A less-intrusive solution to stabilize a Voltage Source Converter (VSC) over an unknown grid strength is presented in this paper. The existence of equilibrium point is investigated as a pre-requisite to stabilization. By partially imposing grid forming control, a simple auxiliary outer loop is proposed to exhaust the physical limit of power delivery in steady state and provide support to fault-ride-through operations over a wide range of grid strength. The proposed control can be used to upgrade a commissioned VSC with inner current loop intact; it also offers a non-intrusive solution to stabilize VSCs externally. The effectiveness of the proposed schemes are verified by analysis in frequency domain and simulations in Electromagnetic Transient (EMT) time domain considering change of grid strength and fault-ride-through.
|Journal||IEEE Journal of Emerging and Selected Topics in Power Electronics|
|Publication status||Accepted/In press - 29 Sep 2020|
- voltage source converter
- weak grids
- voltage stability
- voltage sensitivity
Zhang , Z., Chen, D., Givaki, K., & Xu, L. (Accepted/In press). A less-intrusive approach to stabilize VSC transmission against highly variable grid strength. IEEE Journal of Emerging and Selected Topics in Power Electronics.