1、STD.BSI BS EN b0255-25-ENGL 2000 D Lb24bb7 0877b53 771 D BRITISH STANDARD Electrical relays - Part 25: Electromagnetic emission tests for measuring relays and protection equipment The European Standard EN 60255252000 has the status of a British Standard ICs 29.120.70; 33.100.10 NO COPYING WITHOUT BS
2、I PERMISSION EXCEPT AS PERMITED BY COPRIGH LAW BS EN E0255-25:2000 IEC 50255-25:2000 COPYRIGHT European Committee for Electrotechnical StandardizationLicensed by Information Handling Services STD*BSI BS EN b0255-25-ENGL 2000 = Lb24bb7 0877b5LI b28 BS EN 60255-25:2000 Amd No. This British Standard, h
3、aving been prepared under the direction of the Electrotechnical Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 November 2000 Date Comments O BSI 11-2000 ISBN O 580 36672 3 National foreword This British Standard is the official English lang
4、uage version of EN 60255-252000. It is identical with IEC 60255252000. The UK participation in its preparation was entrusted to Technical Committee PEU95, Measuring relays and protection systems, which has the responsibility to. - aid enquirers to understand the text; - present to the responsible in
5、ternational/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; - monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this commitLee can be obtained on request t
6、o its secretary. From 1 January 1997, all IEC publications have the number 6 added to the old number. For instance, IEC 27-1 has been renumbered as IEC 60027-1. For a period of time during the change over from one numbering system to the other, publications may contain identinem from both systems. C
7、ross-references Attention is dram to the fact that CEN and CENELEC Standards nody include an annex which lists normative references to international publications with their corresponding European publications. “he British Standards which implement international or European publications referred to i
8、n this document may be found in the BSI Standards Catalogue under the section entitled “Int or b) within a screened room; or c) above a metal ground plane which shall extend at least 0,5 m beyond the boundary of the EUT and have a minimum size of 2 m x 2 m. 5.2.2 Measuring receivers Measurements sha
9、ll be carried out using receivers which comply with the requirements of CISPR 16-1. 5.2.3 Measurement of the conducted terminal interference voltage shall be made using a LISN consisting of a 50 !2 / 50 pH V-network, as specified in CISPR 16-1. Line impedance stabilisation network (LISN) The V-netwo
10、rk is required to provide a defined impedance at high frequency and provides isolation of the circuit under test from the ambient noise on the energizing lines. The V-network shall be located so that its closest surface is not less than 0,8 m from the nearest boundary of the EUT. It shall be connect
11、ed to the EUT by a I m length of cable. 8 BSI 11-2000 COPYRIGHT European Committee for Electrotechnical StandardizationLicensed by Information Handling ServicesSTD-BSI BS EN b0255-25-ENGL 2000 D Lb24bb7 0877bbl b m Page 7 EN 602 5 5-2 5 :2000 The ground plane shall be connected to the reference eart
12、h terminal of the V-network with a conductor as short as possible. Earth connections, where required for safety purposes, shall be connected to the reference earth terminal of the V-network and, where not otherwise provided or specified by the manufacturer, shall be 1 m long and run parallel to the
13、auxiliary power supply connection at a distance of not more than Oll m. Other earth connections (for example, for EMC purposes) either specified or supplied by the manufacturer for connection to the same terminal as the safety earth connection shall also be connected to the reference earth terminal
14、of the V-network. The length of these connections shall be as short as possible. It may not be possible to measure at some frequencies due to conducted ambient noise which couples with local broadcast service fields. In order to overcome this difficulty, a suitable additional radiofrequency filter m
15、ay be inserted between the V-network and the auxiliary supply, or measurements may be performed in a shielded enclosure. The components forming the additional radiofrequency filter should be enclosed in a metallic screen directly connected to the reference earth of the measuring system. The requirem
16、ents for the impedance of the V-network should be satisfied, at the frequency of measurement, with the additional radio- frequency filter connected. 5.3 5.3.1 Measurement test site The test site shall, characteristically, be flat, free of overhead wires and nearby reflecting structures and sufficien
17、tly large to permit antenna placement at the specified distance and to provide adequate separation between the antenna, the EUT and any reflecting structures. Requirements for measurement of radiated emissions One such test site which meets the criteria is shown in Figure 1. This test site is within
18、 the perimeter of an ellipse having a major diameter equal to 20 m and a minor diameter of 17,32 m. The EUT and the measuring equipment are placed at the foci, which are IO m apart. The natural ground plane of the test site shall be augmented with a conducting metal ground plane covering the entire
19、area between the EUT and the measuring antenna. The metal ground plane shall extend at least 1 m beyond the perimeter of the EUT at one end and at least 1 m beyond the measuring antenna and its supporting structure at the other end. A ground plane complying with these requirements is shown in Figure
20、 2. In order to comply with the site attenuation requirements, on some sites it may be necessary to install a conducting ground plane covering a larger area than that shown. The conducting metal ground plane shall have no voids or gaps having dimensions larger than one-tenth of a wavelength at the h
21、ighest frequency of measurement (approximately 30 mm at 1 O00 MHz). If tests are conducted at sites that do not have the characteristics described above, evidence shall be obtained that the errors due to such alternative sites do not invalidate the results obtained. One example of an alternative sit
22、e is an anechoic chamber. Test sites shall be validated by making both horizontal and vertical polarisation site attenuation measurements. Antenna spacing used for making site attenuation measurements shall be the same as the spacing used for the radiated emission tests. A measurement test site shal
23、l be considered acceptable if the horizontal and vertical site attenuation measurements are within 14 dB of the theoretical site attenuation for an ideal site (see also CISPR 16-1). O BSI 11-2000 COPYRIGHT European Committee for Electrotechnical StandardizationLicensed by Information Handling Servic
24、esSTD*BSI BS EN bOZ55-25-ENGL 2000 H Lb2LibbS 0877bb2 7TV Page 8 EN 60255-25:ZOOO 5.3.2 Measuring receivers Measurements shall be carried out using receivers with quasi-peak detectors which shall be in accordance with CISPR 16-1. 5.3.3 An ten n a The antenna shall be a balanced dipole. For frequenci
25、es between 30 MHz and 80 MHz, the antenna shall have an 80 MHz resonance length, and for frequencies between 80 MHz and 1 O00 MHz, the antenna shall be resonant in length. Further detailed information is given in CISPR 16-1. The antenna shall be suitable for the measurement of both horizontal and ve
26、rtical polarisation. The centre of the antenna shall be adjustable between I m and 4 m above ground. The nearest point of the antenna to ground shall not be less than 0,2 m from the ground. NOTE Other antennae may be used, provided the results can be correlated with the balanced dipole antenna. 6 Te
27、st procedure for emission tests 6.1 The tests shall be carried out with the equipment under reference conditions as stated in IEC 60255-6. The tests shall be carried out with the rated values of auxiliary energising and input energising quantities applied to the appropriate circuits of the EUT. The
28、applied values shall be representative of normal in-service quiescent conditions and the EUT shall neither be in a transient operational state nor in an operated state. General configuration of the EUT NOTE For most of their operational life, measuring relays and protection equipment are in a quiesc
29、ent state, and the instances when they may be operating or operated are extremely short; in these instances, the emissions from the EUT are not considered to be of significance. Where possible, it is recommended that all power and signal sources used for test purposes should be located outside the b
30、oundary of the test site. The relationship of the EUT to the ground plane shall be equivalent to that occurring in use. All parts of the EUT shall be at least 0,8 m from any other metal surfaces. Normally, the EUT shall be individually tested by being placed on a non-conducting table 0,8 m above the
31、 ground plane. Where the EUT is exclusively mounted in a cubicle, the tests may be carried out with the EUT in the cubicle. The cubicle should be floor-standing, but, for practical reasons, a distance of approximately 0,l m is recommended between the cubicle and the ground plane. Where earth connect
32、ions are required for safety purposes, they shall be connected to the reference earth point. Where they are not otherwise provided or specified by the manufacturer, earth connections shall be, where practicable, 1 m long and run parallel to the auxiliary power supply connection at a distance of not
33、more than 0,l m. Other earth connections (for example, for EMC purposes), either specified or supplied by the manufacturer for connection to the same terminal as the safety earth connection, shall also be connected to the reference earth. The length of these connections shall be as short as possible
34、. Interconnecting cables and connectors shall be as specified by the manufacturer. The exposed wiring is run in a configuration which essentially simulates normal wiring, .e. the wiring is run to the side of the EUT and then either up or down. 8 BSI 11-2000 COPYRIGHT European Committee for Electrote
35、chnical StandardizationLicensed by Information Handling Services- STD-BSI BS EN b0255-25-ENGL 2000 Lb2LibbS 0877bb3 b3O Page 9 EN 60255-252000 6.2 Measurement of conducted emissions Measurements shall be performed on the auxiliary power supply connections only. If the reading of the measuring receiv
36、er shows fluctuations close to the limit, the reading shall be observed for at least 15 s at each measurement frequency; the highest reading shall be recorded, with the exception of any brief, isolated high reading which shall be ignored. 6.3 Measurement of radiated emissions The separation between
37、the EUT and the measuring antenna should be 10 m. In order to measure the emission in all directions, the EUT shall be rotated relative to a fixed antenna by being placed on a turntable. The turntable shall be rotated fully with the measuring antenna oriented for both horizontal and vertical polaris
38、ation. Alternatively, the antenna can be moved. The separation between the EUT and the measuring antenna shall be the horizontal distance between the measuring antenna and the nearest part of the boundary of the EUT. The boundary is defined by an imaginary straight-line periphery describing a simple
39、 geometric configuration encompassing the EUT. All inter-system cables and connected equipment shall be included within this boundary. The centre of the antenna shall be adjusted between 1 m and 4 m above ground to achieve maximum emission measurement at each test frequency. If the reading of the me
40、asuring receiver shows fluctuations close to the limit, the reading shall be observed for at least 15 s at each measurement frequency; the highest reading shall be recorded, with the exception of any brief, isolated high reading which shall be ignored. The relative positions of the EUT and antenna a
41、t which the highest emission is measured shall be used for the final emission measurements. 6.4 Measurement of radiated emissions at alternative distances The separation between the antenna and the EUT shall be as specified in 5.3.1 and 6.3. If the emission levels at the specified distance cannot be
42、 made because of high ambient noise levels (see 5.1), or for other reasons, measurement may be made at distances other than 10 m but not below 3 m. When this is done, the test report should record the distance and the circumstances of the measurement. For measurement distances other than 10 m, an in
43、verse proportionality factor of 20 dB per decade should be used to normalize the measured data to the specified distance for determining compliance. Alternatively, the acceptable field strength L2 in pV/m at a distance d2 corresponding to the specified limit of LI at distance dl can be determined fr
44、om the following expression: L2 = Ll (dlld2) Care should be taken when measuring the emission levels of the EUT at distances of less than 10 m at frequencies near 30 MHz, due to near-field effects. O BSI 11-2000 COPYRIGHT European Committee for Electrotechnical StandardizationLicensed by Information
45、 Handling Services - STDSBSI BS EN b0255-25-ENGL 2000 I LbZYbbS D877bb4 577 I Page 10 EN 60255-25:2000 In the frequency bands where the ambient noise values of 5.1 are exceeded (measured values higher than 6 dB below the limit), the disturbance values of the EUT may be interpolated from the adjacent
46、 disturbance values. The interpolated value shall lie on the curve describing a continuous function of the disturbance values adjacent to the ambient noise. 7 Criteria for acceptance The EUT shall satisfy the requirements of this specification if conducted and radiated emissions during the tests do
47、not exceed the limits given in 4.1 and 4.2. As stated in CISPR 22, the results of an evaluation of the emissions of EUTs having at least one of each type of identical module can be applied to configurations having more than one of each type of those modules. This is permissible because it has been f
48、ound that, in practice, emissions from identical modules are not additive. This non-additive principle can be applied to protection equipment made up of a number of identical measuring relays. 8 Test report The test report shall include e the identification and configuration of the EUT; e the test c
49、onditions; the mounting and orientation of the EUT; the type(s) and number of interconnecting wires used and the interface port (of the EUT) to which these are connected; the operating conditions of the EUT, for example, relay settings and values of input energizing quantities; the position of the antenna; the measuring equipment settings, for example, bandwidth, step size, measurement time; the measuring equipment used; the emission level at each frequency; the test conclusion (pasclfail). O BSI 11-2000 COPYRIGHT European Committee for Electrotechnical Standardizat
