Optimal and small-signal stability improvement of power system operation using multi-terminal VSC-HVDC

The thesis is essentially concerned with some theoretical aspects of the economic and stability studies of power systems with great penetration levels of renewable energy. In part I, firstly, the process of incorporation of VSC MTDC model in ACIDC state estimation is described in detail. The proposed approach simultaneously upgrades the estimated values of the state variables, for a unified solution in a single reference frame. The effectiveness of the proposed ACIMTDC state estimation algorithm and the bad data identification process is demonstrated and validated in modified IEEE test system. Secondly, the optimal power flow (OPF) of a meshed ACIDC power transmission network with Voltage Source Converter based Multi-terminal DC (VSC-MTDC) networks is presented in the thesis. The OPF problem is formulated to minimize the transmission loss of the whole ACIDC network with two different VSC control strategies considered. In addition, Grid Code compliance of wind farms is also embedded in the OPF formulation. The results of the proposed OPF demonstrate that the power losses of the meshed ACIDC power systems can be greatly reduced. In part Il, a novel emergency damping control (EDC) is proposed to suppress inter-area oscillations occurred as anticipated low-probability cases in power system operations. The proposed EDC combines the event-driven and response-based control strategy. It is tested and evaluated in a standard power system and a real large-scale power system in China to compute the optimal location, amount and applying time of generator decreasing and load shedding in order to suppress inter-area oscillations.EThOS - Electronic Theses Online ServiceGBUnited Kingdo