DATA VALIDATION - Wind Resource Assessment: A Practical Guide to Developing a Wind Project - page 118

Table 9-1. Examples of range test criteria

Parameter a Validation criteria

Wind Speed: Horizontal
Average

< <

Offset Avg. 30 m/s

< <

Standard deviation 0 Std. Dev. 3 m/s

Maximum gust Offset < Max. < 35 m/s

Wind Direction
Average 0 ◦ < 360 ◦ Avg. <

3 ◦ < Std. Dev. < 75 ◦ Standard deviation

Temperature Varies seasonally

− 35 ◦ < Avg. < 35 ◦ C Typical range

Wind Speed: Vertical Varies with terrain

Average (S or C) Offset < Avg. < ± (2 or 4) m/s

Standard deviation (S or C) Offset < Std. Dev. < ± (1 or 2) m/s

Maximum gust (S or C) Offset < Max. < ± (3 or 6) m/s

Barometric Pressure Sea level shown

Average 94 kPa < Avg. < 106 kPa

Differential Temperature
Average difference > 1 . 0 ◦ C (daytime)

< 1 . 0 ◦ C (overnight)
Abbreviations : S, simple terrain; C, complex terrain. Source: AWS Truepower.
a All monitoring levels except where noted.

Average difference

Measured Parameter Checks. Three measurement parameter checks are com-
monly performed: range tests, relational tests, and trend tests. These tests are applied
in sequence, and data must pass all three to be deemed valid.

RANGE TESTS. In range tests, the measured data are compared to allowable upper
and lower limiting values. 1 This is the simplest and most common type of test.
Table 9-1 presents examples of range test criteria. A reasonable range for 10-min
average wind speeds is from a minimum of the anemometer offset to a maximum of
30 m/s. Any values that fall below the anemometer offset should be flagged as either
missing or invalid; speeds above 30 m/s are possible but should be verified. The limits
of each range test should be set so they span nearly the full range of plausible values
for the site. In addition, the limits should be adjusted seasonally, where applicable.
For instance, the limits for air temperature and solar radiation should be lower in
winter than in summer.

RELATIONAL TESTS. These tests rely on relationships between various measured
parameters. For example, wind speeds recorded at the same height should be similar

1 Note that a variety of voltage measurement systems exist, which are intended to measure different systems
(communications device, internal battery voltage, external power source measurement). Each system has
different operating ranges, and care should be exercised when creating range and relational tests for these
devices.