Harbor Facilities

Ports and container terminals are large-scale outdoor production sites. Based on their importance, availability, the possibility and consequences of lightning strike failures, their protection level is defined as Class A.

The steel structures of dock cranes and gantry cranes are highly vulnerable to lightning strikes. In addition to external lightning protection, it is also necessary to use appropriate surge protectors (SPDs) to establish a protection network for electrical equipment inside the cranes. Effective lightning barriers should be formed in jibs, cabs, spreaders, land-side and sea-side ground control stations, electrical rooms, etc., to achieve effective discharge of direct lightning strikes and induced overvoltages.

Direct lightning strikes on high-voltage overhead lines in the port area will travel along the power supply lines and be introduced into quay cranes through power supply and distribution facilities such as substations and pad-mounted transformers. The power supply is led out from the port's power distribution room, laid along cable trenches to the bottom of each quay crane, and then introduced into the transformer in the electrical room through cable drag turntables. The main transformer is a 440/690V AC system, mainly supplying power to the drive system; the auxiliary transformer is a 220/380V AC system, supplying power to control power circuits and auxiliary power circuits. From the perspective of the wiring of power supply circuits and the installation location of electrical equipment, the power supply and distribution system in the overhead section is at risk of direct lightning strikes and induced overvoltages. At the same time, the distribution system and terminal equipment are also at risk of potential differences and ground potential counterattacks.