Electrical components must go where the wind takes them
A wind turbine is a complex structure made up of thousands of electrical and mechanical components that together have a simple function – to reliably and efficiently harness the wind to generate electricity.
Components in a wind turbine must be exceptionally robust in the face of multiple environmental challenges, including extremes of temperature, altitude, pollution, salt, sand, dust and lightning.
As their power capacity increases and more electronic systems are added, wind turbines must also be able to cope with increasingly complex electromagnetic environments and heavy vibrations.
Meanwhile, as wind generation technology advances and costs decline, more extreme locations at higher altitudes, featuring greater humidity and very high or very low temperatures are now being considered for wind projects.
Operating in the cold
As a result, developers have to carefully select turbine components that can withstand whatever extremes nature can throw at them. For example, temperatures at some wind generation sites can reach -30°C, so the electronics in essential sub-systems, such as the pitch system, need to be heated in order to function properly.
Even this obvious solution doesn’t solve all potential problems, however, such as how to start a heating system in a turbine that is disconnected from the grid and has no power. Or how to protect electromechanical components that are typically not installed in a heated cabinet, such as an air circuit breaker located in a pad-mounted transformer outside the turbine.
In each case, the best answer is to select products that can operate at very low temperatures.
Operating at altitude
Air is a good insulating medium (dielectric) for most electrical devices at or around sea level, but at higher altitudes the air is thinner, and some of its cooling power and capacity to dissipate heat and provide electrical isolation is lost.
Even so, the wind sector is moving to higher altitudes as suitable space for development becomes harder to find, and because turbine performance actually improves at higher altitudes, where the unobstructed wind is strong and steady. Some recent wind projects have been deployed at 3,000 – 3,500 meters.
At higher elevations electrical components must be selected and used carefully. Reduced cooling capability at higher elevations mean most components are derated (operated below their power rating) in terms of nominal and short-circuit currents and also nominal voltage.
For example, a 100 ampere (A) component at sea level might be derated by 10 percent at 3,000 meters. The same is true for voltages, because of lower isolation capacity at higher elevations. In addition, switching and breaking devices at higher elevations have more difficulty extinguishing arcs, and need to be selected with a higher capacity to break current.
As the wind sector pushes wind generation technology to the limit, electrical components must be made to support the application, wherever it goes. This is the challenge of ensuring a sustainable future, a challenge ABB supports with low voltage solutions that increase reliability, safety and performance in wind turbines, wherever they are.