As part of the energy transition to a low-carbon electricity network, more renewable energy sources are being integrated into the network. Fossil-fuelled power plants, which used to be the sole electricity producers, are being decommissioned and replaced by renewable resources. The European electricity network enjoyed a share of 38% renewables in 2020. However, the downside of this story is the reduced network strength. The modern electricity network’s voltage and frequency are losing their stiffness, leading to a condition known as the ‘low-inertia’ and ‘weak’ network. To address such a challenge, the power converters – with which the renewable energy resources are connected to the network – need a control system that adequately regulates the low-inertia network’s voltage and frequency.
The control system’s design and evaluation were Saman Dadjo Tavakoli‘s main research themes during his virtual 3-month secondment at Red Eléctrica de España (REE), March to May 2021. He and his REE colleagues developed a PSCAD* model for a voltage source converter that is able to properly regulate the voltage and frequency during large disturbances, such as load rejection, network disconnection and fault conditions. And they have plans to improve the model’s dynamics for better fault performance.
* PSCAD: Power System Computer Aided Design.