Windfarm Assessment Tool 4 - Release Notes

WAT 4.7.0.176

April 2024

New features

• Technical loss parameters for individual turbines or turbine groups.
• Uncertainty contributions for individual turbines or turbine groups.
• Support for IEC 61400-50-3 terrain assessment for nacelle-based lidar measurements.
• Import of WAsP vector maps.
• Interpolation of terrain elevation grid map by vector maps.
• Redesigned extrapolation and smoothing of observed turbulence statistics for high wind speed.
• Display of 90% quantile of ambient turbulence intensity.
• Alignment of observed turbulence statistics in WAT and WAsP-CFD result viewer.
• Support for WAsP 12.9 workspace file.
• Synchronized display of IEC 61400-12-1 measurement zones in plot and table when switching between mast or turbine site.
• Save and read IEC wind turbine class S parameters to and from file.
• Show margins around wind farm scaled by turbine hub height.
• Recall program settings from previous WAT session.
• List project model parameters.
• Autosave project file.

Bug fixes

• Problem finding 90% quantile of mixed Weibull and mixed log-normal distributions with zero standard deviation for some wind sectors.
• Problem reading reference wind for IEC class S turbines from WAT project file.
• Missing reports when exporting results to Zip file.
• Undetected climate context when importing WAsP workspace without generalized wind climate at project level.
• Divide-by-zero error in rare cases with equal V50 and V100 extreme-wind estimates.
• Problem reading WAsP workspace file with sites having no wind turbine assigned.
• Sample data were mistaken for Trojan files by some anti-virus protection systems.
• Non-responsive obstacle editor.
• Problem rendering 'Windfarm overview> Effective turbulence table'.

WAT 4.6.0.168

December 2020
• Improved memory management
• New energy estimates after de-selection of the ‘temporary block AEP calculations’ option.

Version 4.6.0.167

December 2020

New features:

• Export of observed turbulence statistics for import to ShowCFD
• Support for local air temperature lapse rate as in WAsP 12.6
• Examine effect of the wind turbine class directly from the PDF plot
Known issues
• Automatic sector management rules may fail for large wind farms
• IFORM results are probably unreliable. They should be based on time series instead of mean and standard deviation in sectors and wind speed bins.

Version 4.5.166 - Release A

Bug fixes
- Dialog for turbine classification now opens with correct setting, also when working with edition 4 of the IEC 61400-1 standard
- Tables and plots exported to file from the main menu are updated and file names are harmonized

Version 4.5.165 Release A

New features

• Aggregated power curve with technical losses for a selectable group of turbines and optional wake effects at reference site

• Updated shelter table for selected site with visualization of wake effects and optional rotor-averaged wake correction

• Support for extreme wind correction of IEC 61400-1 Ed.4 including coefficient of variation of the fitted Gumbel distribution

• Improved quick-setup layout editor for IEC 61400-12-x site assessment

• Separate general options and project-specific options

• Support for WAsP 12.4 workspace files

Bug fixes

• A problem related to interpolation between sites

• A problem reading WAsP workspace files with no turbine type

• A problem with deactivation and reactivation of turbine site groups

• Problems fitting planes to terrain in sectors extended behind the turbine and calculation of terrain variation for terrain assessments as in IEC 61400-1 Ed.4

• Obstacles beyond 20 times the equivalent rotor diameter was not disregarded in the measurement sector analysis as prescribed in IEC 61400-12-1

Known issues

• Automatic sector management rules may fail for large wind farms

• IFORM results are probably unreliable. They should be based on time series instead of mean and standard deviation in sectors and wind speed bins.

Version 4.4.155 Release A

New features

• Export all tables and plots to ZIP archive
• Optional user-defined turbine regulation type avoiding a problem related to power curves with measurement noise above rated wind speed
• Support for obstacle significance estimates as defined in edition 2 of 61400-12-1

Bug fixes

• Missing main plot themes restored
• Automatic update of air density correction for all turbines after modification of air conditions at reference site
• Improved interpolation of turbulence intensity results
• Improved interpolation of turbine-specific wind conditions, a feature mainly used for large offshore wind farms.

Version 4.3

Build 4.3.0.154 – Release B

Bug fixes

• Measurement sector for IEC 61400-12-1 not displayed when using Edition 2 of the standard
• Bad interpolation of observed TI data sometimes caused negative standard deviations
• Improved import of WAsP 12 workspace files

Build 4.3.0.152 – Release A

New features

• Automatic sector-management rules
• Highlight sites with non-IEC-compliant flow conditions in the main plot
• Assessment of site-specific extreme ambient turbulence intensity
• Import of WAsP 12 workspace files
• Air density correction and wake modelling as in WAsP 12

Bug fixes

• Float-to-integer conversion in WAT 4.2 was accidentally set to 'round up' instead of 'round to nearest'.
• Previous versions confused upper limit with mean of wind-speed bins during turbulence calculations and reports.
• Problem reading power curve files in POW format
• Problem reading user-specified TI statistics from file
• Problem with terrain assessment for IEC 61400-12-1 performance measurements
• IEC 61400-12-1 measurement sector was not stored in project file

Version 4.2

Build 4.2.0.144 Release A

• Support for IEC 61400-1 Ed.4 (draft)
• Support for IEC 61400-12-1 Ed.2 (draft)
• Approximate de-trend correction for observed turbulence intensity
• Input for far-offshore sites independent of WAsP Engineering
• Load Excel files on computers without Excel installation
• Graphical improvements of result tables
• New tables for wind-farm overview of effective TI and maximum TI
• New table of inter-turbine distance
• Better guide for project options

Version 4.1

Build 4.1.0.138 - Release A

New features

• more project options for effective turbulence calculation
• default project options depending on IEC 61400-1 edition

Bug fixes

• large-farm turbulence enhancement in wake sectors ignored as in IEC 61400-1/A1 Ed. 3
• recalculation of effective turbulence after modification of project options
• corrected sometimes wrong average ambient turbulence results
• corrected turbulence correction preferences - primary and secondary method were mixed up in the WAT 4.0 option dialogue

Version 4.0

Build 4.0.0.137 - Release A

New features

• Simplified user interface
• AEP uncertainty estimates
• AEP corrections for turbine availability and transmission power loss
• Import of WAsP projects for AEP calculations
• Power-curve correction for local air density
• Turbulence statistics by observed time series
• Improved export and import of turbulence statistics
• Improved indication of neighbour turbines in sector-management dialogue
• Transparent display of IEC 61400-12-1 performance measurement zones
• Improved accuracy when reading IEC 61400-12-1 measurement sectors from WAT project file
• Support for IEC 61400-12-2 terrain and obstacle assessments
• IEC 61400-12-x assessment with no WAsP or WEng input
• Editor for obstacle geometry

Bug fixes

• Corrected IEC 61400-1 terrain complexity plot
• Corrected IEC 61400-12-1 terrain assessment
• Corrected interpolation of WAsP/WEng site conditions 

Version 3.0

Build 3.0.0.128

New features

Bug fixes

• Attempt to write to c:\temp directory
• Yet another *.wtg file read error
• Wat project read error related to unicode strings
• Various errors in site-calibration terrain assessment, including IEC 61400-12-1 criteria badly mistaken for inclination angles [°] but now corrected to terrain slope [%].