import numpy as np
from numpy import newaxis as na
class AEPCalculator():
def __init__(self, site, windTurbines, wake_model):
"""
site: f(turbine_positions, wd, ws) -> WD[nWT,nWdir,nWsp], WS[nWT,nWdir,nWsp], TI[nWT,nWdir,nWsp), Weight[nWdir, nWsp]
wake_model: f(turbine_positions, WD[nWT,nWdir,nWsp], WS[nWT,nWdir,nWsp], TI[nWT,nWdir,nWsp) -> power[nWdir,nWsp] (W)
"""
self.site = site
self.wake_model = wake_model
self.windTurbines = windTurbines
def _get_defaults(self, x_i, h_i, type_i, wd, ws):
if type_i is None:
type_i = np.zeros_like(x_i)
if h_i is None:
h_i = self.windTurbines.hub_height(type_i)
if wd is None:
wd = self.site.default_wd
if ws is None:
ws = self.site.default_ws
return h_i, type_i, wd, ws
def _run_wake_model(self, x_i, y_i, h_i=None, type_i=None, wd=None, ws=None):
h_i, type_i, wd, ws = self._get_defaults(x_i, h_i, type_i, wd, ws)
# Find local wind speed, wind direction, turbulence intensity and probability
self.WD_ilk, self.WS_ilk, self.TI_ilk, self.P_lk = self.site.local_wind(x_i=x_i, y_i=y_i, wd=wd, ws=ws)
# Calculate down-wind and cross-wind distances
dw_iil, cw_iil, dh_iil, dw_order_l = self.site.wt2wt_distances(x_i, y_i, h_i, self.WD_ilk.mean(2))
self.WS_eff_ilk, self.TI_eff_ilk, self.power_ilk, self.ct_ilk =\
self.wake_model.calc_wake(self.WS_ilk, self.TI_ilk, dw_iil, cw_iil, dh_iil, dw_order_l, type_i)
def calculate_AEP(self, x_i, y_i, h_i=None, type_i=None, wd=None, ws=None):
"""Calculate AEP
In addition effective wind speed, turbulence intensity, and the
power, ct and probability is calculated
Parameters
----------
x_i : array_like
X position of wind turbines
y_i : array_like
Y position of wind turbines
h_i : array_like or None, optional
Hub height of wind turbines\n
If None, default, the standard hub height is used
type_i array_like or None, optional
Wind turbine types\n
If None, default, the first type is used (type=0)
wd : int, float, array_like or None
Wind directions(s)\n
If None, default, the wake is calculated for site.default_wd
ws : int, float, array_like or None
Wind speed(s)\n
If None, default, the wake is calculated for site.default_ws
Returns
-------
AEP_GWh_ilk : array_like
AEP in GWh
"""
self._run_wake_model(x_i=x_i, y_i=y_i, h_i=h_i, type_i=type_i, wd=wd, ws=ws)
AEP_GWh_ilk = self.power_ilk * self.P_lk[na, :, :] * 24 * 365 * 1e-9
return AEP_GWh_ilk
def calculate_AEP_no_wake_loss(self, x_i, y_i, h_i=None, type_i=None, wd=None, ws=None):
"""Calculate AEP without wake loss
In addition local wind speed, turbulence intensity, and the
power, ct and probability is calculated
Parameters
----------
x_i : array_like
X position of wind turbines
y_i : array_like
Y position of wind turbines
h_i : array_like or None, optional
Hub height of wind turbines\n
If None, default, the standard hub height is used
type_i array_like or None, optional
Wind turbine types\n
If None, default, the first type is used (type=0)
wd : int, float, array_like or None
Wind directions(s)\n
If None, default, the wake is calculated for site.default_wd
ws : int, float, array_like or None
Wind speed(s)\n
If None, default, the wake is calculated for site.default_ws
Returns
-------
AEP_GWh_ilk : array_like
AEP (without wake loss) in GWh
"""
h_i, type_i, wd, ws = self._get_defaults(x_i, h_i, type_i, wd=wd, ws=ws)
# Find local wind speed, wind direction, turbulence intensity and probability
self.WD_ilk, self.WS_ilk, self.TI_ilk, self.P_lk = self.site.local_wind(x_i=x_i, y_i=y_i, wd=wd, ws=ws)
type_ilk = np.zeros(self.WS_ilk.shape, dtype=np.int) + type_i[:, np.newaxis, np.newaxis]
self.power_ilk = self.windTurbines.power(self.WS_ilk, type_ilk)
AEP_GWh_ilk = self.power_ilk * self.P_lk[na, :, :] * 24 * 365 * 1e-9
return AEP_GWh_ilk
def _WS_eff_map(self, x_j, y_j, h, x_i, y_i, type_i, h_i, wd=None, ws=None):
h_i, type_i, wd, ws = self._get_defaults(x_i, h_i, type_i, wd, ws)
def f(x, N=500, ext=.2):
ext *= (max(x) - min(x))
return np.linspace(min(x) - ext, max(x) + ext, N)
if x_j is None:
x_j = f(x_i)
if y_j is None:
y_j = f(y_i)
if h is None:
h = np.mean(h_i)
X_j, Y_j = np.meshgrid(x_j, y_j)
x_j, y_j = X_j.flatten(), Y_j.flatten()
if len(x_i) == 0:
_, WS_jlk, _, P_lk = self.site.local_wind(x_i=x_j, y_i=y_j, wd=wd, ws=ws, wd_bin_size=1)
return X_j, Y_j, WS_jlk, P_lk
self._run_wake_model(x_i, y_i, h_i, type_i, wd, ws)
h_j = np.zeros_like(x_j) + h
_, WS_jlk, _, P_lk = self.site.local_wind(x_i=x_j, y_i=y_j, wd=wd, ws=ws)
dw_ijl, cw_ijl, dh_ijl, _ = self.site.distances(x_i, y_i, h_i, x_j, y_j, h_j, self.WD_ilk.mean(2))
WS_eff_jlk = self.wake_model.wake_map(self.WS_ilk, self.WS_eff_ilk, dw_ijl,
cw_ijl, dh_ijl, self.ct_ilk, type_i, WS_jlk)
return X_j, Y_j, WS_eff_jlk, P_lk
def wake_map(self, x_j=None, y_j=None, h=None, wt_x=[], wt_y=[], wt_type=None, wt_height=None, wd=None, ws=None):
"""Calculate wake(effective wind speed) map
In addition local wind speed, turbulence intensity, and the
power, ct and probability is calculated
Parameters
----------
x_j : array_like or None, optional
X position map points
y_j : array_like
Y position of map points
h : r None, optional
Hub height of wind turbines\n
If None, default, the standard hub height is used
type_i array_like or None, optional
Wind turbine types\n
If None, default, the first type is used (type=0)
wd : int, float, array_like or None
Wind directions(s)\n
If None, default, the wake is calculated for site.default_wd
ws : int, float, array_like or None
Wind speed(s)\n
If None, default, the wake is calculated for site.default_ws
Returns
-------
AEP_GWh_ilk : array_like
AEP (without wake loss) in GWh
"""
X_j, Y_j, WS_eff_jlk, P_lk = self._WS_eff_map(x_j, y_j, h, wt_x, wt_y, wt_type, wt_height, wd, ws)
return X_j, Y_j, (WS_eff_jlk * P_lk[na, :, :] / P_lk.sum()).sum((1, 2)).reshape(X_j.shape)
def plot_wake_map(self, x_j=None, y_j=None, h=None, wt_x=[], wt_y=[], wt_type=None, wt_height=None, wd=None, ws=None, ax=None, levels=100):
import matplotlib.pyplot as plt
if ax is None:
ax = plt.gca()
X, Y, Z = self.wake_map(x_j, y_j, h, wt_x, wt_y, wt_type, wt_height, wd, ws)
c = ax.contourf(X, Y, Z, levels, cmap='Blues_r')
plt.colorbar(c, label='wind speed [m/s]')
def aep_map(self, x_j, y_j, type_j, x_i, y_i, type_i=None, h_i=None, wd=None, ws=None):
h = self.windTurbines.hub_height(type_j)
X_j, Y_j, WS_eff_jlk, P_lk = self._WS_eff_map(x_j, y_j, h, x_i, y_i, type_i, h_i, wd, ws)
P_lk /= P_lk.sum() # AEP if wind only comes from specified wd and ws
# power_jlk = self.windTurbines.power_func(WS_eff_jlk, type_j)
# aep_jlk = power_jlk * P_lk[na, :, :] * 24 * 365 * 1e-9
# return X_j, Y_j, aep_jlk.sum((1, 2)).reshape(X_j.shape)
# same as above but requires less memory
return X_j, Y_j, ((self.windTurbines.power(WS_eff_jlk, type_j) * P_lk[na, :, :]).sum((1, 2)) * 24 * 365 * 1e-9).reshape(X_j.shape)