886-4-22711021
886-4-22711039
No.21, Yuanqu 1st Rd., Taiping Dist., Taichung City 411008, Taiwan
www.hitachi.com.twProducts
Receiving winds beautifully.
Hitachi has begun by getting to know the wind.
Wind flow and wind direction change virtually every second.
The power of wind can be harnessed and converted into a clean form of energy.
One ideal way to do so is found here.
Downwind rotor
Higher efficiency
Differences in the rotor position
between the upwind and the downwind.
Comparison of power generation
efficiency in winds blowing up between
the upwind and the downwind.
Images of winds blowing uphill.
Wind turbines are often installed on mountains, hills and other rough terrain.
The winds blowing there surge upward on such terrain.
A downwind rotor has its rotor surface inclined downwards when viewed from upwind, so that it can efficiently catch winds blowing up. Therefore, while the power generation efficiency of a system with an upwind wind turbine installed at the same location will decrease when the wind blows up, those with a downwind wind turbine will increase.
At the same time, the downwind rotor is also advantageous in that it allows a wind sensor to be installed ahead of the rotor.
This makes it possible to obtain data on wind direction free of disturbance, resulting in precise yaw control.
The reduced error in yaw angle control displays has effects equivalent to those of response to winds blowing up and higher generating efficiency, thereby leading to low torque ripple.
The response to winds blowing up and changes in wind direction will increase and, therefore, loads imposed on the main shaft and speed-up gear can be reduced, resulting in higher mechanical reliability.
Toward making downwind a reality
Slip stream simulated on a wind turbine
In employing a downwind rotor, we have conducted sufficient simulations and verification tests.
Safety at standstill for storm winds
Conceptual diagram of free yaw
When at standstill for storm winds after cutting out, the system can be set to free yaw, thereby allowing the downwind rotor to let the winds blow by naturally.
As a result, even in case of power failure, the system will not change in permissible wind speeds for storm winds, which makes maintaining a high degree of safety possible.
Lightning protection system
Coping with severe positive-lightning strikes in winter
Sketch of generating equipment LPS
Positive-lightning strikes in some areas have intensity levels rarely seen in the world.
We therefore consider the strength to withstand lightning - the greatest threat to wind turbines an urgent requirement for wind turbine reliability.
The anti-lightning strength of the HTW2.0-80 is set to 250kA, exceeding the lEC standard. This strength can withstand 95 percent of the lightning strikes that occur in winter. The controller panel comes equipped with arrestors according to the concept of LPZs.
| Protection level | Peak current [kA] |
Particular energy [kJΩ-1] |
Total electrical charge transfer [C] |
|---|---|---|---|
| IEC I | 200 | 10,000 | 300 |
| HTW2.0-80 | 250 | 40,000 | 600 |
*
LPS：Lightning Protection System
*
LPZ：Lightning Protection Zone
*
Lightning is a natural phenomenon and its actual current and impact frequency are unpredictable. These descriptions do not guarantee that the product can withstand all kinds of lightning strikes.
Power generation system
Active power control
Generator output when wind velocity changes
Locations of PCS and generator
The HTW2.0-80 employs a generating system based on active power base control that is easy on power systems stability.
This generating system, based on a doubly-fed generator and secondary excitation control, employs active power control.
Abrupt fluctuations in wind velocity affect wind turbine speed, turbine output will also change in systems of general torque control. In contrast, active power base control maintains constant output. This minimizes the effects of such quick changes in wind velocity on the power system.
The system also controls its phase angle to zero, thereby eliminating the inrush current. With the generator-end output raised to 1,400V and transmission loss reduced, the PCS*1 is installed at the bottom of the tower. This permits a lighter and easier-to-maintain nacelle.
*1
PCS: Power conditioning system
Nacelle and Hub
Nacelle and Hub
Hub
The hub consists of the hub housing and a pitch system.
- Construction
The blade mount of the hub housing is reinforced to enhance structural strength, thereby making the equipment lighter in terms of total weight. - Pitch system
The pitch control mechanism is electrically driven to ensure controllability, maintainability, environmental compatibility and other positive characteristics. The system also features three-axis independent control.
Drive train
Nacelle as divided into three
- Main shaft
The drive train is based on a single bearing and a short main shaft, resulting in lighter weight. - Gearbox
The gearbox is conventionally structured based on a one stage planetary gear and a two stage helical gear. It also incorporates a bearing designed specifically to bear thrust loads in order to ensure reliability. - Transport and assembly of the drive train
The main shaft including main shaft bearing and the gearbox come separate as drive train components.
This reduces the total weight of the drive train and the nacelle base to less than 40 tons, making it easier to transport.
Wind sensor
The equipment comes equipped with a vane and an anemometer, both of which can withstand wind velocities in excess of 70 m/s. Both are also protected against ice and snow.
Service crane
The equipment comes equipped with a service crane with a suspension capacity of 200 kg.
Turbine control system
- Power control
The main control unit (wind turbine control panel) is connected to each subsystem and digital data bus. Information from the various sensors and subsystems is used to control each subsystem in order to maintain the equipment in optimal generating condition.
Control Unit - Safety system
The pitch mechanism and several brake systems are used in consideration of all kinds of fail-safe devices, thereby ensuring safety. Particular attention is paid to the main brake (blade feather); each of its three shafts is equipped with an emergency battery to provide a triple fail-safe system. - Vibration reduction
Fast full digital control reduces changes in drive train load. At the same time, changes in output are inhibited. - Operation system
The operation panel on the main control unit employs a user-friendly, large-screen, color liquid crystal touch panel. -
Blade and Tower
Blade
Blade shapeThe high-performance blade shape and three-dimensional geometry are optimized to achieve high efficiency over a wide operating range. The newest blade end shape reduces wind noise.
Tower
Equipment arranged in the tower
Simulated slipstream on the towerThe tower is a steel monopole that comes in two types: one with a hub height of 65m and one of 78m. The 65-meter type is divided into three sections, while the 78-meter type is divided into four.
The equipment is designed to satisfy a wind velocity class of IIA+, the strength to withstand strong typhoons, and economic efficiency in regions of low wind velocity. Moreover, an intra-tower service lift can be provided optionally.
This makes maintenance more efficient.IIA+ specifications 3 seconds
average70.0m/s 10 minutes
average50.0m/s 1 year average 8.5m/s
Supervisory control and Data acquisition (SCADA)
Example of a SCADA network
The SCADA system consists of a server, monitor, UPS, client PC and other equipment. The server collects rotor velocity, azimuth angle, nacelle angle and about 100 other points of analog data, along with wind velocity, generating level and other forms of data.
Client software makes it possible to display the current state of the wind turbine, a trend graph, alarm history and other charts, prepare daily logs and monthly reports, enter wind turbine control commands, and engage in other operations.
Left screen : Analog values, Right screen : Trend history
Performance
Power curve
Efficiency curve
Performance
| Wind speed [m/s] | Power [kW] | Power coefficient [-] |
|---|---|---|
| 4 | 62 | 0.314 |
| 5 | 168 | 0.436 |
| 6 | 320 | 0.482 |
| 7 | 516 | 0.488 |
| 8 | 771 | 0.489 |
| 9 | 1,083 | 0.483 |
| 10 | 1,417 | 0.46 |
| 11 | 1,727 | 0.421 |
| 12 | 1,913 | 0.36 |
| 13 | 2,000 | 0.296 |
| 14 | 2,000 | 0.237 |
| 15 | 2,000 | 0.193 |
| 16 | 2,000 | 0.159 |
| 17 | 2,000 | 0.132 |
| 18 | 2,000 | 0.111 |
| 19 | 2,000 | 0.095 |
| 20 | 2,000 | 0.081 |
| 21 | 2,000 | 0.07 |
| 22 | 2,000 | 0.061 |
| 23 | 2,000 | 0.053 |
| 24 | 2,000 | 0.047 |
| 25 | 2,000 | 0.042 |
*The specifications are subject to change without notice.
Specification
| Rotor | Diameter | 80m |
|---|---|---|
| Swept area | 4,978m2 | |
| Rotor location | Downwind | |
| Rotational speed | 11.1～19.6min-1 | |
| Rated rotational speed | 17.5min-1 | |
| Rotational direction | Clockwise (from upwind) | |
| Tilting angle | -8° | |
| Coning angle | 5° | |
| Blade | Quantity | 3 pcs |
| Length | 39m | |
| Material | GFRP (glass-fiber reinforced resin) | |
| Gearbox | Structure | 1 planetary gear, 2 parallel gears |
| Gear ratio | nearly 1:100 (50Hz) | |
| nearly 1:120 (60Hz) | ||
| Generating system | Generating system | DFIG (doubly fed induction generator) |
| Rated generator output | 2,000kW | |
| Generator voltage | 1,400V | |
| Generator current | 825 A | |
| Number of generator poles | 4 poles | |
| Rated generator speed | 1,736min-1 (50Hz) | |
| 2,098min-1 (60Hz) | ||
| Generator power factor | 100% (operation range: delay 90% to advance 95%) | |
| PCS cooling system | Antifreeze circulation, wind-cooled | |
| PCS control system | Active power control | |
| Incorporation-type transformer | Capacity | 2,222kVA |
| Transformer system | Oil-immersed self-cooled | |
| Voltage | 22kV/1.4kV (Except 22kV series, the set-up transformer, panels, auxiliaries, etc. are placed outside of the tower) | |
| Winding configuration | Δ/Δ | |
| Nacelle | Material | GFRP (glass-fiber reinforced resin) |
| Dimensions | L11.5m/ W3.5m / H4.9m(H excludes the sensor mast.) | |
| Tower | Tower system | Steel monopole |
| Anchor system | Steel monopole (anchor ring) | |
| Hub height | 65m / 78m | |
| Number of divisions | 3 (65cm) / 4 (78cm) | |
| System | Output control | Pitch, variable velocity |
| Cutin wind velocity | 4m/s | |
| Cutout wind velocity | 25m/s | |
| Maximum wind velocity | 70m/s(3 seconds)、50m/s(10 minutes average) | |
| Emergency brake | Blade feather (independent pitch) | |
| Maintenance brake | Disc brake | |
| Yaw control | Active yaw | |
| Standby for storm wind | Free yaw | |
| Lightning strength | 250kA(peak current) | |
| 600C(total charge) | ||
| Environmental conditions |
Wind velocity class | IIA+ (standard) (Provided that the IA type is possible depending on the wind velocity class of the tower) |
| lEC disturbance strength | A | |
| Operation temperature | -20 to 40℃ | |
| Noise power level | 103.8dBA | |
| Altitude | 1,000m or less |
*
The specifications are subject to change without notice.
External view [78-meter tower type]
*The specifications are subject to change without notice.
