ASD-STAN PREN 3475-603-2016 Aerospace series Cables electrical aircraft use Test methods Part 603 Resistance to wet arc tracking (Edition P 5).pdf

1、ASD-STAN STANDARD NORME ASD-STAN ASD-STAN NORM prEN 3475-603 Edition P 5 June 2016 PUBLISHED BY THE AEROSPACE AND DEFENCE INDUSTRIES ASSOCIATION OF EUROPE - STANDARDIZATION Rue Montoyer 10 - 1000 Brussels - Tel. 32 2 775 8126 - Fax. 32 2 775 8131 - www.asd-stan.org ICS: 49.060 Supersedes edition P 4

2、 of June 2009 and will supersede EN 3475-603:2011 Descriptors: ENGLISH VERSION Aerospace series Cables, electrical, aircraft use Test methods Part 603: Resistance to wet arc tracking Luft- und Raumfahrt Elektrische Leitungen fr Luftfahrtverwendung Prfverfahren Teil 603: Lichtbogenfestigkeit, feucht

3、Srie arospatiale Cbles lectriques usage aronautique Mthodes dessais Partie 603 : Rsistance lamorage et la propagation darc lectrique, essai humide This “Aerospace Series“ Prestandard has been drawn up under the responsibility of ASD-STAN (The AeroSpace and Defence Industries Association of Europe -

4、Standardization). It is published for the needs of the European Aerospace Industry. It has been technically approved by the experts of the concerned Domain following member comments. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that inter

5、changeability is affected, physically or functionally, without re-identification of the standard. After examination and review by users and formal agreement of ASD-STAN, it will be submitted as a draft European Standard (prEN) to CEN (European Committee for Standardization) for formal vote and trans

6、formation to full European Standard (EN). The CEN national members have then to implement the EN at national level by giving the EN the status of a national standard and by withdrawing any national standards conflicting with the EN. ASD-STAN Technical Committee approves that: “This document is publi

7、shed by ASD-STAN for the needs of the European Aerospace Industry. The use of this standard is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” ASD-STAN reviews each standar

8、d and technical report at least every five years at which time it may be revised, reaffirmed, stabilized or cancelled. ASD-STAN invites you to send your written comments or any suggestions that may arise. All rights reserved. No parts of this publication may be reproduced, stored in a retrieval syst

9、em or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of ASD-STAN. Order details: E-mail: salesasd-stan.org Web address: http:/www.asd-stan.org/ Edition approved for publication 1st June 2016 Comments should be

10、 sent within six months after the date of publication to ASD-STAN Electrical Domain Copyright 2016 ASD-STAN prEN 3475-603:2016 (E) 2 Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Specimen requirements 3 4 Preparation of specimen 4 5 Apparatus . 5 6 Method 8 7 Requirements . 9 Forewor

11、d This standard was reviewed by the Domain Technical Coordinator of ASD-STANs Electrical Domain. After inquiries and votes carried out in accordance with the rules of ASD-STAN defined in ASD-STANs General Process Manual, this standard has received approval for Publication. prEN 3475-603:2016 (E) 3 1

12、 Scope This standard specifies a method of assessing the behaviour of cable insulation subject to an electric arc initiated and maintained by contaminating fluid along the surface of the insulation. This standard shall be used together with EN 3475-100. The primary aim of this test is: to produce, i

13、n a controlled fashion, continuous failure effects, which are representative of those, which may occur in service when a typical cable bundle is damaged and subjected to aqueous fluid contamination. Electrical arcing occurs along the surface of the insulation between damage sites on adjacent cables;

14、 and to examine the aptitude of the insulation to track, to propagate electric arc to the electrical origin. Originally defined for 115 Vac network, this test also proposes conditions for 230 Vac network. Unless otherwise specified in product standard, only 115 Vac conditions shall be satisfied. Six

15、 levels of prospective fault current have been specified for concerned cable sizes (see Clause 7). It is agreed that sizes larger than 051 need not be assessed since the short-circuit phenomenon becomes dominant at low line impedances. Unless otherwise specified in the technical/product standard siz

16、es 002, 006 and 020 cable shall be assessed. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of

17、 the referenced document (including any amendments) applies. EN 2350, Aerospace series Circuit breakers Technical specification EN 3197, Aerospace series Design and installation of aircraft electrical and optical interconnection systems EN 3475-100, Aerospace series Cables, electrical, aircraft use

18、Test methods Part 100: General EN 3475-302, Aerospace series Cables, electrical, aircraft use Test methods Part 302: Voltage proof test A-A-52083, Tape, lacing and tying, glass 1) 3 Specimen requirements Cables to be tested shall be of traceable origin and shall have passed the high voltage dielectr

19、ic test defined in the product standard. 1) Published by: Department of Defense Industrial Supply Center, ATTN: DISC-BBEE, 700 Robbins Avenue, Philadelphia, PA 19111-5096 USA. prEN 3475-603:2016 (E) 4 4 Preparation of specimen Cut seven separate lengths approximately 0,5 m consecutively from one len

20、gth of cable, and strip each of the ends of insulation to permit electrical connection. Clean each length of cable with a clean cloth moistened with propan-2-ol (isopropyl alcohol) fluid. Damage two lengths of the cable by inflicting a cut around the total circumference at the mid-point of the lengt

21、h, taking care to ensure that the cut penetrates to the conductor around the full circumference and has a width of 0,5 mm to 1,0 mm. Lay up the seven cables as follows: a) Form the cables in a six around one configuration as shown in Figure 1. b) Displace the damaged cables longitudinally such that

22、a separation of (10 0,5) mm of undamaged insulation is provided as shown in Figure 2. This is called the test zone. c) Ensure that cables are straight and geometrically parallel, and restrained by lacing tapes such that they are in continuous contact within the test zone. d) Position the lacing tape

23、s (4 1,0) mm away from outer each notch and then at 15 mm to 20 mm spacing towards the ends of the specimen as show in Figure 2. The tie material used adjacent to the notch shall be PTFE glass lacing tape conforming to A-A-52083 type IV, finish D, size 3. e) Number the cables as shown in Figure 1 su

24、ch that the fault cables are numbers A1 and B1 and the centre is N. Cables C1, A2, B2 and C2 are grouped around N. Key 1 Drop needle A1-A2 : Phase A B1-B2 : Phase B C1-C2 : Phase C N : Neutral cable connected to earth Figure 1 Specimen configuration prEN 3475-603:2016 (E) 5 Key 1 Test zone (10 0,5)

25、mm 2 Notch 0,5 mm to 1 mm 3 15 mm to 20 mm 4 Lacing tape 5 Drop needle Figure 2 Test configuration 5 Apparatus 5.1 Electrical equipment Connect the seven cables of the test specimen within the circuit shown in Figure 3. This circuit shall have the following requirements: a) The provision of adjustab

26、le levels of prospective fault currents for the six A, B and C cables and an electrical return path for the N cable. b) A three phase 115/200 V 400 Hz (115 Vac network) or 230/400 V 400 Hz (230 Vac network) star (Y) connected supply shall be derived from a dedicated rotary machine capable of sustain

27、ing the maximum prospective fault current given in Table 1 (115 Vac network) or Table 2 (230 Vac network) for at least sufficient time for the circuit protection to operate. In any case the generator shall have a sufficient rating to provide these prospective fault currents. prEN 3475-603:2016 (E) 6

28、 c) The (115 - 115 W per phase for 115 Vac network or 230 - 230 W per phase for 230 Vac network) ballast resistors R1, are fitted in order to prevent over voltage during the arc extinction phases (opening of an inductive circuit). d) 115 Vac or 230 Vac circuit breakers (D2) shall be single pole unit

29、s rated at the values specified in Table 3. They shall have trip characteristics in accordance with EN 2350 or as required by the product. NOTE 1 Reference of circuit breakers used shall be recorded. NOTE 2 In particular case, others ratings of thermal breaker protection could be employed in accorda

30、nce with aircraft manufacturer rules. e) The electrical power source shall be appropriately protected and should be established that no combination of test circuit events would activate this protection. f) The resistors shall be non-inductive and have appropriate power rating. Care shall be taken to

31、 position all laboratory wiring such that inductive effects are reduced to a practical minimum. Supply cables shall be as short as possible. g) Cables A, B and C shall be connected to indication and open circuit detectors (Rg) at the entry into the grounded star point. These components shall limit t

32、he standing current to no more than 10 % of the circuit breaker rating. h) An automatic shut down facility shall be provided, which shall upon the detection of any open circuit during the test and after a 10 s delay, shutdown the flow of electrolyte and electrical power. An open circuit in this case

33、 means either a physical break in the specimen or a thermal breaker trip. The facility to override this shut down facility shall be provided so as to restore the power whilst still inhibiting the flow of electrolyte. The physical break in the specimen is to be indicated by lamps in series with resis

34、tor Rg. i) Appropriate instrumentation, recording and switching control shall be installed in accordance with good laboratory practice. j) Adjust resistor Rg so that the current (I) in the circuit is 10 % of value of the circuit breaker rated current. prEN 3475-603:2016 (E) 7 Key 1 Phase A 2 Phase B

35、 3 Phase C 4 Supply protection 5 Test bundle 6 Indicators (lamp) + Rg Figure 3 Test schematic circuit 5.2 Test equipment Construct an apparatus as shown diagrammatically in Figure 3 which includes the following minimum provisions: a) Electrical terminations to provide a ready means of connecting tes

36、t specimens into the circuit as shown in Figure 2. b) A transparent enclosure to protect personnel from ejected molten metal and short wavelength ultra violet light. c) An electrolyte delivery system which provides a constant rate of (100 10) mg per minute and dispenses drops from an 18 gauge needle

37、 cut square at the outlet. NOTE The needle wall thickness should be selected such that the specified flow rate will be delivered at approximately 6-10 drops per minute. 5.3 Test protocol 5.3.1 The procedure embraces copper cable sizes 001 to 051 (26 to 10) or aluminium cable sizes 002 to 051 (24 to

38、10) and for each size six values of prospective maximum fault current to be set by adjustment of resistances Rf have been defined in Table 1 or Table 2. Performance of the cable at a given fault current shall be determined by testing three specimens. Thus 18 specimens are required for each cable siz

39、e. prEN 3475-603:2016 (E) 8 5.3.2 For the purpose of cable qualification at least sizes 002, 006 and 020 shall be tested. Additional testing of other sizes may be deemed necessary in particular cases and values of prospective fault currents, the ratings of thermal breaker protection which are typica

40、l of aircraft use have been included in Table 3. 5.3.3 It is emphasised that electrical arcing tests are essentially destructive and can be hazardous to personnel. Therefore tests should be undertaken with all observers shielded from direct physical and visual exposure as noted in 5.2 b). The use of

41、 video recording for all tests is required. 5.4 Test rig set-up 5.4.1 Install the rating of circuit breaker appropriate to the cable type and size to be tested (Table 3). 5.4.2 Heavy-duty electrical connections shall be fitted in substitution of test specimen to enable prospective fault currents to

42、be set by adjustment of resistances Rf. Because these currents would trip the thermal breakers very rapidly these shall be shunted to permit the pulsing of current until the desired value is obtained. Re-instate the thermal protection. 5.4.3 Prepare an electrolyte solution made by dissolving (3 0,5)

43、 % by weight of sodium chloride in distilled water. 5.4.4 Support the specimen in free air inclined at an angle of 10 to the horizontal with the electrical input connections at the higher end and with the cables forming the test zone uppermost. 5.4.5 Position the delivery system so that the electrol

44、yte contacts the loom from a height of (10 2) mm above the uppermost cables in the loom at a point which shall position the droplets into the upper cut or no more than 2 mm towards the higher end of the specimen. Ensure that the drops strike the cables in the middle of the test zone, the top centre

45、of the circumference such that they fall into the crevice between cables at A1 and B1. 6 Method 6.1 Test procedure 6.1.1 Install a test specimen with electrical connections as shown in Figure 1 and with Rf set, as in 5.4.2 above, to give the required fault current specified in Table 1. 6.1.2 Apply e

46、lectrical power to the specimen and start the flow of electrolyte at a rate of (100 10) mg/min. Particular care should be taken to ensure that the electrolyte flows between the damage sites as the evidenced by the steaming of the electrolyte and the development of scintillation. 6.1.3 Run the test c

47、ontinuously for a period of 8 hours or until an automatic shut down (CB tripping or/and an extinction of lamps occur), whichever is the sooner. 6.1.4 In the event of an automatic shutdown adopt the following procedure: a) After not less than 3 min, nor more than 10 min, and with all thermal circuit

48、breakers closed, reapply power to the specimen with the automatic trip circuit deactivated and with no further flow of electrolyte. b) Maintain the power for 15 min to allow any fault condition to develop fully but do not reset any of the thermal circuit breakers. 6.1.5 Repeat the test to obtain thr

49、ee tested specimens and then repeat the procedure for all the fault currents until all 18 specimens have been tested. prEN 3475-603:2016 (E) 9 6.2 Examination EN 3197, can be used as a guideline to differentiate short-circuit and arc-tracking effects. Noticeable damages may come from either: aptitude of the insulation to become an electrically conducting material (arc-tracking phenomenon); propagation of thermal effects due to estab