We'd like to let you know about the recent updates regarding losses, defined as factors! This should bring more precision to users, especially when evaluating hourly simulation results.
The changes will take effect in the following locations:
DC cabling loss
AC cabling loss
Transformer loss
DC cabling loss
BEFORE | A constant % value can be defined, which is deducted from the effective DC power value of each string, at each timestep.
AFTER | A loss % value representing power loss at Standard Test Conditions (STC) can be defined. As PV plants usually operate at conditions different from STC, the power loss % is adapted at each time instance as a function of the instantaneous operating current and voltage. The annual energy loss % caused by DC cabling will be lower than the power loss % defined at STC conditions, in most climates.
AC cabling loss
BEFORE | A constant % value can be defined, which is deducted from the effective AC power value of each inverter, at each timestep.
AFTER | A loss % value representing power loss at the operating point defined by the nominal inverter output can be entered. As PV plants often operate below nominal inverter output, the power loss % is adapted at each time instance as a function of the momentary AC operating current. In most cases the annual energy loss % caused by AC cabling will be somewhat lower than the power loss % defined at nominal inverter output.
Transformer loss
BEFORE | When the Use simplified input switch is 'On', a constant % value is deducted from the effective AC power value of each inverter, at each timestep. When switching off Use simplified input - the Copper loss % is deducted from the plant effective AC power value, at each timestep.
AFTER | When the Use simplified input switch is 'On', transformer losses are assumed to be caused by Copper loss only. When the Use simplified input switch is 'Off', the Copper loss is defined by entering a loss % value representing power loss at the operating point defined by the nominal inverter output. As PV plants often operate below nominal inverter output, the power loss % is adapted at each time instance as a function of the instantaneous AC operating current. In most cases, the annual energy loss % caused by Copper loss will be somewhat lower than the power loss % defined at nominal inverter output.
Inverter input section
Due to the introduced changes and the following additional inverter inputs, the inverters available in the library may become drafts, and some files may need to be updated:
Also, the old calculations will not change; changes will only be used in new simulations.