WAT 4 release notes


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


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 – 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 – 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 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 - 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 - 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


New features

  • Wind-sector management by alternative turbine modes of operation as a supplement to full shut-down
  • Import and export of sector-management rules
  • Turbulence corrections by reference mast data
  • Support for new IEC 61400-1/A1 sector-based complex terrain assessment
  • AEP estimates under grid limitations
  • More flexible models for turbine class S turbines
  • Temporary blocking of AEP calculations (useful for big projects)
  • Wind-speed dependent WEng turbulence intensity (useful for offshore projects)
  • Improved object hierarchy editing
  • Model options stored with project
  • Legend for main plot
  • List of recent projects
  • Faster calculation
  • Better error messages

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 [%].