The risk of blackouts in offshore wind power generation

• Offshore wind power generation facilities are exposed to extreme environments such as seawater salinity, humidity, wind, and waves, which increases the risk of metal corrosion in structures, cables, and equipment.

• Major methods include electrical corrosion prevention using anti-corrosion coatings, corrosion-resistant alloys, sacrificial anodes, and installation of stainless steel ring grounding electrodes.

• Corrosion prevention measures are essential to ensure the safety of equipment, extend its lifespan, and reduce maintenance costs.

 

The need for surge protection devices (SPDs)

• Offshore wind power facilities are highly vulnerable to direct and indirect lightning strikes due to their high location and open environment, resulting in a high average number of lightning strikes.

• Transient voltages generated by lightning currents and electromagnetic pulses (LEMPs) can cause malfunctions and damage to sensitive electronic and electrical equipment, such as generators, inverters, and communication/control/sensor devices.

• International standards such as IEC 61400-24, IEC 61643, and IEC 62305 specify in detail the installation of SPDs, selection of suitable models, establishment of protection zones (LPZ), and application of SPDs by grade.

• SPDs are placed at the boundaries of each protection zone (tower base, engine room, nacelle, hub, control cabinet, etc.) and effectively combine Type 1 (for lightning surge) and Type 2/3 (for power/signal).

• SPDs must have specifications such as durability, discharge current capacity (up to 12.5 kA 10/350 μs), operating time, backup fuse, status display, and remote alarm function.

• Establish a surge monitoring system to analyze and implement countermeasures for incoming surges.
• Install a lightning forecast system to ensure the safety of life and power generation.

 

Technology of grounding and lightning protection systems

• Wind towers and generators have many metal structures that act as Faraday cages, maximizing the shielding effect.

• Metal structures, cable shielding, and equipotential bonding connections are essential for equipment resistance to lightning and surges and for human and animal protection.

• The grounding system is composed of a mesh network of basic ring grounding electrodes (stainless steel rings, reinforced steel, etc.) connected to the tower base and operating building, minimizing the risk of potential rise and step voltage.

• Structural durability and corrosion resistance are enhanced through grounding electrode materials and cross-sectional areas, corrosion-resistant connections, and concrete covering.

• Proper grounding design ensures that all surge protection and lightning protection functions properly, and the cooperation of grounding and SPD systematically protects the system.

 

Major application cases of wind power equipment protection systems

• We utilize SPDs (high-energy MOV, TPAE technology, etc.) appropriate for each section, including generator lines, transformers, inverters, control panels, hubs, communication and sensor lines.

• Dedicated SPDs and equipotential bonding are applied to sensitive circuits such as environmental or signal LANs.

• Installation standards: Compliance with international and domestic regulations such as IEC/EN 61643-11, UL 1449 (4th), IEEE C62.41, and KS.

• Reliability verification is required according to the operating environment (temperature, humidity, vibration, salt spray, mold, etc.).

 

 

Overview of TAPE Technology

• Metal tape is installed as an exposed conductor or braided tape around the main structure such as a wind turbine or nacelle according to the Faraday cage principle to concentrate and conduct lightning current.

• Typically, copper or aluminum metal tape is placed on the outside of the structure, inside and outside the tower, to provide a ground connection so that when lightning strikes, the lightning current can quickly and safely flow to the ground.

• The tape method has advantages such as simpler installation than the round conductor (cable) method and low grounding resistance due to large-area contact.

Technical features and application methods

• Tape is installed continuously around the outside of the nacelle or blade, surrounding the structure, providing a Faraday cage effect.

• By connecting directly to the grounding grid through a down conductor, damage to sensitive electronic and electrical equipment inside the structure is minimized.

• The width, thickness, and material of the tape are determined according to the specifications, and the installation method and minimum specifications are specified in the wind power generation lightning protection standards such as IEC 61400-24.

• Long-term environmental resistance (salt, humidity, etc.) and corrosion prevention treatment of the joints are essential.

Example of Tape Application in Wind Power Fields

• Installation of copper tape braid on the exterior of an offshore wind tower: continuous connection from the top of the tower to the lower foundation.

• Bonding of the nacelle external structure (including non-metallic parts): Connection of all metal parts.

• Equipotential bonding of structures (using tape) to block potential rises and protect human bodies.

Tape (metal braided tape) technology is a key component of lightning and surge protection and grounding systems for wind power and various power generation facilities.