BS EN 61557-8-2007 低于1000V交流和1500V直流低压配电系统的电气安全.保护措施的测试、测量或监视设备.第8部分IT系统绝缘监视.pdf

BRITISH STANDARD BS EN 61557-8:2007 Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. Equipment for testing, measuring or monitoring of protective measures Part 8: Insulation monitoring devices for IT systems The European Standard EN 61557-8:2007 has the status of a British Standard ICS 17.220.20; 29.080.01; 29.240.01 BS EN 61557-8:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 September 2007 © BSI 2007 ISBN 978 0 580 54797 3 National foreword This British Standard is the UK implementation of EN 61557-8:2007, incorporating corrigendum May 2007. It is identical to IEC 61557-8:2007. It supersedes BS EN 61557-8:1997, which will be withdrawn on 1 May 2010. The UK participation in its preparation was entrusted to Technical Committee PEL/85, Measuring equipment for electrical and electromagnetic quantities. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments EUROPEAN STANDARD EN 61557-8 NORME EUROPÉENNE EUROPÄISCHE NORM July 2007 CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels © 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61557-8:2007 E ICS 17.220.20; 29.080.01; 29.240.01 Supersedes EN 61557-8:1997 English version Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. - Equipment for testing, measuring or monitoring of protective measures - Part 8: Insulation monitoring devices for IT systems (IEC 61557-8:2007 + corrigendum May 2007) Sécurité électrique dans les réseaux de distribution basse tension de 1 000 V c.a. et 1 500 V c.c. - Dispositifs de contrôle, de mesure ou de surveillance de mesures de protection - Partie 8: Contrôleurs d'isolement pour réseaux IT (CEI 61557-8:2007 + corrigendum May 2007) Elektrische Sicherheit in Niederspannungsnetzen bis AC 1 000 V und DC 1 500 V - Geräte zum Prüfen, Messen oder Überwachen von Schutzmaßnahmen - Teil 8: Isolationsüberwachungsgeräte für IT-Systeme (IEC 61557-8:2007 + corrigendum May 2007) This European Standard was approved by CENELEC on 2007-04-11. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 61557-8:2007 2 Foreword The text of document 85/296/FDIS, future edition 2 of IEC 61557-8, prepared by IEC TC 85, Measuring equipment for electrical and electromagnetic quantities, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61557-8 on 2007-04-11. This European Standard supersedes EN 61557-8:1997. The following changes were made with respect to EN 61557-8:1997: definitions complemented; revision of some requirements; addition of information on operating instructions; sections “type tests” and “routine tests” complemented; modification of Table 1; addition of Annexes A and B. This standard is to be used in conjunction with EN 61557-1. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2008-02-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2010-05-01 Annexes ZA and ZB have been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 61557-8:2007, including the corrigendum May 2007, was approved by CENELEC as a European Standard without any modification. _ 3 EN 61557-8:2007 CONTENTS 1 Scope 4 2 Normative references .4 3 Terms and definitions .5 4 Requirements.7 5 Marking and operating instructions9 5.1 Marking.9 5.2 Operating instructions10 6 Tests10 6.1 Type tests .10 6.2 Routine tests .12 Annex A (normative) Medical insulation monitoring devices (IMDs) .14 Annex B (informative) Monitoring of overload and high temperature 18 Annex ZA (normative) Normative references to international publications with their corresponding European publications21 Annex ZB (informative) A-deviations 23 Bibliography .20 Table 1 Requirements applicable to insulation monitoring devices.8 Table A.1 Additional requirements applicable to medical insulation monitoring devices (IMDs) .16 Table A.2 Emission test for medical insulation monitoring devices (IMDs) .17 EN 61557-8:2007 4 ELECTRICAL SAFETY IN LOW VOLTAGE DISTRIBUTION SYSTEMS UP TO 1 000 V a.c. AND 1 500 V d.c. EQUIPMENT FOR TESTING, MEASURING OR MONITORING OF PROTECTIVE MEASURES Part 8: Insulation monitoring devices for IT systems 1 Scope This part of IEC 61557 specifies the requirements for insulation monitoring devices (IMD) which permanently monitor the insulation resistance to earth of unearthed IT a.c. systems, for IT a.c. systems with galvanically connected d.c. circuits having nominal voltages up to 1 000 V a.c., as well as of unearthed IT d.c. systems with voltages up to 1 500 V d.c. independent from the method of measuring. NOTE 1IT systems are described in IEC 60364-4-41 amongst other literature. Additional data for a selection of devices in other standards should be noted. NOTE 2Various standards specify the use of insulation monitoring devices in IT systems. In such cases, the objective of the equipment is to signal a drop in insulation resistance below a minimum limit. NOTE 3Insulation monitoring devices according to this part of IEC 61557 may also be used for de-energized electrical systems. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60364-7-710:2002, Electrical installations of buildings Part 7-710: Requirements for special installations or locations Medical locations IEC 60664-1, Insulation co-ordination for equipment within low-voltage systems Part 1: Principles, requirements and tests IEC 60664-3, Insulation coordination for equipment within low voltage systems Part 3: Use of coating, potting or moulding for protection against pollution. IEC 60691:2002, Thermal-links Requirements and application guide IEC 60721-3-1, Classification of environmental conditions Part 3: Classification of groups of environmental parameters and their severities Section 1: Storage IEC 60721-3-2, Classification of environmental conditions Part 3: Classification of groups of environmental parameters and their severities Section 2: Transportation IEC 60721-3-3, Classification of environmental conditions Part 3: Classification of groups of environmental parameters and their severities Section 3: Stationary use at weatherprotected locations 5 EN 61557-8:2007 IEC 60947-5-1, Low-voltage switchgear and controlgear Part 5-1: Control circuit devices and switching elements Electromechanical control circuit devices IEC 60947-5-4, Low-voltage switchgear and controlgear Part 5-4: Control circuit devices and switching elements Method of assessing the performance of low-energy contacts Special tests IEC 61010-1:2001, Safety requirements for electrical equipment for measurement, control, and laboratory use Part 1: General requirements IEC 61326-2-4, Electrical equipment for measurement, control and laboratory use EMC requirements Part 2-4: Particular requirements Test configurations, operational conditions and performance criteria for insulation monitoring devices according to IEC 61557-8 and for equipment for insulation fault location according to IEC 61557-9 IEC 61557-1, Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. Equipment for testing, measuring or monitoring of protective measures Part 1: General requirements IEC 61810-2, Electromechanical elementary relays Part 2: Reliability CISPR 11, Industrial, scientific and medical (ISM) radio-frequency equipment Electromagnetic disturbance characteristics Limits and methods of measurement 3 Terms and definitions For the purposes of this document, the definitions given in IEC 61557-1 and the following definitions apply. 3.1 extraneous d.c. voltage Ufg d.c. voltage occurring in a.c. systems between the a.c. conductors and earth (derived from d.c. parts) 3.2 insulation resistance RF resistance in the system being monitored, including the resistance of all the connected appliances to earth 3.3 specified response value Ran value of the insulation resistance, permanently set or adjustable, on the device and monitored if the insulation resistance falls below this limit 3.4 response value Ra value of the insulation resistance at which the device responds under specified conditions EN 61557-8:2007 6 3.5 relative (percentage) uncertainty A % response value minus the specified response value, divided by the specified response value, multiplied by 100 and stated as a percentage %100% an ana Iã R RR A 3.6 system leakage capacitance Ce maximum permissible value of the total capacitance to earth of the system to be monitored, including any connected appliances, up to which value the insulation monitoring device can work as specified 3.7 rated contact voltage voltage for which a relay contact is rated to open and close under specified conditions 3.8 response time tan time required by an insulation monitoring device to respond under the conditions specified in 6.1.2 3.9 measuring voltage Um voltage present at the measuring terminals during the measurement NOTE Additionally to the definition given in IEC 61557-1, the measuring voltage (Um) is the voltage present in a fault-free and de-energized system between the terminals of the system to be monitored and the terminals of the protective conductor 3.10 measuring current Im maximum current that can flow between the system and earth, limited by the internal resistance Ri from the measuring voltage source of the insulation monitoring device NOTEMeasuring current is designated as injected current in IEC 60364-7-710. 3.11 internal impedance Zi total impedance of the insulation monitoring device between the terminals to the system being monitored and earth, measured at the nominal frequency 3.12 internal d.c. resistance Ri resistance of the insulation monitoring device between the terminals to the system being monitored and earth 3.13 functional earthing FE earthing a point or points in a system or in an installation or in equipment for purposes other than electrical safety NOTE For insulation monitoring devices this is the measuring connection to earth. 7 EN 61557-8:2007 4 Requirements The following requirements as well as those given in IEC 61557-1 shall apply. 4.1 Insulation monitoring devices shall be capable of monitoring the insulation resistance of IT systems including symmetrical and asymmetrical components and to give a warning if the insulation resistance between the system and earth falls below a predetermined level. NOTE 1A symmetrical insulation deterioration occurs when the insulation resistance of all conductors in the system to be monitored decreases (approximately) similarly. An asymmetrical insulation deterioration occurs when the insulation resistance of, for example, one conductor decreases substantially more than that of the other conductor(s). NOTE 2So-called earth fault relays using a voltage asymmetry (voltage shift) in the presence of an earth fault as the only measurement criterion, are not insulation monitoring devices in the interpretation of this part of IEC 61557. NOTE 3A combination of several measurement methods, including asymmetry monitoring, may become necessary for fulfilling the task of monitoring under special conditions on the system. 4.2 Insulation monitoring devices shall comprise a test device, or be provided with means for the connection of a test facility, for detecting whether the insulation monitoring device is capable of fulfilling its functions. The system to be monitored shall not be directly earthed and the devices shall not suffer damage. This test is not intended for checking the response value. 4.3 Contrary to IEC 61557-1, the PE connection of insulation monitoring devices is a measuring connection and may be treated as functional earth connection (FE). If the IMD additionally has parts which are grounded for protection purposes, this connection shall be treated as protective connection (PE). 4.4When the specified response value Ran of the insulation monitoring device is adjustable, it shall be designed in such a way that it is impossible to modify the settings, except by the use of a key, a tool or a password. NOTEStandards for the installation of electrical systems state the lowest value that is permissible as a setting on insulation monitoring devices with variable response values. 4.5 Insulation monitoring devices shall comprise a visual warning device or be provided with the facility for connecting such a device which indicates its operation. This device shall not be provided with means for being switched off. Built-in or externally connectable audible signalling devices may be fitted with a resetting facility. Sending of an audible signal in the case of a newly occurring fault, following a fault that has been cleared and after the devices may have been reset, shall be ensured. NOTEAn indication of the value of the insulation resistance by means of a measuring facility is, in itself, not sufficient as a facility for visual signalling. 4.6 The maximum operating uncertainty of insulation moni