1 Scope
This part provides information for the design, installation, inspection, maintenance and testing of a LEMP protection measures system (LPMS) for electrical and electronic systems within a structure, able to reduce the risk of permanent failures due to lightning electromagnetic impulse.
This part does not cover protection against electromagnetic interference due to lightning, which may cause malfunctioning of electronic systems. However, the information reported in Annex A can also be used to evaluate such disturbances. Protection measures against electromagnetic interference are covered in IEC 60364-4-44 and in the IEC 61000 series[1]1)。
This part provides guidelines for cooperation between the designer of the electrical and electronic system, and the designer of the protection measures, in an attempt to achieve optimum protection effectiveness.
This part does not deal with detailed design of the electrical and electronic systems themselves.
2 Normative References
The following documents contain provisions which, through reference in this part of GB/T 21714, constitute provisions of this part.For dated referencs, subsequent amendments to (excluding corrections) or revisions of any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to investigate the possibility of applying the latest editions. For undated references, the latest edition of the normative reference applies.
GB 16895.22—2004 Electrical Installations of Buildings—Part 5-53:Selection and Erection of Electrical Equipment—Isolation, Switching and Control—Section 534:Devices for Protection against Overvoltages (IEC 60364-5-53: 2001: IDT)
GB/T 16935.1—1997 Insulation Coordination for Equipment within Low-voltage Systems—Part 1: Principles, Requirements and Tests (idt IEC 664-1: 1992)
GB/T 17626.5—1999 Electromagetic Compatibility—Testing and Measurement Techniques—Surge(Impact) Immunity Test (idt IEC 61000-4-5: 1995)
GB/T 17626, 9—1998 Electromagnetic Compatibility—Testing and Measurement Techniques—Pulse Magnetic Field Immunity Test (idt IEC 61000-4-9: 1993)
GB/T 17626.10—1998 Electromagetic Compatibility—Testing and Measurement Techniques—Damped Oscillatory Magnetic Field Immunity Test (idt IEC 61000- 4-10: 1993)
GB 18802.1—2002 Surge Protective Devices (SPD) Connected to Low-voltage Power Distribution Systems—Part 1: Performance Rrequirements and Testing Methods (IEC 61643-1: 1998, IDT)
GB/T 18802.12—2006 Surge Protective Devices Connected to Low-Voltage Power Distribution Systems—Part 12: Selection and Application Principles (IEC 61643-12: 2002, IDT)
GB/T 18802.21—2004 Low-voltage Surge Protective Devices—Part 21: Surge Protective Devices (SPD) Connected to Telecommunications and Signalling Networks-Performance Requirements and Testing Methods (IEC 61643-21: 2000, IDT)
GB/T 21714.1—2008 Protection against Lightning—Part 1: General Principles (IEC 62305-1: 2006, IDT)
GB/T 21714.2—2008 Protection against Lightning—Part 2: Risk Management (IEC 62305-2: 2006, IDT)
GB/T 21714.3—2008 Protection against Lightning-Part 3: Physical Damage to Structures and Life Hazard (IEC 62305-3: 2006, IDT)
IEC 60364-4-44: 2001 Electrical Installations of Buildings—Part 4-44: Protection for Safety - Protection against Voltage Disturbances and Electromagnetic Disturbances
IEE: 61643-22: 2004 Low Voltage Surge Protective Devices – Part 22: Surge Protective Devices Connected to Telecommunications and Signalling Networks – Part 22: Selection and Application Principles
IEC 61000-5-2: 1997 Electromagnetic Compatibility (EMC) – Part 5: Installation and Mitigation Guidelines – Section 2: Earthing and Cabling
TTU-T K.20: 2003 Resistibility of Telecommunication Equipment Installed in a Telecommunications Centre to Overvoltages and Overcurrents
ITU-T K.21: 2003 Resistibility of Telecommunication Equipment Installed in Customer Premises to Overvoltages and Overcurrent
3 Terms and Definitions
For the purposes of this part of GB/T 21714, the following terms and definitions apply.
3.1
Electrical system
System incorporating low voltage power supply components.
3.2
Electronic system
System incorporating sensitive electronic components such as communication equipment, computer, control and instrumentation systems, radio systems, power electronic installations.
3.3
Internal system
Electrical and electronic systems within a structure.
3.4
Lightning electromagnetic impulse
LEMP
Electromagnetic effects of lightning current.
Note: It includes conducted surges as well as radiated impulse electromagnetic field effects.
3.5
Surges
Transient wave appearing as overvoltage and/or overcurrent caused by LEMP.
Note: Surges caused by LEMP can arise from (partial) lightning currents, from induction effects in installation loops and as a remaining threat downstream of SPD.
3.6
Rated impulse withstand voltage level
Foreword I
Introduction II
1 Scope
2 Normative References
3 Terms and Definitions
4 Design and Installation of a LEMP Protection Measures System (LPMS)
4.1 Design of an LPMS
4.2 Lightning Protection Zones (LPZ)
4.3 Basic Protection Measures in an LPMS
5 Earthing and Bonding
5.1 Earth Termination System
5.2 Bonding Network
5.3 Bonding Bars
5.4 Bonding at the Boundary of an LPZ
5.5 Material and Dimensions of Bonding Components
6 Magnetic Shielding and Line Routing
6.1 Spatial Shielding
6.2 Shielding of Internal Lines
6.3 Routing of Internal Lines
6.4 Shielding of External Lines
6.5 Material and Dimensions of Magnetic Shields
7 Coordinated SPD Protection
8 Management of an LPMS
8.1 LPMS Management Plan
8.2 Inspection of an LPMS
8.3 Maintenance
Annex A (Informative) Basics for evaluation of electromagnetic environment in a LPZ
Annex B (Informative) Implementation of LEMP Protection Measures for Electronic Systems in Existing Structures
Annex C (Informative) SPD Coordination
Annex D (Informative) Selection and Installation of a Coordinated SPD Protection
Bibliography
