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I want to model a static generator (a photovoltaic one) inside a simulation tool. This simulation tool has no static generator (it is quite new and not user friendly). My idea was to model a synchronous generator as static. The first things that came to my mind are:

  1. set inertia constant H=0;
  2. eliminate exciters/PSS/governor;
  3. set all the transient and sub-transient reactances/time constants to 0
  4. eliminate any damping
  5. set the power factor to 1
  6. model the stator resistance and the stator reactance as the equivalent resistance and reactance of a PV plant (including the inverter)

Is this a good way to get an equivalent approximated model of a static generator? Are there any other parameters to consider in order to get a more accurate model? (I want to specify that this static generator will work always in normal state, just some frequency transient will be tested on the grid).

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    \$\begingroup\$ By "static generator" do you mean a PV grid tie inverter? \$\endgroup\$
    – user16324
    Commented Jun 2, 2022 at 19:01
  • \$\begingroup\$ @user_1818839 sorry you are rigth, I mean a PV plant, so PV panels + inverters (no transformer) \$\endgroup\$
    – Samuele Benito Di Gioia
    Commented Jun 3, 2022 at 6:43
  • \$\begingroup\$ For small inverters you might look at G83/2 (1 phase) or G59 (3 phase) for UK practice; or the equivalent in your region. They cover frequency, tolerances, harmonics etc. For big inverters ... ask the manufacturer? With batteries, you can program it to mimic any inertia/damping you like to assist grid stability hornsdalepowerreserve.com.au but I don't know the capabilities of PV-only systems. \$\endgroup\$
    – user16324
    Commented Jun 3, 2022 at 13:14
  • \$\begingroup\$ Related : some of the links may contain relevant content... cleantechnica.com/2022/06/05/… \$\endgroup\$
    – user16324
    Commented Jun 5, 2022 at 12:27
  • \$\begingroup\$ "In a virtual synchronous machine, the underlying machine model parameters dictate its dynamic response. In particular, the damping, inertia, and flux-linkage parameters are virtual and can be tuned (Beck and Hesse 2007; Alatrash et al. 2012; Zhong 2016). Although the response of a virtual synchronous machine is similar to that of an actual machine, its time constants can be compressed. " (p.16, nrel.gov/docs/fy21osti/73476.pdf ). So what you are suggesting (0 inertia etc) may be appropriate for a "grid following" inverter but not for a "grid forming" inverter. \$\endgroup\$
    – user16324
    Commented Jun 5, 2022 at 13:19

1 Answer 1

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How you model the inverter-based generation depends on what you want to understand from the model and what part of its behavior you need to represent. In terms of the parameters you describe:

  1. set inertia constant H=0; Yes, or a small value if the simulation software won't take a value or zero.
  2. eliminate exciters/PSS/governor; Yes.
  3. set all the transient and sub-transient reactances/time constants to 0 Instead of setting the time constants to zero, you can set the reactances equal to each other.
  4. eliminate any damping Yes
  5. set the power factor to 1 Yes, assuming that's how the plant operates.
  6. model the stator resistance and the stator reactance as the equivalent resistance and reactance of a PV plant (including the inverter) This is probably the best you can do with this type of model. Inverter-based generation is generally current-limited, so any impedance value will not be correct. This will only be a problem if you simulate a short-circuit fault close to the generator. Modeling for short-circuit behavior is the most problematic. (A short presentation of the modeling issues)
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