标准编号:	SH/T 3038-2017
中文名称:	石油化工装置电力设计规范
英文名称:	Code for Electric Power Design in Petrochemical Plants
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:	2017-04-12
实施日期:	2017-10-1
标准状态:	现行
替代旧标准:	SH 3038-2000 石油化工企业生产装置电力设计技术规范
翻译语言:	英文
文件格式:	PDF
中文字符数:	100000 字
翻译价格(元):	7000.00 元
交付时间:	付款后 1 个工作日

In accordance with the requirements of “Project Plan for the Second Batch of Petrochemical Professional Standards in 2014” (GONGXINTINGKE [2014] No. 14) of the Ministry of Industry and Information Technology of the People's Republic of China, this specification was revised by the specification drafting group through extensive investigation and study, careful summarization of practical experiences, reference to the relevant international standards and foreign advanced standards, and extensive solicitation of opinions.



This specification consists of 11 clauses and 3 annexes.



Main technical contents of this specification: technical requirements and main principles to be followed in power supply & distribution system, explosive hazardous environment, transformer substation, automatic devices & microprocessor-based integrated automation system, selection & laying of cables, power distribution, grounding and electrical energy saving for electric power design in petrochemical plants.



This specification is revised based on SH 3038-2000 Code for electric power design in petrochemical plants, with the main technical contents revised as follows:



——the title is changed from Code for electric power design in petrochemical plants to Specification for electric power design in petrochemical plants;



——Clause 1 "General provisions" is changed to "Scope"; Clause 3 "Basic provisions" is added to incorporate part of the general provisions; Clause 2 "Normative references" is added; the former clauses of "Terms" and "Lighting" are canceled;



——the example in the definition of Class I load in former 4.1.2 is deleted, and all examples are incorporated in the explanation of provisions;



——the “Division of fire hazardous environments” in former 4.6 is deleted. The division of explosive dust hazardous places is changed from the former "Zones 10 Zone 11" to "Zones 20, 21 and 22"; examples of division of explosive dust environments are added; the whole clause is greatly adjusted in structure, combining the description of design and grounding design of electrical equipment and electrical circuits in explosive gas environment and explosive dust environment which are separately described before;



——the statistical requirements of electrical loads of the whole plant and each production plant in 7.3.11 and 7.4 “Safety and management system for power supply operation” are added in Clause 7;



——the title of the former Clause 10 "Lightning protection and grounding" is changed to "Grounding" and the contents of lightning protection grounding and anti-static grounding are deleted;



——the former Annex A "Classification of protection levels for electrical equipment enclosures" and Annex B "Table for zoning in explosive hazardous environments for petrochemical plants" are canceled, and the former Annex D "Example of classification and grouping of explosive gas or vapor mixture" and Annex E "Table for characteristics of explosive dust" are adjusted. The temperature group column in the former Annex E "Table for characteristics of explosive dust" is canceled.



For the purposes of this specification, China Petrochemical Corporation is in charge of its administration; the Electrical Technology Center Station of China Petrochemical Corporation is responsible for its routine management; Sinopec Ningbo Engineering Co., Ltd. is responsible for the explanation of its specific technical contents. In case of any opinion and suggestion in the process of implementing this standard, please send it to the routine management organization and the chief development organization.



Routine management organization of this specification: Electrical Technology Center Station of China Petrochemical Corporation



Address: No. 21 Anyuan, Anhuibeili, Chaoyang District, Beijing



Postal code: 100101



Tel.: 0086-(0)10-84876626



Fax.: 0086-(0)10-84878825



Chief development organization of this specification: Sinopec Ningbo Engineering Co., Ltd.



Address: No. 660, Yuanshi Road, High-Tech Park, Ningbo, Zhejiang



Postal code: 315103



Participating development organizations of this specification: SINOPEC Luoyang Engineering Co., Ltd. and SINOPEC Shanghai Engineering Co., Ltd.



Chief drafters of this specification: Chen Hejiang, Liu Guanghui, Li Shuhui and Zhou Yong.



Chief examiners of this specification: Wang Caiyong, Zhou Jiaxiang, Chen Hongzhong, Zhu Linsong, Yuan Xuequn, Yang Cheng, Yang Guangyi, Hang Ming, Guo Jianjun, Yang Dongming, Gao Changming, Gan Jiafu, Gong Puzhan, Hou Wenbin, Liang Dongguang, Suo Renhua, Tu Rangjian, Yang Weihong, Chen Liping, Wang Yujie, Gao Suhua, Qiu Ling, Sun Shuyuan, Chen Xinfeng and Ye Yang.



This specification was issued in 1991 and revised for the first time in 2000. This is the second revision.





Specification for electric power design in petrochemical plants



1 Scope



This specification specifies the main design principles to be followed in the electric power design in petrochemical plants.



This specification is applicable to the electric power design of production plant (including oil refining, chemical and coal chemical plants, hereinafter referred to as production plant) of newly constructed, reconstructed or expanded petrochemical enterprises.



2 Normative references



The following reference 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 normative document (including any amendments) applies.



GB 3836.14 Explosive atmospheres - Part 14: Classification of areas - Explosive gas atmosphere

GB 12326 Power quality - Voltage fluctuation and flicker

GB 12476.3 Electrical Apparatus for Use in the Presence of Combustible Dust—Part 3: Classification of Areas Where Combustible Dusts are or May be Present

GB 12476.5 Electrical apparatus for use in the presence of combustible dust - Part 5: Protection by enclosures “tD”

GB/T 14549 Quality of electric energy supply - Harmonics in public supply network

GB/T 15543 Power quality - Three-phase voltage unbalance

GB 50052 Code for design electric power supply systems

GB 50057-2010 Code for design protection of structures against lightning

GB 50058 Code for design of electrical installations in explosive atmospheres

GB/T 50062 Code for design of relaying protection and automatic device of electric power installation

GB/T 50063 Code for design of electrical measuring device of power system

GB/T 50064 Code for design of overvoltage protection and insulation coordination for AC electrical installations

GB 50160 Fire prevention code of petrochemical enterprise design

GB 50217-2007 Code for design of cables of electric engineering

GB 50227 Code for design of installation of shunt capacitors

GB 50260 Code for seismic design of electrical installations

GB 50556 Code for aseismic design of electrical facilities in industrial plants

SH 3097 Code for the design of static electricity grounding for petrochemical industry

CECS 31 Code for design of steel cable tray engineering

CECS 106 Technical specification for aluminum - Alloy cable tray



3 Basic provisions



3.1 The following principles shall be followed in the electric power design of production plant:



a) Earnestly implement national technical and economic policies to ensure personal and equipment safety, reliable power supply, advanced technology and economic feasibility.



b) Give priority to near-term design and combine it with the long-term design according to project characteristic, scale and development planning; properly remain the development side and reserve no land for expansion in principle.



c) Take overall consideration and determine reasonable layout and design scheme according to the nature of the load, capacity and environmental conditions.



d) Take various energy-saving measures actively for electrical design to reduce power consumption.



3.2 The implementation of this specification shall also meet the requirements of the relevant current national and professional standards and codes.



4 Power supply & distribution system



4.1 Load classification



4.1.1 The electrical loads of the production plant shall be classified into Class I loads, Class II loads and Class III loads according to their importance in the production process and requirements for power supply reliability and continuity.



4.1.2 Class I loads refer to the electrical loads for the production plants which need a long time to resume production after power restoration as well as the public works ensuring their normal operation where the working power supply of production plant is interrupted suddenly and thus leads to disruption of key continuous production processes and significant economic losses.



4.1.3 Among Class I loads, upon sudden power interruption of the production plant, those which cannot be subjected to power interruption in order to ensure safe shutdown, avoid causing explosion, fire, poisoning, casualties and key equipment damage, or make timely treatment in case of an accident to prevent accident expansion, protect key equipment, rescue and evacuate the working personnel shall be regarded as particularly important loads.



4.1.4 Class II loads refer to the electrical loads for the production plants which need a long time to resume production after power restoration as well as the public works ensuring their normal operation where the working power supply of production plants is interrupted suddenly and thus leads to significant economic losses.



4.1.5 Class III loads refer to all electrical loads other than Class I loads and Class II loads.



4.2 Power supply requirements



4.2.1 The power supply for Class I loads shall meet the following requirements:



a) Class I loads shall be powered by dual power supply, where one power supply fails, the other shall not be damaged at the same time;



b) where a generator set is installed in the production plant and may be used as an independent working power supply, and it is indeed difficult to obtain a two-circuit power supply from outside, Class I loads may also be powered by an external power supply.



4.2.2 For the particularly important loads among Class I loads, in addition to the dual power supply, an emergency power supply shall be arranged, and no other loads shall be connected to the emergency power supply system.



4.2.3 The following power supplies may be used as emergency power supply:



a) DC battery device;



b) UPS power supply device;



c) EPS power supply device;



d) fast self-starting power generating device;



1) self-starting diesel generator set;



2) self-starting gas generator set;



3) other types of generator sets independent of normal power supply.



e) dedicated feeder line independent of normal power supply, which is lead in from the outside of production plants.



4.2.4 Emergency power supply shall be selected according to the allowable power interruption time, and shall meet the following requirements:



a) a fast self-starting generator set may be selected for the power supply with an allowable power interruption time of greater than 15s;



b) if the action time of auto-switching device can meet the allowable power interruption time, a dedicated feeder line with auto-switching device independent of normal power supply may be selected;



c) an battery static uninterrupted power supply device may be selected for the power supply with allowable power interruption time of millisecond level.



4.2.5 The power supply time of emergency power supply shall be determined according to the allowable shutdown process time required by production technology.



4.2.6 Production equipment powered by emergency power supply should be powered by working power supply under normal conditions; when the working power supply is interrupted, the emergency power supply is adopted.



4.2.7 Class II load power supply system should be powered by two power supplies. Where the load is small or the regional power supply condition is difficult, single-circuit 10(6)kV dedicated overhead line power supply may be adopted.



4.2.8 No special power supply requirements are available for Class III loads.



4.3 Power supply & distribution system



4.3.1 The power supply shall meet the following requirements:



a) the production plant shall be powered by a two-circuit power supply; under normal conditions, two circuits operate simultaneously and be standby for each other. When abnormal operation or short-circuit failure occurs in any part of the power supply system, the other power supply can remain uninterrupted power supply and always maintain a sufficient voltage level, so as to meet the requirements of restarting the electrical load of production plant;



b) the capacity of the emergency power supply for the production plant is determined by the size and nature of particularly important loads among Class I loads and the maximum starting capacity of motor.



4.3.2 35kV or 10(6)kV power supply system is preferentially adopted for the production plant according to the load capacity and distribution in the principle that the power supply line goes deep into the load center.



4.3.3 The main wiring of the power supply system shall be simple and reliable, and the distribution of the power supply system at the same voltage shall not exceed two levels. For the design of power supply system, the circumstance where one power supply system under overhaul or failure while the other fails at the same time is not considered.



4.3.4 Dedicated power supply busbar segments shall be arranged for particularly important loads among Class I loads. Reliable measures shall be taken between the emergency power supply and working power supply to prevent parallel operation.



4.3.5 The main wiring of 10(6)kV distribution system shall meet the following requirements:



a) for the AC busbar of 10(6)kV transformer substation, single busbar or single busbar segment, and wiring for setting of automatic power switching device in section circuit breaker should be adopted. The busbar segmentation shall be based on specific conditions such as production process, and the electrical equipment of the same production system should be connected to the same busbar segment. The low-voltage auxiliary equipment of medium-voltage electrical equipment shall be in the same system with medium-voltage power supply;



b) circuit breaker shall be adopted for the incoming switch of the branch substation;



c) load switch should be arranged at the primary side of transformer, and no switch is arranged when meeting the following requirements:



1) where microcomputer five-prevention configuration is adopted for the system;



2) where the transformer is in this substation;



3) where it is closely connected with the superior substation and power distribution room in production management and can prevent misoperation;



d) on the outgoing line side of 10(6)kV fixed power distribution device, a line disconnecting switch shall be arranged in the cable outgoing circuit where feedback is possible.



4.3.6 TN-S shall be adopted as the grounding type of the 0.38/0.22kV distribution system of the production plant.



4.3.7 Single busbar segment and wiring for setting of automatic power switching device in section circuit breaker shall be adopted for 0.38kV low-voltage distribution system. When only Class III load is available, single-busbar wiring should be adopted.



4.3.8 Single-phase electrical equipment should be evenly distributed in three phases. The neutral current caused by single-phase load imbalance in the low-voltage power grid with TN system grounding shall not exceed 50% of the rated current of the low-voltage winding where three-phase transformer of D, yn11 wiring group is adopted.



4.3.9 Where equipped with a special lighting transformer, the production plant shall share a transformer with the overhaul load.



4.3.10 Busbars of transformer substations with 35kV~0.4kV voltage levels and corresponding main (power distribution) transformer shall be operated separately under normal conditions.



4.3.11 Radial medium- and low-voltage power supply & distribution system should be adopted in the production plant area.



4.3.12 The operational power supply shall meet the following requirements:



a) DC power supply device of fully enclosed maintenance-free lead-acid battery pack should be adopted as the operational power supply of 35kV and 10(6)kV power distribution device, while AC operation should not be adopted;



b) AC operation may be adopted for the low-voltage power distribution device. According to the requirements of automatic device and relay protection, DC power supply device or UPS device of fully enclosed maintenance-free lead-acid battery pack may also be adopted as the operational power supply;



c) a complete set of UPS power supply device shall be adopted as the AC power supply for microprocessor-based monitoring integrated automation system and PLC device.



4.4 Selection of voltage & quality of electric energy



4.4.1 The power supply & distribution voltage of the power consumption unit shall be determined according to factors such as power consumption capacity, electrical equipment characteristics, power supply distance, number of power supply circuits, development planning and economic feasibility.



4.4.2 Where the motor capacity is 200(160)kW and above or the required transformer capacity above 315(200)kVA, medium-voltage 10(6)kV power supply mode should be adopted; where the motor capacity is less than 200(160)kW or the required transformer capacity is less than 315(200)kVA, low-voltage power supply mode should be adopted.



4.4.3 10(6)kV medium-voltage power distribution should be adopted in the production plant; 380V/220V low-voltage power distribution voltage shall be adopted, and 660V may also be adopted where deemed as reasonable through technical and economic comparison.



4.4.4 Power supply & distribution voltage:



a) power supply system voltage and its allowable deviation:



1) 110kV: AC three-phase three-wire system (with neutral point directly grounded), the allowable voltage deviation is ±5% when the power supply is taken from the internal power supply network of the enterprise; the sum of the absolute positive and negative deviations of voltage shall be less than or equal to 10% when the power supply is taken from the external power supply network;



2) 35kV: AC three-phase three-wire system (with neutral point ungrounded, arc-suppression coil grounded and resistance grounded), the allowable voltage deviation is ±10% when the power supply is taken from the internal power supply network of the enterprise; the sum of the absolute positive and negative deviations of voltage shall be less than or equal to 10% when the power supply is taken from the external power supply network;



3) 10(6)kV and below: AC three-phase power supply, the allowable voltage deviation is ±7% when the power supply is taken from the internal power supply network of the enterprise while ±7% when the power supply is taken from the external power supply network;



4) 220V: the allowable deviation of AC single-phase power supply voltage is -10% and +7%;



5) Frequency rating and fluctuation range: 50Hz±0.2Hz;



b) standard voltage of power distribution system:



1) high-voltage power distribution: 110kV, 50Hz, with neutral point directly grounded;



2) medium-voltage power distribution: 35kV, 10(6)kV, 50Hz, with neutral point ungrounded, arc-suppression coil grounded and resistance grounded;



3) low-voltage power distribution: 380/220V, three-phase-four-wire, 50Hz, with neutral point directly grounded (TN-S);



4) variable-speed motor: complying with the manufacturer's standard;



5) lighting system: 380/220V, 50Hz, three-phase+N, with neutral point directly grounded;



6) power socket: 380/220V, 50Hz, three-phase-N, with neutral point directly grounded;



7) lighting sockets and other loads: 220V, 50Hz;



8) control circuit of medium-voltage switch cabinet: DC 220V should be adopted;



9) control circuit of low-voltage motor control center: AC 220V;



10) DCS, PLC, important instruments, automatic devices and microprocessor-based integrated automation system, dispatching telephone, wired and wireless communication system of production plant: AC 220V, powered by UPS power supply device;



11) portable hand lamp: AC 24V, AC 12V shall be used in the tower or container, powered by isolating lighting transformer.



4.4.5 In normal operation, the allowable voltage deviation (expressed as a percentage of rated voltage) at the terminal of electrical equipment should meet the following requirements:



a) terminal voltage of motor, ±5%;



b) terminal voltage of lighting fixture:



1) ±5% in general workplace;



2) -2.5%~5% in indoor places with high visual requirements;



3) possibly -10%~5% in general small-area workplaces away from the substation where it is difficult to meet the above requirements;



4) -10%~5% for emergency lighting, road lighting and 12V and 24V overhaul lighting;



c) other electrical equipment: ±5% unless otherwise specified.



4.4.6 Allowable deviation of motor starting voltage:



a) When AC motor starts, the voltage of power distribution busbar shall meet the following requirements:



1) generally, it should not be lower than 90% of the rated voltage where the motor starts frequently while should not be lower than 85% of the rated voltage where the motor does not start frequently;



2) it shall not be lower than 80% of the rated voltage where no lighting loads or other loads sensitive to voltage fluctuation are connected to the power distribution busbar;



3) it may be determined on the premise of ensuring the starting torque of the motor where no other electrical equipment is connected to the power distribution busbar; for a low-voltage motor, the voltage of contactor coil shall not be lower than the release voltage;



b) when the motor starts, its terminal voltage shall be able to ensure the starting torque required by the machine, and the voltage fluctuation caused in the power distribution system shall not hinder the work of other electrical equipment.



4.4.7 In order to reduce voltage deviation, the design of power supply & distribution system shall meet the following requirements:



a) select correct transformer ratio and voltage tap;



b) reduce the system impedance reasonably;



c) take measures to compensate reactive power;



d) balance the three-phase loads as possible.



4.4.8 When calibrating the voltage deviation of electrical equipment, the voltage regulation effect after taking the following measures shall be considered:



a) automatically or manually regulate the access capacity of the shunt compensating capacitor and shunt reactor;



b) automatically or manually regulate the excitation current of synchronous motor and generator;



c) change the operation mode of power supply & distribution system.



4.4.9 For the step-down transformer directly supplying power to 35kV, 10(6)kV power distribution system of the production plant, where the voltage deviation cannot meet the requirements, on-load voltage regulating transformer should be adopted in the substation.



4.4.10 On-load voltage regulating transformer should not be adopted as the 10(6)kV power distribution transformer in the production plant.



4.4.11 For loads generating high-order harmonics that distort the system voltage or current waveform, measures limiting high-order harmonics shall be taken, and the requirements of GB 50052 Code for design electric power supply systems shall be met.



4.4.12 The allowable limits of harmonic voltage in power distribution system and harmonic current injected into the point of common coupling should meet the requirements of GB/T 14549 Quality of electric energy supply- Harmonics in public supply network.



4.4.13 The limits of voltage fluctuation and flicker in power distribution system at the point of common coupling of power grid shall meet the requirements of GB 12326 Power quality - Voltage fluctuation and flicker.



4.4.14 The allowable limits of three-phase voltage unbalance at the point of common coupling in power supply & distribution system shall meet the requirements of GB/T 15543 Power quality - Three-phase voltage unbalance.



4.5 Reactive power compensation



4.5.1 When the natural power factor of the production plant is low, a shunt reactive power compensating device shall be arranged and the power factor shall not be less than 0.93.



4.5.2 In the power supply design, the capacity of power distribution and electrical equipment shall be correctly selected to reduce the inductive reactance of the line, and a synchronous motor shall be adopted when the process conditions are reasonable, so as to improve the natural power factor.



4.5.3 When a power capacitor is adopted for reactive power compensation, the reactive load of low-voltage part should be compensated by a low-voltage capacitor while that of medium-voltage part should be compensated by a medium-voltage capacitor in the principle of local balance. Power factor compensation should be in the form of a complete set of shunt capacitors.



The electrical loads of petrochemical production plant are relatively concentrated, so the complete set of shunt capacitors for reactive power compensation should be arranged on the 10(6)kV busbar.



4.5.4 When one of the following conditions is met, an automatic switching device for reactive power compensation shall be arranged:



a) where it is economically reasonable to arrange an automatic switching device to avoid overcompensation;



b) where it is economically reasonable to arrange a reactive automatic switching device to avoid overhigh voltage at light load and damage to some electrical equipment;



c) where the allowable voltage deviation under various operating loads are met only after the arrangement of a reactive power automatic switching device.



4.5.5 The capacitor grouping shall meet the following requirements:



a) upon the grouping of switching capacitors, the busbar voltage variation does not exceed ±2.5% of the rated value and resonance should not occur;



b) appropriately reduce the number of groups while increase the group capacity;



c) be adapted to the technical parameters of supporting equipment;



d) meet the allowable voltage deviation.



4.5.6 The setting of capacitors shall meet the requirements of GB 50227 Code for design of installation of shunt capacitors.

Foreword i
1 Scope
2 Normative references
3 Basic provisions
4 Power supply & distribution system
4.1 Load classification
4.2 Power supply requirements
4.3 Power supply & distribution system
4.4 Selection of voltage & quality of electric energy
4.5 Reactive power compensation
5 Explosive hazardous environment
5.1 General provisions
5.2 Division of hazardous zones in the explosive environment
5.3 Measures to prevent explosion
5.4 Ranges of hazardous zones in the explosive gas environment
5.5 Ranges of hazardous zones in the explosive dust environment
5.6 Classification and grouping of explosive gas mixtures
5.7 Electrical equipment in the explosive environment
5.8 Design of electrical circuit in explosive environment
5.9 Explosive environment grounding design
6 Transformer substation
6.1 Site selection
6.2 Selection of 6kV~35kV major electrical equipment
6.3 Selection of low-voltage equipment
6.4 Arrangement of transformation & distribution device
6.5 Requirements for buildings, ventilation & other utilities
6.6 Fire protection requirements
6.7 Quake-proof requirements
7 Automatic devices & microprocessor-based integrated automation system
7.1 Automatic switching-over device of power supply
7.2 Automatic restart of motors
7.3 Microprocessor-based integrated automation system
7.4 Safety and management system for power supply operation
8 Selection and laying of cables
8.1 Selection of cables
8.2 General requirements for cable laying
8.3 Cable laying method
9 Power distribution
9.1 General requirements
9.2 Protection of motor & LV distribution line
9.3 Motor control device settings
10 Grounding
10.1 Grounding methods & basic requirements
10.2 Grounding of electrical equipment
11 Electrical energy saving
Annex A (Informative) Classification and grouping of explosive gas or vapor mixture
Annex B (Informative) Example of characteristics of combustible dust
Annex C (Informative) Example drawing and condition table for division of explosive hazardous zone
Explanation of wording in this specification

石油化工装置电力设计规范
1 范围
本规范规定了石油化工装置电力设计应遵循的主要设计原则。
本规范适用于新建、改建或扩建的石油化工企业生产装置（包括炼油、化工、煤化工，以下简称生产装置）的电力设计。
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（包括所有的修改单）适用于本规范。
GB 3836.14 爆炸性环境 第14部分：场所分类 爆炸性气体环境
GB 12326 电能质量 电压波动和闪动
GB 12476.3 可燃性粉尘环境用电气设备 第3部分：存在或可能存在可燃性粉尘的场所分类
GB 12476.5 可燃性粉尘环境用电气设备 第5部分：外壳保护型“tD”
GB/T 14549 电能质量 公用电网谐波
GB/T 15543 电能质量 三相电压不平衡度
GB 50052 供配电系统设计规范
GB 50057—2010 建筑物防雷设计规范
GB 50058 爆炸危险环境电力装置设计规范
GB/T 50062 电力装置的继电保护和自动装置设计规范
GB/T 50063 电力装置电测量仪表装置设计规范
GB/T 50064 交流电气装置的过电压保护和绝缘配合设计规范
GB 50160 石油化工企业设计防火规范
GB 50217—2007 电力工程电缆设计规范
GB 50227 并联电容器装置设计规范
GB 50260 电力设施抗震设计规范
GB 50556 工业企业电气设备抗震设计规范
SH 3097 石油化工静电接地设计规范
CECS 31 钢制电缆桥架工程设计规范
CECS 106 铝合金电缆桥架技术规程
3 基本规定
3.1 生产装置的电力设计应遵循以下原则：
a）认真执行国家的技术经济政策，做到保障人身和装置安全，供电可靠，技术先进和经济合理。
b）根据工程特点、规模和发展规划，做到远近期结合，以近期为主，适当留有发展端，原则上不预留扩建用地。
c）按照负荷性质、容量和环境条件等，统筹兼顾，合理确定布局和设计方案。
d）电气设计应积极采取各项节能措施，努力降低电能消耗。
3.2 执行本规范时，尚应符合国家和行业现行的有关标准规范的规定。
4 供配电系统
4.1 负荷分级
4.1.1 生产装置用电负荷应根据其在生产过程中的重要性、对供电可靠性及连续性的要求，划分为一级负荷、二级负荷及三级负荷。
4.1.2 一级负荷是指生产装置工作电源突然中断时，将打乱关键性的连续生产工艺过程，造成重大经济损失，供电恢复后需很长时间才能恢复生产的生产装置以及确保其正常操作的公用工程的用电负荷。
4.1.3 一级负荷中当生产装置工作电源突然中断时，为确保安全停车，避免引起爆炸、火灾、中毒、人员伤亡、关键设备损坏，或事故一旦发生能及时处理，防止事故扩大，保证关键设备，抢救及撤离工作人员，而不允许中断供电的负荷，应视为一级负荷中特别重要的负荷。
4.1.4 二级负荷是指生产装置工作电源突然中断时，将造成较大经济损失，恢复供电后，需较长时间恢复正常生产的生产装置及为其服务的公用工程的用电负荷。
4.1.5 三级负荷是指所有不属于一级、二级的其他用电负荷。
4.2 供电要求
4.2.1 一级负荷的供电电源应符合下列规定：
a）一级负荷应由双重电源供电，当一个电源发生故障时，另一个电源不应同时受到损坏；
b）当生产装置内设有发电机组，且确定其可作为独立的工作电源及由外部获得两回路电源确有困难时，一级负荷也可由一个外部电源供电。
4.2.2 一级负荷中特别重要的负荷，除由双重电源供电外，尚应增设应急电源，不得将其他负荷接入应急电源供电系统。
4.2.3 下列电源可作为应急电源：
a）直流蓄电池装置；
b）UPS电源装置；
c）EPS电源装置；
d）快速自起动的发电装置；
1）自起动柴油发电机组；
2）自起动燃气发电机组；
3）独立于正常电源的其他类型发电机组。
e）从生产装置外引入的独立于正常电源的专用馈电线路。
4.2.4 应急电源应根据允许中断供电的时间选择，并应符合下列规定：
a）允许中断供电时间为15s以上的供电，可选用快速自启动的发电机组；
b）自投装置的动作时间能满足允许中断供电时间的，可选择带有自动投入装置的独立于正常电源之外的专用馈电线路；
c）允许中断供电时间为毫秒级的供电，可选用蓄电池静止型不间断供电装置。
4.2.5 应急电源的供电时间，应按生产技术上要求的允许停车过程时间确定。
4.2.6 由应急电源供电的生产设备，在正常情况下宜由工作电源供电；当工作电源中断时，才由应急电源供电。
4.2.7 二级负荷的供电系统宜由两路电源供电。在负荷较小或地区供电条件困难时，也可由一回路10(6)kV专用的架空线路供电。
4.2.8 三级负荷对供电无特殊要求。
4.3 电源和供配电系统
4.3.1 供电电源应满足下列要求：
a）生产装置应由两回路电源供电，且正常情况下两回路电源同时运行又互为备用。当一个电源系统任意一处出现异常运行或发生短路故障时，另一个电源仍能不中断供电并一直保持足够的电压水平，以满足生产装置用电负荷再起动的要求；
b）生产装置应急电源的容量由生产装置一级负荷中特别重要负荷的大小、性质及最大电动机起动容量来确定。
4.3.2 生产装置应根据负荷容量和分布，按照供电线路深入负荷中心的原则，优先采用35kV或10(6)kV供电系统。
4.3.3 供电系统主接线应简单可靠，同一电压供电系统的配电级数不宜超过两级。供电系统设计不考虑一个电源系统检修或故障的同时另一电源系统又发生故障。
4.3 4 一级负荷中特别重要负荷应设专用的供电母线段。应急电源与工作电源之间应采取可靠措施防止并联运行。
4.3.5 10(6)kV配电系统主接线应符合下列规定：
a）10(6)kV变（配）电所的交流母线宜采用单母线或单母线分段、分段断路器设电源自动切换装置的接线。母线的分段应依据生产流程等具体情况，同一生产系统的用电设备宜连接在同一段母线上。中压用电设备的低压辅机应与中压电源为同一系统；
b）分配电所的电源进线开关应采用断路器；
c）变压器一次侧宜装设负荷开关，当满足下列要求时，可不装设开关：
1）系统采用微机五防配置时；
2）变压器在本变电所内时；
3）与上级变配电室在生产管理上联系紧密，且能防止误操作时；
d）10(6)kV固定式配电装置的出线侧，在有反馈可能的电缆出线回路中，应装设线路隔离开关。
4.3.6 生产装置0.38/0.22kV配电系统的接地型式应采用TN-S。
4.3.7 0.38kV低压配电系统应采用单母线分段、分段断路器设电源自动切换装置的接线。当只有三级负荷时，宜采用单母线接线。
4.3.8 单相用电设备宜均匀地分配在三相中，由单相负荷不平衡引起的中性线电流在TN系统接地型式的低压电网中，选用D，yn11接线组别的三相变压器时，不应超过低压绕组额定电流的50%。
4.3.9 当生产装置设有专用照明变压器时，检修负荷可与其共用变压器。
4.3.10 35kV～0.4kV各级电压等级的变（配）电站（所）的母线及相应配置的主（配电）变压器，正常情况下应分列运行。
4.3.11 生产装置区域内中、低压供配电系统宜采用放射式。
4.3.12 操作电源应符合下列规定：
a）35kV、10(6)kV配电装置宜采用全封闭免维护铅酸蓄电池组的直流电源装置作为操作电源，不宜采用交流操作；
b）低压配电装置可采用交流操作。根据自动装置和继电保护的需要，也可采用全封闭免维护铅酸蓄电池组的直流电源装置或UPS装置作为操作电源；
c）微机监控综合自动化系统、PLC装置使用的交流电源应采用成套UPS电源装置。
4.4 电压选择和电能质量
4.4.1 用电单位的供配电电压应根据用电容量、用电设备特性、供电距离、供电回路数、发展规划以及经济合理等因素确定。
4.4.2 电动机容量在200(160)kW及以上或需要变压器容量为315(200)kVA以上者，宜采用中压10(6)kV供电方式；电动机容量小于200(160)kW或需要变压器容量小于315(200)
kVA者，宜采用低压供电方式。
4.4.3 生产装置内中压配电应采用10(6)kV；低压配电电压应采用380V/220V，当经技术经济比较合理时亦可采用660V。
4.4.4 供配电电压：
a）电源系统电压及允许偏差值：
1）110kV：交流三相三线制（中性点直接接地），电压允许偏差值当电源取自企业内部供电网时为±5%；当电源取自外部供电网时正、负偏差绝对值之和应小于或等于10%；
2）35kV：交流三相三线制（中性点不接地、消弧线圈接地、电阻接地），电压允许偏差值当电源取自企业内部供电网时正、负偏差绝对值之和为±10%；当电源取自外部供电网时正、负偏差绝对值之和应小于或等于10%；
3）10(6)kV及以下：交流三相供电，电压允许偏差值当电源取自企业内部供电网时为±7%；当电源取自外部供电网时为±7%；
4）220V：交流单相供电电压允许偏差值为-10%、+7%；
5）频率额定值及波动范围：50Hz±0.2Hz；
b）配电系统标准电压：
1）高压配电：110kV，50Hz，中性点直接接地；
2）中压配电：35kV，10(6)kV，50Hz，中性点不接地、消弧线圈接地、电阻接地；
3）低压配电：380/220V，三相四线，50Hz，中性点直接接地(TN-S)；
4）变速电动机：按制造厂标准；
5）照明系统：380/220V，50Hz，三相+N，中性点直接接地；
6）动力插座：380/220V，50Hz，三相-N，中性点直接接地；
7）照明插座及其他负荷：220V，50Hz；
8）中压开关柜控制回路：宜选用直流220V；
9）低压电动机控制中心控制回路：交流220V；
10）生产装置的DCS、PLC、重要仪表、自动装置和微机综合自动化系统、调度电话、有线及无线通讯系统：交流220V，由UPS电源装置供电；
11）便携式手提灯：交流24V，在塔或容器内应采用交流12V，由隔离照明变压器供电。
4.4.5 正常运行情况下，用电设备端子处电压偏差允许值（以额定电压的百分数表示）宜符合下列要求：
a）电动机的端电压：±5%；
b）照明灯具的端电压：
1）一般工作场所为±5%；
2）视觉要求较高的室内场所为-2.5%～5%；
3）对于远离变电所的小面积一般工作场所，难以满足上述要求时，可为-10%～5%；
4）应急照明、道路照明及12V、24V检修照明为-10%～5%；
c）其他用电设备：无特殊要求时为±5%。
4.4.6 电动机起动电压偏差允许值：
a）交流电动机起动时，配电母线上的电压应符合下列规定：
1）在一般情况下，电动机频繁起动时，不宜低于额定电压的90%；电动机不频繁起动时，不宜低于额定电压的85%；
2）配电母线上未接照明或其他对电压波动较敏感的负荷，且电动机不频繁起动时，不应低于额定电压的80%；
3）配电母线上未接其他用电设备时，可按保证电动机起动转矩的条件决定；对于低压电动机，尚应保证接触器线圈的电压不低于释放电压；
b）电动机起动时，其端子电压应能保证机械要求的起动转矩，且在配电系统中引起的电压波动不应妨碍其他用电设备的工作。
4.4.7 为了减小电压偏差，供配电系统设计应符合下列要求：
a）正确选择变压器的变比和电压分接头；
b）合理减少系统阻抗；
c）采取补偿无功功率措施；
d）尽量使三相负荷平衡。
4.4.8 校验用电设备电压偏差时，应计入采取下列措施后的调压效果：
a）自动或手动调整并联补偿电容器、并联电抗器的接入容量；
b）自动或手动调整同步电动机、发电机的励磁电流；
c）改变供配电系统运行方式。
4.4.9 直接向生产装置35kV，10(6)kV配电系统供电的降压变压器，在电压偏移不能满足要求时，变电所中的变压器宜采用有载调压变压器。
4.4.10 生产装置内的10(6)kV配电变压器不宜采用有载调压变压器。
4.4.11 对产生高次谐波使系统电压或电流波形畸变的负荷，应采取限制高次谐波的措施，并满足GB 50052《供配电系统设计规范》的规定。
4.4.12 配电系统中的谐波电压和在公共连接点注入的谐波电流允许限值，宜符合GB/T 14549《电能质量 公共电网谐波》的规定。
4.4.13 配电系统中的电压波动和闪变在电网公共连接点的限值，应符合GB 12326《电能质量 电压波动和闪变》的规定。
4.4.14 供配电系统中在公共连接点的三相电压不平衡度允许限值，宜符合GB/T 15543《电能质量 三相电压不平衡度》的规定。
4.5 无功补偿
4.5.1 生产装置的自然功率因数较低时，应设并联无功补偿装置，并使功率因数不低于0.93。
4.5.2 供电设计中应正确选择配电和用电设备的容量，降低线路感抗，在工艺条件合理时采用同步电动机等，以提高自然功率因数。
4.5.3 当采用电力电容器进行无功补偿时，宜根据就地平衡原则，低压部分的无功负荷由低压电容器补偿，中压部分的无功负荷由中压电容器补偿。功率因数补偿宜采用并联电容器成套装置的形式。
石化生产装置的用电负荷比较集中，宜将无功补偿并联电容器成套装置集中装设于10(6)kV母线上。
4.5.4 满足下列条件之一时，宜装设无功补偿自动投切装置：
a）避免过补偿，装设自动投切装置在经济上合理时；
b）避免在轻载时电压过高，造成某些用电设备损坏，而装设无功自动投切装置合理时；
c）只有装设无功自动投切装置才能满足在各种运行负荷情况下的电压偏移允许值时。
4.5.5 电容器分组时，应满足下列要求：
a）分组投切电容器时，母线电压变动不超过额定值的±2.5%且不应发生谐振；
b）适当减少分组组数和加大分组容量；
c）应与配套设备的技术参数相适应；
d）应满足电压偏移的允许值。
4.5.6 电容器的设置应满足GB 50227《并联电容器装置设计规范》的要求。
5 爆炸危险环境
5.1 一般规定
5.1.1 当生产、加工、处理、转运或贮存过程中出现或可能出现爆炸性气体混合物和爆炸性粉尘混合物环境时，应进行爆炸性气体环境和爆炸性粉尘环境的电力装置设计。并应遵循以下原则：
a）应根据生产装置的具体情况、生产运行实践及工作经验，通过分析判断，划分爆炸危险环境的等级和范围；
b）在划分危险区域时应根据附录A和附录B对存在的具体爆炸危险介质释放源进行分析和判断，以确定由爆炸性气体混合物、爆炸性粉尘混合物或二者都存在时爆炸危险区域的级别和组别。
5.1.2 爆炸性危险区域应设有两个以上出入口，其中至少应有一个通向非爆炸危险区，且其门应向危险性小的一侧开启。
5.1.3 防爆电气设备应采用通过国家防爆检验机构检验合格的产品，如果采用新试制或非定型防爆产品时，则应有与防爆许可证等效的允许使用证才可使用。
5.1.4 应按照爆炸危险区域对电气设备进行选择，对变电所的位置及结构、电气线路及接地等提出防护措施，以降低由于电气设备和线路的火花、电弧或高温引起爆炸事故出现的概率。
5.1.5 同时存在爆炸性气体环境和爆炸性粉尘环境的场所，应选择能同时满足这两种环境场所的电气设备。
5.2 爆炸性环境危险区域划分
5.2.1 爆炸性气体释放源的分级和爆炸危险区域的划分，应符合GB 50058《爆炸危险环境电力装置设计规范》和GB 3836.14《爆炸性环境 第14部分：场所分类 爆炸性气体环境》中的有关规定。
5.2.2 爆炸性粉尘释放源的分级和爆炸危险区域的划分，应符合GB 50058《爆炸危险环境电力装置设计规范》和GB 12476.3《可燃性粉尘环境用电气设备 第3部分：存在或可能存在可燃性粉尘的场所分类》中的有关规定。
5.3 防止爆炸的措施
5.3.1 在爆炸性气体环境中应采取下列防止爆炸的措施：
a）防止产生爆炸的基本措施，应使产生爆炸的条件同时出现的可能性减到最小程度；
b）工艺设计应采取消除或减少易燃物质的产生或积聚的措施：
1）工艺流程中宜采取较低的压力和温度，将易燃物质限制在密闭容器内；
2）工艺布置应限制和缩小爆炸危险区域的范围，并宜将不同等级的爆炸危险区，或爆炸危险区与非爆炸危险区分隔在各自的厂房或界区内；
3）在设备内可采用以氮气或其他惰性气体覆盖的措施；有明火及高温的设备宜布置在界区边沿；
4）宜采取安全联锁或事故时加入聚合反应阻聚剂等化学药品的措施；
c）防止爆炸性气体混合物的形成，或缩短爆炸性气体混合物滞留时间，宜采取下列措施：
1）工艺装置宜采取露天或开敞式布置；
2）设置机械通风装置；
3）在爆炸危险环境内设置正压室；
d）区域内易形成和积聚爆炸性气体混合物的地点应设置自动测量仪表装置，当气体或蒸气浓度接近爆炸下限值的50%时，应能可靠地发出信号或切断电源。
5.3.2 在爆炸性粉尘环境中应采取下列防止爆炸的措施：
a）防止产生爆炸的基本措施，应使产生爆炸的条件同时出现的可能性减到最小程度；
b）应按照爆炸性粉尘混合物的不同特性，采取相应的措施防止爆炸危险。爆炸性粉尘混合物的爆炸下限随其分散度、湿度、挥发物含量、灰分含量、火源性质和温度等而变化；
c）应优先采取下列消除或减少爆炸性粉尘混合物的产生和积聚的措施：
1）工艺设备宜将危险物料密封在防止粉尘泄露的容器内；
2）宜采用露天或敞开布置，或采用机械除尘措施；
3）宜限制和缩小爆炸危险区域的范围，并将可能释放爆炸性粉尘的设备单独集中布置；
4）提高自动化水平，可采取必要的安全联锁；
5）应对沉积的粉尘进行有效地清除；
6）应限制产生危险温度及火花；应防止粉尘进入产生电火花或高温部件的外壳内；
7）可适当增加物料的湿度，降低空气中粉尘的悬浮量。
5.3.3 在爆炸危险环境区域内应采取消除或控制电气设备和线路产生火花、电弧或高温的措施。
5.3.4 在爆炸性气体环境中符合下列条件之一时，可划为非爆炸危险区域：
a）没有释放源并不可能有易燃物质侵入的区域；
b）易燃物质可能出现的最高浓度不超过爆炸下限值的10%；
c）在生产过程中使用明火的设备附近，或炽热部件的表面温度超过区域内易燃物质引燃温度的设备附近；
d）在生产装置区外，露天或开敞设置的输送易燃物质的架空管道地带，但其阀门处按具体情况定。
5.3.5 爆炸性气体危险区域内的通风，其空气流量能使易燃物质很快稀释到爆炸下限值的25%以下，可定为通风良好。
5.3.6 以下场所可定为通风良好场所：
a）露天场所；
b）敞开式建筑物。在建筑物的壁和/或屋顶开口，其尺寸和位置保证建筑物内部通风效果等于露天场所；
c）非敞开建筑物，建有永久性的开口，使其具有自然通风的条件；
d）对于封闭区域，每平方米地板面积每分钟至少提供0.3m3的空气或至少1h换气6次，则可认为是通风良好。
5.3.7 采用机械通风在下列情况之一时，可不计通风故障的影响：
a）对封闭式或半封闭式的建筑物应设置备用的独立通风系统；
b）在通风设备发生故障时，设置自动报警或停止工艺流程等确保能阻止易燃物质释放的预防措施，或使电气设备断电的预防措施。
5.3.8 在确定了爆炸性气体危险区域的划分后，应根据通风条件调整区域划分，并应符合下列规定：
a）当通风良好时，应降低爆炸危险区域等级；当通风不良时应提高爆炸危险区域等级；
b）局部机械通风在降低爆炸性气体混合物浓度方面比自然通风和一般机械通风更为有效时，可采用局部机械通风降低爆炸危险区域等级；
c）在障碍物、凹坑和死角处，应局部提高爆炸危险区域等级。利用堤或墙等障碍物，限制比空气重的爆炸性气体混合物的扩散，可缩小爆炸危险区域的范围。
5.3.9 爆炸性粉尘危险区域划分应按爆炸粉尘的量、爆炸极限和通风条件确定。符合下列条件之一，可划为非爆炸危险区域：
a）装有良好除尘效果的除尘装置，当该除尘装置停车时，工艺机组能联锁停车；
b）设有为爆炸危险区服务，并用墙隔绝的送风机室，且通向爆炸粉尘环境的风道设有能防止爆炸性粉尘混合物侵入的安全装置，例如单向流通风道及能阻火的安全装置；
c）区域内爆炸性粉尘的量不大，且在排风柜内或风罩下进行操作。
5.4 爆炸性气体环境危险区域范围
5.4.1 爆炸性气体环境危险区域范围应按下列要求确定：
a）应根据释放源的级别和位置、易燃物质的性质、通风条件、障碍物及生产条件、运行经验，经技术经济比较综合确定；
b）建筑物内部宜以厂房为单位划定爆炸危险区域的范围。但也应根据具体情况，当厂房内空间大，释放源释放的易燃物质量少时，可按厂房内分空间划定爆炸危险的区域范围，并应符合下列规定：
1）当厂房内具有比空气重的易燃物质时，厂房内的通风换气次数不应少于2次/h，且换气不受阻碍；厂房地面上高度1m以内容积的空气与释放至厂房内的易燃物质所形成的爆炸性气体混合物的浓度应小于爆炸下限；
2）当厂房内具有比空气轻的易燃物质时，厂房平屋顶平面以下1m高度内，或圆顶、斜顶的最高点以下2m高度内的容积的空气与释放至厂房内的易燃物质所形成的爆炸性气体混合物的浓度应小于爆炸下限；
注1：释放至厂房内的易燃物质的最大量应按1h释放量的3倍计算，但不包括由于灾难性事故引起破裂时的释放量。
注2：相对密度小于0.8的爆炸性气体规定为轻于空气的气体；相对密度大于1.2的爆炸性气体规定为重于空气的气体，0.8～1.2应酌情考虑。
c）当高挥发性液体可能大量释放并扩散到15m以外时，爆炸危险区域的范围应划分附加2区；
d）当可燃液体的闪电高于或等于60°时，在物料操作温度高于可燃液体闪点的情况下，可燃液体可能泄漏时，其爆炸危险区域的范围可适当缩小，但不宜小于4.5m。
5.4.2 爆炸性气体环境的车间采用正压或连续通风稀释措施后，不能形成爆炸性气体环境时，车间可降为非爆炸性环境。通风引入的气源应安全可靠，且应是没有可燃性物质、腐蚀介质及机械杂质，进气口应设在高出所划爆炸性危险区域范围的1.5m以上处。
5.4.3 重于空气的爆炸性气体环境危险区域范围：
a）易燃物质重于空气、通风良好且为第二级释放源的主要生产装置区，其爆炸危险区域的范围划分，宜符合下列规定（图5.4.3-1）：
1）在爆炸危险区域内地坪下的坑、沟划为1区；
2）以释放源为中心，半径为15m，地坪上的高度为7.5m及半径为7.5m，顶部与释放源的距离为7.5m的范围内划为2区；
3）以释放源为中心，总半径为30m，地坪上的高度为0.6m，且在2区以外的范围可划为附加2区；

a）释放源接近地坪时
b）释放源在地坪以上时
图5.4.3-1 易燃物质重于空气、通风良好的生产装置区
b）易燃物质重于空气、释放源在封闭建筑物内，通风不良且为第二级释放源的主要生产装置区，其爆炸危险区域的范围划分，宜符合下列规定（图5.4.3-2）：
1）封闭建筑物内和在爆炸危险区域内地坪下的坑、沟划为1区；
2）以释放源为中心，半径为15m，高度为7.5m的范围内划为2区，但封闭建筑物的外墙和顶部距2区的界限不得小于3m，如为无孔洞实体墙，则墙外为非危险区；
3）以释放源为中心，总半径为30m，地坪上的高度为0.6m，且在2区以外的范围可划为附加2区；

注：用于距释放源在水平方向15m的距离，或在建筑物周边3m范围，取两者中较大者。
图5.4.3-2 易燃物质重于空气、释放源在封闭建筑物内通风不良的生产装置区
c）对易燃物质重于空气的贮罐，其爆炸危险区域的范围划分，宜符合下列规定（图5.4.3-3）：
1）固定式贮罐，在罐体内部未充惰性气体的液体表面以上的空间划为0区，浮顶式贮罐在浮顶移动范围内的空间划为1区；
2）以放空口为中心，半径为1.5m的空间和爆炸危险区域内地坪下的坑、沟划为1区；
3）距离贮罐的外壁和顶部3m的范围划为2区；
4）当贮罐周围设围堤时，贮罐外壁至围堤，其高度为堤顶高度的范围内划为2区。

a）固定式

b）浮顶式
图5.4.3-3 易燃物质重于空气、设在户外地坪上的贮罐
5.4.4 轻于空气的爆炸性气体环境的危险区域范围：
a）易燃物质轻于空气、通风良好且为第二级释放源的主要生产装置区，其爆炸危险区域的范围划分，宜符合下列规定（图5.4.4-1）：
当释放源距地坪的高度不超过4.5m时，以释放源为中心，半径为4.5m，顶部与释放源的距离为7.5m，及释放源至地坪以上的范围内划为2区。

注：释放源距地坪的高度超过4.5m时，应根据实践经验确定。
图5.4.4-1 易燃物质轻于空气、通风良好的生产区装置
b）易燃物质轻于空气，下部无侧墙，通风良好且为第二级释放源的压缩机厂房，其爆炸危险区域的范围划分，宜符合下列规定（图5.4.4-2）：
1）当释放源距地坪的高度不超过4.5m时，以释放源为中心，半径为4.5m，地坪以上至封闭区底部的空间和封闭区内部的范围内划为2区；
2）屋顶上方百页窗边外，半径为4.5m，百页窗顶部以上高度为7.5m的范围内划为2区；

注：释放源距地坪的高度超过4.5m时，应根据实践经验确定。
图5.4.4-2 易燃物质轻于空气、通风良好的压缩机厂房
c）易燃物质轻于空气，通风不良且为第二级释放源的压缩机厂房，其爆炸危险区域的范围划分，宜符合下列规定（图5.4.4-3）：
1）封闭区内部划为1区；
2）以释放源为中心，半径为4.5m，地坪以上至封闭区底部的空间和封闭区外壁3m，顶部垂直高度为4.5m的范围内划为2区。

注：释放源距地坪的高度超过4.5m时，应根据实践经验确定。
图5.4.4-3 易燃物质轻于空气、通风不良的压缩机厂房
5.4.5 对于开顶贮罐或池的单元分离器、预分离器和分离器、溶解气游离装置、生物氧化装置等液体表面为连续级释放源，其爆炸危险区域的范围划分，宜符合下列规定（图5.4.5-1～图5.4.5-3）。
a）对单元分离器、预分离器和分离器的规定：
1）单元分离器、预分离器的池壁外，半径为7.5m，地坪上高度为7.5m及至液体表面上的范围内划为1区；
2）分离器的池壁外，半径为3m，地坪上高度为3m及至液体表面上的范围内划为1区；
3）1区外水平距离半径为3m，垂直上方为3m，水平距离半径为7.5m，地坪上高度为3m及1区外水平距离半径为22.5m，地坪上高度为0.6m的范围内划为2区；

图5.4.5-1 单元分离器、预分离器和分离器
b）对溶解气游离装置（溶气浮选装置）规定：
1）表面至地坪的范围内划为1区；
2）1区外及池壁外水平距离半径为3m，地坪上高度为3m的范围内划为2区；

图5.4.5-2 溶解气游离装置（溶气浮选装置）（DAF）
c）对生物氧化装置规定：
开顶贮罐或池壁外水平距离半径为3m，液体表面上方至地坪上高度为3m的范围内划为2区。

图5.4.5-3 生物氧化装置（BIOX）
5.4.6 对于处理生产装置用冷却水的机械通风冷却塔，当划分为爆炸危险区域时其爆炸危险区域的范围划分，宜符合下列规定（图5.4.6）：

图5.4.6 处理生产装置用冷却水的机械通风冷却塔
5.4.7 无释放源的生产装置与爆炸危险区域相邻，并用非燃烧体的实体墙隔开，其爆炸危险区域的范围划分，宜符合下列规定（图5.4.7-1～图5.4.7-3）。
a）对与通风不良的房间相邻的规定：
1）通风不良、有第二级释放源的房间范围内划分1区；
2）当易燃物质重于空气时，以释放源为中心，半径为15m的范围内划分2区；当易燃物质轻于空气时，以释放源为中心，半径为4.5m的范围内划分2区；

图5.4.7-1 与通风不良的房间相邻
b）对于有第二级释放源有顶无墙建筑物且相邻的规定：
1）当易燃物质重于空气时，以释放源为中心，半径为15m的范围内划分2区；
2）当易燃物质轻于空气时，以释放源为中心，半径为4.5m的范围内划分2区；
3）与爆炸危险区域相邻，用非燃烧体的实体墙隔开的无释放源的生产装置区，门窗位于爆炸危险区域内时为2区，门窗位于爆炸危险区域外时划为非危险区；

a）门窗位于爆炸危险区域内

b）门窗位于爆炸危险区域外
图5.4.7-2 对有顶无墙建筑物相邻
c）对于通风不良房间且释放源上有排风罩时的规定：
1）第一级释放源上方排风罩内的范围内划分1区；
2）当易燃物质重于空气时，1区外半径为15m的范围内划分2区；
3）当易燃物质轻于空气时，1区外半径为4.5m的范围内划分2区。

图5.4.7-3 释放源上有排风罩时的爆炸危险区域范围
5.4.8 对生产设备的压力和容器不同，应结合具体情况并考虑各种因素及生产条件，运用实践经验经分析判断来确定，爆炸危险区域的等级和划分详见附录C；生产设备压力和容器分级见表5.4.8。
表5.4.8 生产设备的压力和容器分级
分级 小容量（低压力） 中容量（中压力） 大容量（高压力）
压力范围/MPa ＜0.7 0.7～3.5 ＞3.5
容积/m3 ＜19 19～95 ＞95
5.4.9 对工艺设备容积不大于95m3、压力小大于3.5MPa、流量不大于38L/s的生产装置，且为第二级释放源，按照生产的实践经验，其爆炸危险区域的范围划分，宜符合下列规定（图5.4.9）：
a）在爆炸危险区域内地坪下的坑、沟划为1区；
b）以释放源为中心，半径为4.5m，至地坪上以上范围内划为2区。

图5.4.9 易燃液体、液化易燃气体、压缩易燃气体及低温液体释放源位于户外地坪上方
5.4.10 爆炸性气体环境内的局部地区采用正压或连续通风措施后，可降为非爆炸危险环境，但应满足下列要求：
a）通风引入的气源应安全可靠，且应没有易燃物质、腐蚀介质及机械杂质。对重于空气的易燃物质，进气口应高出所划爆炸危险区范围的1.5m以上处；
b）送风系统应有备用风机，正压室应维持20Pa～60Pa（2mm～6mm水柱），当低于该值时应报警；
c）建筑物应采用密闭非燃烧材料的实体墙，非开启难燃烧材料的密闭窗和自动关闭的难燃烧材料的门；
d）应设置易燃气体浓度检测装置，当浓度达到爆炸性气体混合物的爆炸下限的50%时发出报警；
e）室内所有通向外部的孔洞和地沟应用非燃性材料进行隔离密封。