Abstract. This article proposes new fuzzy controller to regulation the voltage, damp the oscillations and limit the overshoot behavior in single-machine infinite-bus power system. Two different independent MISO fuzzy controllers are designed. First controller, is voltage stabilizer and it composes of two adaptive fuzzy modules and proportional gain AVR. The voltage stabilizer is designed to regulate the terminal voltage, damp the voltage oscillation and limit the voltage overshoot to the industrial maximum allowable limit. The input signals of this stabilizer is are taken from the terminal voltage and the imposed voltage disturbance that can be read from any smart relay. The fuzzy output is used as feedback signal to control the AVR in order to achieve stabilized voltage equal to the reference voltage. The second fuzzy controller is designed with two input signals; “mechanical angle” and its derivative, and one output which is used as feedback signal to adapt the damping torque in order to damp the mechanical oscillation fast and with maximum overshoot not exceeding 10%, and hence damp the power angle oscillation that is important in the PSS improvement. MATLAB-SIMULINK was used for modelling and the test cases simulation. The results show very good performance for the proposed fuzzy controllers.

Background Limited data are available from randomized trials comparing outcomes between transcatheter aortic valve replacement (TAVR) and surgery in patients with different risks and with follow-up >2 years. Objective In this large, population-based cohort study, long-term mortality and morbidity were investigated in patients undergoing aortic valve replacement (AVR) for severe aortic stenosis using a surgically implanted bioprosthesis (sB-AVR) or TAVR. Methods Individual data from the Austrian Insurance funds from 2010 through 2020 were analysed. The primary outcome was all-cause mortality, assessed in the overall and propensity score–matched populations. Secondary outcomes included reoperation and cardiovascular events. Results From January 2010 through December 2020, a total of 18 882 patients underwent sB-AVR (n=11 749; 62.2%) or TAVR (n=7133; 37.8%); median follow-up was 4.0 (interquartile range 2.1–6.5) years (maximum 12.3 years). The risk of all-cause mortality was higher with TAVR compared with sB-AVR: hazard ratio (HR) 1.552, 95% confidence interval (CI) 1.469–1.640, p<0.001; propensity score–matched HR 1.510, 1.403–1.625, p<0.001. Estimated median survival was 8.8 years (95% CI 8.6–9.1) with sB-AVR vs 5 years (4.9–5.2) with TAVR. Estimated 5-year survival probability was 0.664 (0.664–0.686) with sB-AVR vs 0.409 (0.378–0.444) with TAVR overall, and 0.690 (0.674–0.707) and 0.560 (0.540–0.582), respectively, with propensity score matching. Other predictors of mortality were age, sex, previous heart failure, diabetes, and chronic kidney disease. Conclusions In >2-year follow-up, selection for TAVR was significantly associated with higher all-cause mortality compared with sB-AVR in patients ≥65 years with severe, symptomatic aortic stenosis.