Detail of DL/T 402-2007

Introduction of DL/T 402-2007

1 General 1.1 Scope This standard is applicable to a.c. circuit-breakers designed for indoor or outdoor installation and for operation at 50 Hz frequency on systems having standard voltages from 6kV to 1000kV. It is only applicable to three-pole circuit-breakers for use in three-phase systems and single-pole circuit-breakers for use in single-phase systems. Two-pole circuit-breakers for use in single-phase systems and application at frequencies lower than 50 Hz are subject to agreement between manufacturer and user. This standard is also applicable to the operating mechanism of circuit-breakers and to their auxiliary equipment. A circuit-breaker with a closing mechanism for dependent manual operation is not covered by this standard, as a rated short-circuit making-current cannot be specified, and such dependent manual operation is objectionable because of safety considerations. This standard does not cover circuit-breakers intended for use on mobile power stations for electric traction equipment; these are covered by IEC 60077 [4] . Generator circuit-breakers installed between generator and step-up transformer are not within the scope of this standard. Switching of inductive loads is covered by IEC 62271-301. Circuit-breakers with an intentional non-simultaneity between the poles, with the exception of circuit-breakers providing single-pole auto-reclosing, are not within the scope of this standard. This standard does not cover self-tripping circuit-breakers with mechanical tripping devices or devices which cannot be made inoperative. By-pass circuit-breakers installed in parallel with line series capacitors and their protective equipment are not within the scope of this standard; these are covered by IEC 60143-2 [6].

Contents of DL/T 402-2007

Foreword I 1 General 1.1 Scope 1.2 Normative References 2 Normal and Special Service Conditions 3 Terms and Definitions 4 Rated Values 4.1 Rated Voltage (Ur) 4.2 Rated Insulation Level 4.3 Rated Frequency (fr) 4.4 Normal Current (Ir) and Temperature Rise 4.5 Rated Short-time Withstand Current (Ik) 4.6 Rated Peak Withstand Current (Ip) 4.7 Rated Short-circuit Duration (tk) 4.8 Rated Supply Voltage of Operating Mechanisms and of Auxiliary and Control Circuits (Ua) 4.9 Rated Supply Frequency of Operating Mechanisms and Auxiliary Circuits 4.10 Rated Pressures of Compressed Gas Supply for Insulation, Operation and/or Interruption 4.101 Rated Short-circuit Breaking Current (ISC) 4.102 Transient Recovery Voltage Related to the Rated Short-Circuit Breaking Current 4.103 Rated Short-circuit Making Current 4.104 Rated Operating Sequence 4.105 Characteristics for Short-line Faults 4.106 Rated Out-of-phase Making and Breaking Current 4.107 Rated Capacitive Switching Currents 4.108 Small Inductive Breaking Current 4.109 Rated Time Quantities 4.110 Number of Mechanical Operations 4.111 Classification of Circuit-breakers as a Function of Electrical Endurance 5 Design and Construction 5.1 Requirements for Liquids in Circuit-breakers 5.2 Requirements for Gases in Circuit-breakers 5.3 Earthing of Circuit-breakers 5.4 Auxiliary Equipment 5.5 Dependent Power Closing 5.6 Stored energy Closing 5.7 Independent Manual Operation 5.8 Operation of Releases 5.9 Low- and High-pressure Interlocking Devices 5.10 Nameplates 5.11 Interlocking Devices 5.12 Position Indication 5.13 Degrees of Protection by Enclosures 5.14 Creepage Distances 5.15 Gas and Vacuum Tightness 5.16 Liquid Tightness 5.17 Flammability 5.18 Electromagnetic Compatibility (EMC) 5.101 Requirements for Simultaneity of Poles During Single Closing and Single Opening Operations 5.102 General Requirement for Operation 5.103 Pressure Limits of Fluids for Operation 5.104 Vent Outlets 5.105 Other Requirements 6 Type Test 6.1 General 6.2 Insulation tests 6.3 Radio Interference Voltage (r.i.v.) Tests 6.4 Measurement of the Resistance of the Main Circuit 6.5 Temperature-Rise Tests 6.6 Short-Time Withstand Current and Peak Withstand Current Tests 6.7 Verification of the Degree of Protection 6.8 Tightness Tests 6.9 Electromagnetic Compatibility (EMC) Tests 6.10 Additional Tests for Auxiliary Circuit and Control Circuit 6.101 Mechanical and Environmental Tests 6.102 Miscellaneous Provisions for Making and Breaking Tests 6.103 Test Circuits for Short-Circuit Making and Breaking Tests 6.104 Short-circuit Test Quantities 6.105 Short-circuit Test Procedure 6.106 Basic Short-circuit Test-Duties 6.107 Critical Current Tests 6.108 Single-phase and Double-earth Fault Tests 6.109 Short-line Fault Test 6.110 Out-of-phase Making and Breaking Tests 6.111 Capacitive Current Switching Tests 6.112 Special Requirements for Making and Breaking Tests on Circuit-breakers class E2 6.113 Inductive Current Switching Tests 7 Delivery Test 7.1 Insulation Test on the Main Circuit 7.2 Insulation Test 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 7.101 Mechanical Operation and Mechanical Characteristics Tests 7.102 SF6 Gas Moisture Determination 8 Guide to the Selection of Circuit-breakers for Service 8.101 General 8.102 Selection of Rated Values for Service Conditions 8.103 Selection of Rated Values for Fault Conditions 8.104 Selection for Electrical Endurance 8.105 Selection for Capacitive Current Switching 9 Information to be Given with Enquiries, Tenders and Orders 9.101 Information to be Given with Enquiries and Orders 9.102 Information to be Given 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 Appendix A (Normative) Calculation of Transient Recovery Voltage for Short-line Faults from Rated Characteristics A.1 Basic Approach A.2 Transient Voltage on Line Side A.3 Transient Voltage on Source Side A.4 Example of Calculations Appendix B (Normative) Tolerances on Test Quantities During Type Tests Appendix C (Normative) Records and Reports of Type Tests C.1 Information and Results to be Recorded C.2 Information to be Included in Type Test Reports Appendix D (Normative) Determination of Short-circuit Power Factor D.1 Method 1 - Calculation from D.C. Component D.2 Method 2 - Determination with Control Generator Appendix E (Normative) Method of Drawing the Envelope of the Prospective Transient Recovery Voltage of a Circuit and Determining the Characteristic Parameters E.1 Introduction E.2 Drawing the Envelope E.3 Determination of Parameters Appendix F (Normative) Method of Determining the Prospective Transient Recovery Voltage Waves F.1 Introduction F.2 General Summary of the Recommended Methods F.3 Details of the Recommended Methods F.4 Comparison of Methods Appendix G (Normative) Rationale Behind Introduction of Circuit-breakers Class E2 Appendix H (Informative) Inrush Currents of Single and Back-to-back Capacitor Banks H.1 General H.2 Example 1 – One capacitor to be Switched in Parallel (see Figure H.1) H.3 Example 2 - Two Capacitors to be switched in parallel (see Figure H.2) Appendix I (Informative) Note Explicatives I.1 General I.2 Explanatory Note Regarding the D.C. Component of the Rated Short-circuit Breaking Current (Article 4.101.2) I.3 Explanatory Note Regarding Performance of Circuit-breaker During Tests (Articles 6.102.8 and 6.111.11) I.4 Explanatory Note Regarding Capacitive Current Switching Tests (Section 6.111) Appendix J (Informative) Test Current and Line Length Tolerances for Short-line Fault Test Appendix K (Informative) Symbols and Abbreviation Used in DL/T 402-2007 Bibliography