1、BRITISH STANDARD BS 7404-4: 1991 IEC 870-4: 1990 Incorporating Amendment No. 1 Telecontrol equipment and systems Part 4: Specification for performance (Implementation of CENELECHD546.4S1)BS7404-4:1991 This British Standard, having been prepared under the directionof the Power Electrical Engineering
2、Standards Policy Committee, was published underthe authority of the Standards Board and comes intoeffect on 31 October 1991 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference PEL/89 Draft for comment 89/33074 DC ISBN 0 580 20110 4 Committees responsible
3、 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. EEA
4、(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 (BEAM
5、A Ltd.) Amendments issued since publication Amd. No. Date Comments 7172 November 1992 Indicated by a sideline in the marginBS7404-4:1991 BSI 08-1999 i Contents Page Committees responsible Inside front cover National foreword ii Introduction 3 1 Scope 3 2 Object 3 3 Classification of operational para
6、meters 3 3.1 Reliability 4 3.2 Availability 4 3.3 Maintainability 5 3.4 Security 6 3.5 Data integrity 6 3.6 Time parameters 6 3.7 Overall accuracy 8 4 Expandability 10 5 Influence of telecontrol equipment on the environment 10 5.1 Electrical influence 10 5.2 Acoustic noise 11 5.3 Thermal influence 1
7、1 Appendix A Measures to enhance system performance 12 Appendix B Evaluation of expandability 15 Annex ZA (normative) Other international publications quoted in this standardwith the references of the relevant european publications 18 Figure 1 Processing of analog information 9 Figure 2 Noise criter
8、ia (NC) curves for speech communication 11 Table 1 Reliability classes 4 Table 2 Availability classes 5 Table 3 Maintainability classes 5 Table 4 Repair time classes 5 Table 5 Data integrity classes 6 Table 6 Separating capability classes 7 Table 7 Time resolution classes 7 Table 8 Overall accuracy
9、classes 9 Table 9 Starting current classes 10 Table B.1 Extensions to process data 15 Table B.2 Extensions to application functions 16 Table B.3 Extensions to additional processing functions 16 Table B.4 Extensions to data transmission 17 Publication(s) referred to Inside back coverBS7404-4:1991 ii
10、BSI 08-1999 National foreword This Part of BS 7404 has been prepared under the direction of the Power Electrical Engineering Standards Policy Committee and is identical with IEC Publication 870-4:1990 “Telecontrol equipment and systems Part4:Performance requirements”, published by the International
11、Electrotechnical Commission (IEC), which has been endorsed by CENELEC as HD 546.4 S1. The International Standard does not give the up-to-date relation between this Part of the IEC standard and the other published and envisaged Parts and Sections. Other Parts and Sections of this British Standard are
12、 as follows. Part 1: General considerations; Section 1.1: General principles; Section 1.2: Guide for specifications; Section 1.3: Glossary; Section 1.4: Basic aspects of telecontrol data transmission 1) ; Part 2: Operating conditions; Section 2.1: Specification for classes of environmental condition
13、s and power supplies; Section 2.2: Specification for electromagnetic compatibility and erosive and corrosive influences 2) ; Part 3: Specification for interfaces (electrical characteristics); Part 4: Specification for performance; Part 5: Transmission protocols; Section 5.1: Specification for transm
14、ission frame formats; Section 5.2: Specification for transmission procedures 3) ; Section 5.3: Specification for structure of application data 4) ; Section 5.4: Specification for coding specifications of application data 5) ; Part 6: Specification for telecontrol protocols compatible with ISO and CC
15、ITT standards 2) . The Technical Committee has reviewed the provisions of IEC 50(371), IEC51, IEC271, IEC 271A, IEC 300 and the IEC 688 series, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this British Standard. 1) Will be published aft
16、er IEC 870-1-4 has been published. 2) Not yet published, envisaged as future work by IEC. 3) Will be published after IEC 870-5-2 has been published. 4) Will be published after IEC 870-5-3 has been published. 5) Will be published after IEC 870-5-4 has been published. Cross-references International St
17、andard Corresponding British Standard BS 7404 Telecontrol equipment and systems IEC 870-1-1:1988 Section 1.1:1991 General principles (Identical) IEC 870-5-1:1990 Section 5.1:1991 Specification for transmission frame formats (Identical)BS7404-4:1991 BSI 08-1999 iii A British Standard does not purport
18、 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. Summary of pages This document comprises a front cover, an inside front cove
19、r, pages i to iv, theHDtitle page, pages2 to 18, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankHARMONIZATION DOCUMENT DOCUMENT DHARMO
20、NISATION HARMONISIERUNGSDOKUMENT HD 546.4 S1 January 1992 UDC 621.398:621.316.1:681.3 Descriptors: Electronics, telecommunications, telecontrol, remote control, operating characteristics, reliability, availability, maintenance, safety, specification English version Telecontrol equipment and systems
21、Part4:Performancerequirements (IEC 870-4:1990) Matriels et systmes de tlconduite Quatrime partie: Prescriptions relatives aux performances (CEI 870-4:1990) Fernwirkeinrichtungen und Fernwirksysteme Teil 4: Anforderungen an die Leistungsmerkmale (IEC 870-4:1990) This Harmonization Document was approv
22、ed by CENELEC on 1991-12-10. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for implementation of this Harmonization Document on a national level. Up-to-date lists and bibliographical references concerning national implementation may be o
23、btained on application to the Central Secretariat or to any CENELEC member. This Harmonization Document exists in three official versions (English, French, German). CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, I
24、reland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassa
25、rt 35, B-1050 Brussels 1992 Copyright reserved to CENELEC members Ref. No. HD 546.4 S1:1992 EHD546.4S1:1992 BSI 08-1999 2 Foreword The CENELEC questionnaire procedure, performed for finding out whether or not the International Standard IEC 870-4:1990 could be accepted without textual changes, has sh
26、own that no CENELEC common modifications were necessary for the acceptance as Harmonization Document. The reference document was submitted to the CENELEC members for formal vote and was approved by CENELEC as HD 546.4 S1 on10December 1991. The following dates were fixed: For products which have comp
27、lied with the relevant national standard before 1992-12-01, as shown by the manufacturer or by a certification body, this previous standard may continue to apply for production until 1997-12-01. Annexes designated “normative” are part of the body of the standard. In this standard, Annex ZA is normat
28、ive. latest date of announcement of the HD atnational level (doa) 1992-06-01 latest date of publication ofa harmonized national standard (dop) 1992-12-01 latest date of withdrawal ofconflicting national standard (dow) 1992-12-01BS7404-4:1991 BSI 08-1999 3 Introduction Reliable and secure remote moni
29、toring and control of a geographically widespread process is the ultimate goal of a telecontrol system. This standard covers those aspects which contribute to achieving a level of system performance consistent with that goal. The approach adopted in this standard has been to treat the subject of per
30、formance requirements on the basis of the inherent properties of telecontrol systems. The inherent properties of a system are those intangibles, such as availability, time parameters, etc., which in many ways affect the overall system performance. During normal system operation, these properties and
31、 their effect on the system performance go largely unnoticed. Their real value is only noticed in exceptional circumstances, such as on detection of a fault, or when it is necessary to extend the system. The system performance, especially under these conditions, reflects the consideration given to t
32、hese properties in the planning, design and manufacture of the equipment. In determining the performance requirements for a particular telecontrol system, care should be taken to stipulate standards which are adequate for the specific application, without being tempted to place excessive demands. A
33、balance should be found between the ideal requirements on the one hand, and the technical and financial consequences on the other hand. 1 Scope This series of standards applies to telecontrol equipment and systems with coded bit serial data transmission for monitoring and control of geographically w
34、idespread processes. The scope of this standard embraces telecontrol systems in the restricted sense, as shown in IEC Publication 870-1-1, Figure 2. 2 Object This part deals with those characteristics which affect the performance of telecontrol systems and relates the characteristics to the applicat
35、ion and processing functions. The object of this part is to establish a set of rules which can be used to assess and specify the performance requirements of telecontrol systems. It is intended that this part serves as a common platform for the system planner and the supplier or manufacturer of telec
36、ontrol systems. The system planner will find the contents helpful in determining the requirements for a particular telecontrol system. In addition, these rules provide a means of comparing the products of different suppliers. The supplier or manufacturer will find guidelines for the system design an
37、d a base for classification of system performance. This part comprises a main body, which contains the actual standard, together with two appendices, which contain further information and recommendations. The main body is devoted chiefly to a treatment of the various characteristics as operational p
38、arameters. A short description of each operational parameter is followed by a list of the necessary performance requirements and, where feasible, a classification of the operational parameters in performance classes. The performance classes serve to specify the system requirements for a particular a
39、pplication and to evaluate the system performance of different telecontrol systems. The performance classes used are to be optimized for each application and agreed upon between the user and the supplier. 3 Classification of operational parameters This clause covers those properties which influence
40、the performance of telecontrol systems. Appropriate requirements and, where feasible, performance classes have been specified for each of the properties covered. The classification ratings given apply in general to the performance of the units of the overall system. The performance of the overall sy
41、stem shall be derived from the performance of all components of a telecontrol system (in the restricted sense), excluding the process and the operators equipment. Certain properties, however, such as reliability and availability, can be applied as performance criteria to individual items of equipmen
42、t. The components of an overall system are, for instance: substations; nodes; transmission lines; central processor; man/machine interface.BS7404-4:1991 4 BSI 08-1999 The requirements for a particular telecontrol system are dependent on the specific application and are invariably subject to agreemen
43、t between supplier and user. 3.1 Reliability Reliability is defined as a measure of an equipment or system to perform its intended function under specified conditions for a specified period of time (see IEC Publications 271, 271A and 300). It is a probability figure, based on failure data and length
44、 of operating time. The reliability of a telecontrol system is expressed by the “mean time between failures” in hours (MTBF), and can be calculated from the reliability figures of the individual system components (seethe standards of Technical Committee No. 56). The reliability of a system depends o
45、n the following factors: the reliability of the system equipment and the software; the configuration of the system. Measures which may enhance the reliability are listed in Appendix A, clause A.1. 3.1.1 Reliability requirements The overall system reliability and partial reliabilities of certain spec
46、ified sections of the telecontrol system are to be calculated by the supplier from the reliability figures of the individual components, and proved against the actual performance in the field over a given trial period. The start and duration of the trial period should be agreed upon between the supp
47、lier and the user and should exclude the early failure period. The equipment supplier should provide on request failure distribution data for all components, assemblies and units which, on failure, could cause loss of a function or malfunction of the system. The failure modes and the effects of fail
48、ures on the system performance shall be analysed by the supplier and the results made available on request. 3.1.2 Reliability classes In the reliability classes provided in Table 1, the values given refer to the reliability of the units of the overall system. Table 1 Reliability classes 3.2 Availabi
49、lity The availability of a unit of a system characterizes its ability to perform its required function at any given moment. The availability is a probability figure which concerns operation at a given instant, in contrast to reliability which concerns operation over a given period. The availability of a unit of the overall system, expressed in “A”, may be calculated using the equation: In applications where outages due to preventive maintenance degrade system operation, the down
