1、BRITISH STANDARD BS 7494-1: 1991 Performance and testing of teleprotection equipment of power systems Part 1: Specification for narrow-band command systems (Implementation of CENELEC HD543.1S1)BS 7494-1:1991 This British Standard, having been prepared under the directionof the Power ElectricalEngine
2、ering StandardsPolicy Committee, waspublished underthe authorityof the Standards Boardand comes into effect on 29November 1991 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference PEL/89 Draft for comment 89/33073 DC ISBN 0 580 20127 9 Committees responsi
3、ble for this British Standard The preparation of this British Standard was entrusted by the Power Electrical Engineering Standards Policy Committee (PEL/-) to Technical Committee PEL/89, upon which the following bodies were represented: Association of Consulting Engineers BAMEMA (BEAMA) BEAMA Ltd. E
4、EA (the Association of Electronics, Telecommunications and Business Equipment Industries) Electricity Supply Industry in United Kingdom GAMBICA (BEAMA Ltd.) North of Scotland Hydro-Electric Board Telecommunication Engineering and Manufacturing Association Transmission and Distribution Association (B
5、EAMA Ltd.) Amendments issued since publication Amd. No. Date CommentsBS 7494-1:1991 BSI 11-1999 i Contents Page Committees responsible Inside front cover Foreword ii Section 1. General 1 Scope 1 2 Object 1 3 Service conditions 1 3.1 Ambient conditions 1 3.2 Supply voltage with battery operation 1 3.
6、3 Supply voltage with a.c. mains operation 1 3.4 Storage conditions 1 4 Telecommunication circuit used 1 Section 2. Terminology 5 Terminology 2 Section 3. Definitions of teleprotection systems 6 General 3 7 Types of teleprotection schemes 3 8 Overall operating time of teleprotection systems (telecom
7、municationcircuit included) 3 9 Transmission time (telecommunication circuit excluded) 4 10 Security 4 11 Dependability 5 12 Nominal frequency band 5 13 Nominal impedance 5 14 Guard Command signals 5 15 Levels of guard signals 5 16 Levels of command signals 6 Section 4. Requirements 17 General equip
8、ment interface requirements 6 17.1 Insulation 6 17.2 Impulse withstand level 6 17.3 High-frequency disturbance level 6 18 Specific power supply requirements 7 18.1 Power supply variations 7 18.2 Interruptions 7 18.3 Reflected noise 7 18.4 Reverse polarity 7 19 Requirements for the teleprotection sys
9、tem performance 7 19.1 Interrelationship of requirements 7 19.2 Monitoring and alarms 9 Section 5. Methods for performance testing 20 General equipment interface tests 10 20.1 Insulation 10 20.2 Impulse withstand level 10 20.3 High-frequency disturbance level 10 21 Specific power supply tests 11 21.
10、1 Power supply variations 11 21.2 Interruptions 11 21.3 Reflected noise 11BS 7494-1:1991 ii BSI 11-1999 Page 21.4 Reverse polarity 11 22 Teleprotection system performance tests 11 22.1 Security 12 22.2 Dependability 12 22.3 Transmission time 13 22.4 Interference by discrete frequencies 13 22.5 Inter
11、ference by frequency deviation 13 22.6 Checking alarm functions 14 22.7 Multicommand equipment 14 22.8 Additional tests 14 Appendix A Supplement to Clause 22: Teleprotection system performance tests 27 Appendix B Bibliography 30 Appendix Z 30 Figure 1 Audio frequency configuration 14 Figure 2 Carrie
12、r frequency configuration 14 Figure 3 Fundamental terms on protection and teleprotection 15 Figure 4 Typical operating times for protection systems 16 Figure 5 Circuit for impulse generator 17 Figure 6 Circuit configuration for differential mode impulse withstandtestwith blocking of d.c. circulation
13、 on impulse generator 17 Figure 7 Circuit configuration for common mode impulse withstand testwithblocking of d.c. circulation on impulse generator 18 Figure 8 Circuit configuration for impulse withstand test ond.c.powersupplyterminals 18 Figure 9 Circuit for high-frequency disturbance generator 19
14、Figure 10 Test circuit for testing power supply interruptions 19 Figure 11 Test circuit for measuring reflected noise 19 Figure 12 Examples of probability of missing command versus S/N for a 200-baud channel 20 Figure 13 Test set-up for dependability measurement 21 Figure 14 Test set-up for security
15、 measurement 22 Figure 15 Examples of probability of unwanted commands versus S/N for 200-baud channel 23 Figure 16 Test set-up for measuring transmission time 24 Figure 17 Test set-up for measuring interference by discrete frequencies 25 Figure 18 Test set-up for measuring interference by frequency
16、 deviation 26 Figure 19 Frequency deviation versus time for test set-up in Figure 18 26 Figure A.1 Graph showing the uncertainty of the probability for a confidence level of 95% for various E and N 28 Figure A.2 Examples of probability of unwanted commands versus S/N for 200-baud channel 29 Publicat
17、ion(s) referred to Inside back coverBS 7494-1:1991 BSI 11-1999 iii Foreword This Part of BS7494 has been prepared under the direction of the Power Electrical Engineering Standards Policy Committee. It is based on IEC834-1:1988 “Performance and testing of teleprotection equipment of power systems” Pa
18、rt 1 “Narrow-band command systems” published by the International Electrotechnical Commission (IEC), which has been endorsed by CENELEC as HD543.1 S1. For the sake of clarity, the CENELEC common modifications have been incorporated at the appropriate places in the IEC text and are marked by a vertic
19、al line at the left-hand margin. The foreword of IEC834-1:1988 and the deleted parts of the original IEC text have been quoted inAppendix Z. IEC Publication834 is divided into two Parts. Part2 “Analogue systems” (IECPublication834-2) is under consideration by IEC and may be published as Part2 to thi
20、s British Standard. The Technical Committee has reviewed the provisions of IEC50(448):1987, IEC255-4:1976, and IEC495:1974, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. There are no equivalent British Standards. A British
21、 Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Correspond
22、ing British Standard IEC 50 (151):1978 BS4727 Glossary of electrotechnical, power, telecommunication, electronics, lighting and colour terms Part 1:Group 02:1980 Electrical and magnetic devices terminology (Technically equivalent) IEC 255-5:1977 BS 5992 Electrical relays Part 3:1983 Specification fo
23、r the insulation testing of electrical relays (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi toiv, pages1to32, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This
24、will be indicated in the amendment table on the inside front cover.iv blankBS 7494-1:1991 BSI 11-1999 1 Section 1. General 1 Scope This standard applies to narrow-band single-signal and multi-signal equipment for teleprotection. It also applies to voice frequency equipment which is used in connectio
25、n with various telecommunication systems, such as power line carrier (PLC), radio link, rented circuits, leased or owned cables. Narrow-band systems include audio frequency systems operating within a4kHz maximum band, and PLC channels within a maximum of4kHz bandwidth (for one direction of transmiss
26、ion). 2 Object The object of this standard is to establish performance requirements and recommended methods for testing channels used for transmitting signals related to the command information required by the protective devices in power systems, and to give the associated terminology. Both the powe
27、r supply belonging to the equipment and the performance of the teleprotection equipment shall be tested. All the tests should be considered as type tests (see IEC Publication50(151), International Electrotechnical Vocabulary (IEV), Chapter151): Type test (151-04-15) A test of one or more devices mad
28、e to a certain design to show that the design meets certain specifications. 3 Service conditions 3.1 Ambient conditions The stated performance requirements shall be satisfied for the following conditions: 3.2 Supply voltage with battery operation The stated performance requirements shall be satisfie
29、d for the following conditions: Voltage tolerances + 15% to 20% NOTEThe variation figures quoted are typical for lead-acid batteries, the nominal voltage being taken as2.1V per cell. 3.3 Supply voltage with a.c. mains operation The stated performance requirements shall be satisfied for the following
30、 conditions: 3.4 Storage conditions The equipment, during shipment or storage, shall not suffer any damage when the ambient temperature lies between 40 C and +70 C unless otherwise agreed upon between user and manufacturer. 4 Telecommunication circuit used Figure 1 shows the configuration of telepro
31、tection equipment working at an audio frequency band (using part of a4kHz baseband). The signals arc conveyed from the transmitter to the receiver via a telecommunication circuit. The telecommunication circuit can be: a) cable link for audio frequency transmission; b) carrier frequency links for cab
32、les and overhead lines; Temperature range 5 C to + 40 C Maximum rate of change 10 C/h Relative humidity 5% to 95% Maximum water content 28 g/m 3 Voltage tolerance +10% to 15% Frequency tolerance 5% Harmonic content 10%BS 7494-1:1991 2 BSI 11-1999 c) carrier frequency links on aerial cables on power
33、lines; d) power line carrier links (PLC); e) point-to-point radio-links (microwave); f) rented circuits; g) optical wave guides (fibre optics). The telecommunication circuits should be chosen with care, as they will be influenced by noise, change of parameters and any kind of interference which may
34、cause maloperation or nonoperation of the teleprotection equipment. Figure 2 shows the configuration when the guard and command signals are generated and received at power line carrier frequencies. Figure 1 andFigure 2 apply to both frequency shift and normally quiescent systems. Section 2. Terminol
35、ogy 5 Terminology The following terms, derived from Chapter448 of International Electrotechnical Vocabulary (IEV) IEC Publication50(448) are given for the sake of understanding.Figure 3 is intended to clarify the concepts and the relations among terms in use. 5.1 Protection (448-01-01) 5.2 Protectio
36、n equipment (448-01-04) 5.3 Protection system (448-01-06) 5.4 Selectivity (for a protection system) (448-01-07) 5.5 Absolutely selective protection system (448-01-08) 5.6 Relatively selective protection system (448-01-09) 5.7 Distance protection system (448-03-01) 5.8 Underreaching (for a distance p
37、rotection system) (448-03-02) 5.9 Overreaching (for a distance protection system) (448-03-03) 5.10 Teleprotection equipment Equipment specially designed to be used in conjunction with a protection system requiring a telecommunication link between the ends of the protected circuit, to transform the i
38、nformation given by the protection equipment in a way suitable for transmission. a) Teleprotection system System composed by the teleprotection equipment and associated telecommunication system needed, in a protection system requiring a telecommunication link, between the ends of the protected circu
39、it. b) Teleprotection channel 1) The frequency band at disposal on the telecommunication system in order to permit the transmission of protection signals in both directions. 2) System composed, for testing purposes, by teleprotection equipment connected back-to-back without the associated telecommun
40、ication system. c) Telecommunication system Telecommunication link System composed by telecommunication equipment and the associated physical link needed to transmit information signals over the distance.BS 7494-1:1991 BSI 11-1999 3 5.11 Pilot wire protection system (448-01-16) 5.12 Power line carri
41、er pilot protection system (448-01-17) 5.13 Microwave pilot protection system (448-01-18) 5.14 Communication aided distance protection system 5.15 Permissive protection system (448-03-04) 5.16 Permissive underreach distance protection system (448-03-06) 5.17 Permissive overreach distance protection
42、system (448-03-09) 5.18 Accelerated distance protection system (448-03-07) 5.19 Blocking protection system (448-03-05) 5.20 Blocking overreach distance protection system (448-03-08) 5.21 (Longitudinal) differential protection system (448-03-11) 5.22 Phase comparison protection system (448-03-13) 5.2
43、3 Directional comparison protection system (448-03-14) 5.24 Intertripping (448-01-20) Section 3. Definitions of teleprotection systems 6 General The following clauses deal with the terms used in the description and/or specification of teleprotection systems (see also Sub-clause19.1). 7 Types of tele
44、protection schemes a) Permissive trip schemes (reference Section 2) This term denotes channels operating in an audio frequency band, or in a PLC frequency band. The channel is designed with the premise that the dependability of operation is high even under conditions when, due to a power system dist
45、urbance, the telecommunication medium may be adversely affected. Frequency shift signalling with or without coding techniques is usually employed. b) Intertripping schemes (Direct trip) (reference Section 2) Intertrip channels are similar in operation to permissive trip channels with the exception t
46、hat security against unwanted operation and dependability of correct operation are prime requirements. Speed of operation is usually sacrificed to meet security and dependability requirements. c) Blocking protection schemes (reference Section 2) These channels are similar to permissive trip channels
47、, except in the more stringent requirement for dependability of operation and in the speed requirements. 8 Overall operating time of teleprotection systems (telecommunication circuit included) Overall operating time T is the time elapsed between the moment of change of state at the transmitter input
48、 and the moment of the corresponding change of state at the receiver output including propagation time and additional delay due to noise. Overall operating time is part of the fault clearance time (seeFigure 4). NOTEFault clearance time T cis shown inFigure 4 as typical only.BS 7494-1:1991 4 BSI 11-
49、1999 9 Transmission time (telecommunication circuit excluded) The transmission time of a teleprotection channel is the time elapsed between the moment of change of state at the transmitter input and the moment of the corresponding change of state at the receiver output excluding propagation time. The nominal transmission time is normally specified for a noise-free transmission path and implies zero loss probability. The transmission time of a particular change of state can be related to a specifie
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