Surge Protective Device (spd) Selection - Comply With Iec Regulations
The selection of surge protective devices (SPDs), power supply systems (based on the concept of lightning protection zones in 1EC62305-4 (EN62305-4), and the establishment of advanced lightning and surge protection systems for electrical equipment are essential basic conditions for ensuring trouble-free and damage-free operation of complex electrical and electronic equipment. The requirements for SPDs in lightning and surge protection systems in lightning protection zones specified in 1EC62305-4 (EN62305-4) are specified in IEC60364-5-53/A2 (IEC64/1168/CDV:2001).
SPDs used as part of building fixtures are divided into "Class 1", "Class 2" and "Class III" SPDs according to IEC61643-1 (EN61643-11). They are tested separately according to different requirements and their loads according to the different installation locations they choose.
The selection of surge protection device requires the highest discharge capacity of the first-level SPD. It is mainly used for lightning The protection of LPZ0~LPZ1 and higher lightning protection zones in the lightning strike and surge protection system is shown in the figure below. These protection devices must be able to discharge lightning impulse currents with a waveform of 10/350us multiple times and ensure that they will not be damaged. The first-level SPD is also called a lightning current protector. Its main task is to prevent the destructive part of the lightning impulse current from invading the electrical equipment in the building.
The selection of surge protective device, at the interface of LPZO to LPZ1 and higher lightning protection zones, or at the interface of LPZ1 to LPZ2 and higher lightning protection zones, use a second-level surge protector with a discharge capacity of about tens of kiloamperes (8/20μs waveform).
The selection of surge protectors (SPDs), the last link of the lightning strike and surge protection system of power supply equipment is the protection of terminal equipment (located in LPZ2~LPZ3 and higher lightning protection zones). The third-level protection (terminal protection) is mainly to prevent residual surges between lines in the power supply system (such as surges between L-N) and various operating overvoltages.
