I am trying to simulate a solar photovoltaic (PV) system in PowerFactory. Can I do that and if yes, how to perform the simulation?
It is possible to represent photovoltaic (PV) systems in PowerFactory for the purpose of power system analysis. It is important to decide from the very beginning on the type of analyses being carried out in the study because PowerFactory offers multiple possibilities for PV modelling.
- Medium to long-term analyses should be carried out mainly using “Quasi-Dynamic Simulation” as this one will include in the PV system appropriate functionality like: estimation of solar irradiance based on GPS coordinates, PV panel model using datasheet parameters, different mounting options, including single/dual axis MPP trackers, various steady state voltage/reactive power control options applied either locally or in coordination with other units etc. The Quasi-Dynamic Simulation is able to execute a long term analysis (e.g. days, months, years) with a much lower execution time as compared to RMS/Stability type simulations. The power system can be investigated in terms of voltage limitations (over/under), loading violations, reverse power flow in distribution networks, primary/secondary frequency regulation, similar analyses in microgrids including diesel gen-sets and battery systems, etc. Should any customized behaviour be needed for the PV system (e.g. custom voltage control options, etc) then PowerFactory offers modelling techniques based on the so-called Quasi-Dynamic Simulation Language (QDSL models) which allows integration of any kind of load flow and QDS behaviour including integration of states defined by their time derivatives. Refer to the User Manual, “Quasi-Dynamic Simulation” chapter for more information.
- Short term analyses should be carried out mainly using the “RMS stability” dynamic simulation tool. This tool can be used for example when analysing the fault ride through behaviour of PV units, voltage and frequency stability of the power system, stability in a micro-grid system with/without diesel generators etc. For grid-connected studies, PowerFactory provides a number of PV templates (available in PowerFactory under the global Library->Templates) which can be used for this purpose. The templates are modelled such that short-time transients are correctly represented. Using this template for medium to long term studies may be counter-productive as the simulation time is highly increased. Also, the fast dynamics of controllers will not play any significant role in such long term simulations and may even introduce modelling difficulties when trying to run the simulation with very large time steps. The PV template is provided in un-encrypted format, hence any customized modifications can be applied to fit specific purposes. For stability studies, the slow reacting controllers are only marginally influencing the results, hence they usually are either idealized or excluded from the model. Refer to the User Manual, “RMS/EMT Simulations” chapter for more information.
- Very fast transients should be captured using the EMT simulation where, for example, the PV system disconnection from the grid could be analysed. In such a case, only a minimum set of controllers and auxiliary elements need be modelled e.g. for switching/islanding transients the fast reacting over-current protection, over/under voltage/frequency protection and a couple of other fast acting blocks are needed. In such an analysis, solar models (where the power is calculated based on irradiance), MPPT models, slow acting voltage regulators with relatively large time constants are typically not needed. Refer to the EMT examples for further modelling approaches. Refer also to the User Manual, “RMS/EMT Simulations” chapter for more information.
- For investigating harmonics or flicker generated by a PV system the “Harmonic Load Flow” tool should be used. Refer to the User Manual for more information on how to perform a harmonic load flow calculation.
- For calculating short circuit according to various standards (IEC, ANSI, etc.), the “Short Circuit” calculation function should be used. Refer to the User Manual for more information on how to perform a short circuit calculation.