Detail of SH/T 3164-2021

Introduction of SH/T 3164-2021

Design specification for instrument system lightning surge protection in petrochemical industry 1 Scope This specification specifies the design specification for lightning surge protection engineering of instrumentation. This specification is applicable to the design of lightning surge protection for instrumentation used in explosive atmospheres and non-explosive atmospheres in petrochemical industry and for new construction, extension and renovation of factories using coal as raw materials to prepare fuel and chemical products. 2 Normative references The following documents contain requirements which, through reference in this text, constitute provisions 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. GB 50057-2010 Code for design protection of structures against lightning GB/T 18802.21 Low-voltage surge protective devices - Part 21: Surge protective devices connected to telecommunications and signaling networks - Performance requirements and testing methods 3 Terms and abbreviations 3.1 Terms For the purposes of this specification, the following terms apply. 3.1.1 air-termination system metal object and metal structure used for directly receiving or withstanding lightning strikes, such as air-termination rod (formerly known as "lightning conductor"), air-termination belt (line) and air-termination grid 3.1.2 down conductor system conductor connecting the air-termination system to the earth termination system 3.1.3 earth termination system set of bonding conductors between earthing electrodes 3.1.4 earth electrode buried metal object forming conductive contact with the earth; various metal components, metal facilities, metal pipelines, metal equipment, etc., which are in direct contact with the earth, may be regarded as earth electrode, which is called natural earth electrode 3.1.5 bonding connection of the equipment, instrument and bonding bar that need to be earthed into an earthing system with bonding wires and conductors 3.1.6 bonding conductor conductor used for connecting various pieces of equipment and bonding bar that need to be earthed into an earthing system 3.1.7 direct lightning flash lightning that directly strikes actual objects such as buildings, earth, facilities or equipment 3.1.8 lightning current current in the lightning discharge path 3.1.9 thunderstorm day number of days when one or more thunders are heard; the average annual thunderstorm day in a region is the average of annual thunderstorm day statistics for many years in this region, and it is one of the indicators to characterize the frequency of lightning activity in this region 3.1.10 lightning induction electrostatic induction and lightning electromagnetic induction generated in the space surrounding lightning current 3.1.11 lightning electromagnetic induction phenomenon that lightning current generates an electromagnetic field in the surrounding space and a conductor generates an induced electromotive force in this electromagnetic field 3.1.12 electromagnetic shielding shield to the protected target with a material capable of reducing the passage of electromagnetic field 3.1.13 lightning surge current and voltage in the form of pulses conducted along a circuit or conductor generated by lightning electromagnetic induction 3.1.14 equipotential bonding conductive connection among various metal components, metal facilities, metal pipelines and metal equipment with conductors, so that the potentials of the objects are approximately equal 3.1.15 bonding strip strip metal installed in the cabinet that collects and connects the bonding wires, which may be classified into working bonding strip, protective bonding strip, etc. based on the application 3.1.16 bonding bar strip metal installed out of the cabinet, which has a large overall dimension and is used for collecting multiple bonding wires or composing earthing grid 3.1.17 surge protective device device that uses gap discharge, bypass conduction and voltage limiting methods for shunting surge current and limiting instantaneous overvoltage to protect electrical or electronic devices 3.1.18 maximum continuous operating voltage maximum voltage that is continuously applied to a surge protective device without affecting the signal transmission process and signal quality, also known as maximum operating voltage   3.1.19 nominal discharge current max. anti-surge current capacity of a surge protective device without being damaged, that is, the maximum discharge capacity of the surge protective device to surge current if it is subjected to the standard experimental waveform current and the specified number of experiments 3.1.20 voltage protection level maximum voltage present at the rear end of a surge protective device when the surge protective device discharges the max. anti-surge current, that is, the residual voltage, also known as limited voltage 3.1.21 nominal voltage long-term normal operating voltage of a surge protective device between wires or between wires and the earth under specified environmental conditions and limited leakage current 3.1.22 maximum leakage current limited leakage current of a surge protective device at the nominal voltage 3.1.23 nominal current long-term normal operating signal current of a surge protective device under specified environmental conditions and nominal voltage 3.1.24 instrumentation general term for electric and electrical signal instruments and control systems in this specification 3.1.25 simple apparatus electrical components whose electrical parameters conform to the intrinsic safety performance of the circuit, components and combinations of components such as capacitors, inductors and batteries without internal energy sources and with strictly limited energy storage parameters, that is, a specific term for intrinsic safe system 3.1.26 bonding terminal bonding plate for connecting an instrumentation earthing grid with an electrical earth termination system 3.1.27 safety extra-low voltage voltage for insulation and isolation between electrical system and other power supply systems that does not exceed the limit: ≤ AC 50 V, or ≤ DC 120 V, and exposed conductive part earthed, and that complies with the voltage specified in GB/T 16895.21-2020/IEC 60364-4-41:2017 on safety extra-low voltage 3.2 Abbreviations For the purposes of this specification, the following abbreviations apply: Abbreviation English name SPD Surge protective device Un Nominal voltage Uc Maximum continuous operating voltage Up Voltage protection level In Nominal discharge current Ic Maximum leakage current IN Nominal current SELV Safety extra-low voltage 4 General 4.1 In the design of lightning surge protection engineering, according to the specific situation of the protection target, an appropriate protection scope shall be determined and an appropriate protection scheme shall be adopted to reduce the risk of lightning strikes to a tolerable level, meet the investment conditions of disaster prevention and mitigation, effectively protect from lightning strikes, and reduce the losses caused by lightning strikes on instrumentation. 4.2 The lightning surge protection engineering for instrumentation shall adopt all of the following means: a) Setting of the surge protective device; b) Instrumentation earthing; c) Shielding of instrumentation signal cables; d) Shielding of instrumentation equipment. 4.3 The protective earthing, working earthing, intrinsic safe earthing, shielding earthing, static electricity protection earthing and surge protective device earthing of the instrumentation shall be finally connected to the electrical earth termination system, and the earthing resistance shall comply with the earthing resistance of the earth termination system. 4.4 The core twisted type shall be used in the instrumentation signal cables and communication cables. 4.5 The optical cables should be used in the communication network of outdoor instrumentation.

Contents of SH/T 3164-2021

Foreword i 1 Scope 2 Normative references 3 Terms and abbreviations 3.1 Terms 3.2 Abbreviations 4 General 5 Decision of lightning surge protection engineering for instrumentation 6 Earthing system in lightning surge protection engineering for instrumentation 6.1 Instrumentation earthing system in control room 6.2 Cabinet and operating console earthing 6.3 Bonding conductor and wire 6.4 Laying of cables and wire 6.5 Bonding method 6.6 Earthing sign 7 Surge protective device 7.1 General 7.2 Type of surge protective device 7.3 Parameters of surge protective device for signal type 7.4 Surge protective device setting 7.5 Lightning surge protection in AC power supply 8 Lightning surge protection for instrumentation in control room 8.1 Shielding for instrumentation in control room 8.2 Installation for surge protective device 8.3 Earthing and bonding for surge protective device 9 Lightning surge protection for field instrumentation 9.1 Lightning protection for field instrumentation 9.2 Installation for surge protective device 9.3 Field instrumentation earthing 10 Lightning surge protection for cables 10.1 Shielding of cables 10.2 Earthing for cable shielding 10.3 Spare cable and spare core of cable 11 Lightning surge protection for intrinsic safety system 11.1 Surge protective device for intrinsic safety system 11.2 Installation for surge protective device 11.3 Bonding in intrinsic safety system 12 Lightning surge protection for fieldbus system 12.1 Surge protective device for fieldbus system 12.2 Surge protective device application 12.3 Fieldbus system earthing 13 Lightning protection for control building Appendix B (Informative) Network type earthing referenced drawing Appendix B (Normative) Shielding of cables earthing referenced drawing Bibliography Explanation of wording in this specification