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.
According to the requirements of "Notice on Printing and Distributing the Development and Revision Plan of National Engineering Construction Standards in 2005 (the Second Batch)" (JIANBIAO [2005], No.124) issued by the original Ministry of Construction, this code was revised on the basis of the former national standard "Code for Design of Electric Power in Mine" (GB 50070-94) by SCIEG Beijing Huayu Engineering Co., Ltd. jointly with organizations concerned.
This code consists of 8 chapters, of which the main contents are: general provisions, terms, basic requirements, subterranean part of underground mine, open pit and dump of surface mine, electric traction, preparation plant and major fixed equipment.
As for this revision, the chapter "power distribution of surface blasting equipment storage and its processing room" in the former code is deleted; the chapter of "Terms" is added; important provisions like the 6kV or 10kV neutral earthing mode of system, electromagnetic compatibility level of power supply and distribution system in mine, protection for underground low-voltage indirect contact and the distribution voltage grade of mining enterprise are added or modified according to national principles and policies by reference to relevant national and international standards and codes based on the production practice experience , new technological advances and the former code.
In this code, the provision(s) printed in bold type is (are) compulsory one(s), and must be enforced strictly.
Ministry of Housing and Urban-Rural Development is in charge of the administration of this code and the explanation of the compulsory provisions, China National Coal Construction Association is in charge of routine management, and SCIEG Beijing Huayu Engineering Co., Ltd. is responsible for the explanation of specific technical contents. During the process of implementing this code, all relevant organizations are kindly requested to seriously sum up experience in combination with engineering practice; in case of any modification or supplement, please send your opinions and suggestions to SCIEG Beijing Huayu Engineering Co., Ltd. (address: No. 67 Ande Road, Beijing; postal code: 100120) for future reference in revision.
Chief development organization, participating development organizations and chief drafting staff of this code:
Chief development organization: SCIEG Beijing Huayu Engineering Co., Ltd.
Participating development organizations: Northern Engineering & Technology Corporation, MCC.
China Nonferrous Engineering and Research Institute
Shenyang Design & Research Institute of Sino Coal International Engineering Group
Hefei Design Research Institute for Coal Industry
Chief drafting staff: Zeng Tao, Tian Youlian, Shi Qiang, Guan Hengzhu and Dong Guangzhong
Chief examiners: Jiang Maizhan, Gu Yonghui, Wang Jun, Wang Puzhou, Feng Qiang, Bi Kongsi, Xing Guocang, Liu Yi, He Guanhua, Shao Yu, Zhao Yuanying, Zhang Peizhu, Zhao Zhenhai, Yan Xiaoguo, Tao Shaobin, Huang Mintong and Bao Weichao
Contents
Foreword I
1 General Provisions 1
2 Terms 2
3 Basic Requirement 4
4 Subterranean Part of Underground Mine 8
4.1 Power Supply System 8
4.2 Electric Apparatus and Protection 9
4.3 Cable Lines 11
4.4 Electric Equipment Chamber 12
4.5 Lighting 13
4.6 Protective Earthing 14
5 Open Pit and Dump of Surface Mine 17
6 Electric Traction 21
6.1 General Requirement 21
6.2 DC Traction Substation 21
6.3 DC Overhead Contact Network 22
7 Preparation Plant 27
7.1 Power Supply System 27
7.2 Process Control 27
8 Major Fixed Equipment 29
8.1 Hoist of Underground Mine 29
8.2 Main Fan of Underground Mine 31
8.3 Main Drainage Pump of Underground Mine 32
8.4 Air Compressor 32
8.5 Belt Conveyor 32
8.6 Cargo Ropeway 33
Explanation of Wording in This Code 34
List of Quoted Standards 35
Code for Design of Electric Power in Mine
矿山电力设计规范
1 General Provisions
1.0.1 This code is formulated with view to implementing national laws, regulations, principles and policies during the design of electric power in mine, guaranteeing life safety and equipment safety and realizing reliable power supply and distribution, energy conservation, favorable environment protection, advanced technology and economic rationality.
1.0.2 This code is applicable to the design of electric power in various newly-constructed, renovated and extended mines (except petroleum mine).
1.0.3 The design scheme and equipped level of electric power in mine shall be reasonably determined according to the mine scale, process characteristics, load property, power utilization and local power supply conditions.
1.0.4 For the design of electric power in mine, the relationship between the short-term development and the long-term development of electric power construction in mine shall be properly treated, namely short-term development is mainly concentrated, accompanied with long-term development. If conditions permit, the fundamental construction shall be combined with the production of electric appliance.
1.0.5 The design of electric power in mine shall not only meet the requirements stipulated in this code, but also complies with those in the current relevant ones of the nation.
2 Terms
2.0.1 Substation (distribution station)
A constituent part of power system able to receive and collect power supply from electric power system, transfer the voltage and then distribute the electric power. Where it is provided with all of the above main functions, it is referred to as substation; where there is no main transformer (without voltage transformation function), it is referred to as distribution station.
2.0.2 Mining area
Substation (distribution station) used for the power distribution of the whole or partial mining area; generally the power distribution scope includes several mines, surface mines, dressing plant, mining area administration, production management mechanism and auxiliary and affiliated enterprises.
2.0.3 Surface main substation (distribution station)
The enterprise substation/distribution center arranged in mines or on surfaces mine and used to receive and collect the external power supply of this enterprise. It is provided with power distribution function for the whole or partial load within this enterprise, and is also known as main step-down substation.
2.0.4 Underground main substation (distribution station)
The substation/distribution center arranged on the underground shaft station or main haulage roadway, used to receive ground supply connected from the mine and provided with function to distribute power for the whole or partial load of this mining level (sometimes the adjacent mining level is also included). It is also known as the underground central substation (distribution station).
2.0.5 Working section substation (distribution station)
The substation (distribution station) mainly distributing power to the load within the range of one or more underground working section(s).
2.0.6 Plant of utilizing castoff or by-product in mine for generating electricity
An enterprise producing electric power and heating power with fuel of mining by-product like the low heat waste and coalbed gas generated during the production and processing of mine.
2.0.7 Mining electric apparatus for non-explosive atmospheres
The electric apparatus in accordance with specific safety requirements of mine and applicable to the underground normal non-explosive atmospheres.
2.0.8 Underground main earthed electrode
The metal sheet earthed electrode arranged in the main and auxiliary water sump or drainage sump on the shaft bottom of underground mining level.
2.0.9 Underground local earthed electrode
Earthed electrode (in addition to the main earthed electrode) arranged in underground site equipped with concentrated or single electric apparatus.
2.0.10 Underground earthing conductor
Metal conductor used to connect the earthing terminal of electric apparatus to the earthing plate, including: earthing branch, earthing busbar and earthing trunk line. Thereinto, the earthing conductor connecting the earthing terminal of equipment to the earthed electrode is referred to as the earthing branch, the tandem busbar of earthing branches is referred to as the earthing busbar, and the earthing conductor used for the interconnection of earth devices is referred to as the earthing trunk line.
2.0.11 Underground earth device
A generic term for the underground earthed electrode, earthing branch and earthing busbar. Thereinto, the earth device containing underground main earthed electrode is referred to as major earth device while the remaining is referred to as local earth device.
2.0.12 Underground general earth network
A complete conductive earthing system at one or more mining level(s) or in the local underground area which is formed by the scattered major earth devices and local earth devices connected with earthing trunk line.
3 Basic Requirement
3.0.1 The mine power load shall be classified into Grade I load, Grade II load and Grade III load, and the load classification shall meet the following requirements:
1 Grade I load:
1) Main drainage pump for flood hazardous atmosphere and drainage pump in the working section of mine;
2) Main ventilator in mine with explosive hazardous atmosphere or serious injury for human health;
3) Vertical shaft hoist in mine with frequent personnel hoisting;
4) Drainage pump in open pit of surface mine with flood hazardous atmosphere or drainage pump draining through laneway;
5) Other equipment which shall be regarded as Grade I load according to the requirements of current national or professional standards.
2 Grade II load:
1) Single equipment or interconnected grouping equipment in large-sized enterprises which are directly related to mineral exploitation, transportation, hoisting, processing and outward transportation (except the Grade I load);
2) The underground fixed lighting equipment without portable lighting fixture; emergency lighting equipment used to guarantee the continuous operation of normal activity in Grade I load workplace on surface or Grade II load workplace of large-sized enterprises;
3) Power supply equipment for the communication and safety monitoring device in mine;
4) Drainage pumps in large surface mine;
5) Signal power supply equipment for the large railway station of surface mine;
6) Other equipment which shall be regarded as Grade II load according to the requirements of current national or professional standards.
3 Grade III load: electrical equipment not belonging to Grade II load and Grade I load.
3.0.2 The power supply of mining enterprise should be connected from the substations (distribution stations) of regional power system and mining area or the self-supply power plant of coal & electricity joint power plant or mining area (mine). Where the above sources are unavailable, it may be connected from the substation (distribution station) of adjacent enterprise.
3.0.3 The power supply and power line of mining enterprise shall meet the following requirements:
1 Double power supply shall be adopted for the mining enterprise with Grade I load; where one power supply fails, the other shall not be damaged simultaneously; thereof the power supply capacity shall be at least guarantee all electricity demands of Grade I load of the mining enterprise, and should meet the electricity demand of Grade II load of large mining enterprise.
2 Two-circuit power line should be adopted for the power supply of large mining enterprise; where any circuit fails, the remaining power line should guarantee the supply for all electricity demands of Grades I and II load.
3 One-circuit power line may be adopted for the power supply of small mining enterprise without Grade I load.
3.0.4 The arrangement of self-contained power supply of mining area (mine) shall be determined according to the regional electric power development planning, general planning of mining area, comprehensive utilization planning, relevant national industrial policy, industry access policy and environment and water resource protection policy through technical and economical comparison; it shall also meet one of the following conditions:
1 The mine is far away from the electric power system, and it is difficult to obtain the required power supply from the electric power system.
2 It is suitable to construct plant of utilizing castoff or by-product in mine for generating electricity because there are sufficient by-products like the low heat waste or coalbed gas generated during the production and processing of mine to be used as the fuel.
3 The mine is provided with reliable heat load and centralized heat supply conditions, and it is suitable to develop combined heat and power engineering.
4 It is provided with conditions to develop other distributed power source.
3.0.5 10~110kV supply voltage should be adopted for the power supply of mining enterprise, voltage of other grade may be adopted where it is determined as reasonable through technical and economical comparison. Where the difference of economic and technical norms of two voltages is small, the higher voltage should be adopted.
3.0.6 For the mine engineering of mining enterprise with supply voltage larger than or equal to 20kV, 10kV voltage should be adopted for the Grade 1 distribution voltage of mining enterprise; voltage of 6kV or partial voltage of 20kV or above may be adopted where it is determined as reasonable through technical and economical comparison.
3.0.7 The number of main transformers in the surface main substation of mining enterprise shall be determined according to the following requirements:
1 2 sets should be adopted for large or medium mine engineering.
2 2 sets shall be adopted where the voltage transformation of both power supplies of the Grade I load of mine is carried out through main transformer.
3 More than 2 sets may be adopted where it is determined as reasonable through technical and economical comparison.
4 1 set may be adopted for small mine engineering without Grade I load.
3.0.8 Where there are 2 or more main transformers in the surface main substation of mining enterprise, if one of them stops, the capacity of remaining transformer shall guarantee the power supply of Grades I and II load. Where there is one main transformer in the surface main substation, an allowance equal to 15%~25% the whole load of mine should be reserved.
3.0.9 The 6kV or 10kV neutral earthing mode of system of mining enterprise should be selected according to the uninterrupted power supply requirements of mining enterprise, the effect of single-phase earthing fault voltage on personal safty, the size of capacitance current, the overvoltage of single-phase earthing and the requirements of electric apparatus; this mode shall also meet the following requirements:
1 In case that the fault circuit is not required to be removed immediately and the short-term operation of fault circuit should be maintained during the single-phase earthing fault of the 6kV or 10kV system, non-earthing, high-resistance earthing or arc suppression coil earthing shall be adopted, and the current flowing through the single-phase earthing fault point shall be controlled within 10A.
2 In case that the fault circuit is required to be removed immediately during the single-phase earthing fault of the 6kV or 10kV system, low-resistance earthing may be adopted, and the current passing through the single-phase earthing fault point shall be controlled within 200A.
3 Neutral point direct earthing shall not be adopted for the 6kV or 10kV system supplying power for the open pit and dump of underground or surface mine.
3.0.10 The 6kV or 10kV feed out line on each circuit of surface main substation (distribution station) of mine and surface mine or other substation (distribution station) distributing power to the open pit and dump of underground and surface mine shall be equipped with single phase earthing protection according to the following requirements:
1 Where non-earthing, high-resistance earthing or arc suppression coil earthing is adopted for the neutral point of 6kV or 10kV system of mine, selective single-phase earthing protection shall be installed, and the protection shall act before the signal or trip.
2 Where low-resistance earthing is adopted for the neutral point of 6kV or 10kV system of mine, two-section zero-sequence current protection shall be arranged; the first section shall be quick break of zero-sequence current with time limit not exceeding 0.5s while the second section shall be zero-sequence overcurrent protection with time limit same as that of the interphase overcurrent protection.
3.0.11 The electromagnetic compatibility level of internal coupling point of power supply and distribution system in mine should comply with the electromagnetic compatibility level requirements for the Category 3 plant as specified in relevant requirements of the current national standard "Electromagnetic compatibility - Environment - Compatibility Levels in Industrial Plants for Low-frequency Conducted Disturbances" (GB/T 18039.4).
Where the internal coupling point supply of power supply and distribution system is used for the equipment and device sensitive to the power supply disturbance, necessary measures should be taken to improve partial electromagnetic environment, or the adopted equipment or device is connected with the power supply complying with the electromagnetic compatibility level requirements for the electromagnetic environment of Category 2 or Category 1 plant as specified in relevant requirements of the current national standard "Electromagnetic compatibility - Environment - Compatibility Levels in Industrial Plants for Low-frequency Conducted Disturbances" (GB/T 18039.4).
3.0.12 The location selection for surface main substation (distribution station) in mining enterprise shall meet the following requirements:
1 Close to the load center and convenient for inlet and outlet lines.
2 Land conservation.
3 Underground resources with no or few compression.
4 Kept away from dirtiness, fire accidents, non-explosive atmospheres and noisy and vibrating atmospheres.
5 Provided with proper geological, geographic and geomorphic conditions, and kept away from adverse geological areas like fault, landslide and subsidence area.
6 The safety height shall be added to the flood protection design elevation of substation site according to the calculation based on 100-year flood recurrence interval.
7 The distance to the productive limit of open pit in surface mine shall not be less than 200m and the distance to the standard gauge railway shall not be less than 40m.
3.0.13 The route selection of fixed high-voltage overhead power line in mine shall not only comply with relevant national and professional requirements, shall also meet the following requirements:
1 It shall not be arranged in blast area and unstabilized waste discharge area and shall be kept away from such area with proper safety distance.
2 The well (ore) field boundary, fault jamb or other jamb should be used; where there is no available jamb, the length of line in the road section passing through the mine surface shall be reduced and the initial subsidence area shall be avoided.
3 Where it must pass through subsidence area due to the restriction of conditions, the length of road section passing through the subsidence area shall be reduced, and adequate safety distance and other necessary safety measures shall be provided and taken between the two-circuit power lines passing through the subsidence area. The mine power line arranged on the same pole (tower) should not pass through area with potential subsidence or the unstablized subsidence area.
4 Subterranean Part of Underground Mine
4.1 Power Supply System
4.1.1 The arrangement of underground substation (distribution station) shall be determined according to the surface power distribution system, underground production scale and power distribution scope, drainage pattern and mining method; it shall also meet the following requirements:
1 The underground main substation (distribution station) shall be arranged at the principal mining level as the substation/distribution center of such level and several adjacent mining levels; the shaft station at the principal mining level and adjacent to the main draining pump room should be arranged in underground main substation (distribution station).
2 The underground main substation (distribution station) should be directly powered by the surface main substation (distribution station).
3 The working section substation (distribution station) and main draining pump room substation (distribution station) with large load or far away from the underground main substation (distribution station) may be directly powered by the surface main substation (distribution station) in mine or other substation (distribution station) arranged on the mine surface.
4.1.2 The selection of underground distribution voltage and electric apparatus voltage shall meet the following requirements:
1 The voltage of high-voltage power distribution in underground power grid should be the same with the distribution voltage of surface high-voltage power grid of the same grade, and the rated voltage shall not be greater than 10kV.
2 660V voltage should be adopted for the low-voltage power distribution of underground power grid while 380V voltage may be adopted for small mine.
3 1140V voltage may be adopted for the comprehensively mechanized mining and exploitation working surface.
4 The voltage of portable electric apparatus shall not be greater than 127V.
4.1.3 The earthing type of underground low-voltage distribution system shall be adopted with IT system, and shall meet the following requirements:
1 The live part on the power supply end of power distribution system shall not be earthed or shall be adopted with high-impedance earthing; where the first fault with negligible impedance occurs between the phase conductor and the exposed conductive part of power distribution system, the fault current shall not be greater than 5A.
2 N wire should not be led out from the power distribution system.
4.1.4 The power supply and power supply circuit of underground substation (distribution station) shall be arranged according to the following requirements:
1 For the power cable led to the underground main substation (distribution station) and other underground substation (distribution station) from the surface, the total number of circuits shall not be less than 2. Where any circuit stops, the power supply capacity of the remaining circuit shall be able to undertake all underground loads.
2 Double power supply shall be adopted for the underground main substation (distribution station) with Grade I load, main draining pump room substation (distribution station) and other substation (distribution station).
3 Two-circuit power supply should be adopted for the substation (distribution station) distributing power to underground mineral exploitation and transportation of large mine.
4.1.5 As for the power supply cable led to the underground substation (distribution station) through surface overhead line, lightning-protection device shall be installed at the connection of overhead line and cable.
4.1.6 Automatic reclosing control device shall not be installed on the lines distributing power to the underground from surface or other underground lines.
4.1.7 The mobile substation power distribution should be adopted under one of the following conditions:
1 The power distribution for the comprehensively mechanized mining and exploitation working surface.
2 Where the power distribution by the fixed substations (distribution stations) like the working section substation (distribution station) is difficult or uneconomic.
3 Where there is no available low-voltage power supply for the dead load tunneling power distribution.
4.1.8 The voltage of underground lighting network shall meet the following requirements:
1 220V or 127V may be adopted for the fixed lighting voltage of main roadway.
2 36V voltage shall be adopted for the courtyard and the area between the courtyard and stope face.
3 36V voltage shall be adopted for the mining and exploitation working surface while 127V voltage may be adopted where the mining explosion-proof light fixture is selected.
4 The voltage of portable light shall not be greater than 36V.
4.2 Electric Apparatus and Protection
4.2.1 The type selection of underground electric apparatus shall meet the following requirements:
1 Mining electric apparatus for non-explosive atmospheres should be adopted for the mine with non-explosive atmospheres.
2 The mine with explosive atmospheres shall be implemented according to relevant current national and professional standards.
3 Oily material shall not be adopted for the insulation of electric apparatus.
4.2.2 The number of distribution transformers for underground main substation (distribution station) and the substation (distribution station) with low-voltage Grade I load shall not be less than 2; where one of them stops, the remaining transformers shall undertake the whole load.
4.2.3 Breaker shall be installed on the power supply inlet line, bustar section and feed out line of the underground main substation (distribution station) and other substation (distribution station) directly powered from surface.
4.2.4 Except the underground main substation (distribution station) and the substation (distribution station) directly powered from surface, the arrangement of high-voltage breaker for other substation (distribution station) shall meet the following requirements:
1 The power supply inlet line breaker shall be arranged for dual-power inlet line substation (distribution station); where two circuits of power supply simultaneously transmit power, the busbar shall be sectioned and section breaker shall be arranged.
2 As for the substation (distribution station) with single power supply inlet line, where the number of transformers exceeds 2 or the high-voltage outlet line is available, inlet line breaker shall be installed.
3 Breaker shall be installed on feed out line.
4.2.5 The arrangement for the primary and secondary side of transformer shall meet the following requirements:
1 As for the mine with non-explosive atmospheres, load switch should be installed on the primary side of transformer; where the transformer capacity is 315kVA and below, disconnector fuse may be installed.
2 As for the mine with explosive atmospheres, the breaker should be installed on the primary side of transformer.
3 Breaker should be installed for the master switch on the secondary side of transformer.
4.2.6 Interphase short circuit and overload protection shall be installed for the underground high- and low-voltage line.
4.2.7 Where breaker is adopted for the shortcircuit protective apparatus of low-voltage distribution line, the minimum short-circuit current on the end of protected line shall not be less than 1.5 times the instantaneous current of breaker or the setting current of tripping device.
4.2.8 The arrangement of single-phase earthing protection for underground 6kV or 10kV system shall meet the following requirements:
1 Where non-earthing, high-resistance earthing or arc suppression coil earthing is adopted for the neutral point of 6kV or 10kV system, the high-voltage feed out lines of underground main substation (distribution station) and substation (distribution station) directly powered from surface shall be equipped with selective single-phase earthing protection; the earthing protection shall act before the trip or signal; the high-voltage feed out line supplying power for the mobile substation shall be equipped with selective single-phase earthing protection, and the protection shall act before trip without time limit.
2 Where low-resistance earthing is adopted for the neutral point of 6kV or 10kV system, the high-voltage feeders of all-level substations (distribution stations) shall be equipped with two-section zero-sequence current protection: zero-sequence current quick break with action time limit not longer than 0.3s shall be adopted for the first section; zero-sequence current quick break without time limit shall be adopted for the high-voltage feeder directly supplying power for the motor, transformer and mobile substation; zero-sequence overcurrent protection shall be adopted for the second section, and the time limit shall be the same with that of the interphase overcurrent protection.
4.2.9 Indirect contact protective measures automatically cutting off the power supply shall be taken for the underground low-voltage power distribution IT system, and shall meet the following requirements:
1 Insulation monitoring device shall be installed for the low-voltage power distribution IT system; where the insulation drops to the setting value, the insulation monitor shall send out audible and (or) visible signal.
2 As for mine with explosive atmospheres, where single earth fault occurs to the exposed conductive part or the ground, the protective device shall rapidly cut off the faulty line.
3 As for the mine with non-explosive atmospheres, where the single earth fault to the exposed conductive part and the ground occurs with the expected contact voltage not exceed 36V, the power supply of fault circuit may not be cut off to maintain short-time operation. The insulation monitoring device shall send out audible and (or) visible alarm signal; where the second outphase earth fault occurs, the electrical device shall be protected by overcurrent or the fault circuit shall be cut off by the residual current protector. The operating characteristics of protection device shall meet the requirements of the current national standard "Low-voltage Electrical Installations - Part 4-41: Protection for Safety - Protection against Electric Shock" (GB 16895.21). Where single earth fault to exposed conductive part or the ground occurs and the expected contact voltage exceeds 36V, the protective device shall rapidly cut off the faulty line.
4 Equipotential bounding shall be carried out according to the requirements of Article 4.2.10 and Article 4.2.11 in this code.
4.2.10 General equipotential bonding shall be adopted between the earthing busbar of underground substation (distribution station) directly receiving power supply from the surface and the nearby underground external conductive parts listed as follows:
1 Metal pipe used for drainage, air compression and watering.
2 Steel structure is installed along the laneway.
4.2.11 As for the underground substation (distribution station) and mobile substation not directly receiving power supply from the surface, partial equipotential bonding shall be adopted between its earthing busbar and nearby external conductive part as specified in Article 4.2.10 in this code.
Foreword I
1 General Provisions
2 Terms
3 Basic Requirement
4 Subterranean Part of Underground Mine
4.1 Power Supply System
4.2 Electric Apparatus and Protection
4.3 Cable Lines
4.4 Electric Equipment Chamber
4.5 Lighting
4.6 Protective Earthing
5 Open Pit and Dump of Surface Mine
6 Electric Traction
6.1 General Requirement
6.2 DC Traction Substation
6.3 DC Overhead Contact Network
7 Preparation Plant
7.1 Power Supply System
7.2 Process Control
8 Major Fixed Equipment
8.1 Hoist of Underground Mine
8.2 Main Fan of Underground Mine
8.3 Main Drainage Pump of Underground Mine
8.4 Air Compressor
8.5 Belt Conveyor
8.6 Cargo Ropeway
Explanation of Wording in This Code
List of Quoted Standards
