Power curve for wind farm greater than single turbine

[vob]

Hi there,

I'm running Wasp 11.4 and I've noticed an apparent inconsistency in the wind farm power curve generation, which appears to produce greater output under partial load than for a single turbine. I've checked that with a Bonus 2MW turbine included in Wasp. I set up a wind farm that contains only one turbine, define a reference site and calculate the wind farm power curve.


The results I get are
P(4m/s)=0.054MW, P(5m/s)=0.149MW, P(6m/s)=0.286MW, ...
for the win dfarm power curve, while the Bonus 2MW power curve holds these values
P(4m/s)=0.043MW, P(5m/s)=0.133MW, P(6m/s)=0.237MW, ...


What's more, the wind farm power curve seems to direction dependent, which makes no sense for a single turbine with out wake shading, because 5m/s should be 5m/s no matter if wind comes from North or West.


I also checked this with more than one turbine (N>1) and the wind farm power curve delivers power greater than N times the power of the single turbine power curve for several sectors. Here, the number of sectors with excess power seems to increase with wind speed.


Is there something wrong in the implementation of the wind farm power curve, or am I getting something seriously wrong here?


Kind regards

[Ole Rathmann]

Hi "vob" - agree that this looks mysterious. First, please make sure that the reference mast is located at the same position as the turbine and has the same height as the hub-height of the turbine - otherwise you cannot make that comparison.

If nothing is wrong there we need to have your workspace to solve the case. So in that case I invite you to send the case and the workspace to us on WASPSUPPORT@dtu.dk, full confidentiality of course - and we will find out what is the matter.
Ole Rathmann