Performance Of Protection System Research Articles

Performance of steel protective structure for historical masonry aqueducts against rockfall: Numerical and field studies

This study investigates the design and impact performance of novel steel protection system intended to safeguard historical masonry aqueducts from damage caused by hazardous rocks. The historical aqueduct under consideration is located on the Sumela Monastery campus. To achieve this, we developed a three-dimensional (3D) photogrammetric model of the study area and identified all risky blocks along with their real positions. Subsequently, we conducted 3200 probabilistic rockfall analyses in eight critical trajectories with four different rock sizes to calculate the velocity, kinetic energy, and run-out distance of fallen blocks. In the second part of the study, finite element models of the steel protective structure were created using Abaqus software. A nonlinear dynamic impact analysis method was applied to analyze nine rockfall scenarios with two different geometries and four different sizes. Based on the rockfall and impact analyses, sections of the protection structure were designed using plastic design criteria. The steel protection structure for aqueducts demonstrated high effectiveness against rockfall, with a risk index (Ir) ranging from 0.93 to 1.00 (except for the upper end of the column–beam connection impacts). Even in these scenarios, the structure provided protection by reducing rock energy and altering its trajectory. In the third part, a steel structure was constructed in the field, and a rock cleaning process was carried out. During rock cleaning, punctures occurred while breaking sharp rocks. To mitigate this risk, a parametric study was conducted using a steel angle stopper. The proposed simple steel angle stopper effectively reduced rockfall damage to historical structures by blocking rock passages and rapidly reducing kinetic energy. Ultimately, during the removal of 5000 m³ of hazardous rocks, no damage was inflicted on the historical structure. The protection system showed a near 100 % success rate in safeguarding the aqueduct. This temporary structure can be employed to protect historical structures from rockfall hazards.

Evaluasi Kinerja Sistem Proteksi Penyulang Trawas PT. PLN (PERSERO) ULP Pandaan

The primary objective of this research was to minimize disruptions in the feeder at ULP Pandaan by analyzing the coordination between recloser outgoing and incoming feeders. This study addressed the frequent issue of recloser trips, which caused instability in power supply. The purpose of this research was to provide conclusions and solutions to mitigate these disruptions. The methodology involved a detailed analysis of OCR (Over Current Relay) settings for protective devices on Trawas feeder. This included measurements of primary current settings and TMS (Time Multiplier Setting) values using both standard inverse and normal inverse configurations. Specific settings, such as 25518 A for the Trawas Recloser primary current and a TMS of 0.07, were determined to yield optimal performance. Additional settings for the Outgoing CB (Circuit Breaker) (357061 A, TMS 0.04) and the Incoming CB (181865 A, TMS 1.0) were also established. The important findings revealed that these settings significantly enhanced the reliability of the protective devices, ensuring better coordination between the recloser and CB systems. The implications of this research were substantial, as the optimized settings were expected to reduce the frequency and impact of feeder disruptions. This improvement in system reliability directly benefited both the electricity provider, PT. PLN (Persert), and the consumers by providing a more stable and efficient power supply. In conclusion, this study offered a comprehensive analysis and practical solutions for enhancing the protection system's performance on the Trawas feeder, which could be applied to similar electrical distribution networks to achieve better stability and reliability.

Limit protection systems for safety operational envelope of submarine

To enhance the operational stability of submarines, this study conducts a comparative analysis of three pitch limit protection systems based on the reference model, potential function, and dynamic trim algorithm. The proposed depth limit protection system adjusts the depth command by comparing the desired depth, calculated by the outer-loop controller, against a predefined depth limit. Similarly, the pitch limit protection systems modify the command pitch calculated by the inner-loop controller to ensure it does not exceed the pitch limit. Submarine maneuvering simulations were conducted to verify the performance of the envelope protection system, which comprises depth and pitch limit protection systems. Simulation results confirmed the effectiveness of these methods, with the dynamic trim algorithm demonstrating superior control efficiency. This study advances submarine safety and stability by developing and validating advanced pitch limit protection systems.

Enhanced distance-based protection for high impedance faults considering dynamic load modelling

The load can be represented by different models, including static and dynamic representations; each has different responses when analysing a power system, which also impacts the protection system's performance. For instance, in the distance relay, the estimated impedance can present overreach or underreach, affecting the selectivity of the protection and causing malfunction of triggering schemes. Under fault conditions, the load modelling effect can be magnified by the fault resistance effect, where the combination of both effects has not been addressed in the revisited bibliography. The present paper analyses the effect of load modelling for non-bolted faults in the distance relay impedance estimation. Distance relays are of interest due to their wide use in transmission systems and the emerging applications in distribution systems and microgrids. The fundamental contribution of the present paper is to propose a countermeasure for the effects of four different load types and fault resistance. The results demonstrate that the distance estimation is correctly enhanced, and then a close to the real positive sequence impedance is estimated from the relay point to the fault point. The proposal can be included in distance relays without requiring additional hardware, allowing countermeasure of the load type and fault resistance effects.

Control modeling and optimization of network information security system based on deep learning data interaction

In order to solve the problem of poor network security protection performance of traditional network information security protection systems, the author proposes a network information security system control modeling based on deep learning data interaction. Adopt CY8C2453 type processor to improve system data exchange and data processing speed, enhance system stability through peripheral backplane, and evaluate network information security, at the same time, the authority management mechanism is set, and the general strategy form of the network attack and defense game is defined as a triple, calculate the attacked path in a certain network area and the defense strategy that the defender should choose, so as to complete the network information security protection based on the attack-defense game model. Experimental results show that: The number of attacked information of the system is 58 less than that of the traditional system; In the webpage attack, the number of attacked information of the designed system is 82 less than that of the traditional system; In the data interception attack, the number of attacked information of the designed system is 77 less than that of the traditional system. ConclusionUnder different attack behaviors, the number of successful attacks on the network information security protection system based on the attack-defense game model designed this time is less than the number of successful attacks on the traditional system, which improves the security of network information.

Structure Design and Heat Transfer Performance Analysis of a Novel Composite Phase Change Active Cooling Channel Wall for Hypersonic Aircraft.

Efficient and stable heat dissipation structure is crucial for improving the convective heat transfer performance of thermal protection systems (TPSs) for hypersonic aircraft. However, the heat dissipation wall of the current TPS is limited by a single material and structure, inefficiently dissipating the large amount of accumulated heat generated during the high-speed maneuvering flight of hypersonic aircraft. Here, a convection cooling channel structure of TPS is proposed, which is an innovative multi-level structure inspired by the natural honeycomb. An active cooling channel (PCM-HC) is designed by using a variable-density topology optimization method and filled with phase change material (PCM). Numerical simulations are used to investigate the thermal performance of the PCM-HC wall, focusing on the influence of PCM properties, structural geometric parameters, and PCM types on heat transfer characteristics. The results demonstrate that the honeycomb-like convection cooling channel wall, combined with PCM latent heat of phase change, exhibits superior heat dissipation capability. With a heat flux input of 50 kW/m2, the maximum temperature on the inner wall of PCM-HC is reduced by 12 K to 20 K. Different PCMs have opposing effects on heat transfer performance due to their distinct thermophysical properties. This work can provide a theoretical basis for the design of high-efficiency cooling channel, improving the heat dissipation performance in the TPS of hypersonic aircraft.

Evaluation of the acoustic performance of a novelty cathodic protection system against guitar steel strings corrosion

This work was conducted to establish the efficiency of an impressed current cathodic protection system for musical instruments’ steel strings in protecting them from corrosion caused by human sweat. To conduct this research, the harmonic content degradation of a guitar string subjected to different corrosion stages by artificial human sweat, with and without cathodic protection by an impressed current, was studied. String corrosion is characterised by not only the electrochemical technique of polarisation resistance, but also by weight loss by gravimetric measurements and FESEM microscopy. From the correlation between the acoustic and electrochemical results, it can be concluded that harmonic content degradation of guitar strings increases corrosion but is less significant in the strings protected by impressed current.

Social (de)stratification in Europe: An empirical analysis of 22 welfare systems

EU national governments and the EU itself are committed to improving the ef-fectiveness of social protection systems to promote the spread of ‘horizontal' relationships between individuals and remove inequalities that prevent people from fully participating in political, economic, and social life. We evaluate this process by examining the performance of social protection systems in 22 Euro-pean countries, focusing on the phenomenon of social stratification over the pe-riod 2007-2017. For this purpose, we refer to both a multidimensional perfor-mance index and principal component analysis. The empirical evidence suggests that the financial crisis of 2007 and the Great Recession that started after 2011 changed (in many ways downsized) the objectives of social protection systems, contributing only partially to the de-stratification of the population of European states over the period covered.

Experimental and numerical investigation into the local scour of bridge cofferdam with anti-scour ribs

Cofferdam is widely employed in the construction of underwater bridge foundations. Its crucial attribute lies in providing a dedicated platform for construction activities and enhancing the water resistance dimensions in structural design, consequently amplifying local scour. However, previous research on local scour has seldom investigated the effect of construction facilities on the life cycle development of local scour on foundations. This gap has led to a misunderstanding of protective strategies against local scour throughout the construction period. In this paper, a scour experiment platform was implemented with a unidirectional flume. Physical model experiments were conducted to scrutinize the protective impact of anti-scour rib structures against local scour. The experimentally determined scour depth was compared to assess the performance of the anti-scour rib protection system. Oblique photogrammetry was subsequently used to capture the morphology of the equilibrium scour pit in the experiments. The associated topographical data were imported into Fluent commercial fluid software for in-depth flow field analysis. A numerical flume model was established to examine the hydraulic characteristics under two distinct topographical conditions: a smooth riverbed during the initial stage of scour and a scoured riverbed at the equilibrium stage of scour. To further determine the protective mechanism of anti-scour rib protection, the influence of anti-scour rib protection on shear stress was investigated numerically. Analyses revealed that incorporating scour protection ribs during cofferdam construction alters the flow field characteristics, hindering the downward movement of subsurface flow beneath the structure, reducing bed shear stress, and consequently mitigating scour effects. The instantaneous protective effect of scour protection ribs strengthens as the scour topography develops. The protective effectiveness of scour protection ribs was mainly influenced by rib length, spacing, and shape.

RESEARCH OF ANTİ-AİRCRAFT MİSSİLE COMPLEXES WİTH RADİO TRACKİNG SYSTEM

It should be noted that missiles with a radio tracking system are used for several purposes. Air defense systems use missiles with radio tracking systems to defend against enemy flying objects. These missiles follow the targets of the enemy's air vehicles, head towards them and destroy them. Ship missiles and defense systems use radio-guided missiles to pick off enemy missiles and aircraft. This ensures the safety of ships and the areas near them. Also, missiles with a radio tracking system can be used to hit long-range targets. This is important for quickly and accurately engaging enemy targets. Missiles with a radio tracking system are used in operational and tactical operations to carry out the command of the command and destroy targets. Space defense systems against missile attacks with radio tracking systems play an important role in tracking, analyzing and protecting enemy ballistic missiles or hypersonic munitions. These analyzes are conducted within the framework of various research and training programs. Initially, information on the position, speed and targeting of enemy missiles is collected through radio tracking sensors. In the next process, the received data is analyzed and the performance of space protection systems is evaluated according to different scenarios. During the analysis, the burning effect, interference, and other wheel factors are considered according to the distance requirement of the sensors. Also, the analysis process focuses on errors and deficiencies in the sensor. As a result, analysis data helps space defense systems work more effectively and provide appropriate responses to attack missiles. One of the important factors required in the process of processing anti-aircraft missiles guided by a modern and visionary system is that these devices should be equipped according to natural conditions and should be ready for battle at any time. The article examines space defense systems against missile attacks with radio tracking systems. In general, there are many types of anti-aircraft missile complexes equipped with a radio tracking system. As we mentioned in the article, this system of complexes is a system consisting of military and technical means that are functionally interconnected and play the role of defense against air-space vehicles. The start of the rocket process, i.e., the starting position, takes place primarily from the transport launch containers, with the subsequent activation of the engine and the launching device. This process is mainly carried out in 3 stages: Anti-aircraft missiles that take a vertical starting position and are controlled tend to the calculated rendezvous point until launch. Information about the calculated rendezvous point is entered into the headquarters in the previous period and is refined according to the movement parameters of the tracked targets during all flights. The rendezvous point, including the target coordinates, in the control areas with a certain inertial structure are entered into the anti-aircraft missile boards of the multifunctional radar stations. In this field, control teams are formed in parallel in the launch calculation machine of those anti-aircraft missiles. Here, too, the information obtained about the coordinates of the target by radio line is used in the control system. The last stage is the field of self-guidance, where the devices, which are considered the last stage of self-guidance, activate the dynamic form of the control system during the flight of anti-aircraft missiles in the direct approach of the missile to the target. Thus, energetic maneuvers are performed to eliminate target evasion. The destruction of the target takes place in two forms - by direct collision and by impacting the destruction elements of the anti-aircraft missile with the command of a non-contact detonator. Keywords: anti-aircraft, missile, radar, complex, defense, attack, radar.

Boon and burden: economic performance and future perspectives of the Venice flood protection system

Sea-level rise (SLR) and flooding are among the climate change stressors challenging human society in the twenty-first century. Many coastal areas and cities are implementing innovative solutions to mitigate flood risks and enhance resilience. Venice has recently developed a system of storm surge mobile barriers, known as the MoSE (Modulo Sperimentale Elettromeccanico or Experimental Electromechanical Module). This study aims to investigate the economic viability of MoSE operations in light of the potential future evolution of SLR. To conduct a cost-benefit analysis, a system dynamics model is utilised to assess the impact of MoSE operations on economic and residential activities of Venice and its port. Simulations are conducted until the end of the century, considering two SLR scenarios. The results suggest that the economic benefits largely outweigh the combined costs of investment and foregone port revenues resulting from the MoSE closures. Nevertheless, the increasing number of closures due to SLR seriously challenges the viability of the infrastructure in the medium to long term. Even more importantly, very frequent closures will have serious impacts on the quality of the lagoon ecosystem. These findings suggest a revision and stronger integration of the city’s safeguarding strategies, including the increase of the MoSE closure level officially set at 110 cm, and other coordinated interventions, such as sewer system consolidation.

Enhancing resilience of advanced power protection systems in smart grids against cyber–physical threats

AbstractRecently, smart grids introduce significant challenges to power system protection due to the high integration with distributed energy resources (DERs) and communication systems. To effectively manage the impact of DERs on power networks, researchers are actively formulating adaptive protection strategies, requiring robust communication schemes. However, concerns remain over the occurrence of communication connection failures and the potential risks presented by cyber‐attacks. This work addresses these challenges by investigating the impact of cyber‐attacks on different adaptive overcurrent relays (OCRs) approaches. Here, modern adaptive OCR coordination approaches using different group settings has integrated in evaluating high voltage/medium/low voltage (HV/MV/LV) network model with real network parameters at the MV/LV level. Additionally, a voltage‐based relay is developed and employed to enhance protection system performance under various cyber threats, aiming to reduce tripping time and to minimize energy that is not supplied. The results show that voltage‐based scheme outperform the traditional adaptive OCRs in terms of response time and mis coordination events under cyber‐attacks. In the proposed MV/LV real network scenario characterized by an 89% availability of a 4 MW photovoltaic system, even a brief interruption caused by cyber‐attacks can result in significant cost consequences.

Innovative probabilistic approach to reduce zone-2 time delay setting of distance relays

The time delay of distance relay zone-2 has considerable impacts on the protection system performance. Traditional deterministic techniques for adjustment of this parameter only consider the worst cases, even with a low probability of occurrence. This leads to the increment of the fault clearing time for most of the high-probability scenarios and endangers the system's stability. To diminish this issue and achieve a suitable tradeoff between protection system selectivity and operation time, a novel probabilistic framework is proposed in this paper for proper adjustment of zone-2 time delay. This framework includes two major parts; the fault and protection system are appropriately modeled in the first part, and then in the second part, the Monte Carlo method is employed as the computational engine for analyzing the system attributes under different conditions considering local and pilot protection schemes. Finally, two indices are proposed for the quantitative assessment of operation speed and selectivity of the protection system. The simulation studies fairly reveal that the operation speed of zone-2 is significantly improved using the proposed settings. In addition, the obtained results indicate that the proposed probabilistic approach not only improves the dependability, but also does not endanger the security of the protection system.

Cathodic protection systems: approaches and open challenges

Cathodic Protection System (CPS) is used on a variety of structures to prevent corrosion in ship hulls, pipelines, and underground storage tanks. Transmission pipelines extend over wide distances that may extend for hundreds of kilometers, the problem of corrosion exists in pipelines transporting liquids such as oil, petroleum or water, as well as in pipelines transporting gases. Corrosion leads to leakage into the surrounding environment, causing pollution. Artificial intelligence (AI) is used in risk management to determine the possibility of corrosion growth rates, considering all the determinants and factors that contribute to corrosion, including alternating currents, soil properties, environmental conditions, and geographical features. According to research, there are two ways to enhance the performance of cathodic protection systems: one is to design cathodic protection in unconventional ways based on different algorithms and methods that show superiority over the traditional method in determining the number and location of anodes, and the other is to continuously monitor the environmental conditions surrounding the structure to be protected, which includes soil and weather. A study will be conducted to determine the most effective factors in protecting the pipelines and other factors to determine the required energy in an efficient method.

Development of fragility models for process equipment affected by physical security attacks

The vulnerability of chemical and process facilities toward physical security attacks depends on the equipment resistance against such attacks and on the performance of Physical Protection Systems (PPS) in place. To enhance the protection against intentional attacks, the development of quantitative vulnerability metrics is essential, nevertheless current standard approaches only offer qualitative or semi-quantitative evaluations. The aim of the present work is to develop a quantitative methodology for the assessment of chemical and process facilities vulnerability towards external acts of interference. The proposed methodology is based both on the evaluation of equipment structural integrity in response to different types of specific impact vectors characterizing intentional attacks and on the quantitative performance assessment of related PPS. In particular, specific fragility models were developed for impact vectors associated with improvised explosive devices, firearms, and incendiary weapons. The novel fragility models were implemented in a comprehensive security vulnerability assessment (SVA) based on Bayesian Networks, in which the contribution of PPS performance was also considered. A case study was defined and analyzed to exemplify the application of the proposed approach. The results obtained allowed for the identification of the most critical security-related escalation scenarios and thus for an improved quantitative SVA.

COLLABORATIVE LIVING LABORATORIES TO INFORM CANADIAN DESIGN GUIDANCE FOR COASTAL NATURE-BASED SOLUTIONS

Nature-based solutions (NbS) have been widely applied for managing coastal flood and erosion risk (Bridges et al. 2021). However, they are underutilized in Canada, owing to a variety of factors including, e.g.: (i) uncertainty surrounding the performance of different nature-based solutions across Canada’s diverse coastal climates, geographies, and land uses; and (ii) the lack of authoritative, regionally appropriate design guidance (Vouk et al. 2021). The Nature-based Infrastructure for Coastal Resilience and Risk Reduction project is bringing together a multi-disciplinary team of Canadian researchers, practitioners, and community leaders to develop an improved understanding of the performance of nature-based shore protection systems in diverse Canadian coastal environments. The project involves conducting synchronized and coordinated parallel research activities – laboratory experiments, field monitoring, and numerical modelling – centered on multiple pilot sites along Canada’s Pacific and Atlantic coasts.

Analyzing the Effect of Lightning Channel Impedance on the Lightning Overvoltages in Wind Turbines

Lightning is a natural phenomenon that can cause serious damage to power systems including wind farms. Wind Turbines (WTs) are tall structures and are often installed in areas with high lightning activity levels which makes them exposed to direct strikes. One of the parameters affecting the performance of the lightning protection system is the impedance of the lightning channel. In this paper, the effects of this impedance on the lightning overvoltages in wind turbines, and the energy absorbed by Surge Arresters (SAs), as the main lightning protection device, are investigated. The case study is carried out on a WT with 2 MVA of rated power where a direct lightning strike with a maximum current magnitude of 50 kA is struck to one of the WT's blades. Accurate models, designed for transient studies, are used for modeling different parts of the WT. The results of different scenarios are compared, and it is shown that as the value of lightning channel impedance gets higher, the overvoltage caused by the corresponding lightning strike, with the same current magnitude, increases too. In addition, it is shown that the higher the lightning channel impedance, the higher the absorbed energy by the arrester. This shows the importance of the lightning channel impedance's effect on high-voltage studies of WTs, as it can help in selecting proper lightning protection devices.

Optimal protective relaying scheme of distributed generation connected distribution network using particle swarm optimization-gravitational search algorithm technique

<span lang="EN-US">This paper develops particle swarm optimization integrated with gravitational search algorithm (PSO-GSA) to coordinate the relays in a distribution system with distributed generation (DG) connectivity. This algorithm combines PSO and GSA to improve the performance of the relay protection system. To prevent relay malfunctions following DG penetration, a suitable primary and backup relay is chosen. The PSO-GSA is coded using MATLAB software and tested on an IEEE 4-bus system simulated in Simulink. Results indicate that, when compared to using regular PSO and GSA procedures individually, the PSO-GSA technique reduces the operating time of the relay significantly.</span>

A Study on the Sensitivities of an Ice Protection System Combining Thermoelectric and Superhydrophobic Coating to Icing Environment Parameters

The hybrid Ice Protection System combining thermoelectric and superhydrophobic coating is efficient and benefits from low-energy consumption. In order to explore the application details of superhydrophobic coating, this paper investigated the sensitivities of the Ice Protection System parameters including the range of the superhydrophobic coating, heating range and power to icing environmental parameters. In this paper, an icing wind tunnel test was adopted to study the performance of this Ice Protection System under different icing conditions, as well as the influence of the superhydrophobic coating range, heating range and power variation on ice protection. The results showed that the superhydrophobic coating is effective only when it covers the droplet impingement area, with the heating power requirement emerging as a critical design consideration that is extremely sensitive to environmental temperature changes. Additionally, median volumetric diameter determines the protection area to be protected, while liquid water content variation has little effect on the designed Ice Protection System in contrast.

Drought Resistance and Ginsenosides Biosynthesis in Response to Abscisic Acid in Panax ginseng C. A. Meyer.

Drought stress adversely affects the production of the perennial medicinal herb Panax ginseng C.A. Meyer. Phytohormone abscisic acid (ABA) regulates many processes in plant growth, development, and response to environments. However, whether drought resistance is regulated by ABA in Panax ginseng remains unknown. In this study, we characterized the response of drought resistance to ABA in Panax ginseng. The results showed that the growth retardation and root shrinking under drought conditions in Panax ginseng were attenuated by exogenous ABA application. Spraying ABA was shown to protect the photosynthesis system, enhance the root activity, improve the performance of the antioxidant protection system, and alleviate the excessive accumulation of soluble sugar in Panax ginseng under drought stress. In addition, ABA treatment leads to the enhanced accumulation of ginsenosides, the pharmaceutically active components, and causes the up-regulation of 3-hydroxy-3-methylglutaryl CoA reductase (PgHMGR) in Panax ginseng. Therefore, this study supports that drought resistance and ginsenosides biosynthesis in Panax ginseng were positively regulated by ABA, providing a new direction for mitigating drought stress and improving ginsenosides production in the precious medicinal herb.