Project design > Results > Simulation variables: Grid system

The following variables are calculated during the simulation process, and available as results:

Meteo and irradiation variables: see previous page.

PV array behavior

PNomArray	Nominal Installed Power	( = Nb. PV modules * nameplate PNom)
EArrRef	Array reference energy for PR calculation (as defined in the IEC EN 61724 norm)	= GlobInc * PNomArray
EArrNom	Array nominal energy at STC, according to the one-diode model Starting point of the array energy evaluation in the loss diagram	= GlobEff * Pmpp (STC)
GIncLoss	PV loss due to irradiance level	(low-light efficiency)
TempLoss	PV loss due to temperature	(see Uc and UV parameters)
SpctCor	Spectral correction	(amorphous modules, CdTe, Sandia model)
LigSoak	Light soaking for CIS/CIGS modules
ShdElec	Electrical loss for mismatch due to shadings	(calculation "according to module strings" or "ModuleLayout")
ModQual	Module quality loss	(users choice concerning real performance of the modules)
LIDLoss	Light Induced degradation	(for mono-crystalline modules, p-type wafer only)
MisLoss	Module array mismatch loss
OhmLoss	Ohmic wiring loss in the DC array
EArrMPP	Array MPP energy after all array losses	(on the loss diagram)
EArray	Effective energy at the array output	(taking inverter operating point displacements into account - not represented on the Loss diagram)
Iarray	Array current	(taking inverter operating point displacements into account)
Uarray	Array voltage	(taking inverter operating point displacements into account)

Inverter behavior (see also Inverter operating limits)

InvLoss	Global inverter loss
IL_Oper	Inverter Loss during operation	(efficiency curve)
IL_Pmin	Inverter Loss due to power threshold
IL_Pmax	Inverter Loss due to power overload
IL_Vmin	Inverter Loss due to low voltage MPP window
IL_Vmax	Inverter Loss due to upper voltage MPP window
IL_Night	Inverter night energy	(usually negligible or null)
Syst_ON	System operating duration
EOutInv	Available Energy at Inverter Output

Energy output and use

Aux_Lss	Auxiliaries consumption	(Fans, other... )
EacOhmL	AC ohmic loss	(wiring up to injection point)
ETrfLss	External transfo loss	(iron loss and ohmic contribution)
UnavLss	System Unavailability loss	Specified or random periods of shutdown
E_Solar	Energy supplied to the user from solar	if load is defined (Netmetering)
E_User	Energy need of the user	if load is defined (Netmetering)
E_Avail	Energy available from the sun	= EOutInv - losses after inverter (Wiring, night losses)
E_Grid	Energy injected into the grid
EApGrid	Apparent energy into the grid	when Power factor defined
ERegrid	Reactive energy into grid	when Power factor defined
SolFrac	Solar fraction	ESolar / EUser

Efficiencies

EffArrR	Array Efficiency	EArray / rough area
EffArrC	Array Efficiency	EArray / cells area (=0 when cells area not defined)
EffSyR	System efficiency	EOutInv / rough area
EffSyC	System efficiency	EOutInv / cells area.
EffInvB	Inverter efficiency	Threshold loss included
EffInvR	Inverter efficiency	When operating

Normalised performance index (cf IEC EN 61724, usually expressed and plotted as values per day)

Yr or	Reference Incident Energy in collector plane	= GlobInc [kWh/m²] (kWh irradiance)
Yr	Normalized Reference nominal energy at STC	= EArrRef / PNomArray [kWh/kWp] (kWh electrical)
Ya	Normalized Array Production	= EArray / PNomArray [kWh/kWp]
Yf	Normalized System Production	= EGrid or EAvail / PNomArray [kWh/kWp]
Lc	Normalized Array Losses	= Yr - Ya
Ls	Normalized System Losses	= Ya - Yf
PR	Performance Ratio	= Yf / Yr = E_Grid / (GlobInc * PNomArray)

NB: The Normalized Reference nominal energy at STC Yr [kWhel/kWp] is the electrical energy which would be produced by the Reference incident energy on the collector plane under STC conditions (1 kWirrad/m2, 25°C). This explains that the values are identical.