No abstract

Three possible strategies to achieve Fault Ride-Through of offshore wind farms connected through voltagesourced converter (VSC) based HVDC links are investigated in this paper. Dissipation of excess energy by a braking resistor, fast wind power reduction by voltage modulation and a combination of these two are analyzed. The studies are performed in a fourterminal HVDC grid connecting two 1000 MW wind farms comprised of variable-speed full scale converter wind turbines. Simulation results demonstrate improvements in the performance of the synergistic approach (coordinated operation of the first two strategies). This type of analysis can aid in the design of cost-effective FRT schemes of the envisioned HVDC multiterminal systems.

This paper proposes a comprehensive methodology to estimate the financial losses incurred by voltage sags and short interruptions to industrial plants. The proposed methodology uses various techniques to tackle different levels of failure risk assessment. Failure risks of sensitive industrial equipments, subprocesses and processes are assessed in sequence before the failure risk and financial losses of an industrial plant are estimated. The most important part of the methodology involves failure risk assessment of sensitive equipments, where a fuzzy logic based model is built to address the inherent uncertainties in equipment behavior when subjected to voltage sags and short interruptions. Failure risk assessment at sub-process level considers the composition ratio and importance level of each equipment type in the sub-process. Finally, failure risk assessment of processes and the entire plant adopts the technique of fault tree analysis. By considering more risk affecting factors, the proposed methodology promises improved accuracy and practicability.

No abstract