Synchronous Condenser for European Grid Code Compliance: A Case Study of a PV Power Plant in Spain

Abstract

The massive integration of renewable energies into the grid towards the de-carbonisation of the power system has a major impact on the stability of the grid. This has led the European Union to establish guidelines on how renewable plants should be connected to the grid, in order to continue to guarantee their operation and stability. These requirements are contained in the European Grid Code. In this code, there are requirements concerning voltage control, reactive power capacity, fault-ride-through and short-circuit current contribution capabilities of renewable power plants. These plants, in particular those powered by photovoltaic inverters, have issues of reactive power capacity, so in order to be able to connect to the grid, they usually require an oversized of the inverters or the installation of reactive power compensation elements, such as capacitor banks, static VAR compensator or synchronous condensers. Moreover, the fault-ride-through and short-circuit current contribution are difficult to fulfil as they are inverter-based generators have a low capacity to supply short-circuit current and, in some cases, they disconnect from the grid. These facts have produced large power losses and protection malfunctions in power system with high photovoltaic power penetration. This paper studies the compliance of the European Grid Code of a 500 MW photovoltaic power plant with and without a synchronous condenser. The results show that not only the use of the synchronous condenser helps for reactive power regulation but also for fault-ride-through and short-circuit current contribution.

Keywords

• European grid code
• inverter
• reactive power capability
• RMS simulations
• renewable energy
• robustness