The first level (B level):
Originally: in the power supply introduced at the main distribution box should be installed Ⅰ test surge protector. The voltage protection level value of the surge protector shall be less than or equal to 2.5 kV.The inrush current value of each protection mode can be calculated according to formula ( 4.2.4-6) when the power line has no shielding layer, and can be calculated according to formula ( 4.2.4-7) when there is a shielding layer; the inrush current shall be taken to be equal to or greater than 12.5 kA when it can not be determined.
Location: the power supply main switch in the main distribution room Outlet side; SPD selection: Iimp:≥25kA (10/350μs); Up (protection level) ≤2.5kV surge protector (according to the actual situation can choose three-phase or single-phase, most of them are three-phase).
The second level (C level):
Originally:
When there is no line leading out of the building can be installed in the busbar Ⅱ test surge protector, each Ⅱ test surge protector should be equal to or greater than the nominal value of the discharge current 5kA, the value of the voltage protection level should be less than or equal to 2.5kV,
Location: the floor distribution cabinets (or the main distribution of the next level of distribution cabinets), Ⅱ test surge protector (according to the actual situation can choose three-phase or single-phase, most of the three-phase). The location: floor distribution cabinet (or lower distribution cabinet of the main distribution), SPD selection: Imax: ≥10kA; Up (protection level) ≤2.5kV surge protector (according to the actual situation can choose three-phase or single-phase).
No matter how the configuration, mainly a protection level selection. Ultimately, the protection level is suppressed at about 1KV. According to the actual situation of the second level of power protection, the third level of power protection for selection. Such as the second level can choose the maximum discharge current 40KA, the third level can choose the maximum discharge current 10kA. but the ultimate requirement is to suppress the protection level within the range of equipment can withstand.