Requirement
For the case of the connection of a power station to the French HV network (HTA RTE), the PV power generation company must prove that its infrastructure will not cause instability on the grid. For this situation, RTE (Réseau de Transport d’Electricité) defined the specifications regarding the constructive capacities to be respected. These specifications are adapted to this case in terms of the power station’s “size”, its location on the power grid and the type of electricity generation (wind turbines, photovoltaic cells).
The PV power generation company must submit a technical document consisting of simulation analysis files and test files in order to check the respect of the connection specifications.
The aim of the study was to simulate the connection of a 33MW photovoltaic power station to the 63kV HV grid.
Moreover, during this study, CAPSIM was asked to analyse the primary voltage regulation system which controls the active power of the solar park by acting on the photovoltaic inverters set point.
Realization
Firstly, CAPSIM built a numerical model using ETAP software in order to perform static simulations. This model helped to validate the sizing of the equipments and to execute the study on the reactive constructive capacities of the solar park (PQ diagram- file n°5). It can also be checked whether the photovoltaic park is able to produce/absorb reactive power required by RTE for different power levels.
Secondly, CAPSIM built a numerical model of the photovoltaic power station using via PSIM which enabled to execute dynamic simulations. This model represented the response time of the photovoltaic inverters, of the calculation step of the reactive power regulation system, measure and communication delays.
This model also helped to perform a study of the system with voltage dips (file n°9) and the definition and validation of the primary voltage regulation with respect to validity criteria of the file n°6 (in terms of response time and analysis of gain margins and Nyquist diagrams).
Results
This study enabled the execution of the following tasks :
- Validation of the installation’s capacity to provide/absorb reactive power as per the file n°5 required by RTE
- Definition of the primary voltage regulation scheme allowing to respect stability criteria and execute the RTE file n°6
- To check the installation’s behaviour towards voltage dips by the realisation of RTE file n°9
