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
