Bosch Rexroth Optimizes Wind Turbine Gearboxes

The competitive pressure as well as the pricing pressure in the wind energy industry is mounting. If the sector wants to continue to expand, reducing the cost of energy (CoE) is a must. When developing new wind turbine generations, manufacturers can contribute a great deal towards that aim by striving to optimize the performance of their turbines without compromising reliability. Simulations across drive trains, intelligent drive train solutions and innovative pitch solutions are the latest examples of their efforts to develop new, efficient turbine types. On top, manufacturers are looking for solutions to improve the availability of wind power plants, which is why Bosch Rexroth came up with condition monitoring and a comprehensive service portfolio, both of which will increase the reliability of wind turbines and reduce the CoE.

Improved development methods increase reliability rates

Wind turbulences and feedbacks from the electric grid are the main cause for dynamics in the drive train. Reducing these vibrations combined with optimum gearbox design achieved by calculating the dynamic loads on the individual gearbox components will increase the service life of a wind turbine and thus help to lower the CoE. Bosch Rexroth conducts a wide range of simulations developed based on the company's long years of industry knowledge. From the system level and multibody simulation all the way to finished-element models these simulations help manufacturers to further boost wind turbine performance without compromising reliability.

Simulation and design experience is a big asset when it comes to developing new drive generations. The Rexroth differential gearbox, REDULUS GPV-D, offers manufacturers an especially reliable gearbox solution. On request, the gearbox will be factory-fitted with an optimally adjusted Bosch Rexroth cooling filter system, which reduces installation costs and, consequently, manufacturers' overall costs.

E-Pitch: maximum safety and availability

Safety plays an important role in the development of new wind power plant concepts. The risk analysis to be performed within the scope of the certification of new wind turbines in Europe as set forth in Directive 2006/42/EC on machinery and EN ISO 13849-1 respectively requires safety-relevant functions to fulfil "safety level 2" and "performance level d" standards. In order to meet the new requirements the Rexroth pitch system has been fitted with a patented safety inverter that enables emergency operation with AC motors if a converter fails. Special cables fitted with external shielding capable of carrying lightning current and internal EMC braid additionally protect the turbine against induced voltages caused by indirect lightning strikes. Furthermore, solutions in place so far caused the wind turbine to shut down immediately if a converter failed as the individual systems are not coupled. Thanks to intelligently interconnected electronics the Rexroth solution provides for an intact converter to take over the control function for the drive of another axis. These options - safety inverter, patented converter operation as well as lightning protection and EMC concept - help manufacturers to sustainably increase safety and the turbine's availability.

Lifecycle monitoring and service minimize downtimes

Effective manipulative values to enhance the reliability of wind turbines and thus lower the CoE are available not only in development but in running operations, too. The larger the wind turbine the more significant condition monitoring becomes. Rexroth lifecycle monitoring solutions assist wind farm operators in minimising downtimes. As such, the turbine operator can employ Rexroth's BLADEcontrol system to recognize and follow up on rotor blade damage at an early stage. If the damage occurs suddenly, the turbine can be shut down automatically and promptly. An ice detection device determines the actual ice accretion on rotor blades. The operator may also use the system to automatically restart the turbine. Production downtimes can thus be reduced substantially with BLADEcontrol. Bosch Rexroth's extensive service portfolio - ranging from solutions for preventive maintenance and monitoring all the way to field service, OEM spare parts, trainings and a gearbox pool - supports the efforts of manufacturers to increase the efficiency and availability of wind turbines.