New small turbine technologies - Wind Power Generation and Wind Turbine Design - page 408

Type
Certification

Foundation
Design
Evaluation
(optional)

Type
Characteristic
Measurements
(optional)

Design
Evaluation

Manufacturing
Evaluation

Type
Testing

Safety and
Function Tests
PowerPerforman
Measurements

Duration Tests

Other Tests
(Environmental impacts, etc.)

Control
and
Protection
System

Test
and
Design
Data

Load
and
Load
Cases

All
Compo-
nents

Static
Blade
Tests

Componets
Test

(Evaluation of)

Foundation
Design
Require-
ments

Manufactur
-ing
Plan

Mainten-
ance
Plan

Design
Control

Installation
Plan

Personnels
Safety

Figure 11: Structure of IEC type certifi cation of SWTs .

in a wind tunnel seriously differ from the dynamic rotor performances obtained in
the turbulent fl ow, sometimes gusty fl ow over a natural open test fi eld.
A wind tunnel test is capable of verifying the basic stable design power perfor-
mance. If proper corrections of the wind tunnel wall effect are not done, the power
curve might be higher than the actual because of the channel fl ow effect of the
wind tunnel. If the tested WT is scale-down model, Reynolds number effect shall
be carefully analysed.

9.2.2 Track test
Track test is an alternative method with wind tunnel test, in which relative wind
speed is realized by driving a vehicle with a test turbine on it along a test course
of a vehicle. The relative wind speed is as high as that of running vehicle. If the
maximum speed is 180 km/h, even an extreme wind speed of 50 m/s can be cre-
ated. Since an extreme wind speed, which is a maximum 10-min averaged wind
speed with 50 years recurrence period for IEC Class I turbines, is a very rare
case to occur and cannot usually happen during a few years fi eld test. Therefore,
it is quite useful test method for structural safety tests and power regulation or
brake tests.
Figure 12 shows a vehicle for track test. A SWT is fi xed on a support structure
on the vehicle. An anemometer is also mounted on the vehicle at a suitable
position where fl ow distortion by the vehicle is the least.