8 research outputs found
Modelling of a wind turbine with permanent magnet synchronous generator
This investigation presents the implementation and simulation of a Simulink-based controlled permanent magnet synchronous generator (PMSG) wind turbine in the dq0 reference frame. The model consists of a current control subsystem, a PMSG model, a mechanical subsystem, a pitch angle controller and a wind turbine model. The current control subsystem makes use of PI controllers governing the wind turbine speed, the direct and quadrature stator currents and the pitch angle of the turbine blades. The pitch angle controller measures the speed and the active power from the generator limiting both in case of high-speed wind conditions. In order to verify the functioning and the effectiveness of the proposed controllers, simulations- for different operation conditions- are presented and discussed
Interaction of dietary fat intake with APOA2, APOA5 and LEPR polymorphisms and its relationship with obesity and dyslipidemia in young subjects
WIDE AREA CONTROL STRATEGY FOR MULTIPLE VSC-BASED DC LINKS INTERCONNECTING DISPERSED WIND FARMS
ABSTRAC
Fault Detection and Localization in Transmission Lines with a Static Synchronous Series Compensator
This paper proposes a fault detection and localization method for power transmission
lines with a Static Synchronous Series Compensator (SSSC). The algorithm is based on
applying a modal transformation to the current and voltage signals sampled at high
frequencies. Then, the wavelet transform is used for calculating the current and voltage
traveling waves, avoiding low frequency interference generated by the system and the SSSC.
Finally, by using reflectometry principles, straightforward expressions for fault detection
and localization in the transmission line are derived. The algorithm performance was
tested considering several study cases, where some relevant parameters such as voltage
compensation level, fault resistance and fault inception angle are varied. The results
indicate that the algorithm can be successfully be used for fault detection and localization
in transmission lines compensated with a SSSC. The estimated error in calculating the distance
to the fault is smaller than 1% of the transmission line length. The test system is simulated
in PSCAD platform and the algorithm is implemented in MATLAB software
Fault Detection and Localization in Transmission Lines with a Static Synchronous Series Compensator
Empagliflozin and Kidney Function Decline in Patients with Type 2 Diabetes: A Slope Analysis from the EMPA-REG OUTCOME Trial
Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study
International audienceBackground: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society