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FAULT - OSTI GOV

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Last Updated: 24 September 2022

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Bearing Fault Detection on Wind Turbine Gearbox Vibrations Using Generalized Likelihood Ratio-Based Indicators: Preprint

Rolling element bearing failures are common defects in turbo machinery, according to several studies in condition monitoring literature. A new indicator family using a generalized likelihood ratio test is the first step in capturing the rolling element bearing degradation. This research extends the NREL Wind Turbine Gearbox Condition Monitoring Round Robin study for bearing fault determination purposes. The data set is collected on an experimental test bench of a wind turbine gearbox, so the noise characteristics are similar to that of a real case. In addition, the latest indicators are also tested with signals that include multiple fault signatures. The result shows that the new strategy can be used to distinguish between healthy and damaged vibration signals measured on a complicated wind turbine gearbox.

Source link: https://www.osti.gov/biblio/1885698


Improving DFIG performance under fault scenarios through evolutionary reinforcement learning based control

During system fault events, the double-fed induction generator typically experiences high rotor current and DC capacitor link voltage. By changing the optional reference signals, an advanced reinforcement learning algorithm called guided surrogate-gradient-based evolution scheme is used to control the DFIG power and capacitor DClink voltage. The effectiveness of the new GSES-based control algorithm in improving the DFIG's results under fault scenarios has been established by analysis.

Source link: https://www.osti.gov/biblio/1887238


Market Barriers and Drivers for the Next Generation Fault Detection and Diagnostic Tools

Commercial buildings in the United States use up to 30% more electricity than buildings that operate fault-free and efficiently. This market is still lacking, according to fault AUTOcorrection integrating with commercial FDD services filled the void. Seven innovative AUTOcorrection algorithms were embedded into two FDD platforms and deployed over four buildings. Though fault AUTO-correction has been established in the field, it has yet to be effective in market change, and opportunities and barriers must be understood to realize its full potential in market transition. This paper discusses the new technology that automatically corrects HVAC defects. Future efforts are required to crack the barriers that include cybersecurity and accountability from building designers and standardization of control parameters used in building automation systems in order to allow for scalable deployment.

Source link: https://www.osti.gov/biblio/1887573


A Universal Refrigerant Charge Fault Detection and Diagnostics Method Based on Pump Down Operation

The heat pump system's results can vary greatly depending on the refrigerant charge amount. The ability of improving the refrigerant charge fault detection and diagnostics of vapor compression systems has the possibility of increasing energy efficiency and lowering service cost. Pump down operations are common HVAC technicians' daily activities, with only a few experimental results with high prediction accuracy. The new charge estimation scheme is firstly developed through theoretical investigation, followed by a quasi-state simulation of the pump down process for a residential heat pump system, and then verified and calibrated by a quasi-steady state simulation of the pump down process for a residential heat pump system.

Source link: https://www.osti.gov/biblio/1885328


Inverter Design with High Short-Circuit Fault Current Contribution to Enable Legacy Overcurrent Protection for Islanded Microgrids

The microgrid's resiliency could be lost if the microgrid is not properly covered against short-circuit faults within its boundaries. In microgrids, the limited short-circuit capability of DERs typically prevents the use of durable and inexpensive overcurrent protective equipment. Although extensive microgrid safety data is available in the literature, to date, no such study has resulted in a cost-effective, readily available relay that addresses the challenges of microgrid protection. This paper explores hardware upgrades to extend the existing contribution of an energy storage inverter with the intention of enabling the use of legacy overcurrent protection for islanded microgrids. During three-phase failures, a three-phase energy storage inverter was modified to provide three times its rated current during three phases, which included sufficient current for enough time to enable fuse relay and relay-to-relay coordination, which led to fuse-relay and relay-to-relay coordination.

Source link: https://www.osti.gov/biblio/1885345


Real-Time Fault Location Using the Retardation Method

The difference between the times in which a signal is detected in two detectors can be used to determine the error can be used to determine the fault due to delay phenomena. Although a summary of faults in terms of a lumped circuit is helpful in clarifying the procedures for finding the source of the error, this analysis will not be sufficient to describe the fault signal propagation; therefore, distributed models are required, which are described in terms of the telegraph equations. Those equations were used to determine a transmission line transfer function, and an exact analytical description of the fault signal propagation in the transmission line was obtained.

Source link: https://www.osti.gov/biblio/1878186


Evaluate the impact of sensor accuracy on model performance in data-driven building fault detection and diagnostics using Monte Carlo simulation

Sensor accuracy and sensor selection are well-studied academic research topics, but sensor accuracy and sensor placement in particular, as well as FDD measurement's subsequent effect on FDD results, have yet to be determined and quantified. Monte Carlo simulation is used to deal with several stochastic sensor failures and provide probabilistic analysis results of sensor quality and FDD accuracy as a result of sensor calibration and calibration results.

Source link: https://www.osti.gov/biblio/1820573


New Geomechanical Computation Analysis Evaluating Behavior of the Fault nearby BC-4

For several reasons, 1 the cavern was leached into the caprock; 2 it is similar to BC-7, a brining cavern on the northwest corner of the dome that collapsed in 1954 and now is the home to Cavern Lake; 3 a similar failure of BC-4 would have catastrophic consequences for the site's future.

Source link: https://www.osti.gov/biblio/1813901


Fault Location Using the Natural Frequency of Oscillation of Current Discharge in MTdc Networks

The establishment of a correlation between the calculated natural frequency of oscillation of the transmission line current and the fault location is established. The fault current is interrupted by the hybrid dc circuit breaker, whereby the transmission line current attenuates in the absence of any driving voltage source. At a certain rate of oscillation and rate of attenuation, the line capacitance discharges into the fault.

Source link: https://www.osti.gov/biblio/1772618


Effect of stacking fault energy on damage microstructure in ion-irradiated CoCrFeNiMn concentrated solid solution alloys

Kr 2+ ion irradiation was applied to FCC-type CoCrFeNiMnx alloys in order to investigate the effect of stacking fault energy on microstructural change in concentrated solid solution alloys. In CoCrFeNiMn 1. 3, the comparison of microstructural evolution among CoCrFeNiMn x alloys showed less faulted loop number and size. The stacking fault energy of each alloy was determined using the deformed CoCrFeNiMn x alloys, and it was discovered that CoCrFeNiMn 1. 3 had the highest stacking fault energy, which is higher than that of 316SS.

Source link: https://www.osti.gov/biblio/1779045

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions