GB 5959.2-1998 Safety of electric heating equipment Part 2: Special requirements for electric arc furnace equipment
Some standard content:
GB5959.21998
This standard is equivalent to IEC519-4:1995 (Second Edition) Safety of electric heating equipment Part 4: Special requirements for electric drive furnace equipment.
This standard is numbered GB 5959.2-1998, because the number of GB5959.4 has been occupied by other standards. This standard should be used in conjunction with GB5959.1-1986 Safety of electric heating equipment Part 1: General requirements. Compared with GB 5959.2-1986 (eq. IEC 519-4; 1977), this standard adds safety requirements for new technologies of electric arc furnaces in terms of technical content; the writing format is all in accordance with the provisions of GB/T1.1. The contents of Chapters 1 to 15 of this standard are mainly revisions and supplements to the corresponding chapters of GB 5959.1-1986, and the content of Chapter 16 is a revision of the content of Chapter 3 in GB 5959.2-1986. This standard was first issued on July 2, 1986. It was first revised in December 1998. This standard shall be implemented from October 1, 1999, and all relevant products shall comply with the requirements of this standard. From the date of implementation, this standard will replace GB5959.2-1986. Appendix A and Appendix B of this standard are standard appendices. Appendix C of this standard is a reminder appendix.
This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Industrial Electric Heating Equipment. The drafting unit of this standard is Xi'an Electric Furnace Research Institute of the Ministry of Machinery Industry. The drafter of this standard is Liu Xiping.
This standard is entrusted to the Secretariat of the National Technical Committee for Standardization of Industrial Electric Heating Equipment for interpretation. GB 5959. 2—1998
IEC Foreword
1) IEC (International Electrotechnical Commission) is a world standardization organization composed of national electrotechnical committees (IEC National Electrotechnical Committees). The objective of the IEC is to promote international cooperation on all matters concerning standardization in the electrical and electronic fields. For this and other purposes, the IEC publishes International Standards. Standards are entrusted to Technical Committees, in which any IEC National Committee interested in the subject may participate. International, governmental and non-governmental organizations in contact with the IEC may also participate. The IEC and the International Organization for Standardization (ISO) work closely together in accordance with rules agreed upon by the two organizations. 2) Formal IEC resolutions or agreements on the subject, drawn up by technical committees in which all National Committees with a particular interest in the technical question concerned participate, express as far as possible the international consensus on the subject involved. 3) These resolutions or agreements are published in the form of recommended standards, technical reports or guidelines for international use and are recognized by the National Committees in this sense.
4) In order to promote international unification, the IEC National Committees explicitly commit themselves to adopt IEC International Standards as far as possible in their national and regional standards. Any inconsistency between IEC standards and corresponding national or regional standards shall be clearly indicated in the national or regional standards. 5) The IEC does not provide any explicit procedure to demonstrate its agreement with, and does not assume any responsibility for, any equipment claiming to conform to an IEC standard.
International Standard IEC519-4 was prepared by IEC Technical Committee 27: "Industrial Electrothermal Equipment". This second edition repeals and replaces the first edition published in 1977. This part of IEC519 should be used in conjunction with the second edition of IEC519-1. As special requirements for arc furnace equipment, it modifies, replaces or supplements IEC519-1.
The content of this standard is based on the following documents: Draft International Standard (DIS)
27(CO)104
Voting Report
27(CO)109
For details of the voting on this standard, please refer to the voting report listed in the table above. Annexes A and B form an integral part of this standard..comNational Standard of the People's Republic of China
Safety of electrothermal equipment
Part 2: Particular requirements for arc furnace equipmentSafely in electrohcat installations-Par1 2 : Particular requirements for arc furnace installations1 Scope
This standard applies to the following electric heating equipment:
Direct arc heating furnaces, such as direct arc furnaces, arc heating ladle furnaces, indirect arc heating furnaces.
2 Referenced standards
CB 5959.2--1998
idtIEC519-4:1995
Replaces GB 5959. 2 -1986
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. At the time of publication of this standard, the versions shown are valid. All standards are subject to revision: parties using this standard should investigate the possibility of using the latest versions of the following standards. GB/T 2900.23—1995 Electrical terminology T industrial electric heating equipment (neq IEC 50(841):1983)GB5959.1—1986 Safety of electric heating equipment Part 1: General requirements (neg1EC519-1.1984)IEC73:1991 Color and auxiliary marking of segment indicating devices and operating devicesIEC364-4-43:1977 Electrical equipment of buildings Part 4: Safety protection Chapter 43: Overcurrent protectionIEC364-4-473:1977 Electrical equipment of buildings Part 4: Safety protection Chapter 47; Application of safety protection measures Chapter 4 Section 73 Overcurrent protection measures
[EC479-11994 Effects of current through human body and sexual animals Part 1: General conditions 3 Definitions
The definitions given in GB5959.1-1986 and GB/T2900.23-1995 apply to this standard. 4 Classification of electric heating devices by voltage
Except for the following requirements, follow 3.1 of GB5959.1-1986. 4.1 Supplement
The voltage range is determined by the open-circuit rated power supply voltage between the lines connected to the electrodes. 5 Classification of electric heating devices by frequency
Except for the following requirements, follow 3.2 of GB 5959.1-1986. 5.1 Supplement
DC belongs to the low frequency category.
Approved by the State Administration of Quality and Technical Supervision on December 21, 1998, and implemented on October 1, 1999
6 General requirements
CB 5959.2-1998
In addition to the following requirements, in accordance with Chapter 4 of GB 5959.1-1986. 6.1.3 Alternatives
Even when the refractory lining is not built, the furnace should also be guaranteed to have sufficient mechanical stability. For rectangular buried furnaces, refractory linings should be built to ensure mechanical stability. The expansion of the furnace should be considered and adjusted during design. The operating device should be placed in an area that the operator can reach easily and safely from his normal position. It should be as reasonable and practical as possible. The design and placement of the operating device should prevent their malfunction and be as reasonable and practical as possible. The operating device designed for the head connection should have a mechanically lockable connector that does not move with the power connection line. 6.1.5 Replacement
Public pipelines (water pipes, hydraulic pipes, etc.) should not be subjected to excessive mechanical stress during the operation of the equipment. 6.2.1 Replacement
Electrical devices installed near high-temperature components should have sufficient thermal strength and adequate protection performance. 6.2.3 Replacement
In the positive operation of circuits composed of transformers, reactors and inductors, transient voltages will be generated. Precautions should be taken to avoid any harm to people caused by such transient voltages. The design of electrical devices should be able to suppress and/or withstand very high voltages generated during normal operation of electric drive furnaces.
6. 3. 2 Replacement
Similar precautions should be taken for electromagnetic leakage (stray field) effects, such as exhaust current and induced voltage, and try to be reasonable and practical. 6.5 Supplementary
This requirement also applies to other water-cooled components, such as the bottom electrode of a DC arc furnace. See also 15.4.7. 6.5.6 Supplement
e) Minimum and maximum inlet positive force.
7 It is prohibited to use the earth as part of the effective circuit according to Chapter 5 of GB5959.1-1986
8 Nameplate content, marking and circuit diagram
In addition to the following requirements, ammonium GB 5959.1--1986 Chapter 6. 8.1 Supplement
k) Identification of main connections (for example, the number of the furnace principle circuit diagram). 8.2 Supplement
The nameplate is preferably placed on the main control panel of the electric furnace. When any part of the equipment has a significant change in details, the nameplate should be updated. 8.4 Supplement
In addition to the approval, the arc furnace equipment shall be provided with functional descriptions of each component, operating instructions and circuit diagrams as well as maintenance instructions. The language of these documents shall be agreed upon by the manufacturer and the user. Unless otherwise agreed, these documents shall be in the language of the country where the equipment is installed. 9 Overcurrent and overvoltage protection
Except for the following requirements, in accordance with Chapter 7 of GB 5959, 1--1986. 9 Joint generation
Where relevant, overcurrent protection measures shall be provided in accordance with IEC364-4-43:1977 and IEC3644-4731977. Where necessary, protection measures for overcurrent (overload and short circuit) shall be provided based on the scope beyond the provisions of these standards. GB 5959. 21998
Note: IEC 364-4-43:1977 and IEC 364-4-473:1977 involve the protection of cables and wiring with voltages up to 1000 V. Supplement:
9.1 The switchgear connecting the electric heating equipment to the power supply shall be able to reliably cut off all currents that may occur, including fault currents. When two switches are operated in series, they shall be able to safely pass and reliably cut off all currents that may occur, including fault currents. 9.2 Special precautions shall be taken to avoid the generation of extremely high overvoltages on the secondary side that can damage the equipment. 10 Isolation and switching
In addition to the following requirements, according to Chapter 8 of GB 5959.1-1986. Supplement:
10.5 The emergency disconnection device shall be connected to IEC73:1991, marked in red, and the bottom area where the operating handle is located shall be painted yellow as a backing to make the handle clearly visible. The operating device of the emergency disconnection device shall be placed outside the danger zone and easily accessible to the operator.
10.6 Before going up to the furnace roof or allowing work in the area near the electrode or other conductive parts, the isolation and/or grounding procedures listed in Appendix A shall be implemented. Measures should be provided to prevent the circuit from being accidentally reconnected. Further requirements and explanations are given in 15.1, 15.3.7, 15.3.8 and 15.3.9. 10.7 Special attention should be paid to the buck-boost power supply system (Figure A3 of Appendix A) to ensure that during the operation of the electrode, the operator's position is connected to the grounding point of the low-voltage short-circuit and grounding device as safely and reliably as possible. During shutdown, special indicators of current and voltage should trip the high-voltage circuit breaker in the event of any system failure to ensure that the current-time relationship specified in IEC 479-1:1994 is not exceeded. 110.8 All control devices related to the furnace should be designed as "fail-safe protection" type, and the emergency disconnection function should be independent of electronic components. These requirements should be as reasonable and practical as possible. 11 Connection to the power grid
Except for the following requirements, follow Chapter 9 of GB 5959.1-1986. 12 Protection against electric shock
Except for the following requirements, follow Chapter 10 of GB 5959.1-1986. 12.1 Supplement
National standards of various countries should apply to equipment in voltage band 3 until otherwise notified. 12.4.1 In electric arc furnaces, all accessible metal parts that are liable to become accidentally energized in the event of insulation failure shall be electrically connected safely and firmly to the ground terminal or the ground terminal of the connector plug through the shortest possible path. 13 Protection against thermal effects
According to Chapter 11 of GB5959.1-1986.
14 Fire and explosion prevention
According to Chapter 12 of GB5959.1-1986.
15 Inspection, commissioning, use and maintenance of arc protection equipment shall be in accordance with Chapter 13 of GB5959.1-1986 in addition to the following requirements. 15.1 Supplementary
Specific requirements for isolation shall be specified in a separate instruction manual. These requirements shall be posted in the switch operating area and/or approved instructions shall be issued to relevant personnel.
15.3 Supplement
GB5959.2-1998
15.3.4 All personnel shall wear protective clothing suitable for furnace work, suitable underwear and other protective equipment, such as: - protective boots
- fire helmet (non-conductive)
- protective face (for example, mask and tinted glasses) - earmuffs;
- waist,
- heat-insulating gloves
tinted sun goggles.
15.3.5 No one except authorized personnel shall be allowed to approach the live parts of the furnace. 15.3.6 Workers shall be warned of various hazards associated with the furnace. In addition, warning signs shall be used to warn them not to approach any dangerous areas under the furnace and the current-carrying conductor area. The entrances to these dangerous areas shall be blocked by one or more fences, as reasonable and practical as possible. 15.3.7 Work related to loosening, re-clamping, changing and connecting electrodes and work on electrode accessories may only be carried out after the protective measures mentioned in 10.6 have been taken. The above requirements also apply to automatic connection of electrodes. 15.3.8 The requirements of 15.3.7 may be relaxed if personal safety is fully guaranteed by other appropriate precautions (e.g., operators are located in an insulated area, maintain an adequate safety distance, use insulated tools, and only touch one electrode). 15.3.9 If the furnace is powered, tools, oxygen lances, bath temperature guns and other metal pipes should be effectively grounded or, when possible, their accessible metal parts should be insulated or only used by personnel who are insulated from the ground. If practicable, the length of these tools (including the charging car arms) should not allow them to approach the electrode area. If this is not possible, appropriate operating procedures should be adopted, namely lifting the force electrode and keeping it in the raised position during the operations listed above. When automatic guns are used, these guns should be reliably grounded and tilted at an angle so that they are immersed in the bath away from the electrode.
The above requirements do not necessarily apply to DC arc furnaces. For DC arc furnaces, other appropriate precautions should be taken to avoid personal injury due to voltage.
15.4 Supplementary
15.4.6 When performing maintenance work in the furnace, appropriate safety precautions should be taken to prevent electrodes or electrode fragments or furnace charge from falling into the furnace.
15.4.7 When welding the cooling system in a hot furnace, the following precautions should be taken: - The relevant cooling components should be turned off and any liquid should be drained; - All dangerous movements of furnace components should be stopped and locked if necessary; - If a material is used to cover the hot components and/or residual molten steel at the bottom of the furnace, the material should not produce dangerous gases when its temperature rises:
- To protect personnel welding in a hot furnace, the hanging basket should be insulated. The basket should be manufactured and maintained in accordance with national standards. Welding machines and other electrical tools used for maintenance work inside the furnace should be of a type suitable for working in steel containers and comply with relevant national standards.
15.4.8 Operators responsible for flushing the furnace cooling water pipes (for example, with hydrochloric acid solution) should be trained and well protected (wearing protective eyewear and taking other protective measures suitable for the special purpose, such as rubber gloves, acid-proof sun goggles, showers, eye washing devices, etc.). 15.4.9 When using auxiliary power to perform maintenance work on or near secondary current-carrying conductors, access to all other windings and their connections should be avoided unless these windings are short-circuited and grounded. The reason for emphasizing this requirement is that when the secondary connections are energized, dangerous voltages will be generated in other windings. This situation mainly occurs during welding work. The same precautions apply to testing and/or other operations on secondary instruments and control devices. If it is difficult to properly ground its parts during access to the tap changer, welding, testing and other operations should be avoided on the relevant secondary side.
See also 12.4.1 and Appendix A.
Supplement:
16 Design requirements
16.1 Electrodes and auxiliary devices
16.1.1 General requirements
GB 5959.2—1998 Www.bzxZ.net
The electrode support mechanism should be insulated from the drive mechanism (electric positioning mechanism) and the furnace frame. The drive mechanism and the furnace frame should be well grounded. 16.1.2 Each electrode lifting system should be provided with two limit switches or similar devices. The second limit switch or similar device can be used to detect overshoot. In addition, a mechanical end-of-travel stop device should be provided. Note: If the end-of-travel stop has been considered in the design of the electrode lifting system, there is no need for a second limit switch. 16.1.3 For self-baking electrodes (Saderberg electrodes), care should be taken to ensure that the electrode upper clamp is reliably closed before the electrode holder is released. For pneumatic clearing systems, the gas source should have a gas storage tank of sufficient capacity. 16.1.4 A mechanical locking device should be provided to prevent any uncontrolled movement of the electrode column: to ensure safe operation, etc. 16.1.5 Suitable interlocks or similar devices shall be used to properly control all movements of the electrode lifting system to prevent damage to parts. 16.1.6 For furnaces equipped with bottom electrodes, means shall be provided to monitor these electrodes and limit the voltage between each bottom electrode and the grounded shell, otherwise the voltage will damage the insulation. 16.2 Water-Cooled Electrodes
16.2.1 Composite Electrodes
In addition to monitoring flow and temperature, a leakage monitoring system shall be provided to interrupt the energy supply to the furnace and cut off the water supply (inlet and outlet pipes) to lift the electrode.
16.2.2 Water Spray Cooling
Each electrode shall be equipped with a device to regulate the flow rate of the water supply. The water flow rate shall be adjusted so that under normal operating conditions (including tilting and copper tapping), all the heat is evaporated on the electrode. It is necessary to take adequate measures to cut off the spray cooling (possibly after a delay) when the furnace is powered off. 16.3 Furnace Shell and Furnace Cover
16.3.1 All types of furnace shells (e.g., skeleton structure furnace shells) should be either directly grounded or connected to the furnace shell frame which should also be grounded.
1 The furnace cover of an arc furnace can be isolated from the ground.
2 The furnace shell of a rotary submerged arc furnace can be grounded through a current-limiting resistor to prevent fault current that can cause the grounding wire to burn and damage the rotor bearing. An overvoltage relay should be provided to cut off the power supply to the furnace when a dangerous voltage appears between the furnace shell and the ground. Measures should be provided to prevent any uncontrolled movement of the furnace to ensure safe operation. 16.3.2 All movements of furnace components, such as tilting of the furnace, rotation of the furnace shell and unscrewing of the furnace cover, should be well controlled by suitable interlocking mechanisms or similar devices to prevent any misoperation or damage to components. 16.3.3 Backup measures should be provided so that when the tilting mechanism fails , the furnace can be returned to or maintained in a safe position. 16.3.4 Each movement of the furnace parts shall be limited by mechanical terminal stops. If necessary, overshoot limit switches shall be used. 16.3.5 Access to the furnace superstructure (furnace cover support and electrode arms) is not allowed unless the furnace has been reliably powered off. See Appendix A, and for exceptions, see 15.3.8.
16.3.6 The operating status of the furnace (power on or off) shall be indicated by a light signal, and the position of the light signal shall be visible to all personnel near the furnace.
16.3.7 The furnace shall be provided with a mechanism for lifting the electrode to a safe position. When the power is off, the electrode shall stop in its position, or, if necessary, the electrode shall be sent to a safe position.
Note: This does not apply to submerged arc furnaces.
16.4 Charging, slag removal and unloading
GB 5959.2—1998
16.4.1 The charging device is an integral part of the furnace equipment and shall be grounded in a practical and reliable manner or electrically insulated in an appropriate manner.
16.4.2 A shelter with appropriate protective measures and escape routes shall be provided where the operators are located to prevent flame hot particles from falling into the furnace charge, etc. Similar protection and routes shall also be provided for the charging device. 16.4.3 During slag removal and steel tapping, personnel approaching the dangerous area of the furnace are limited to those who are closely related to the operation of the furnace and are trained and authorized.
16.5 Additional requirements
16.5.1 During slag removal and steel tapping, personnel approaching the dangerous area of the furnace are limited to those who are closely related to the operation of the furnace and are trained and authorized. The area should be free from water accumulation. In case of water leakage, all measures should be taken to remove any water accumulation in the steel tapping area.
Note: This requirement does not apply to furnaces with granulating equipment. In this case, special safety precautions should be taken to avoid explosion. 16.5.2 Various parts of the furnace that need to be monitored and maintained (electrical insulation, electrode arms, electrode support equipment, cooling parts, service motors, etc.) should be easily accessible. For this purpose, ladders, platforms, walkways and other facilities should be provided. All working areas should be equipped with handrails that meet national standards. 16.5.3 The steel tapping pit for ladles should be built with sufficient free space to facilitate the transfer of ladles. The steel tapping pit should be surrounded by handrails as far as practical in accordance with national standards.
16.5.4 When pressurized gas storage containers (various gas cylinders), pipeline systems and related equipment are placed near the furnace, measures should be taken to protect them from possible overheating, electric shock and splashing of red-hot materials. Similar safety precautions should be taken for portable pressure vessels (for example, various gas bottles, various spherical gas containers on trolleys, etc.). 16.5.5 When a key is used to power the furnace, the key should not be pulled out unless the furnace switch is in the off position. 16.5.6 The electric furnace transformer should only be closed from the main control panel. In special maintenance circumstances, if necessary, it should be allowed to remotely control the furnace according to the prescribed safe working procedures.
16.5.7 The furnace is preferably designed to prevent any contact between conductive parts and the crane wire rope. One method is to provide an interlock so that the conductive parts cannot come into contact with the crane wire rope.
For submerged arc furnaces, if it is necessary to use a crane to lift the electrode while the furnace is running, an insulating rope must be used or the crane must be completely insulated from the ground. GB 5959.2—1998
Appendix A
(Standard Appendix)
Additional safety protection system for personnel working near electrodes and other live parts of secondary circuits
Taking into account the increase in voltage and/or new switch technology, one of the following design requirements for personal safety is required: a) The high-voltage furnace switch or high-voltage furnace circuit breaker is in the open position, and the high-voltage circuit breaker is also in the open position (Figure A1): b) The commercial voltage furnace switch or high positive current circuit breaker is in the open position, and the high-voltage grounding switch is in the closed position (see A2); c) For step-down-step-up (intermediate circuit) transformers: an intermediate circuit switch is in the open position, and the low-voltage grounding device and short-circuit device are in the closed position (see Figure A3, step-down-step-up transformer).
In the case of Figures A1 and A2, no protection measures are provided for any accidental feeding on the secondary side. In order to make the secondary side potential close to the ground voltage. Additional measures should be provided.
Step-down-boost transformer or intermediate circuit transformer* should be provided with special indicators. When the system fails during the furnace is in the off state of Figure A1
, the high-voltage circuit breaker will trip
Figure:
GB 5959. 21998
High-voltage circuit breaker closed
High-voltage circuit breaker opened
High-voltage furnace switch or high-voltage furnace breaker opened or intermediate circuit switch opened
According to the fault level, the high-voltage earthing switch is closed and the low-voltage short-circuit device and earthing device are closed to keep the potential close to zero. Note: The symbols shown in the figure show the switch states that each switch device should be in to allow electrode installation and related operations. Appendix B
(Standard Appendix)
Additional safety requirements for non-electrical parts of arc furnace equipment The following safety requirements are minimum requirements.
B1 Water cooling system for furnace shell and furnace cover
In addition to 6, 5 of this standard and 4.6 of GB 5959.1--1986, the following requirements shall also be met. B1.1 The cooling system shall be divided into several water circuits that are individually controlled and monitored. The water flow rate shall be monitored and, if necessary, the outlet water temperature of each parallel branch shall also be monitored. If there is any inadmissible deviation between the measured value and the specified rated value, a fault display shall be made. B1.2 An overpressure valve shall be provided for each closed cooling system. It is necessary to take adequate measures to ensure that no inadmissible overpressure occurs during maintenance. B1.3 The overpressure valve, hose connector 1 and other outlets shall be placed outside the furnace T. working area as reasonably and practically as possible. B2 Evaporative cooling of furnace shell and furnace cover
B2.1 For evaporative cooling, the cooling system of the furnace shell and furnace cover shall be divided into several separate water circuits. B2.2 The water flow rate of each water circuit shall be monitored. If there is any inadmissible deviation between the measured value and the specified rated value, a fault indication shall be given. Each water circuit shall be equipped with a device for regulating the water flow. In addition, each water circuit shall be capable of being shut off separately by a non-return valve and/or a manually operated valve. 1" The original text is "hoiat couplings", which is incorrect. It should be "bose couplings" GB 5959. 2—1998
3 For common components of the cooling system, such as air collection bags, pumps, etc., relevant national safety regulations shall be observed. B2.3
Steel tapping method
B3.1 Bottom tapping (central type)
If water cooling is provided for the bottom tapping flange, the water flow and water temperature in the return water circuit shall be measured. B3.2
2 Eccentric bottom tapping
See B3.1.
The tapping process should be monitored by an inclination indicator. 4
Burners (auxiliary burners)
The supply of each burner should be well monitored. Appropriate instructions and/or interlocks should be used to ensure that the burner is only used when the arc is started. Otherwise, when the burner is used to heat the charge during a power outage of the furnace, a reliable ignition cover (e.g., auxiliary flame) should be configured.
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