PO9 Model Validation Guide

Purpose of document

Explanation of the dynamic model validation process related to the PO9 (operating procedure 9), a necessary step for the commissioning of installations; for its connection to the distribution or transmission grids, and presentation of the services offered by CERE with respect to this process.

CERE, because of its experience in grid codes, its knowledge of REE procedures and its experience in the PO9 process, performs the necessary simulations and issues the validation report of the dynamic models (comparison between simulations and tests).

This procedure is independent of the NTS [4] certification process, although the models shall comply the requirements of the current applicable grid code; therefore, they have to comply with the requirements of the NTS [4] and ministerial order 749 [5].


The PO9 regulates the exchange of information with the SO (system operator), REE, including the exchange of information related to dynamic simulation models.

PO9 sets out the requirements and information of the installations to be connected to the electrical network that is needed to provide to the SO. REE needs the dynamic simulation model to represent the behaviour of the  power plant for which the PO9 is carried out, in such a way that, studying it as a black box connected to the electrical grid, you can carry out electrical studies of the network to know its behaviour and operate it safely.

Documentation and necessary files

It is necessary the following information to perform the process:

  • Simulation model manuals
  • Simulation models in PSSE, that can be executed in version 33 of software and that comply with the specifications of [1], [2] and [3]. The models shall have the control strategies required in the grid code in force, currently the NTS [4] and ministerial order 749 [5].
  • In case that you do not have these models, it is possible to use a general plant model and a general protection model developed by REE. If this way is chosen, it will be necessary to parameterize the models so that they represent the actual operation of the installation. The models shall have the control strategies required in the grid code in force, currently the NTS [4] and ministerial order 749 [5].
  • Measured testing data files to perform the validation of the models by comparing the results of the tests with the results of the simulations. In case of PPM (Power park modules) in which a plant controller is installed, it will be necessary to perform the validation against the measurements of the system formed by the UGE (Generation unit; inverter in the case of photovoltaic technology) and the PPC; that is, the measurements correspond to the operation of the inverter and PPC together. These measurements may correspond to laboratory testing site measurements or measurements performed in the field.
  • In the case that the plant certification for the NTS has been carried out through complementary simulations using dynamic models validated and appropriately certified by an accredited certification body, the validation described for the dynamic models of PO9 will not be necessary and the certification according to NTS SEPE or SENP will be accepted, always in case that the simulations have been carried out in PSSE. This point will be articulated as explained in the NTS document in the Commissioning Procedure, a document also issued by REE.

Subject responsible for sending information to REE

Regarding the information exchanged with REE, it will be the owner of the PPM (power generation plant), or an agent commissioned by the owner who will carry out the process.

In the particular case of information related to dynamic models, there are two possibilities:

  • The manufacturer or manufacturers may deliver a validation reference, previously provided by REE, to the owner of the PPM to communicate the reference to REE. This case is more problematic if the manufacturer of the UGE (Generation unit) is not the same as the PPC manufacturer (Power Plant Controller) since the measures of the system consisting of PPC and inverter are necessary. Therefore, the two manufacturers have to agree to perform tests to obtain the real measured testing data which is used to make the comparison with the simulation.

If the generation plant does not include PPC, then the measures will be only of the UGE (Generation unit)

  • The owner delivers a validation report from a third part (independent entity of the owner) to REE together with the simulation models. In this case, no reference will be necessary.

Independently of the option chosen, it will be the owner of the plant who shall obtain the approval of PO9, being able to provide the reference or providing the validation report to REE that evaluates.

Acceptance of the simulation model validation report

REE will determine if the provided model or models are valid based on their performance and the model validation reports.


First step is to have all the necessary information available: Real measurements of laboratory test site or field tests, models, manuals, etc.

Second step of the process is to carry out the simulations for the validation, active power as a function of frequency (PvsF) and simulation of the robustness and current injection requirements during voltage ride through, (LVRT). Next, the graphic comparison between real measurements and simulations is carried out. This step can be done by CERE.

Afterwards, the model or models’ validation report is written and issued. This step would also be performed by CERE.

Sending to REE for the evaluation of the model or models and study of the report, is the final step. The delivery must be made by the manufacturer or the owner of the plant depending on which option of those presented in the section “Subject responsible for sending information to REE” has been chosen. The acceptance of the models depends on the criteria of REE.

Estimated dates

In the case of using the models developed by REE and having all the necessary information: The process will take approximately 1-2 weeks for the simulations and parameterization, and 1-2 weeks for the preparation and issuance of the validation report.

In the case of using the user models developed by manufacturers and having all the necessary information: The process will take approximately of 1-2 weeks for the simulations and parameterization, and 1-2 weeks for the preparation and issuance of the validation report.

Once the information is sent to REE, CERE is not responsible for the deadlines that REE needs to communicate the acceptance of the report.


[1] Commissioning procedure. Available in:


[2] Conditions of validation and acceptance of the models. Link in document [1].

[3] Requirements of the models of wind, photovoltaic, storage installations and of all those installations that do not use synchronous generators directly connected to the grid. Link in the document [1] [4] Norma técnica de supervisión de la conformidad de los módulos de generación de electricidad según el Reglamento UE 2016/631.

[5] Orden TED/749/2020, de 16 de julio, por la que se establecen los requisitos técnicos para la conexión a la red necesarios para la implementación de los códigos de red de conexión.

Samuel Rodríguez Carmona
Simulation and Grid Compliance Engineer

About us

CERE is an independent testing, simulation, certification and inspection body that was originally set up as a Certification Entity for Renewable Energies in 2015. Our services include technical assessment, inspection, testing, simulation and certification according safety, EMC, grid quality, grid connection requirements, design certification and complete installations certificates.