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Setting up the simulation

In PVsyst, it is possible to define a requirement from the grid manager in term of Power factor. It is specified for the whole system. To activate it, open the menu Energy Management and go the tab Power Factor

There, the power factor may be specified in yearly or monthly values. The implementation of finer time resolution specifications is planned, but not yet implemented. Other control modes, such as constant reactive energy production during the day or dynamic control following a profile will be considered for future versions.

Note 1: The value of cos(φ) does not distinguish between leading and lagging power factor conditions. Some references use tan(φ) for this purpose. However, this distinction is not particularly relevant in PVsyst, as the focus is primarily on active energy.

Note 2: The inverter specifications delimit the range of power factor it can deliver. In the .OND file, this range can be found under the tab Output Parameters, where it is specified equivalently as cos(φ) or tan(φ) limits for the leading and lagging mode separately. If the requested power factor defined in the Energy Management tab is beyond the inverter capability, an information message is displayed and the inverter will operate using its limit power factor during the simulation instead of the requested one.

Impact on the inverter overload conditions

Requesting the inverter to produce reactive energy may affect its overload conditions, depending on its nominal power specifications:

  • either the nominal power PNom is specified in active power [kW]. In this case, the production of reactive energy doesn't impact the overload conditions and the active energy produced by the inverter is independent of the requested Power factor.
  • or the nominal power PNom is specified as apparent power [kVA], so that the power limitation will occur for an active power PNom(act)[kW] = PNom(app)[kVA] × cos(φ). As PNom(act) is lower, the overload loss will be higher, and depends on the specified cos(φ).

In this second case, one should consider adapting the dimensioning of the DC / AC ratio to mitigate those losses. After you defined a requested power factor, the estimation of the overload losses in the Sizing menu will take into account its effect (denoted "Overload loss, with PF").

Note: Since the version 7.3.3, each inverter operates according to its own PNom specification, i.e. either defined as active or apparent. The derogation options "Force as apparent/active power" will force all inverters to operate under a single definition, without modifying the .OND file. This has been kept here for compatibility with old versions < 7.3.3, and for possible tests, but this is not recommended. This should only be used for tests.