Line Failure Research Articles

Experimental study of a barge-type floating offshore wind turbine under a sequential mooring line failure

Experimental study of a barge-type floating offshore wind turbine under a sequential mooring line failure

P0919 Correlation between trough levels of risankizumab and clinical and biological remission in patients with moderate to severe Crohn’s disease: a retrospective multicenter study (RISE-CD)

Abstract Background Inflammatory bowel disease management has evolved in recent years, with the emergence of new biotherapies such as risankizumab,(RZB) an interleukin (IL) 23 p19 inhibitor, with demonstrated efficacy in moderate-to-severe Crohn’s disease. While the relationship between trough levels and clinical remission is well established for anti-TNF alpha agents, it has yet to be demonstrated for new molecules of interest. The aim of this study was to investigate the correlation between RZB trough levels and clinical and biological remission at 6, 12 and 18 months. Methods This retrospective multicenter study included patients with moderate-to-severe Crohn’s disease from 4 centers, who were being treated with RZB after failure of all other approved biotherapy lines. Clinical activity, assessed by the Harvey-Bradshaw Index (HBI) and biological activity with CRP and fecal calprotectin, as well as serum RZB levels by Elisa technique (Biosynex) were collected. The primary endpoint was clinical and biological remission at 12 months, defined as HBI < 4, CRP < 5 mg/L and fecal calprotectin < 250 µg/g of stool. Secondary objectives were the correlation between RZB levels and clinical and biological remission at 6 and 18 months, treatment persistence, and safety. Results Overall, 43 patients were included in 4 centers. Most patients had ileocolic Crohn’s disease (44.7%), 50% had ano-perineal lesions, 23.7% had extra-intestinal manifestations and 71.7% had a history of bowel resection. Six patients (15.8%) were receiving a combination of advanced therapies with upadacitinib or golimumab. At 12 months, 30.2% of patients were in clinical and biological remission (n=13) and had significantly higher RZB trough levels than patients who were not in remission (8.26 ± 4.66 vs. 4.44 ± 2.37 respectively; p=0.002). The ROC curve identified an optimal risankizumab trough levels threshold of 7.7 µg/mL for predicting clinical and biological remission at 12 months (sensitivity 61.5%; specificity 92%). At 6 and 18 months, 11.7% (n=5) and 34.9% (n=15) of patients were in clinical remission and had significantly higher RZB trough levels. At 6 months, 12 months and 18 months, 43 (100%), 38 (88.4%) and 31 (72%) patients were still on RZB. No patient developed anti-risankizumab antibodies. Conclusion In our multicenter study, with the largest number of patients analyzed to date, trough levels of risankizumab were correlated with clinical and biological response at 12 months in patients with moderate-to-severe Crohn’s disease, in line with data from previous single-center studies but larger prospective studies are still needed.

Dynamic response of a semi-submersible floating wind turbine-point absorption wave energy hybrid energy system under rated and extreme conditions

In this paper, the response of a semi-submersible offshore wind turbine, combined with an absorbing wave energy converter (WEC), is analyzed within the FAST to AQWA coupling framework after single mooring line (ML) failure, under rated and extreme (1 in 10 years wind and wave) conditions. Comparisons are made among the six-degree of motions of the platform, power output, and tensions of the unbroken MLs. With upwind mooring line, the hybrid system suffers the most: surge up to 3.3 times the rotor diameter (D) due to the large hub forces and turbine power reduction by 80%, owing to the pitch response of the platform in both rated and extreme conditions; more likelihood of fatigue in unbroken ML under extreme conditions. Regardless of the failure line condition, the mean tension of the unbroken MLs reduces at the expense of larger motions, compared to a non-faulty line condition. The shutdown measures can reduce significantly the tensions in the MLs at rated conditions, owing to turbine larger influence on the platform than WEC, higher motion response and damping processes. The effect of the WEC on the platform is mainly reflected in heave and roll, providing more stability than in a stand-alone floating turbine case. During extreme conditions, the turbine shuts down, and thus, the response is more attributed to the drift of the platform rather than turbine or WEC operation. On a wider level, research is also needed to determine the response in simultaneously ML failures and misaligned operating flows.

Resilient gas dependency-based planning of electricity distribution systems considering energy storage systems.

This article presents a planning framework to improve the weather-related resilience of natural gas-dependent electricity distribution systems. The problem is formulated as a two-stage stochastic mixed integer linear programing model. In the first stage, the measures for distribution line hardening, gas-fired distributed generation (DG) placement, electrical energy storage resource allocation, and tie-switch placement are determined. The second stage minimizes the electricity distribution system load shedding in realized hurricanes to achieve a compromise between operational benefits and investment costs when the dependence of electricity distribution system on the natural gas exists. The proposed stochastic model considers random failures of electricity distribution system lines and random errors in forecasting the load demand. The Monte Carlo simulation is employed to generate multiple scenarios for defining the uncertainties of electricity distribution system. For the sake of simplicity, weather-related outages of natural gas pipelines are considered deterministic. The nonlinear natural gas constraints are linearized and incorporated into the stochastic optimization model. The proposed framework was successfully implemented on an interconnected energy system composed of a 33-bus electricity distribution system and a 14-node natural gas distribution network. Numerical results of the defined case studies and a devised comparative study validate the effectiveness of the proposed framework as well.

Evaluating The Effectiveness Of Laparoscopic Longitudinal Gastric Resection Surgery On Early Postoperative Complications And Obesity-Related Comorbidities

Studying of the corrective effect of longitudinal gastrectomy on concomitant diseases in patients with morbid obesity. This scientific work is based on the results of a comprehensive examination and treatment of 187 patients with MO who were treated in the our clinical bases from 2021 to 2023. The analysis of comorbidities in the compared groups showed that one or more comorbidities were detected in 72% of the control group, 77% of the main group. The main part of these patients was made up of patients with obesity of the III degree. The proposed modification of SG in morbidly obese patients improved the cardioesophageal function and the strength of the gastroduodenal staple line, eliminating the observed complication of staple line failure of 2.2%. It also led to a decrease in the symptoms of gastroesophageal reflux disease from 14% to 6.1%. In the longitudinal gastric resection procedure, the use of local hemostatic powder "HEMOBEN" along the gastric staple line reduced the bleeding complication from 3.2% to 1.1% and the duration of the procedure by an average of 15±3 minutes.In particular, if in the control and main groups, arterial hypertension was detected in 50 and 59.3% of patients before the surgical procedure, then 3 months after the surgical procedure, an increase in blood pressure was observed in 45.4 and 37% of the patients. After surgery, the clinical signs of arterial hypertension and arthralgia in patients with morbid obesity gradually disappeared with the elimination of obesity. In conclusion, these clinical signs were caused by obesity, and its elimination led to the disappearance of these clinical signs.

Evaluation of the corrective effect of modified laparoscopic longitudinal gastric resection practice on existing metabolic changes in morbidly obese patients

To study the corrective effect of laparoscopic longitudinal gastric resection (LLGR) on obesityrelated metabolic disorders in morbidly obese patients. This scientific work is based on the results of a comprehensive examination and treatment of 187 patients treated for morbid obesity in our clinical bases from 2021 to 2023. Analysis of comorbidities in the compared groups showed that 64% of the comparison groups had metabolic disorders. The majority of these patients were patients with 3rd degree of obesity. Positive changes in lipidogram analysis were observed in patients after LOBR procedure. Also, when hemostasis indicators were studied, convincing positive changes were observed in the 1st and 3rd stages of coagulation hemostasis. In patients with chronic obesity, our recommended modification of LOBR increased cardio esophageal and gastric stapler line strength, eliminating the 2.2% stapler line failure observed in our control group in our main cohort. It also led to a reduction in gastroesophageal reflux disease symptoms from 14% to 6.1%. In conclusion, these pathological changes are closely related to obesity, and the elimination of obesity led to the elimination of these metabolic disturbances

Evaluation of the semi-submersible oil platform under different operational scenarios with a mooring line failure

Evaluation of the semi-submersible oil platform under different operational scenarios with a mooring line failure

Aggregated vulnerability assessment of power transmission lines under operational and hurricane induced outages

Power transmission lines are at risk during extreme weather events and their outage can be disastrous for the power grid operation. Extreme weather event forecasting is not always precise, making it difficult to predict transmission line failures and the resultant consequences. These potential contingencies demand careful examination in power system planning. Conventionally, contingency ranking using operational performance indexes (PIs) based on line flows and voltage violations has been adopted. For a further in-depth reliability evaluation, weather-based uncertainties should be considered in conjunction with performance-based metrics. In this paper, a hurricane is considered as an extreme weather event. Multiple possible paths and intensities of the hurricane are simulated for the line wear-out stage to calculate a weather-based failure rate index (FRI). FRI states how much a particular line is affected by the hurricane and which line requires immediate attention. Finally, transmission line vulnerability rankings are generated through the unification of line operational performance and weather-based parameters. A fuzzy inference system calculates an aggregated vulnerability index based on the PI and FRI of the lines. The proposed model and techniques have been tested on IEEE 14-bus and IEEE 30-bus systems.

The impact of high‐voltage circuit breaker condition on power system reliability indices

AbstractCondition monitoring data can be used to assess the health of a power system component but is rarely used to assess the reliability of the power system they are part of. For high‐voltage circuit breakers (HVCBs), the susceptibility to various failures can be assessed by examining trip coil current (TCC) measurements. HVCBs have two failure modes, failure to trip on command and tripping without a command, which are triggered by various failure mechanisms that in turn may depend on the technical condition of the HVCBs. The aim of this article is to demonstrate a methodology for quantifying the impact that the technical condition of HVCBs has on the power system reliability indices. An equivalent transmission line failure rate considering protection system failures, including failures related to HVCBs, can be calculated by computing contributions from various fault types (FTs). This article proposes a framework that can quantify the frequency of the FTs that are affected by HVCB condition. The system‐level effects are then evaluated using approximate methods for power system reliability evaluation. To demonstrate the principles and benefits of this methodology, a case study is presented that incorporates HVCB condition data from the Icelandic transmission grid into an illustrative 4‐bus test system; a dataset of 83 TCC measurements from 38 HVCBs from the Icelandic Transmission System Operator is used, together with an outage database of life histories of 464 HVCBs from the Icelandic transmission grid. Results indicate that the condition deterioration associated with the probability of an HVCB failing to trip on command can significantly degrade the reliability indices.

Dynamic response analysis of alternative mooring system designs for a 15 MW floating wind turbine with an emphasize on different limit states

With the advancement of wind turbines into deeper and more distant waters, and the increase in turbine power, the design of mooring systems for large floating wind turbines presents significant challenges. This paper, based on a water depth of 100 meters, focuses on a 15 MW eccentric semi-submersible wind turbine platform. A time-domain fully coupled numerical model is established, and the mooring system design is carried out. A parametric investigation is conducted on the influence of different mooring parameters on the floater's motion, line configuration, mooring tension, and pretension. The study considers operational conditions, extreme conditions, and accidental conditions such as mooring line failure. It emphasizes the effects of factors such as mooring line length, horizontal mooring angle, fairlead height, and components in hybrid mooring systems, including concentrated mass, buoy volume, and the configuration scheme of weight and buoy blocks. Among various mooring schemes, an optimized design is selected for further dynamic response analysis to verify the feasibility of the scheme. Through comprehensive analysis of various mooring parameters, this paper summarizes the influence patterns of different mooring system design parameters on the dynamic response of floating wind turbines, providing a theoretical foundation and design guidance for subsequent engineering applications.

Enhancing production system resilience with digital twin-driven management

ABSTRACT In the last decade, significant advancements in digital technologies have revolutionized production systems, leading to the development of Cyber-Physical Systems (CPS) and Digital Twins (DT). This paper proposes a design of a production management system that leverages a Digital Twin associated with the shop floor. The objective is to enhance the resilience of production systems by providing real-time monitoring and enabling cloud-based outsourcing during production line failures. The methodology involves creating a Digital Twin model of the CPS, which is used to monitor the production process and visualize key performance indicators through a business intelligence tool. The contribution of this study lies in addressing the growing need for resilient production systems capable of withstanding disruptions and unexpected events. The DT provides accurate information useful for making informed decisions during disruptions. This research contributes to improving management practices by integrating production and enterprise data, facilitating decision-making processes aligned with company objectives, and enhancing the overall resilience of production systems. These findings illustrate the potential of cloud production services to maintain service levels. Among the academic contributions of this paper, is the use of System Dynamics as a suitable approach to modeling the behavior of a digital twin.

Multiphysics Modeling of Power Transmission Line Failures Across Four US States

The failure of overhead transmission lines in the United States can lead to significant economic losses and widespread blackouts, affecting the lives of millions. This study focuses on analyzing the failure of transmission lines, specifically considering the effects of wind, ambient temperature, and current demands, incorporating minimal and significant pre-existing damage. We propose a multiphysics framework to analyze the transmission line failures across sensitive and affected states of the United States, integrating historical data on wind and ambient temperature. By combining numerical simulation with historical data analysis, our research assesses the impact of varying environmental conditions on the reliability of transmission lines. Our methodology begins with a deterministic approach to model temperature and damage evolution, using phase-field modeling for fatigue and damage coupled with electrical and thermal models. Later, we adopt the probability collocation method to investigate the stochastic behavior of the system, enhancing our understanding of uncertainties in model parameters, conducting sensitivity analysis to identify the most significant model parameters, and estimating the probability of failures over time. This approach allows for a comprehensive analysis of factors affecting transmission line reliability, contributing valuable insights into improving power line’s resilience against environmental conditions.

Experimental study on internal damage mechanisms and performance state perception of tunnel linings under different loading paths

The state of tunnel lining structures plays a crucial role in determining safety and service quality throughout their serving life. Therefore, establishing a quantitative method for evaluating the bearing capacity of linings is crucial. Understanding the process and status of crack propagation is key to ensuring structural safety. The three-dimensional development of lining damage cracks is closely related to structural safety. Unveiling the spatial growth of these cracks and the evolution of structural performance is vital for an accurate assessment of lining safety. Key factors in crack propagation, along with non-destructive detection methods, serve as primary approaches for evaluating the safety condition. This paper explores the evolution law and evaluation model of the bearing capacity of plain concrete linings under different loading paths. The distribution of structural stiffness changes significantly under different boundary settings. Therefore, full-scale loading tests of lining components were conducted, designing two types of linings: one intact and the other with initial defects, to simulate the failure of plain concrete linings under diverse loading conditions. The results show that: (1) The damage development of linings exhibits clear staged evolution characteristics; (2) The spatial development of lining cracks can be divided into three stages; (3) There are significant differences in ultrasonic parameters at different stages. Consequently, a method for evaluating the local bearing capacity state of linings based on the coupling of crack characteristics and ultrasonic parameters is proposed; (4) This method is also applicable to linings with initial damage, where damage evolution follows similar stages. The findings provide theoretical guidance for predicting and preventing crack propagation in operational tunnel linings.

A probabilistic assessment of ship blackout incident with Fault Tree Analysis into (FTA) Bayesian Network (BN)

Blackouts in maritime activities can cause propulsion loss and dangerous maritime conditions. Bayesian risk analysis is applied to ship blackout incidents in this study to improve understanding and reduce risks. Using Fault Tree Analysis (FTA), a Bayesian Network (BN) model incorporates fuel quality, lubricating oil quality, sensor error, injector error, and mechanical defects to estimate blackout probability. The model analyses how hazards and their interactions affect this situation using probabilistic inference. Sensitivity analysis identifies variables that affect blackout probabilities and prioritises risk mitigation solutions. Based on prior and posterior probabilities, ‘Automatic Voltage Regulator Failure’ (0.03 prior, 0.17 posterior), ‘Rotor Mechanical Fault’ (0.03 prior, 0.15 posterior), and ‘High Cooling Water Temperature’ (0.03 prior, 0.13 posterior) are the top three blackout causes. Other significant variables include ‘Switchboard Line Failure,’ ‘Faulty Fuel Pump,’ ‘Rotor Open Circuit,’ and ‘Temperature Sensor Failure’ in relative amounts. Bayesian risk analysis can identify and minimise marine blackout concerns, giving decision-makers a comprehensive framework for informed decision-making and proactive risk management. This research emphasises blackout accidents’ importance, improving maritime transportation safety and reliability.

Study on the law of ore dilution and loss and control strategies under brow line failure in sublevel caving mining

To improve ore recovery ratio and the quality of medium-length hole blasting in non-pillar sublevel caving method, this study first investigated the effects of brow line failure on rock movement and ore recovery indexes based on rock blasting fragmentation mechanisms, the granular dynamics theory and ore drawing theory. Subsequently, control strategies to enhance blasting quality and reduce brow line failure were explored through energy impact crushing experiments, experiments on the radial rock-breaking effects of blast holes with different detonation velocities, and underground physical simulation experiments using full blast hole length detonating cord blasting. The experimental results indicate that as the degree of brow line failure increases, the ore recovery ratio gradually decreases, while the waste ratio gradually increases. Bottom initiation and the use of the full blast hole length detonating cord were identified as the optimal initiation method and charging structure for medium-length hole blasting in non-pillar sublevel caving method, effectively improving blasting quality and reducing damage to the brow line.

Two-Stage Robust Resilience Enhancement of Distribution System against Line Failures via Hydrogen Tube Trailers

Two-Stage Robust Resilience Enhancement of Distribution System against Line Failures via Hydrogen Tube Trailers

Proactive Prevention Strategies for Grid Risk Scenarios Based on Pumped Storage Participation

Given the increasing importance of cascading trip prevention, this study presents the pumped storage characteristics to cooperate with thermal units and further ensure the safety of grid operation. The proposed model comprises two phases: the first phase is the day-ahead decision-making phase, which synergistically optimizes thermal units and pumped storage to improve the flexibility of grid operation; the second phase is the intra-day adjustment phase considering the uncertainty of the wind-photovoltaic and transmission line failure outage to enhance the robustness. Furthermore, this model employs a column and constraint generation algorithm to solve the two-phase, three-layer optimization problem, thereby minimizing the adjustment cost under the riskiest scenarios. The experimental results show that adding pumped storage reduces the total system operating cost by 3.99%, the renewable energy abandonment rate to 0.65%, and the thermal power unit output standard deviation to 74.13 MW.

A hybrid SATS algorithm based security constrained optimal power flow using FACTS devices

In the realm of power systems, achieving optimal operation while ensuring security remains a paramount challenge. The security constrained optimal power flow (SCOPF) problem deals with optimizing power system operations while taking into account security limitations. Flexible alternating current transmission system (FACTS) is a system consisting of static equipment used for transmitting electrical energy in the form of AC. The static synchronous series compensator (SSSC) is a specific form of series FACTS device. The unified power flow controller (UPFC) is a FACTS device that is connected in parallel and series with a transmission line. In this research, hybrid simulated annealing and tabu search (hybrid SATS) algorithm is designed to solve SCOPF problems that involve use of FACTS devices. The combination of simulated annealing and tabu search is intended to improve algorithm's pace of convergence and the quality of its solutions. Hybrid SATS with FACTS devices are used to investigate line flow limit violations during single line failures and ensure power flows remain within their security limitations. The efficacy of proposed algorithm is demonstrated through case studies utilizing IEEE 30 bus system. These case studies demonstrate algorithm's capabilities to achieve optimal and secure power system functioning to demonstrate its effectiveness.

Tensile testing in feline ventral abdominal coeliotomy closure with different sizes of polydioxanone suture material: a biomechanical study.

The aim of this study was to evaluate, in vitro, the load and type of failure of the sutured ventral abdominal fascia of cats with different sizes of suture material made of polydioxanone (PDX) (2-0, 3-0, 4-0, 5-0 USP). A total of 32 samples of the ventral abdominal wall from 16 cadaveric cats were harvested using an hourglass-shaped template. The samples were sectioned longitudinally along the linea alba and then sutured together in a continuous pattern using four different randomly assigned sizes of pdx suture material (2-0, 3-0, 4-0, 5-0 USP). A universal testing machine was used for linear distraction of the samples. The tensile strength and type of failure were recorded and analysed. Three types of failure were defined: suture material failure (S), suture line failure (T1) and failure of the abdominal wall further away from the linea alba (T2). The frequency of suture material failure decreased with increasing suture size. Suture size 5-0 failed due to a S failure in 6/8 samples, PDX 4-0 failed in 2/8 samples and PDX 3-0 failed in only 1/8 samples. However, PDX 2-0 failed due to only T1 or T2 failures, with both failures being almost equally represented. No statistically significant differences in the load to failure between PDX 2-0, 3-0 and 4-0 were noted (P >0.05). The risk of suture failure increased with decreasing suture size diameter. PDX 2-0 and 3-0 can be used without reservation for the closure of ventral midline coeliotomy in cats. Although there was no statistically significant difference between PDX 2-0, 3-0 and 4-0, PDX 4-0 showed a higher probability for suture breakage and should be used only after careful consideration of the patient while clinical evaluation is pending. Pdx 5-0 cannot be recommended as a safe suture size for this type of surgical closure.

MCS-ML based line vulnerability for infrastructural resilience assessment with multi-wind speed cyclonic zones

The resilience of critical infrastructure is paramount for power systems prone to cyclonic activities characterized by varying wind speeds. This study conducts a thorough examination of the impact of cyclone lasting for a week on transmission lines for each passing day. Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) is applied to extract hourly wind speed data for the cyclone. Sequential Monte Carlo Simulation (SMCS) is used to model the day-wise hourly transmission line fragility and determination of line vulnerabilities across high, medium, and low wind speed zones. Fragility curves are developed to depict the correlation between wind speeds and line failure probabilities in each zone. The line outage scenarios are generated based on the critical wind speeds and collapse wind speeds for each zone. Line Vulnerability Index (LVI) is proposed to determine the vulnerability and the resilience status of the transmission lines. Machine Learning (ML) based models, FFNN (Feed Forward Neural Network) and RFC (Random Forest Classifier), are proposed for assessment of infrastructure resilience by vulnerability ranking of the lines. Hourly wind speed and hourly line failure probability are the inputs to train the ML models and, LVI and ranking are predicted for the IEEE 30-bus system.