The grounding method for offshore wind power generation is designed to ensure safety in the marine environment, protect the equipment, and respond to lightning and surges.

 

Structural principles of offshore wind power grounding

• Offshore wind power structures (towers, blades, nacelles, etc.) most commonly use an integrated (common) grounding method utilizing the metal body and foundation structure .

• Install ring-shaped ground electrodes or mesh grounding nets on tower foundations (piles, jackets, etc.) and subsea structures to ensure a consistent ground path throughout the system.

• By connecting all turbine structures, power generation equipment, control panels, transformers, and communication equipment to the ground network through equipotential bonding, the potential rise and potential difference of each part are minimized.

• By installing copper grounding plates in parallel at the cable connection and fixed parts (seabed), the contact area with seawater is increased and the grounding resistance is reduced.

 

Core technical elements of grounding method

• Designed to reflect the ground conditions (ground resistivity, salinity, etc.) of the sea, seabed, and offshore structures (when installing metal grounding electrodes on the seabed, use stainless steel and copper plates to prevent corrosion).

• Although independent grounding is sometimes applied to individual turbines , the integrated equipotential bonding method is superior in terms of overvoltage reduction and safety, and increases the operational reliability of the entire wind farm.

• IEC 61400-24, KEC (Korea Electrical Installation Code) clearly requires the use of equipotential bonding conductors and the establishment of a common grounding network.

• By connecting multiple turbines and infrastructure structures in parallel to reduce ground resistance, lightning current and surge current are more effectively discharged to the ground.

 

Considerations when designing and operating grounding methods

• Grounding system and grounding resistance measurement, durability according to operating environment (seawater salinity, water depth, soil quality, etc.).

• The entire metal body of the wind turbine is used as a structural Faraday cage, and the internal equipment is protected by equipotential bonding.

• Corrosion prevention and continuous maintenance of exposed and connected parts of the grounding net are required.

• Each turbine is protected against direct and induced lightning strikes, and it is important to resolve potential differences through grounding network connection for the entire complex.

 

The core of offshore wind power grounding methods is "integrated grounding network + equipotential bonding + response to seabed characteristics," and design and construction must be based on international standards and actual measurement data.