Standard No.:	DL/T 404-2007
English Name:	Alternating-current metal-enclosed switchgear and controlgear for rated voltages above 3.6kV and up to and including 40.5kV
Chinese Name:	3.6kV～40.5kV交流金属封闭开关设备和控制设备
Chinese Classification:	K43    High voltage switchgear
Professional Classification:	DL    Professional Standard - Electricity
ICS Classification:	29.130.10 29.130.10    High voltage switchgear and controlgear 29.130.10
Issued by:	NDRC
Issued on:	2007-12-03
Implemented on:	2008-6-1
Status:	superseded
Superseded by:	DL/T 404-2018 Alternating-current metal-enclosed switchgear and controlgear for rated voltages above 3.6 kV and up to and including 40.5 kV
Superseded on:	2019-5-1
Superseding:	DL/T 404-1997 Indoor AC High Voltage Switchgear Panel
Language:	English
File Format:	PDF
Word Count:	34000 words
Price(USD):	680.0
Delivery:	via email in 1 business day

1 General 1.1 Scope This standard specifies technical requirements for factory-assembled alternating-current metal-enclosed switchgear and controlgear of rated voltage above 3.6kV and up to and including 40.5kV and of frequency 50Hz for indoor or outdoor installation. The enclosures may include fixed or removable components and may be filled with fluid (liquid or gas) to provide insulation. Note 1: Although primarily dedicated to three-phase systems, this standard can also be applied to single-phase or two-phase systems. This standard defines several types of metal-enclosed switchgear and controlgear which differ due to ——the consequences on network service continuity in case of maintenance on the switchgear and controlgear; ——the need and convenience of maintenance of the equipment. Note 2: Safety of the equipment results from the design, application, adjustment and coordination of products, installations and operations. For metal-enclosed switchgear and controlgear containing gas-filled compartments, the design pressure is limited to a maximum of 0.3MPa (relative pressure). Note 3: Gas-filled compartments having a design pressure exceeding 0.3MPa (relative pressure) should be designed and tested in accordance with GB 7674. Metal-enclosed switchgear and controlgear for special use, for example, in flammable atmospheres, in mines or on board ships, may be subject to additional technical requirements. Components contained in metal-enclosed switchgear and controlgear are to be designed and tested in accordance with their various relevant standards. This standard supplements the standards for the individual components regarding their installation in switchgear and controlgear assemblies. This standard does not preclude that other equipment may be included in the same enclosure. In such a case, any possible influence of that equipment on the switchgear and controlgear is to be taken into account. Note 4: Switchgear and controlgear having an insulation enclosure are covered by IEC 60466. Note 5: Metal-enclosed switchgear and controlgear for rated voltage above 40.5kV insulated by ambient air may be covered by this standard taking into account the insulation levels of DL/T 593. 1.2 Normative References The following standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest edition of these documents is applicable. For undated references, the latest edition of the normative document is applicable to this standard. GB/T 1408.1 "Methods of Test for Electric Strength of Solid Insulating Materials-Tests at Power Frequencies" (eqv IEC 60243-1:1988) GB 1984-2003 "High-voltage Alternating-current Circuit-breakers" (IEC 62271-100.2001 MOD) GB 1985 "High-voltage Alternating-current Disconnectors and Earthing Switches" (IEC 62271-102: 2002 MOD) GB/T 2900.20 "Electrotechnical Terminology-High-voltage Switchgear" [neq IEC 60050(441), IEC 60056, etc.] GB 3804 "High-voltage Alternating-current Switches for Rated Voltage above 3.6kV and less than 40.5kV" (IEC 60265-1:1998 MOD) GB/T 4208 "Degrees of Protection Provided by Enclosure (IP Code)" (eqv IEC 60529:1989) GB/T 7354 "Partial Discharge Measurements" (IEC 60270:2000 IDT) GB/T 8905 "The Guide for Processing and Measuring SF6 Gas in Power Apparatus" (neq IEC 60480:1974) GB/T 11022 "Common Specifications for High-voltage Switchgear and Controlgear Standards" (eqv IEC 60694:1996) GB/T 14808-2001 "High-voltage Alternating Current Contactors and Contactor-based Motor-starters" (eqv IEC 60070:1999) GB 16926 "High-voltage Alternating Current Switch-fuse Combinations" (eqv IEC 60420:1990) GB/T 16927.1-1997 "High Voltage Test Techniques-Part 1: General Test Requirements" (eqv IEC 60060-1:1989) DL/T 593-2006 "Common Specifications for High-voltage Switchgear and Controlgear Standards" (IEC 60694:2002 MOD) IEC 60466:1987 "AC Insulation-enclosed Switchgear and Controlgear for Rated Voltages above 1kV and up to and Including 38kV" IEC 60909:2001 "Short-circuit Currents in Three-phase AC Systems-Part 0: Calculation of Currents" IEC 61634:1995 "High-voltage Switchgear and Controlgear-Use and Handling of Sulphur Hexafluoride (SF6) in High-voltage Switchgear and Controlgear" ISO/IEC Guide 51:1999 "Safety Aspects-Guidelines for Their Inclusion in Standards" 2 Normal and Special Service Conditions Clause 2 of DL/T 593-2006 is applicable with the following addition: unless otherwise specified in this standard, the metal-enclosed switchgear and controlgear is designed to be used under normal service conditions. 3 Terms and Definitions For the purposes of this standard, the following terms and definitions as well as the ones specified in GB/T 2900.20 and GB/T 11022/DL/T 593 apply. 3.101 Switchgear and controlgear General term covering switching device and their combination with associated control, measuring, protective and regulating equipment, also assemblies of such devices and equipment with associated electrical connections, accessories, enclosures and supporting structures. 3.102 Metal-enclosed switchgear and controlgear Switchgear and controlgear assemblies with an external metal enclosure intended to be earthed and completely assembled, except for external connections. 3.103 Functional unit (of an assembly) Part of metal-enclosed switchgear and controlgear comprising all the components of the main circuits and auxiliary circuits that contribute to the fulfilment of a single function. Note: Functional units may be distinguished according to the function for which they are intended, for example, incoming unit, outgoing unit, etc. 3.104 Multi-tier Two or more functional units arranged vertically within a single enclosure. 3.105 Transport unit Part of metal-enclosed switchgear and controlgear suitable for shipment without being dismantled. 3.106 Enclosure Part of metal-enclosed switchgear and controlgear providing a specified degree of protection of equipment against external influences and a specified degree of protection against approach to or contact with live parts and against contact with moving parts. 3.107 Compartment

Foreword I 1 General 1.1 Scope 1.2 Normative References 2 Normal and Special Service Conditions 3 Terms and Definitions 4 Ratings 4.1 Rated Voltage (Ur) 4.2 Rated Insulation Level 4.3 Rated Frequency (fr) 4.4 Rated Current and Temperature Rise 4.5 Rated Short-time Withstand Current (Ik) 4.6 Rated Peak Withstand Current (Ip) 4.7 Rated Duration of Short Circuit (tk) 4.8 Rated Supply Voltage of Closing and Opening Devices and of Auxiliary and Control Circuits (Ua) 4.9 Rated Supply Frequency of Closing and Opening Devices and of Auxiliary Circuits 4.10 Rated Pressure of Compressed Gas Supply of Controlled Pressure System 4.11 Rated Filling Level of Gas or Liquid for Insulation and/or Operation 5 Design and Construction 5.1 Requirements for Liquids in Switchgear and Controlgear 5.2 Requirements for Gases in Switchgear and Controlgear 5.3 Earthing 5.4 Auxiliary and Control Equipment 5.5 Power Operation 5.6 Stored Energy Operation 5.7 Independent Manual Operation 5.8 Operation of Releases 5.9 Low- and High-pressure Interlocking and Monitoring Device 5.10 Nameplates 5.11 Interlocking Devices 5.12 Position Indication 5.13 Degrees of Protection by Enclosure 5.14 Creepage Distances 5.15 Gas and Vacuum Tightness 5.16 Liquid Tightness 5.17 Flammability 5.18 Electromagnetic Compatibility (EMC) 5.19 X-ray Radiation 5.20 Corrosion 5.101 Internal Fault 5.102 Enclosure 5.103 Compartments 5.104 Removable Parts 5.105 Provisions for Dielectric Tests on Cables 5.106 Requirements for the Minimum Air Gap 6 Type Tests 6.1 General 6.2 Dielectric Tests 6.3 Radio Interference Voltage (r.i.v) Test 6.4 Measurement of the Resistance of Circuits 6.5 Temperature-rise Tests 6.6 Short-time Withstand Current and Peak Withstand Current Tests 6.7 Verification of the Protection 6.8 Tightness Tests 6.9 Electromagnetic Compatibility Tests (EMC) 6.10 Additional Tests on Auxiliary and Control Circuits 6.11 X-ray Test Procedure of Vacuum Cut-off Device 6.101 Verification of Making and Breaking Capacities 6.102 Mechanical Operation Tests 6.103 Pressure Withstand Test and Gaseous State Detection for Gas-filled Compartment 6.104 Tests on Non-metallic Partitions and Shutters 6.105 Weatherproofing Test 6.106 Internal Arcing Test 7 Routine Tests 7.1 Dielectric Test on the Main Circuit 7.2 Tests on Auxiliary and Control Circuits 7.3 Measurement of the Resistance of the Main Circuit 7.4 Tightness Test 7.5 Design and Visual Checks 7.6 Tests on Mechanical Operation and Mechanical Characteristic 7.101 Partial Discharge Measurement 7.102 Pressure Tests of Gas-filled Compartments and Measurement of Gaseous State 7.103 Tests of Auxiliary Electrical, Pneumatic and Hydraulic Devices 7.104 Tests after Erection on Site 7.105 Measurement of Fluid Conditions after Filling on Site 8 Guide to the Selection of Metal-enclosed Switchgear and Controlgear for Service 8.1 Selection of Rated Values 8.2 Selection of Design and Construction 8.3 Internal Arc Classification 9 Information to be Given with Enquiries, Tenders and Orders 9.101 Information with Enquiries and Orders 9.102 Information with Tenders 10 Rules for Transport, Storage, Installation, Operation and Maintenance 10.1 Conditions during Transport, Storage and Installation 10.2 Installation 10.3 Operation 10.4 Maintenance 11 Safety 11.101 Procedure 11.102 Internal Arc Aspect Annex A (Normative) Method for Testing the Metal-enclosed Switchgear and Controlgear under Conditions of Arcing due to an Internal Fault Annex B (Normative) Partial Discharge Measurements Annex C (Normative) Additional Requirements for Alternating-current Metal-enclosed Switchgear and Controlgear from 3.6kV to 40.5kV to Be Used in Severe Climatic Conditions Annex D (Normative) Calculation Method of Cross Sectional Area of Bare Conductor in Accordance with Thermal Effect of Short-time Persistent Current Annex E (Informative) Explanatory Notes Bibliography