background:Commercial AFCI • 60 Hz AFCB’s are commercially available. • Aircraft AFCB’s must: • Be at least 50% smaller in size. • Operate in an aircraft environment. • Work in an aircraft electrical system. Photos courtesy Eaton Corp. and Texas Instruments

  11. Background:Commercial AFCB Photo courtesy Eaton Corp.

  12. AFCB Research and Development

  13. AFCB Progress • Two R&D contracts awarded in December 1999 • Eaton Aerospace Controls • Hendry Telephone Products • September 2002: • Both contracts complete • 20 prototype AFCBs delivered and flight tested • 115V, 400 Hz • Smaller than the MS-24571 objective

  14. AFCB Progress

  15. AFCB Progress • Load and Power Characterization • Extensive load characterization • FAA B727 (N40) • Navy C-9 • Boeing Power Lab • Extensive power characterization • FAA B727 (N40) • Boeing Power Lab • Navy C-9 • Nuisance trip testing • FAA B727 (N40) • Boeing Power Lab

  16. AFCB Progress Typical Flight Recorder Start-up (Current)

  17. AFCB R&D Flight Test

  18. R&D Flight Test:Objectives • Fly AFCB’s on a variety of aircraft and electrical loads • Evaluate nuisance tripping • Demonstrate AFCB technology readiness for introduction into civilian and military transport aircraft.

  19. AFCB Installation on Navy C-9 Aircraft (VR-56) First Navy Flight of Eaton AFCB on August 24, 2001

  20. AFCB Installation on FAA B727 (N40) Eaton AFCB’s Data Recording

  21. R&D Flight Test:FAA • B727 Flight Test Loads

  22. AFCB Results • Eaton Flight Test • 30.9 Flight Hours • 228.2 Total Operational Hours • Hendry Flight Test • 99.2 Flight Hours • 793.6 Total Operational Hours Note: Does not include Navy C-9 flight test data or FAA ground time

  23. AFCB Results • Flight Test Accomplishments • Several nuisance trip modes identified, corrected, and validated. • Several AFCB power supply problems identified, corrected, and validated. • Several AFCB hardware problems identified, corrected, and validated. • AFCB Technology ready for prime time.

  24. AFCB Program Status • FAA has accepted and is currently processing two STC applications for AFCB installation • Limited installation • Non-critical circuits • Develop operational experience

  25. AFCB Specification Development

  26. AE-8B1 AFCB Performance Specification • Draft is nearly complete • Applicable to 115V/Single Phase devices only • Broad concurrence of the AE-8B1 committee members • AE-8B General Committee Ballot • SAE Council Level Ballot • Get the word out and support a YES vote on the specification ballot

  27. AE-8B1 AFCB Performance Specification • All current requirements for thermal circuit breaker performance retained. • Arc Fault Specific Requirements: • Extensive • Rigorous • Represent and address REAL conditions

  28. AE-8B1 AFCB Performance Specification • Guillotine Test

  29. AE-8B1 AFCB Performance Specification • Guillotine Test

  30. AE-8B1 AFCB Performance Specification • Wet Arc Test • Hot Re-Close Wet Arc Test • Cold Start-Up Time Test

  31. AE-8B1 AFCB Performance Specification • Loose Terminal Test

  32. AE-8B1 AFCB Performance Specification • Operation Inhibition (Masking) Test

  33. AE-8B1 AFCB Performance Specification • Nuisance Trip Immunity (Arc Fault Discrimination)

  34. AE-8B1 AFCB Performance Specification • Cross-Talk Immunity

  35. AE-8B1 AFCB Performance Specification • Feedback Immunity Test

  36. AE-8B1 AFCB Performance Specification • Other Arc Fault Performance Tests • Arc Fault Cycling (Endurance) • Temperature (DO-160) • Altitude (DO-160) • EMC (DO-160) • Susceptability – Radiated and Conducted • Emissions – Radiated • Lightning Induced Transients • Electrostatic Discharge

  37. AE-8B1 AFCB Performance Specification • Other Arc Fault Performance Tests (Cont’d) • Power Quality (DO-160) • AFCB Reverse Installation – no adverse safety effects

  38. AFCB Implementation Considerations and Operational Issues

  39. AFCB Implementation • Prevents catastrophic damage to wiring system • Reduce arc energy for starting fires • Identifies circuits on which arc faults are occurring • Actively monitors circuits

  40. AFCB Implementation • Determining Overload vs. Arc Fault vs. Nuisance Trip • Assurance of AFCB Functionality • Additional wire maintenance due to potential increases in trip rates from interconnect system degradation • Post trip troubleshooting, determining location of arc fault

  41. AFCB Implementation • Fire and Smoke Incident Data • Maintenance Data • Reliability Data • Risk Analysis • Wiring Zones • SWAMP • Environmental Conditions • High Maintenance Areas • Avionics bay • Passenger Cabins • Cargo compartments

  42. AFCB Implementation • Connected Equipment • Non-Flight Critical Equipment • Passenger/cargo • Flight Critical With Redundancy • Emergency Flight Loads • Risk Analysis • Functional/Physical • Intra-system hazards

  43. Future AFCB R&D

  44. Future AFCB R&D • Joint FAA, NAVAIRSYSCOM, ONR, USAF • 28VDC, 1-25A • Three-phase, 5-25A • MS3320 package • Communication interface • Remote control • Integration of 115V/400Hz AFCB and 28VDC into single breaker

  45. Future AFCB R&D • Contract Awards Pending • Eaton Aerospace • AMETEK • Schedule • Year 1 – Prototype Demonstration • Possible Down Select • Years 2 & 3 – Engineering Development, Test and Evaluation

  46. AFCB Conclusions

  47. AFCB Conclusions • Present aircraft circuit breakers are not designed to mitigate the effects of arcing faults. • 115V/Single-Phase AFCB development is complete. • Select mitigation/prevention technology appropriate to the hazard.

  48. Wire Test & Inspection Technology

  49. Wire Test & Inspection Technology Wire Indenter Excited Dielectric Test Pseudo-Random Binary Sequence Reflectometry Broadband Impedance Measurement Smart Connectors Terahertz Reflectometry Neural Network Processing of TDR/FDR Waveforms Optical Chafe Detector Hi-Voltage Micro-Energy Pulsed Arrested Spark Discharge Validation Test Bed

  50. Wire Degradation Research

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