Ac Surge Protector Selection Guide
Note: The selection of AC surge protector must meet the acceptance requirements of lightning protection standards and the actual protection needs of the product!
The selection book of AC surge protective device is based on the standards:
GB50057-2010 "Building Lightning Protection Design Code"
GB50343-2012 "Building Electronic Information System Lightning Protection Technical Specifications"
IEC61312 "Lightning Electromagnetic Pulse Protection"
1. The meaning of surge protection device level 1, 2, 3, BCD, T1 and T2
1. Level 1 power supply lightning arrester, according to the national standard, refers to the surge protector of T1 test (AM-10/350, AM-L/ N-BD series belongs to the first-level surge protector)
2. Second-level power supply lightning arrester, according to the national standard, refers to the surge protector with T2 test ≥40kA (AM40, AM60, AM80 series belong to the second-level surge protector)
3. Third-level power supply lightning arrester, generally refers to 20kA surge protector (AM20 series belongs to the third-level power supply lightning arrester)
4. Class B surge protector, including surge protectors for T1 test and surge protectors with T2 test 60kA and above flow rate
(AM-10/350, AM60, AM80, AM100, AM120, AM160 series are all Class B surge protectors)
5. Class C surge protectors refer to surge protectors with a maximum flow rate of 40kA in the T2 test (AM40 series)
6. Class D surge protectors refer to surge protectors with a maximum flow rate of 20kA in the T2 test (AM20 series)
7. Class T1 refers to the T1 test level, the test waveform is 10/350μs, and the main parameters are marked with impulse current Iimp.
Class T2 refers to the T2 test level, the test waveform is 8/20μs, and the parameters are marked with maximum discharge current Imax and nominal discharge current In.
2. Selection of the maximum continuous operating voltage Uc of the surge protector
AC surge protector selection book, the maximum continuous operating voltage of the surge protector should not be less than the minimum value specified in Table J.1.1; when the power supply voltage deviation at the installation location of the surge protector exceeds the specified 10% and the harmonic increases the voltage amplitude, the minimum value of the maximum continuous operating voltage specified in Table J.1.1 should be increased for the voltage-limiting surge protector according to the specific situation.
3. Selection of surge protector current capacity/discharge current (Iimp, Imax, In)
AC surge protector selection book, the distribution system should adopt a hierarchical configuration according to standard requirements. The first level protection should be able to withstand most of the lightning current, and the second level configuration discharges the residual lightning current, limits the residual voltage at the equipment end, and cooperates with the first level protection.
Surge protectors are generally installed in parallel and are not affected by the power of the system. You can refer to the multi-level lightning protection concept according to the installation position in the figure below for configuration:
Multi-level lightning protection is shown in the figure below:
Level 1 protection of power supply:
According to the national standard requirements, the AC surge protector selection manual should be installed at the main distribution box where the power supply is introduced. The voltage protection level of the surge protector should be less than or equal to 2.5 kV. The impact current value Iimp of each protection mode, when it cannot be determined, the impact current should be equal to or greater than 12.5 kA.
Therefore, the first-level surge protector needs to use products with T1 test (10/350μs test waveform) parameters, and the impact current Iimp≥12.5kA.
Second-level protection of power supply:
The second level uses products with T2 test (8/20μs test waveform) parameters, with maximum current capacity (Imax): 40~100kA, and nominal current capacity (In): 20~50kA.
Power supply third level protection:
The third level is generally a single-phase power supply surge protector. The third level uses products with T2 test (8/20μs test waveform) parameters, maximum current capacity (Imax) 20kA, nominal current capacity (In), maximum continuous working voltage 275VAC, protection level Up: 1.2kV.
