Construction and Installation of Components Affecting Airfield Lighting Circuits

Reliability and Performance

Richard Larivée, Eng.

Aviation CommitteeAviation CommitteeIlluminating Engineering Illuminating Engineering

Society Society Memphis 2008Memphis 2008

Outline

1. Introduction2. Airfield lighting circuit

o System and reliability3. Basic components

o Cableo Transformero Connector/connection

4. Experimentation o Theoryo Findings and results

5. Conclusion

1-Introduction

- Past conferences and issues about meggering and values- Fundamentals of meggering, Seward Ford - Insulation resistance testing for airfield lighting circuits, Carl Johnson 2008 IESALC- ‘’… A Passive System.. R. Farmer/L.

Blizzard 2007 IESALC stated ‘’… Different plug/receptacle system …’’

- ‘’Power Distribution for the all LED circuit ‘’ FAA 2006 IESALC

2-Airfield Lighting CircuitEquipments• 2 Variables

o Factory made equipment

o Field installation

• Standards & Guidelines

2-Airfield Lighting CircuitReliability of cables and cable joints

• Airfield lighting circuito 1 circuit – 7930 meters (25 774 feet) = 0.158 failure/yearo 58 edge and 16 threshold lights = 0.288 failure/year

*1 From IEEE Std 493-1997. Modify for joint as per double ratio of utility*2 Factory installation, multiplier of 50% from site value*3 2 crimps per connection, double value of primary

Field

Factory

or

11 places3 cable joints

Equipment Failure unit/year*1

Cable joint – primary*2 (factory) 0.000432Cable joint – primary (site) 0.000864Cable joint – secondary*2,3 (factory) 0.000864Cable joint – secondary*3 (site) 0.001728Cable (failure / 1000’) 0.006130

2-Airfield Lighting CircuitReliability of cables and cable joints

Comparaison of failure cable versus connection

0,086 0,033 0,0130,158

0,038

0,1130,330

0,288

0,245

0,051

-0,050

0,050

0,150

0,250

0,350

0,450

0,550

0,650

0,750

Taxiway De-icing Apron Runway Approach

Failu

re p

er y

ear

Cable Connection

2-Airfield Lighting CircuitReliability of cables and cable joints• Defense Estates*4

o Installation and maintenance of aeronautical ground lighting cables circuits - Technical Bulletin (2002)

o Rate of decline of insulation resistance3 causes: accessory design, installation and maintenance

Cable – excessive pulling tension in trench and in out of light base Cable joints

Heat shrink, tape joints, misuse of cutting toolo Maintenance, Commissioning and Safety Datum

Safety RSD = KVA/primary current/body current (th=10mA) kΩ

RSD = 23.5/6.6/10x10-3 = 356 kΩ*4 Ministry of Defence in UK

2-Airfield Lighting CircuitReliability of cables and cable joints• Defence Estates

Policy Instruction 2005o Derived from 2002 Technical Bulletin o Maintenance Remedial Level (MRL) => 10 RSD now

called Safety Datum Level (SDL) – Do something now!o 5 MΩ minimum for 500V. insulation tester on

secondary cableo ALC and GP cables IR down to 2 MΩ - OK

3-Basic ComponentDetails• Cable

o Indoor – cable tray, conduito Underground - conduit or direct

burial • Transformer

o In pull pit, light base or anything else

• Connector o At cableo At transformero At CCRo And exposed to various

conditions

3-CableDescription• Standards and approvals

o CSA C22.2 no 179-00 (R2005) o FAA AC 150/5345-7E (ICEA/NEMA)o IEC TS 62100 (2004)

• Characteristicso CSA - Resistance max @25oC

1.38 Ω/km, AWG#6 2.10 Ω/km, AWG#8

o Insulation − Ethylene propylene-rubber (EPR)− Crosslink polyethylene (XLPE)

o Stress controlo Jacket

3-CableCharacteristics

Megohmeter testing - Insulation Resistance (IR)IR = K . Log (D/d) (per 1000 feet) *5

• IR for bigger OD and related to material• CSA AWG#8 Min. IR

o 2200 GΩ.m (@15oC) K = 6000 o 16.6 GΩ.m (@90oC) K = 45

*5 Field testing excerpt - Prysmian’s Wire and Cable Engineering Guide

Stranddia

AWG 8 dia.(d)

Shield thickness

Insulation thickness

Jacket thickness

Cable O.D. Dia(D)

IRMΩ for 1000’

A .0486’’ 0.146’’3.71 mm

0.015’’0.38 mm

0.110’’2.79 mm

0.405’’10.3 mm

8 862

B 0.125’’3.18 mm

0.080’’2.03 mm

.600’’15.1 mm

12 192

C 0.146’’ 0.110’’ 0.375’’ 8 193

Bra

nd

3-CableConstruction• FAA AC 150/5345-7E

o Type‘’B’’ EPR (ethylene propylene rubber)o Type‘’C’’ XLPE (cross-link polyethylene)

− Not recommended for high water table

• Engineering brief - Announced by FAA in 2007 for cable selection

• Stress control of electrical field

WO semi con W semi con W shieldFrom BETAlux 5 kV Airfield Lighting Cables

3-CablePreparation-Installation• FAA 5370-10C L-108

o Cable end sealing – transport, storage & layingo ‘’Cable shall not be dragged across base can or

manhole edges, pavement or earth. … lay cable out on a canvas tarp or other means … to prevent abrasion to the cable jacket.’’

o 50 MΩ minima 1000V megger• Pulling tension (PT) and method• Skinning cable tool

o Semiconductive layer - conduction issues• Cleaning prior to connector installation

and direction of contaminant

Ripley WS-49

• ‘’Mechanical stresses during installation are generally more severe than those encountered while in service’’ Southwire – Power Cable Installation Guide

• From and to base

3-CablePreparation-Installation

Figure 23 AC 150/5340-30C

3-CablePreparation-Installation• Cable bend – see manufacturer’s

recommended minimum bending radius

3-TransformerDescription• Standards and approvals

o FAA AC 150/5345-47Bo CSA C22.2 no 180-M1983 (R2004)o IEC 61823 (2002)

Winding under Test Voltage Applied(kV DC)

Minimum InsulationResistance(Megohms)

Maximum LeakageCurrent

(Micro amps)

Hot/Cold Primary up to 150 W 15.0 7500 2.0

Hot/Cold Secondary up to 150 W 5.0 2500 2.0

Hot/Cold Primary over 150 W 15.0 3000 5.0

Hot/Cold Secondary over 150W 5.0 1000 5`0

From FAA AC 150/5345-47B

• CSA, IEC Leakage (max) primary 2 μA at 15 kV

3-ConnectorAt Cable and Transformer• Standards and approvals • Characteristics

o Electricalo Environmentalo Various

• Construction• Installation

3-ConnectorStandards and Approvals• Definition: Electromechanical system

separable electrical connection between two subsystems

• FAA AC 150/5345-26C o Class A – Factoryo Class B – Field attached

• Type I - Primary cable• Type II - Secondary cable

• IEC Draft

3-ConnectorOther Standards• ASTM B868 - 96 (reapproved 2002)

o Standard Practice for Contact Performance Classification of Electrical Connection Systems

o Developed to standardize format and language for expressing the contact performance of electrical connections and changes in time

o 2 categories – Based on resistance− Power connection – temperature rise (30oC at rated

current) and voltage drop requirement− Signal connection (max 1 amp) – requirement of 10 to 20

mΩ change in resistance o Rd 1.1 < Rc < 1000 Rd

Rc = resistance changeRd ~ Resistance equivalent to size of cable diameter AWG #8=6.84 μΩ AWG #12=10.94 μΩ

• ASTM B539 – Test method for Measuring Resistance of Electrical Connections

3-ConnectorCharacteristics• Electrical

• Primary criteria – low electrical resistance

From FAA AC 150/5345-26C

• Across the contact (Voltage drop)o From primary cable pin and socket connectiono Calculation for 6.6 amp – 1140 μΩ

** AC says 750 MΩ

Type of connect

or

Voltage drop max. (mV)

Test Voltage

(kV)

Min. insulation resistance MΩ (Dielectric test)

Min. insulation resistance MΩ(Production test)

I 7.5 15 25 000 75 000**

II 6.0 4.7 25 000 23 500

3-ConnectorCharacteristics• Electrical

o Contact area and contact pressure requiremento Thermal expansion and contraction

phenomenon due to current flow o Use a crimping tool designed for the specific

type of connector to ensure that crimps or indents meet the necessary tensile strength. AC150/5340-30C 12.4 a 5

• Environmentalo FAA -55 to +65oC

(IEC draft -40 to 55oC)o Corrosion deteriorate contact

Timron Scientific Consulting

3-ConnectorInstallation• Connector• Wire• Working

conditions

3-ConnectorInstallation• Manufacturer’s instruction

o Cable preparationo Cleaning of cable prior to physical

installation• Electrician but a very good one

3-ConnectorInstallation with crimping toolCrimping tool usage• Dimension of the tool compare to crimp needed• Jaws position over connection and contact surface• Key crimp tooling characteristics (ref #42)

o Geometry and associated toleranceso Materialso Surface condition o Surface treatment

• Can we make a bad connection?

3-ConnectorInstallation with crimping toolCrimping tool usage• Improper alignment of die – increase of resistance• Harmful

R = 81 μΩ R= 2150 μΩFrom Fixed-position electric heaters report - R. Butturini January 2002

3-Other Types of ConnectorFor cable and CCRCompression lug

3-Other Types of ConnectorFor cable and CCRLug, crimp, …

Water protection or drained?

3-Other Types of ConnectorFor cable and CCR• Bolted connection

o Loosening due to vibration, expansion and contraction (load cycle & ambient temp.) resulting in resistance and temperature rise

o Control dynamic movement – select proper mechanical arrangement

o Why tightening bolted connection? Does it have a limit?

o Bonding resistance: 1000 μΩ consider a good connection – with clean and proper pressure (ref #36)

o Torque of bolt for a good connection 10 N.m give 150 μΩ (ref #38)

Solon Manufacturing

3-Other Types of ConnectorFor cable and CCR• Utility industries (ref #34)

o 15 μΩ normal valueo 3000 psi instead of 8000 psi 30 μΩo Defect 500 mΩ

Solon Manufacturing

• Use of heat shrinko Small diameter cableo Thin wall requiremento Difficulties to execute a good heat shrink

− Temperature (PVC 90oC – XLPE 120oC)− Heating direction− Characteristics on data sheet and selection

• Cold shrinko Flexibleo Max. 1000V. Not appropriate for voltage insulation o 5 to 8 kV and size of wire or connectoro Edges of connector

3-ShrinkProperties

Montréal International Airport – Mirabel

• Goal: Identify heat signature of good and bad connections with infrared technique on airfield lighting circuits

• Montreal airport staff

4-Experimentation Planning

4-Experimentation Planning• Testing during day time and night

time• Work plan

o Light fitting connector (P & S)−Runway & Taxiway edge light−Inset light−Approach light – steady burning and flashing

o Splice on primary cableo Connections at CCRo High voltage relay (Vacuum switch)o Test bench of failed connection

• Future testing

4-Experimentation Infrared measurement

2 types of instrument

- 0.05oC res.- 0.10oC res.

4-Experimentation Theory of infrared measurement• Thermography also IR measurement• Detection of loose connections or bad

splice. High resistance, create an increase of temperature and radiate electromagnetic energy

• ASTM E 1934 - 99a ‘’Standard Guide for Examining Electrical and Mechanical Equipment with Infrared Thermography’’

4-Experimentation Theory of infrared measurement• 4.1.9 Infrared Thermometer AC150/5340-26

Infrared thermometers are hand-held devices that can give a direct temperature readout of any surface from several feet away. They can be aimed at the target via a laser target sight. In addition to identifying loose connections in panel boards, these instruments may be used for troubleshooting of ground faults in airfield lighting circuits. By measuring the temperature of different light bases on the runway or taxiway and comparing the temperature differential between light bases, it is possible to find the location of a ground fault if the cable and transformer assembly have been arcing and burning inside a light base.

1

2

3

4-Experimentation Theory of infrared measurement

Optical resolution D:S ratio

Image from R&C instrumentation

4-Experimentation Findings• Rule of thumb: 40% of cable capacity to

detect changes in temperature Δ T ~ RI2o Secondary cable ok o Primary cable less than 15%

• Faulty secondary connector ∆T 2oC

4-Experimentation Findings• Heat and surface

• Heat and sun

T 29.9 oCT 35.5.9 oCT 39.1 oC

4-Experimentation Findings• Secondary connector failed

• At regulator – loose connection

4-Experimentation Findings• At regulator – loose connection

• Other findingso Can not measure with plexi

4-Experimentation Findings• Other findings

o Can not measure behind insulating material such Bakelite

4-Experimentation Future test

By passed 6.6 amps regulator20 amps regulator (raised heating)Transformer out of circuit Load bank

5-Conclusion General• Cable specification and installation influence

characteristic of airfield lighting circuito AGL cable leakage 0.02 μA/100 m, transformer

0.02 μA o 1 kV tester 2 ma output (from DE) –

faulty joint factor of 100 o Values at 20oC, double for each 10oC

increase• What is the influence of material

surrounding the cablingo PVC tube?o Soil?

• Would shielded cable be better for reliability?

Current leakage

5-ConclusionGeneral• Possible improvement of contact

resistance at connector• Are the existing standards for contact

measurement appropriate?• Infrared measurements are possible with

some limitation• Potential increase of susceptibility of field

installed connection with lower current circuit (2.8 amps)o Will the present connector for LED technology

will be adequate?

5-Conclusion Reliability• Can we identify the main failures and increase the

reliability of airfield lighting circuits?Failure of Electrical Distribution SystemComponent %

1- Loose connections / parts 30.3

2- Moisture 17.4

3- Line disturbance (other than lightning) 10.4

4- Defective / inadequate insulation 9.9

5- Lightning 8.1

6- Foreign objects / short circuiting 7.3

7- Collision 3.9

8- Overloading / inadequate capacity 2.4

9- Accumulation of dust, dirt and oil 2.2

10- All others causes 8.1

Based on: Hartford Steam Boiler Claims Data

5-ConclusionInstallation• Can we improved on-site installation for

connectors and investigate to monitor failures ?• Is it possible to have a tool combining

connectors and cables for on-site installation?• Care during pulling cable installation in light

base is a must• Is there room to improve guidance material and

standards about field installation?• Areas of future work and study:

o Cable failure analysiso Connector/connection failure analysiso Resistance of connectiono Statistic for IR measurements, including circuit

parameter and data

5-ConclusionSpecial thanks

• Cristian Faraon, Eng. – Montreal Airport• Denis Piché and his crew – Montreal Airport• Claude Boudreault – ITM instrument• André-Pierre Sweeney – coop student BPR• John Stubbs and Andrew Dunn – Defence

Estates • Jim Cotoara and Harman Dhillon – Amerace

QUESTIONS?

Reference

1. Fundamentals of Meggering Seward Ford - Visual Aids Digest - September 20072. Electrical Power Cable Engineering – William A. Thue3. Technical bulletin – a comparison of Three Different Methods of Marking Primary - Amerace4. Installation, commissioning and maintenance of AGL cable circuits Policy Instruction number

29 2005 Defence Estates – Ministry of Defence

5. Installation and maintenance of AGL cable circuits – Technical Bulletin 02/13 Defence Estates – Ministry of Defence

6. Southwire – Power Cable Installation Guide7. FAA AC 150/5345-7E SPECIFICATION FOR L-824 UNDERGROUND ELECTRICAL CABLE FOR

AIRPORT LIGHTING CIRCUITS 8. FAA AC150/5370-10C STANDARDS FOR SPECIFYING CONSTRUCTION OF AIRPORTS 9. CSA C22.2 no 179-00 Airport Series Lighting Cables 10. IEC TS 62100 Cables for aeronautical ground lighting primary circuits11. Screened versus Non-Screened – Eupen Airfield Lighting Cable12. FAA AC 150/5345-47B SPECIFICATION FOR SERIES TO SERIES ISOLATION TRANSFORMERS

FOR AIRPORT LIGHTING SYSTEMS 13. CSA C22.2 no 180-00 M1983 Series Isolating Transformers for Airport Lighting 14. IEC 61823 Electrical installations for lighting and beaconing of aerodromes – AGL series

transformers15. AMERACE web site16. FAA AC 150/5345-26C FAA specification for L-823, plug and receptacle, cable connectors17. IEC Draft standard Connecting Devices Equipement specifications and tests18. ASTM B 868-96 (Reapproved 2002) Standard Practice for Contact Performance Classification

of Electrical connection systems19. Stored Energy Electrical Connectors – Carl R. Tamm –CYTO Meridian Inc. 6C-TPC-320. Splicing and Terminating Excerpt Prysmian’s wire and cable engineering guide21. Performance classification for electrical connections using ASTM B 868

nReference

22. Electrical Contact Resistance: Review of Elementary Concepts – R.S. Timsit – Timron Scientific Consulting Inc.

23. Final report on fixed-Position Electric Heaters – Randy Butturini – January 200224. Critical Reliability Aspects of Electrical Contacts – Piet van Dijk25. A perspective on Connector Reliability Dr. Robert S. Mroczkowski connNtext associates26. Connector Design/Materials and Connector Reliability - Robert S. Mroczkowski AMP

incorporated27. Estimating the Reliability of Electrical Connectors – Robert S. Mroczkowski & James M.

Maynard IEEE Transaction on Reliability December 199128. N.A.29. Mechanical Analysis of the Crimping Connection S. Ogihara, K. Takata, Y. Hattori, K. Yoshida

IEEE30. Connector Theory and Application – FCI Burndy Products31. Optimization of Cable Terminations – S.V. Nikolajevic, N.M. Pekaric-Nad, R.M. Dimitrijevic

IEEE Transactions on Power Delivery April 199732. Stability and Contact Resistance Failure Criteria Robert D. Malucci33. NEBS Level 3 for Power and Grounding Lugs Thomas J. Turner Panduit34. Aging of Defective Electrical Joints in Underground Power Distribution Systems – Daniel

Founier IREQ35. Compression Technology Applied to the Construction of Primary Grounding Systems – E.W.

Perry jr, F.A. O’Loughlin, J.F. Rodrigues – Thomas and Betts Corporation36. Military Handbook – Grounding, bonding and shielding for electronic equipments and

facilities – volume 1 basic theory – MIL-HDBK-419A December 198737. Maintain Bolt Preload on Electrical Connections Using Belleville Springs – George Davet -

Solon Manufacturer company38. Failure Analysis on Bolt-Type Power Connector’s Application – Guo-Ping Luo, Ji-Gao Zhang –

IEEE39. Effect of Connection Design on the Contact Resistance of High Power Overlapping Bolted

Joints – M. Braunovic from MB Interface – IEEE 2001

nReference

40. Effect of Connector Design on the Performance of Service Entrance Power Connectors – Milenko Braunovic – IEEE Transaction on Components and Packaging Technologies March 2004

41. The Effect of Initial Connector Insertions on Electrical Contact Resistance R.L. Jackson, W.R. Ashurts, G.T. Flowers, S. Angadi, S. Cloe, M.J. Bozack IEEE

42. Crimp tooling – Where form meets function – Tyco Electronics43. Wire Crimp Connectors Verification using Ultrasonic Inspection –K. E. Cramer, D. F. Perey, W.

T. Yost NASA-Langley Research Center44. Lubrication of Electrical Contacts Bella H. Chudnovsky Schneider Electric / Square D45. Primary series circuits cables ADB-Siemens46. 3M web site47. Principles of infrared temperature measurement part 1and 2 – R & C Instrumentation.48. Fluke Web site