Page 216 - Wind Energy Handbook

190 WIND-TURBINE PERFORMANCE

4.6 Wind-turbine Field Testing

4.6.1 Introduction

Wind-turbine field testing is undertaken in the main for two different reasons. First,
as part of the development of new designs, manufacturers and researchers under-
take a wide range of measurements to check on the operation of a given machine
and in some instances to validate wind turbine models used in the design process.
The second, and perhaps the most common, reason for testing is to establish the
performance of a given wind turbine for commercial reasons. Because in the second
case the objectives are better defined and since many of the problems are common
to both sorts of tests, there will be a concentration on performance measurement.
Performance measurement is also the area best covered by agreed standards and
recommendations, although some difficulties and inconsistencies still remain. It
should be mentioned that testing is also increasingly undertaken, in a commercial
context by the operators, to verify the manufacturer’s performance warranty. Such
tests will tend to follow the agreed performance testing methodology although the
context is often more demanding, involving possibly complex terrain and also the
influence of adjacent turbines.
There are other specialized tests that are of importance, such as for determining
the acoustic emission characteristics, and the assessment of noise at a given site.
Other areas such as the evaluation of fatigue, including the associated mechanical
loads, and power quality can involve direct measurement.
This section will provide an overview of field testing, and in particular will:

• describe the reasons for undertaking field testing,

• identify recognized testing procedures,
• examine practical aspects of transducers and data loggers,
• discuss the difficulties associated with aerodynamic performance assessment,
and
• look at errors and uncertainty.

4.6.2 Information sources for wind-turbine testing

Wind turbines have increasingly become part of mainstream technology over the
last decade, and this is reflected by the attention paid to them by the national and
international standards bodies.

International Electro-technical Commission (IEC)

The IEC is currently developing a range of standards specifically applicable to wind
turbines. The work is being undertaken in the main by its TC88 Technical Committee,