Surge protection devices(SPD) are commonly used against lightning electromagnetic impulse during the lightning strikes.

In order to protect electronic equipment against the damage of surge voltage,the basic working principle,classification and its action of surge protector SPD were discussed,the application of surge protector SPD was introduced from power system,feedback system,signal system and grounding system,which can provide references for design of lightning protection of electronic equipment in building.

To reduce the ensuing excessive voltage and current so as to safeguard the electronic equipment,this paper elaborates on the method about programming the thunderbolt shield subarea,determining the thunderbolt shield grade,sorting out the protected equipment and then configuring suitable surge protective device(SPD) for the dispatching automation system.

The paper lays an emphasison taking advantage of Surge Protection Device to protect themicrocomputer system from lightning strike by way of power sup-ply line.

The paper measures the impedance characteristics of different electrical connection wires of surge protection device under lightning current impulse,and find it very important to correctly choose wires specifications and the length of electrical connection wires of surge protection device in design and construction of lightning protection for electronic system.