标准编号:	SH/T 3081-2019
中文名称:	石油化工仪表接地设计规范
英文名称:	Design code for instrument earthing in petrochemical industry
行业分类:	SH    石油化工行业标准
发布机构:	中华人民共和国工业和信息化部
发布日期:	2019-08-02
实施日期:	2020-1-1
标准状态:	valid
替代旧标准:	SH/T 3081-2003 石油化工仪表接地设计规范
翻译语言:	英文
文件格式:	PDF
中文字符数:	17000 字
翻译价格(元):	1190.0
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. This specification was revised by the drafting group according to the requirements of Notice on printing and distributing the development and revision plan on the third batch of professional standards in 2015 (GONGXINTINGKE [2015] No.115) issued by the Ministry of Industry and Information Technology of the People's Republic of China, through extensive investigation, careful summarization of practical experience on specification implementation and actual engineering, reference to relevant international and foreign advanced standards and extensive solicitation of opinions. This specification comprises 7 clauses and 2 annexes. The main technical contents of this specification include: function types and earthing method; earthing system configuration; bonding; earthing resistance and bonding resistance. This specification is a revision of SH/T 3081-2003 Design code for instrument grounding in petrochemical industry, with the main technical contents revised as follows: ——network type earthing configuration is added; ——Annex A (normative) Shielded cable earthing referenced drawing is added; ——Annex B (informative) Network type earthing referenced drawing is added; China Petrochemical Corporation (SINOPEC) is in charge of the administration of this specification, Automatic Control Design Technology Center Station of China Petrochemical Corporation is responsible for the routine management, and SINOPEC Engineering Incorporation is responsible for the explanation of the specific technical contents. In case of any opinion or suggestion in the process of implementing this specification, please send it to the routine management organization and the chief development organization. This specification was firstly issued in 1997 and revised for the first time in 2003. This is the second revision. Design specification for instrumentation earthing in petrochemical engineering 1 Scope This specification specifies the design principles and technical requirements of earthing types, earthing system configuration, earthing method, engineering implementation, earthing resistance and design scheme of instrumentation system in petrochemical engineering. This specification is applicable to the engineering design for instrumentation and automatic control system in petrochemical engineering and in new construction, extension and renovation of enterprises using coal as raw materials to prepare oil and chemical products. 2 Normative references The following documents are indispensable for the application of this specification. 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 3 Terms and definitions For the purposes of this specification, the following terms and definitions apply. 3.1 earthing system earthing network with bonding wire, bonding conductor, bonding bar, bonding terminal bar, earthing termination system, etc. 3.2 protective earthing earthing for personal safety and electrical equipment safety, also known as safety earthing 3.3 common bonding connection between instrumentation signal or DC power supply and common potential reference point   3.4 shield earthing earthing of shielding layer and shielding body to realize electric field shielding and electromagnetic field shielding functions 3.5 electrostatic protective earthing earthing for discharging static electricity 3.6 lightning protective earthing earthing for discharging lightning current 3.7 isolative signal circuit of input signal (or output signal) and circuit of output signal (or input signal) being isolated conductive circuits, both ends of this signal circuit, as well as this signal circuit and other circuits being electrically insulated and insulated from the ground 3.8 TN-S system a form of low-voltage distribution system, with the protection line PE at the power supply being grounded and the protection line PE being separated from the neutral line N in the whole system 3.9 equipotential bonding electrical connection among various conductive objects such as metal components, metal facilities, metal pipelines and metal equipment with wire or conductor, so that the objects have approximately equal potentials 3.10 common earthing system earthing system with various earthing facilities, bondings, earthing equipment, equipotential bonding systems and earthing termination systems, which can be used for instrumentation earthing, low-voltage distribution system earthing and lightning protection system earthing 3.11 bonding connection of the equipment, instrumentation and bonding bar that need to be earthed into an earthing system with bonding wires and conductors   3.12 bonding conductor conductor used for connecting various equipment and bonding bar that need to be earthed into an earthing system 3.13 bonding bar strip metal with relatively small specifications used for collecting various bonding wires in the cabinet, also known as bonding strip, which may be classified into common bonding bar, protective bonding bar, etc. based on the application 3.14 bonding terminal bar strip metal terminal bar with large specifications used for collecting multiple bonding wires or bonding trunk wires, which may be classified into common bonding terminal bar, protective bonding terminal bar, main bonding terminal bar, etc. based on the application 3.15 bonding wire insulated wire for bonding 3.16 bonding trunk wire insulated wire for connecting various bonding bars 3.17 earthing electrode buried metal conductor forming electrical contact with the earth, also known as earthing body. Various metal components, metal facilities, metal pipelines, metal equipment, etc., which are in direct contact with the earth, may also be used as earthing electrode, which is called natural earthing electrode 3.18 earthing termination system set of bonding conductors between earthing electrodes 3.19 bonding resistance sum of the wire resistance from the earthing terminal of the instrumentation or equipment to the earthing termination system and the contact resistance of the connection point 3.20 earthing resistance resistance of earthing termination system to ground 3.21 earthing system resistance sum of bonding resistance and earthing resistance 4 Function types and earthing method 4.1 Protective earthing 4.1.1 The exposed conductive parts of instrumentation and control system shall be provided with protective earthing. 4.1.2 The metal panels, tables, boxes, cabinets and racks equipped with instrumentation or control system should be provided with protective earthing. 4.1.3 The earthed metal panels, tables, boxes, cabinets and racks with good electrical contact, or the exposed conductive parts of instrumentation and control systems which are electrically connected may not be separately provided with protective earthing. 4.1.4 In the non-explosion hazard environment, the metal enclosure, metal protective box and metal junction box of field instrumentation with power supply voltage lower than 36V may not be provided with protective earthing, but those that may contact with equipment with voltage higher than 36V shall be provided with protective earthing. 4.1.5 In explosion hazard environment, the metal enclosure, metal protective box and metal junction box of field instrumentation in non-intrinsic safety system shall be provided with protective earthing, while those in intrinsic safety system may not be provided with protective earthing. 4.1.6 The metal enclosure, metal protective box and metal junction box of field instrumentation used for lightning protection shall be provided with protective earthing. 4.1.7 The metal enclosure, metal protective box and metal junction box of field instrumentation requiring protective earthing shall be connected to the earthing network nearby, or connected to the metal components such as earthed metal cable trough, metal protective pipe, cable armor layer, metal support, frame, platform, fence and equipment. 4.1.8 The metal cable trough and metal protective box shall be provided with protective earthing by being directly welded or connected with bonding wire to the earthing network or metal components such as earthed metal support, frame, platform, fence and equipment; if the cable trough is very long, iterative earthing at multiple points shall be conducted, with the distance between earthing points not greater than 30m. 4.1.9 If the instrumentation, metal protective box and metal junction box in 4.1.4, 4.1.5 and 4.1.6 fail to meet the earthing conditions in 4.1.7, special bonding wire may be laid according to those specified in 6.1.2 b). 4.1.10 Metal cable trough and protective metal pipe shall be connected to the nearby earthing network outside the building before entering the building. 4.2 Common bonding 4.2.1 The instrumentation signal circuit requiring earthing for instrumentation and control systems shall be provided with common bonding. 4.2.2 For non-isolative signal, the negative terminal of DC power supply shall be used as the common terminal as the common bonding reference point. 4.2.3 The isolative signal may not be earthed; the circuits for isolative signals (input or output signals) shall be electrically insulated from the circuits for other signals (input or output signals). 4.2.4 The common bonding shall not be mixed with protective earthing before being connected to the terminal bar or network type bonding bar. 4.2.5 The common bonding wires, connecting points, common bonding strip, etc. shall be insulated from other conductors before being connected to the terminal bar or network type bonding bar. 4.2.6 Single point earthing shall be adopted for the signal circuit. 4.2.7 Multi-point earthing shall be avoided in instrumentation signal circuit. If the signal source and signal receiving terminal on the same wire are inevitably earthed, isolator shall be used to isolate the two earthing points.

Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Function types and earthing method 4.1 Protective earthing 4.2 Common bonding 4.3 Intrinsic safety system earthing 4.4 Shield earthing 4.5 Electrostatic protective earthing 4.6 Lightning protective earthing 5 Earthing system configuration 5.1 Earthing principle 5.2 Branch type configuration 5.3 Network type configuration 5.4 Combined configuration 6 Bonding 6.1 Bonding wire 6.2 Bonding wire laying 6.3 Bonding bar or terminal bar 6.4 Bonding conductor 7 Earthing resistance and bonding resistance 7.1 Earthing resistance 7.2 Bonding resistance Annex A (Normative) Shielded cable earthing referenced drawing Annex B (Informative) Network type earthing referenced drawing Bibliography Explanation of wording in this specification

石油化工仪表接地设计规范 1 范围 本规范规定了石油化工仪表系统的接地分类、接地系统结构、接地方法、工程实施、接地电阻和设计方案等设计原则和技术要求。 本规范适用于石油化工和以煤为原料制取油品及化工产品的企业新建、扩建和改建工程中仪表及自动控制系统的工程设计。 2 规范性引用文件 下列文件对于本规范的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本规范。凡是不注日期的引用文件，其最新版本(包含所有的修改单)适用于本规范。 GB 50057—2010 建筑物防雷设计规范 3 术语和定义 下列术语和定义适用于本规范。 3.1 接地系统 earthing system 将接地导线、接地连接导体、接地汇流排、接地板、接地装置等连接在一起的接地网络。 3.2 保护接地 protective earthing 保护接地是为人身安全和电气设备安全而设置的接地，也称为安全接地。 3.3 工作接地 common bonding 仪表信号或直流电源与公共电位参考点的连接。 3.4 屏蔽接地 shield earthing 为实现电场屏蔽、电磁场屏蔽功能对屏蔽层、屏蔽体所做的接地。 3.5 防静电接地 electrostatic protective earthing 用于泄放静电的接地。 3.6 防雷接地 lightning protective earthing 用于泄放雷电流的接地。 3.7 隔离信号 isolative signal 输入信号(或输出信号)的电路与输出信号(或输入信号)的电路是隔离传导电路，本信号电路两端，以及本信号电路与其他电路电气上是绝缘的、对地是绝缘的。 3.8 TN-S系统 TN-S system 低压配电系统的一种形式，电源处的保护线PE是接地的，整个系统中，保护线PE与中线N是分开的。 3.9 等电位连接 equipotential bonding 用导线或导体将各种金属构件、金属设施、金属管道、金属设备等导电物体实施导电连接，使各物体之间具有近似相等的电位。 3.10 共用接地系统 common earthing system 将包括仪表接地、低压配电系统接地及防雷系统接地的各类接地设施、接地连接、接地设备、等电位连接系统及接地装置连接成一个接地系统，合用接地装置。 3.11 接地连接 bonding 将需要接地的设备、仪表、接地汇流排等，用接地导线、接地导体连接成接地系统。 3.12 接地连接导体 bonding conductor 用于连接各个需要接地的设备、各类接地排等，形成接地系统的导体。 3.13 接地汇流排 bonding bar 机柜内用于汇集连接各接地线的规格比较小的条形金属，也称接地汇流条。根据用途可分为工作接地汇流排、保护接地汇流排等。 3.14 接地汇总板 bonding terminal bar 用于汇集连接多条接地线或接地干线的规格比较大的条形金属接线板。根据用途有工作接地汇总板、保护接地汇总板、总接地板等。 3.15 接地线 bonding wire 用于接地连接的绝缘导线。 3.16 接地干线 bonding trunk wire 用于连接各种接地排的绝缘导线。 3.17 接地体 earthing electrode 埋入地下并与大地形成电气接触的金属导体，也称接地极。直接与大地接触的各种金属构件、金属设施、金属管道、金属设备等可以兼作接地体，称为自然接地体。 3.18 接地装置 earthing termination system 接地体和接地体之间连接导体的集合。 3.19 接地连接电阻 bonding resistance 从仪表或设备的接地端子到接地装置之间的导线电阻和连接点接触电阻的总和。 3.20 接地电阻 earthing resistance 接地装置对地电阻。 3.21 接地系统电阻 earthing system resistance 接地连接电阻和接地电阻之和。 4 接地功能分类与接地方法 4.1 保护接地 4.1.1 仪表及控制系统的外露导电部分应实施保护接地。 4.1.2 装有仪表或控制系统的金属盘、台、箱、柜、架等宜实施保护接地。 4.1.3 与已经接地的金属盘、台、箱、柜、架等电气接触良好，或与其实施了导电连接的仪表和控制系统的外露导电部分可不另外实施保护接地。 4.1.4 非爆炸危险环境中，供电电压低于36V的现场仪表金属外壳、金属保护箱、金属接线箱，可不实施保护接地，但对于可能与高于36V电压设备接触的应实施保护接地。 4.1.5 爆炸危险环境中，非本质安全系统的现场仪表金属外壳、金属保护箱、金属接线箱应实施保护接地，本质安全系统的现场仪表金属外壳、金属保护箱、金属接线箱可不实施保护接地。 4.1.6 用于雷电防护的现场仪表金属外壳、金属保护箱、金属接线箱应实施保护接地。 4.1.7 需要实施保护接地的现场仪表金属外壳、金属保护箱、金属接线箱应就近连接到接地网，或连接到已经接地的金属电缆槽、金属保护管、电缆铠装层、金属支架、框架、平台、围栏、设备等金属构件上。 4.1.8 金属电缆槽、电缆保护金属管应实施保护接地，应直接焊接或用接地导线就近连接到接地网或己接地的金属支架、框架、平台、围栏、设备等金属构件上，当电缆槽较长时，应多点重复接地，接地点间距不应大于30m。 4.1.9 当本规范4.1.4、4.1.5、4.1.6条中的仪表、金属保护箱、金属接线箱等不具备本规范4.1.7条的接地条件时，可按照本规范6.1.2条b)项的规格敷设专用接地线。 4.1.10 金属电缆槽、电缆保护金属管在进入建筑物之前应就近接到建筑物外部的接地网。 4.2 工作接地 4.2.1 仪表及控制系统需要进行接地的仪表信号回路，应实施工作接地。 4.2.2 非隔离信号应以直流电源的负端为公共端作为工作接地参考点。 4.2.3 隔离信号可不接地；隔离信号(输入或输出信号)的电路与其它信号(输入或输出信号)的电路应是电气绝缘的。 4.2.4 工作接地在接到汇总板或网型接地排之前不应与保护接地混接。 4.2.5 工作接地的导线、各连接点、工作接地汇流条等在接到汇总板或网型接地排之前应与其它导体绝缘。 4.2.6 信号回路的接地应采用单点接地方式。 4.2.7 仪表信号回路中应避免产生多点接地，如果一条线路上的信号源和信号接收端都不可避免接地，则应采用隔离器将两点接地隔离开。 4.3 本质安全系统接地 4.3.1 采用隔离式安全栅的本质安全系统可不接地。 4.3.2 采用齐纳式安全栅的本质安全系统应接到工作接地。 4.3.3 齐纳式安全栅的本安系统接地与仪表信号回路接地不应分开。 4.3.4 齐纳式安全栅的接地汇流排(或接地导轨)应与直流电源的负端相连接。 4.3.5 齐纳式安全栅应符合图4.3.5的本安系统接地连接示意图。 危险场所 安全场所 机柜 齐纳安全栅 汇流排 相线 中线 PE线 现场仪表 接地导线 电源公共端 工作接地汇总板 接地干线 总接地板 接地装置 图4.3.5 齐纳式安全栅本安系统接地连接示意图 4.3.6 机柜内齐纳式安全栅的接地汇流排应接到本机柜的工作接地汇流排，再经接地干线接到工作接地汇总板。 4.3.7 齐纳式安全栅各汇流排至工作接地汇总板之间的接地连接导线、接有齐纳式安全栅的工作接地汇总板与总接地板之间的接地连接导线均宜分别采用两根单独的导线。 4.4 屏蔽接地 4.4.1 信号线的屏蔽层应采用表4.4.1所示的接地方式。 表4.4.1 屏蔽层的接地方式 电缆形式 接地形式 内屏蔽层 外屏蔽层 铠装层或金属保护管 单层屏蔽电缆 单端接地 — 两端接地 单层屏蔽铠装电缆 单端接地 — 两端接地 分屏总屏电缆 单端接地 两端接地 两端接地 分屏总屏铠装电缆 单端接地 两端接地 两端接地 4.4.2 信号线的内屏蔽层应在控制室一侧接到工作接地，已经在现场仪表处自然接地的屏蔽层不宜在控制室一侧重复接地。 4.4.3 信号线的外屏蔽层、金属保护管、铠装电缆的金属铠装保护层应在两端接到保护接地。 4.4.4 当有多根信号屏蔽电缆的屏蔽层接地时，宜先将各信号屏蔽电缆的屏蔽层汇接到端子或接地汇流排。 4.4.5 进出仪表接线箱的屏蔽电缆的内外屏蔽层应按本规范附录A中图A-1～图A-4所示在接线箱和机柜处接地。 4.4.6 备用电缆的屏蔽层、不带屏蔽层的电缆备用芯宜在控制室一侧接到工作接地；对屏蔽层已接地的屏蔽电缆或穿钢管敷设或在金属电缆槽中敷设的电缆，备用芯可不接地。 4.4.7 非金属电缆槽的屏蔽层连接线或静电释放线应接到保护接地。 4.5 防静电接地 4.5.1 对于需要防静电的设备，应连接到保护接地。 4.5.2 对于已经实施保护接地或工作接地的设备，可不进行单独的防静电接地。 4.5.3 安装分散控制系统等各种控制设备的控制室或机柜室的导静电地面、防静电活动地板、金属工作台等应进行等电位连接并接地。 4.6 防雷接地 4.6.1 仪表及控制系统防雷接地应采用本规范5.3条的网型结构。 4.6.2 电涌防护器的接地汇流排应直接接到或通过机柜的保护接地汇流排接到机柜下方的网型结构接地排。 5 接地系统结构 5.1 接地原则 5.1.1 每台需要接地的仪表、设备均应采用单独的接地线接到接地汇流排，不应采用任何形式的串联链接的连接方式。 5.1.2 每台机柜均应采用单独的接地干线接到网型接地排或接地汇总板，不应采用任何形式的串联链接的连接方式。 5.1.3 仪表接地应根据等电位接地的原则，实现等电位接地连接网。 5.1.4 仪表接地应与电气系统接地共用接地装置，应接到电气系统的接地板上。 5.1.5 仪表供电应采用TN-S形式，从电气引过来的PE线应接到总接地板或网型结构接地排。 5.2 分支集中结构 5.2.1 仪表及控制系统的接地系统可采用分支集中接地结构。 5.2.2 典型的分支集中接地结构应符合图5.2.2所示的接地连接结构，宜设置接地汇流排、接地汇总板、总接地板等用于多台仪表及设备的接地。