The Swedish transmission system operator’s perspective on planning series-compensated network sections containing wind power plants

The rapid proliferation of wind power plants has generated an increasing demand to modify the series-compensated network sections in Sweden. Moreover, the network planning must consider factors such as the expected load increase and series-capacitor refurbishments or renewal. This work discusses the Swedish transmission system operator’s perspective on planning series-compensated network sections containing wind power plants, providing in-depth summaries of essential studies conducted using frequency domain- and electromagnetic transient tools. Such studies include transient overvoltages, temporary overvoltages, and subsynchronous oscillation studies. However, the initial planning that determines the series capacitor’s design parameters is also covered to capture the entire system design chain. The initial planning consists of steady-state calculations, phasor-based transient simulations, and relay protection considerations, such as current inversion. Finally, this work thoroughly discusses how the study results are incorporated into the series capacitor design specification to achieve the best possible system solution. •Summary of studies concerning the planning of series-compensated network sections.•Mitigation strategies for transient overvoltages and subsynchronous oscillations.•Evaluation of the system design concurrently with the series-capacitor design.