Harbor and container wharf belong to large outdoors production place. For its importance, usability, the chance of lightning trouble and consequence, is defined as category 2 lightning protection equipment.

The steel structure of quay crane and gantry crane is easy to get lightning stroke. SPD is required to protect electrical equipment within the crane and produced an effective protective system at the boom, cab, slings, on shore ground station and power supply room, which could discharge over-voltage of direct lightning and induced surge. The direct lightning might attach equipment from transmission lines to crane along with power supply lines, via substation. Power is supplied from port power room along with cable down to the bottom of each crane, then to the transformer of electrical room through cable dragging wheel. The main transformer is 440/690 Vac system, mainly supplies power to driving system while the auxiliary transformer is 220/380 Vac system, supplies power to control power circuit and auxiliary power circuit.

In accordance to:

     1. IEC 61643-21: Low-voltage Surge Protective Device for Specific Application including d.c.

     2. IEC 62305: Protection against lightning

     3. IEC 61312: Protection against lightning electromagnetic impulse

     4. IEC 61643-11: Low-voltage surge protective devices