Based on the model of thyristor short circuit emitter, a novel multi cell structure model for silicon surge protection device is proposed in this paper.

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.