1. DESCRIPTION

The VESTAS V66. 1.65 MW is a wind generator that operates in the direction of the wind, with adjustable blade inclination, automatic positioning and a three-blade rotor.

For wind speeds of approximately 7 ms-1, the turbine will connect itself to the network through the secondary generator, with a rotation speed of approximately 15 rpm. thus achieving a significant reduction of noise emission.

The blades are manufactured using glass fibre-reinforced epoxy. Each blade consists of two halves joined lengthwise to a supporting beam. The blade is joined to the blade bearing through special steel anchorages. The blade bearing is a four point-ball bearing screwed to the axis of the blades. 
The main axis transmits the power to the generators through the gearbox. The gearbox is a combined planet worm gear. From the gearbox, the power is transmitted to the primary generator through a maintenance-free joint and to the secondary one through a transmission axis. The primary generator  is an asynchronous special 4-pole generator with OptiSlip®. The secondary generator is an asynchronous standard generator of 4 poles. The connection to the network is obtained through thyristors over which a by-pass is generated immediately after the generator connects to the network. 

The blade inclination regulation system, combined with the OptiSlip®-equipped generator maintains the nominal exit power with strong winds independently of the temperature and density of the air. With slower wind speeds, the blade inclination regulation system optimises the exit power by choosing the correct angle according to the speed of the wind. 

The turbine stops by turning the blades on their axis until they no longer offer any resistance to the wind. Likewise, a break is installed in the high-speed axis, connected to the gearbox, to maintain the stopped position. 

All the functions of the turbine are controlled and monitored by several control units based on microprocessors. The control system, including the transformer, is located in the nacelle. The changes in the inclination of the blades are obtained through hydraulic actuators. This hydraulic system also provides pressure to the break system. Each blade is equipped with a hydraulic cylinder that allows it to rotate 95º. 

The orientation of the nacelle is achieved using four electrically-impelled jagged wheels that they are mounted on a great jagged ring located at the top part of the tower. The bearing system of the orientation device is of plain bearing. 

The glass fibre-reinforced cover of the nacelle protects all the components in its interior. The access to the nacelle is through a central opening. The nacelle includes a 500 kg service crane that can be modified to lift objects of up to 8000 kg. 

The tubular steel tower is metallic and coloured. The service lift inside the tower is optional.

2. MAIN DATA

3. OPTISLIP® DESCRIPTION

Up to now, the normal way of operating asynchronous wind generators had been at a constant speed. An induction generator usually works at almost constant speed between 100% and 101% of its nominal speed. For a four-pole generator, this means operating at 1500 rpm. (without load) to 1515 rpm. (on a full load) to a frequency of 50 Hz. This small variation is considered to be insignificant, therefore the reason why this operating mode is considered to be at constant speed. 

Changes in wind speed will originate similar changes in the exit power. When reaching nominal power, power fluctuations are undesirable. VESTAS introduced the blade inclination regulation because this regulation allows limitation of the exit power as an average to the nominal one with high-speed winds. However, with a fixed-speed generator, power fluctuations are so quick that it is not possible to keep instantaneous power constant. 

Quick fluctuations will occur, which will contribute to the load of the turbine. In order to minimise loads, VESTAS introduced the OptiSlip® concept in the 600 kW turbine. This characteristic enables electronic varying of the generator’s error up to 10% (1500. 1650 rpm.). 

OptiSlip® is simple, reliable and a more economic way of achieving load reductions, in comparison to other, more complex solutions, e.g. the total speed variation.

V66 is only equipped with Optislip® on its primary generator, as loads are relatively small when the turbine operates with the secondary generator in line.

4. POWER CURVE

 

5. ESTIMATE PRODUCTION

PRODUCTION: 8.707 GW per year