Demand is increasing for reliable turbines with network compatibility and quality power. One turbine manufacturer has incorporated these elements into a recent model. DeWind says it has built on its 2-MW series since 2002, and its latest 2-MW D9.2 is especially grid friendly.
Just as its predecessor, the D8.2 introduced in 2006, the company says the D9.2 boasts a reliable drivetrain that offers excellent grid support and power with increased conversion efficiency through its larger 93-m rotor. The turbine also uses a fixed-speed synchronous generator. In combination with blade and rotor design, the generator provides high-quality power while eliminating the need for a converter or power electronics at the point of interconnect.
By nature of their design, power converters are expensive. To minimize cost, they are designed with small tolerances to overheating that occurs each time a system is required to operate outside of its tolerances. Thus, converters shut down when the grid becomes unstable and outside of its tolerances. Hence, wind farms are required to provide additional compensation devices at the point of interconnect—adding cost to the project—to account for converter-based turbines’ inability to deal with grid instability.
However, DeWind says the D9.2’s design not only operates through grid instability, but also provides dynamic reactive power to support the grid through extreme events. What’s more, because the generator works at high voltage, it can connect to the grid directly through a synchronizing switch without power conversion electronics, converters, or a main power transformer.
The efficiency of a variable-speed blade rotor with the power quality of fixed-speed synchronous generation is possible through a hydraulic torque converter, the WinDrive, supplied by Voith Turbo. The WinDrive converts variable-speed input to constant speed output for the fixed-speed generator, and is a hydraulic couple between the generator and a two-stage planetary gearbox. The coupling dampens excessive forces, such as strong wind gusts, creating a more reliable drivetrain. The converter is based on technology that has been applied successfully in many different industries for over 50 years.
Combining fixed-speed synchronous generation, the work horse of traditional power generation, and the WinDrive with a mean-time-between-failures over 39 years produces a drivetrain with high availability. The durability of the turbine is evident through its successful operation at high elevations. For example, since 2008, a D8.2 turbine installed at an elevation over 4,100m has been generating electricity at a mine site near Veladero, Argentina.
Furthermore, the turbine manages noise emissions using customer-defined criteria, such as wind direction, wind speed, or time of day. The control system works with the turbine active power management system to maximize energy production while complying with local noise codes.