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1、- CENELEC HD*21.2*S2/ A13 95 I 3404583 0159438 902 m HARMONIZATION DOCUMENT HD 21.2 S2lA13 DOCUMENT DHARMONISATION HARMONISIERUNGSDOKUMENT June 1995 UDC (621.31 5.21 1.2+ 621.31 5.321.027.475-036.743.22-001.2.001.4 ICs 29.060.20 Descriptors: See HD 21.2 S2 English version Polyvinyl chloride insulate
2、d cables of rated voltages up to and including 450/750 V Part 2: Test methods Conducteurs et cbles isoles au polychlorure de vinyle, de tension assigne au plus gale 450/750 V Partie 2: Mthodes dessais Polyvinylchlorid-isolierte Leitungen mit Nennspannungen bis 450/750 V Teil 2: Prfverfahren This ame
3、ndment Al3 modifies the Harmonization Document HD 21.2 S2:1990; it was approved by CENELEC on 1995-05-1 5. CENELEC members are bound to comply with the CENICENELEC Internal Regulations which stipulate the conditions for implementation of this amendment on a national level. Up-to-date lists and bibli
4、ographical references concerning such national implementation may be obtained on application to the Central Secretariat or to any CENELEC member. This amendment exists in three official versions (English, French, German). CENELEC members are the national electrotechnical committees of Austria, Belgi
5、um, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Eiectrotechnique Europisches Komitee fr Ele
6、ktrotechnische NOtTnUnQ Centrai Secretariat: rue de Stassart 35, B *- 1050 Brussels 1995 Copyright reserved to CENELEC members Ref. No. HD 21.2 S2:1990/A13:1995 E - - - 7 CENELEC HD*ZL=E!*SZ/ AL3 95 m 3404583 0359439 849 Page 2 HD 21.2 S2:1990/A13:1995 Foreword This amendment was prepared by the Tec
7、hnical Committee CENELEC TC 20, Electric cables. The text of the draft was submitted to the Unique Acceptance Procedure and was approved by CENELEC as amendment Al 3 to HD 21.2 S2:1990 on 1995-05-1 5. The following dates were fixed: - latest date by which the existence of the amendment has to be ann
8、ounced at national level (doa) 1996-01 -01 - latest date by which the amendment has to be implemented at national level by publication of a harmonized national standard or by endorsement . (dop) 1996-07-01 - latest date by which the national standards conflicting with the amendment have to be withdr
9、awn (daw) 1996-07-01 For products which have complied with HD 21.2 S2: 1990 and its amendments A2: 1 990, A3:1993, A4:1993, A6:1995 and A l 1 :1995 before 1996-07-01, as shown by the manufacturer or by a certification body, this previous standard may continue to apply for production until 1997-07-01
10、 . -,-,- Page 3 HD 21.2 S2:1990/A13:1995 Because of screened cables, replace the existing sub-clause 2.2 by the following: 2.2 Voltage test carried out on comaleted cables A sample of cable as delivered shall be immersed in water if the cable has no metallic layer. The length of the sample, the temp
11、erature of the water and the duration of immersion are given in Part 1, Table III. A voltage shall be applied in turn between each conductor and all the others connected together and to the metallic layer, if any or to the water; and between all conductors connected together and the metallic layer o
12、r water. The voltage and the duration of its application are given for each case in Part 1, Table 111. Add a new sub-clause 2.7 to HO 21.2: 2.7 Screenina efficiency 2.7.1 General The screening efficiency of a cable depends both on the screening against currents and the screening against voltages. Th
13、e screening efficiency against currents is specified in terms of the transfer impedance due to resistive and magnetic coupling per unit length, against voltages in terms of the transfer admittance due to electric coupling (see Note below) per unit length. Transfer impedance is defined in an elementa
14、ry length of cable as the ratio of the voltage measured along the screen in the disturbed system to the current flowing in the interfering system. This may be of interest at any frequency up to 10,000 MHz. In general, there is no problem where homogeneous cylindrical shields are used since the scree
15、ning effect in such cases can be readily calculated, but where a braided or taped construction is employed it becomes necessary to measure the screening efficiency. The present state of experience shows that the surface transfer impedance remains constant at frequencies from O Hz to 0.1 MHz or 1 MHz
16、, depending on the type of cable and is equal to the direct current resistance of the screen. At frequencies over 0.1 MHz or 1 MHz the transfer impedance increases. Depending on the construction of the screen, this increase starts directly or after having passed through a minimum. Over 1 O MHz to 15
17、 MHz, the increase is proportional to the frequency. Transfer admittance is defined in an elementary length of cable as the ratio,of the current flowing into the disturbed system to the voltage originating it in the specified interfering system. Measurements show that the transfer admittance may be
18、represented by a capacitance which is independent of frequency from audio frequencies up to 1,000 MHz at least. Note: Attention is drawn to the fact that in some countries the term transfer admittance is taken to be the reciprocal of transfer impedance which is not the case in this standard. - ,7 CE
19、NELEC HD*Zl.Z*SZ/ A13 95 = 3404583 0359443 4T7 Page 4 HD 21.2 S2:1990/A13:1995 2.7.2 Transfer impedance due to resistive and maanetic coupling 2.7.2.1 Test amratus The apparatus is of the triple coaxial form (see Figure 6). A short length of the cylindrical screen under investigation forms both the
20、inner conductor of an energised coaxial system and, at the same time, the outer conductor of another coaxial line. The signal in the inner coaxial system is caused by the surface transfer impedance of the screen. The cable with the screen to be measured is terminated at one end by a resistance the v
21、alue of which is numerically equal to the characteristic impedance of the screen. The terminal resistance is shielded by a metal sleeve whose edge at the open end is soldered to the screen. Terminal resistance and cable are coaxially mounted inside a metal tube. This tube is terminated at the side o
22、pposite the resistance by a short-circuiting disk, which is soldered to the screen (see Figure 6). The length of the cable in the metal tube is not to exceed 0.1L to 0.35L according to the measuring equipment used. The length of the projecting cable is of no consequence. 2.7.2.2 Test Drocedure The o
23、uter coaxial system, formed by the screen under investigation and the metal tube, is fed from a generator through an interconnected resistance (Method 1) or by way of a direct connection (Method 21. The measurement shall be carried out at 30MHz. Note: For both methods a cable length of l m is mostly
24、 adequate. The correction factor at 30 MHz is approximately 1. Method 1 : Feeding through a resistance The generator feeds the outer system through a pure resistance (RI which, to best advantage, should be equal to about 1.4 times the value of the characteristic impedance of the outer system. The in
25、put voltage to the resistance is measured by means of a suitable voltmeter. The output voltage of the inner system, which is formed by the cable proper, is measured by means of a matched voltmeter. -,-,- CENELEC HD*ZL.Z*SZ/ AL3 95 = 3404583 0359442 333 D Page 5 HD 21.2 S2: 1990lA13: 1995 The transfe
26、r impedance may then be calculated from the equation: 2R uz I ZTl = - x - x F where: 2, = R= L= u, = u , = F = the transfer impedance, in ohms per metre the feeding resistance, in ohms the length of the screen under test, in metres (see Figure 6) the input voltage of the outer system measured before
27、 the resistance R, in volts the output voltage of the inner system measured at the end of the screen, in volts a factor, which allows for the frequency response (see Figure 7). The exact value can be calculated from the relation: where: 2 1 m = - the ratio of the impedance characteristic R af the ou
28、ter system t o the resistance R Z, = the characteristic impedance of the outer system, in ohms A, = the electrical wavelength in the outer system A , = the electrical wavelength in the inner system Method 2 : Direct feeding The transmitter feeds the outer system directly. The input voltage of this s
29、ystem is measured at the beginning of the screen. The output voltage of the inner system is measured as indicated above. -,-,- -i CENELEC HD*21=2*S2/ A13 95 = 3404583 0159443 27T Page 6 HD 21.2 S2: 1990/A13: 1995 This method is preferable if it is necessary to operate at greater input voltages, as f
30、or instance with screens of a very high screening efficiency or with less sensitive output voltmeters. For this method, higher frequencies may be used than for the first method The surface transfer impedance may be calculated from the equation: The designations of the equation have the same meaning
31、as indicated for Method 1. Fu (see figure 8) may be calculated from the relation: FI = (1 -n sin x l/n2 (cos x - cos n*)2 + (sin x - n sin m)2 with the same abbreviations as for method 1. Instead of measuring U, and U2 separately, the ratio U,/U, may, using either method, be ascertained directly by
32、means of a calibrated attenuator. The maximum value for transfer impedance shall be given in the relevant cable standard. -,-,- CENELEC HD*21.2*S2/ AL3 95 I 3404583 0359444 Loh Page 7 HD 21.2 S2:1990/A13:1995 Outer coaxial system Inner coaxial system Screen under tes! Terminating resitor u1 R u2 Fig
33、ure 6 NOTE: For the measurements of electric coupling, the sheath should be removed from the cable as the field .strength at the outer conductor is seriously affected by the sheath. . -,-,- Page 8 HD 21.2 S2:1990/A13:1995 F Figure 7 - Correction Factor F - _ _ _ _ _ _ _ _ _ _ _ CENELEC HD*ZL-Z*SZ/ A
34、L3 75 I 3404583 0257446 T87 I F “ I i Page 9 HD 21.2 52:1990/A13:1995 Figure 8 - Correction Factor F# -,-,- Page 10 HD 21.2 S2:1990/A13:1995 Sub-clause 3.1 - Flexina test Add to the end of sub-clause 3.1.1 (as amended by Amendment No. 4). In addition the test is not applicable to cables having more
35、than 18 cores laid up in more than two concentric layers. Add to Table A (as amended by Amendment No. 2) the following additional cable types: Number of cores 5 6 7 12 18 Nominal csa (mmz) 0.5 0.5 0.75 1 1.5 2.5 0.5 0.75 1 1.5 2.5 0.5 0.75 1 1.5 2.5 0.5 0.75 1 1.5 2.5 Mass of weight (kg) 1 1 1.5 1.5
36、 2.0 3.5 1 1.5 1.5 2.5 3.5 1.5 2.0 3.0 4.0 7.0 2.0 3.0 4.0 6.0 7.5 Diameter of pulley mm) 80 120 120 120 120 160 120 120 120 160 160 120 160 160 160 200 160 160 160 200 200 i11 Cables with numbers of cores between 7 and 18, but not specified in this table, are non-preferred cable types. They may be tested using the mass of weight and the pulley diameter for the same conductor size at the next highest specified number of cores.