Using ModelChain with Plane of Array (POA) as weather input

Question

I really love the concept of the ModelChain in pvlib. However, I would like to be able to use the ModelChain to model DC and AC output of a given system (more than one module and inverter) using Plane of Array irradiance as the weather input, rather than inputting the GHI, DNI and DHI components (which I don't have measurements of) and then specifying a transposition model as part of the ModelChain . Is this possible?

here's my system design

`system=pvlib.pvsystem.PVSystem(surface_tilt=22.5,
                        surface_azimuth=180,
                        modules_per_string=30,
                        strings_per_inverter=100,
                module_parameters=cec_modules['Yingli_Energy__China__YL300P_35b'],                        inverter_parameters=cec_inverters['SMA_America__SC800CP_US_360V__CEC_2012_'])`

Here's a sample of my weather data:

`weather.loc['2018-07-01 10:00:00':'2018-07-01 12:00:00'].head()
Out[420]: 
                            poa_global  temp_air  wind_speed
Timestamp                                                   
2018-07-01 10:00:00-07:00  1031.487152  41.69515     0.77450
2018-07-01 10:05:00-07:00  1031.917903  41.62194     0.82462
2018-07-01 10:10:00-07:00  1033.182229  46.01999     0.54983
2018-07-01 10:15:00-07:00  1031.597900  38.67440     0.95819
2018-07-01 10:20:00-07:00  1031.660918  39.16293     0.86196`

And this is what I would ideally like to do with ModelChain:

`mc=pvlib.modelchain.ModelChain(system,location,
                               aoi_model='physical',
                               transposition_model='None',
                               dc_model='singlediode',
                               ac_model='snlinverter',
                               spectral_model='no_loss',
                               losses_model='pvwatts')`

`mc.run_model(times=weather.index,weather=weather)`

Answer 1

It is not currently possible to use ModelChain.run_model with plane of array weather input. I recommend that you make a feature request on the pvlib issue tracker. You can, however, inspect the ModelChain.run_model source code and copy the post-POA steps into your own function that accepts a ModelChain object as an input. See Demystifying ModelChain internals for background.

Answer 2

This feature was added in pvlib 0.8.0 (check pvlib.__version__ to see what version you have installed).

See the docs page here: https://pvlib-python.readthedocs.io/en/stable/generated/pvlib.modelchain.ModelChain.run_model_from_poa.html