Selection and Optimization Design of Main Transformers in Wind Power Plants

1 Significance of Selecting and Optimally Designing Wind Turbine Transformers in Wind Farms

As wind power systems spread, more power transformers are integrated, boosting total equipment capacity and operating losses. Transformers, made mainly from costly silicon steel sheets, copper windings, and foils, are also tough to design. Thus, optimal design and scientific selection are needed to meet technical, national - standard, and user requirements.

To ensure stable transformer operation, study their operating conditions, service scenarios, design processes, and principles. Build an optimal design model, use scientific methods for analysis and problem - solving, and form a cost - effective design.

In short, optimal design boosts wind energy use, clean energy promotion, grid loss control, product quality, and transformer stability, advancing wind power development. During design, scientifically select wind - farm transformers. With deeper research, experts integrate IT, creating methods like genetic, particle swarm, and neural network algorithms. Applying these helps design better - fitting transformers.

2 Characteristics and Technical Requirements of Wind - Farm Power Transformers

Current wind - farm power transformers often use a combined structure. Their appearance and high - low voltage control boxes are arranged in a “pin” or “mesh” shape, depending on installation sites. The low - voltage box connects to wind turbine outlets.

Transmission lines between turbines and transformers may have phase - to - phase shorts. Turbines have auto - protection to shield transformers. Install a knife - fuse switch on the transformer protection side. Designers add current limiters and load - control switches on the high - voltage side. Due to high voltage and grid - side vulnerability to transmission - line surges, install lightning protection on the high - voltage side.

2.1 Operating Characteristics

Generators have small capacities. High winds may exceed turbine ratings, triggering auto - protection to limit or pause operation. Then, the connected transformer runs at low load, leading to short overall overload times.

Transformers need strong structural design. Wind farms are in complex areas like plateaus, Gobi, or offshore. These demand professional structural design and functions (see Figure 1 for transformer structural design principles).

3 Technical Requirements

• Low Heat Generation:Wind farms are highly season - affected, and transformers have long no - load periods. So, during design, reduce no - load losses. Scientifically select the installation location for effective heat dissipation, enabling high - speed operation even under load.
• Strong Weather, Weathering & Corrosion Resistance:In coastal wind - rich areas, harsh climates can damage transformers. Without generator protective devices, exposure and corrosion may cause operation failures.
• Lightweight, Compact, High - Strength & Easy to Install/Operate:Given small, irregular installation spaces, when selecting transformers, consider safety space between equipment, unit capacity, and weight. Design for compact size, shape, and proper weight. Wind turbine units need tailored transport/hoisting based on distances to avoid collisions/vibrations and boost mechanical strength.
• Transformer Technical Features:In some wind farms, wind turbines face traffic/natural environment challenges, making maintenance difficult and costly. Large - scale overhauls cause long outages, hurting efficiency. So, choose economical, reliable, safe transformers. Design from multiple angles: use split - tank structures for load switch - transformer connections. Tanks must meet national standards for size, tightness. For high - voltage cables, follow “one - in, one - out”. Install heat sinks with protective devices to prevent collisions and oil leaks. The transformer tank structure is shown in Figure 2.

4 Selection and Optimal Design of Main Transformers in Wind Farms
4.1 Transformer Cooling Methods

Transformers use different cooling methods, mainly oil-immersed, dry-type and gas-insulated. Oil-immersed ones are small, high-voltage resistant and good at heat dissipation but risk oil leakage, injection or combustion in high-temperature faults, consuming much energy and polluting the environment—so choose cautiously. Dry-type ones are safe, clean, flame-resistant, easy to maintain and short-circuit resistant, yet large and hard to install. Gas-insulated ones use non-toxic, non-flammable gas as medium, with a structure similar to oil-immersed types. They avoid the above drawbacks, are easy to maintain and worth promoting.

4.2 Protection for Cooling Fins

Wind farm transformers’ cabinets have three parts: radiator, oil tank and front chamber, with the radiator needing key protection. As they are often installed in harsh coastal wilds, prone to human damage, a steel plate cover is usually set around the radiator. It prevents collisions and ensures heat dissipation, so the cabinet and cover need scientific design.

4.3 Split-Cabinet Design for Load Switches

Given wind farm transformers’ operating environment and conditions, load switches and transformers need split-cabinet design:

• Connect the transformer’s outlet to the main line; ensure high operation efficiency of load switches in ordinary combined transformers.
• Arcs from internal load switches during operation cause insulating oil aging and carbon deposition, harming insulation. Thus, a fixed oil tank, isolated from the transformer’s own tank and independently designed, can ensure stable operation.

5 Practical Application of Optimal Design

Optimizing parameters, variables and operating conditions via upgraded particle swarm algorithm yields the optimal transformer design. Compared with ordinary schemes, it reduces material use and costs, and improves load loss, no-load current and coil-to-oil temperature rise. Though material use drops, load loss increases. So, design based on actual operation, analyzing material, loss and design costs to select the best scheme.

6 Conclusion

In wind farm construction and operation, ensure stable power system operation by scientifically selecting transformers per actual needs and standards to maximize their role. Due to their special design and operating conditions, design scientifically per national standards, experience and specifics; optimize processes, integrate new concepts and compare schemes to ensure the final one meets requirements.