scholarly journals Risk Assessment for Alternating Current / Direct Current (AC/DC) Hybrid Systems with Renewables Penetration

2021 ◽  
Vol 2109 (1) ◽  
pp. 012002
Author(s):  
Ye Chen ◽  
Qiongqian Yang ◽  
Zhenting Li ◽  
Mengmeng Liu ◽  
Jianfeng Zhang ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Hybrid Systems ◽  
Power Flow ◽  
Sequential Monte Carlo ◽  
Assessment Method ◽  
Risk Level ◽  
Test Case ◽  
Sequential Monte Carlo Method ◽  
Actual Operation ◽  
Power Grid Planning

Abstract In this paper, a risk assessment method is proposed for AC/DC hybrid systems with renewables penetration, considering the effect of renewables penetration and the application of DC transmission. The sequential Monte Carlo method is introduced to simulate the output of renewables generators, and the unified iterative method is used to solve the problem of AC/DC hybrid system power flow calculation. By establishing the quantized risk assessment indices, the risk of AC/DC hybrid systems with renewables penetration can be analysed. The results of EPRI of China 6-machine-22-bus Test case show that the proposed method can effectively evaluate the risk level of AC/DC hybrid systems with renewable energy penetration and provide reference for power grid planning and the actual operation in advance.

scholarly journals Biological risk assessment: A challenge for occupational health and safety practitioners during the COVID-19 (SARS-CoV-2) Pandemic

Work ◽  
2021 ◽  
pp. 1-11
Author(s):  
Carlos Carvalhais ◽  
Micaela Querido ◽  
Cristiana C. Pereira ◽  
Joana Santos
Keyword(s):  
Risk Assessment ◽  
Occupational Safety ◽  
Assessment Method ◽  
Occupational Safety And Health ◽  
Risk Level ◽  
Biological Risk ◽  
Occupational Risks ◽  
Qualitative Risk Assessment ◽  
Safety And Health ◽  
Medium Risk

BACKGROUND: The COVID-19 global pandemic brought several challenges to occupational safety and health practice. One of these is the need to (re)assess the occupational risks, particularly, biological risks. OBJECTIVE: The purpose of this work is to promote guidance to occupational safety and health practitioners when conducting a biological risk assessment in this context. METHODS: The main steps of the biological risk assessment are explained with some inputs regarding the novelty posed by SARS-CoV-2 and an example of a qualitative risk assessment method is presented. Also, its application to two different activities was exemplified. RESULTS: In both cases, the assessment considered that vulnerable workers were working from home or in medical leave. The results showed low or medium risk level for the assessed tasks. For medium risk level, additional controls are advised, such maintain social distancing, sanitize instruments/equipment before use, use proper and well-maintained PPE (when applicable), and promote awareness sessions to spread good practices at work. Employers must be aware of their obligations regarding biological risk assessment and OSH practitioners must be prepared to screen and link the abundance of scientific evidence generated following the outbreak, with the technical practice. CONCLUSIONS: This paper could be an important contribution to OSH practice since it highlights the need to (re)assess occupational risks, especially biological risk, to ensure a safe return to work, providing technical guidance.

A New Fine-Kinney Method Based on Clustering Approach

2020 ◽  
Vol 28 (03) ◽  
pp. 497-512
Author(s):  
Cansu Dagsuyu ◽  
Murat Oturakci ◽  
Esra Sarac Essiz
Keyword(s):  
Risk Assessment ◽  
Conventional Method ◽  
Clustering Algorithms ◽  
Assessment Method ◽  
Distance Functions ◽  
Risk Level ◽  
New Approach ◽  
Clustering Techniques ◽  
Risk Assessment Method ◽  
Clustering Approach

In this study, a new approach to Fine-Kinney risk assessment method is developed in order to overcome the limitations of the conventional method with clustering algorithms. New risk level of classes are attempted to determine with K-Means and Hierarchical clustering algorithms with using two different distance functions which are Euclidean and Manhattan distances. According to the results, K-Means algorithms have provided accurate and sensitive cluster of classes. Classes from conventional and K-Means algorithms are applied and compared to the identified risks of a workshop of a medium sized textile company. Results of the study indicate that clustering techniques are new, original and applicable way to define new classes in order to prioritize risks by overcoming the drawbacks of conventional Fine-Kinney method.

scholarly journals Risk Assessment of Boot Hydropower Projects in Nepal Using Fuzzy Logic Approach

2018 ◽  
Vol 3 ◽  
pp. 115
Author(s):  
Pramesh Tripathi ◽  
Santosh Kumar Shrestha
Keyword(s):  
Risk Assessment ◽  
Evaluation System ◽  
Risk Index ◽  
Assessment Method ◽  
Risk Level ◽  
Hydropower Project ◽  
Hydroelectric Project ◽  
Extreme Risk ◽  
Fuzzy Logic Approach ◽  
College Of Engineering

<p>Many Hydropower Projects in Nepal are carried out with insufficient risk assessment because of which time over run or variations are predominant. Many projects are stuck in preconstruction phase and others in construction phase. In this study all possible risks associated with the BOOT Hydropower Project in Nepal were identified and evaluated. Fuzzy rating tool has been used to quantify the risk associated with the BOOT Hydropower Projects in Nepal. It provides a flexible and easily understood way to analyze the project risks.  The relative importance (impact) of risk factors was determined from the survey results. A set of questionnaire was prepared for the survey. The survey was conducted with the experts that have experience in BOOT hydropower projects. From the survey, among the type of risks, Grid Connection / Power Evacuation, Political risk and Geological risk were found to be predominant risk respectively in BOOT hydropower projects in Nepal. The risk assessment method enabled a Risk Index (R) value to be calculated, establishing a 4-grade evaluation system: low risk having R values between 1.17 and 1.69; medium risk, between 1.69 and 2.08; high risk, between 2.08 and 2.47; extreme risk, between 2.47 and 2.78. Applicability of the methodology was tested on a real case hydropower project namely Middle Modi Hydroelectric Project (15.1 MW) which is in construction phase on Modi River in Western Region in Nepal and Madhya Bhotekosi Jalavidyut Company Ltd. (102 MW) which is also in construction phase on Bhotekoshi River in Central Region in Nepal.  The risk analysis method will give investors a more rational basis on which to make decisions and it can prevent cost and schedule overruns. An overall risk index can be used as early indicators of project problems or potential difficulties. Evaluators can keep track to evaluate the current risk level with the progress of investments.</p><p><strong>Journal of Advanced College of Engineering and Management</strong>, Vol. 3, 2017, Page: 115-125</p><p> </p>

scholarly journals A Dynamic Risk Assessment Method for Deep-Buried Tunnels Based on a Bayesian Network

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Yan Wang ◽  
Jie Su ◽  
Sulei Zhang ◽  
Siyao Guo ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Bayesian Network ◽  
Influencing Factors ◽  
Assessment Method ◽  
Assessment Model ◽  
Risk Level ◽  
Dynamic Risk ◽  
Risk Rating ◽  
Risk Assessment Method ◽  
Dynamic Risk Assessment

In view of the shortcomings in the risk assessment of deep-buried tunnels, a dynamic risk assessment method based on a Bayesian network is proposed. According to case statistics, a total of 12 specific risk rating factors are obtained and divided into three types: objective factors, subjective factors, and monitoring factors. The grading criteria of the risk rating factors are determined, and a dynamic risk rating system is established. A Bayesian network based on this system is constructed by expert knowledge and historical data. The nodes in the Bayesian network are in one-to-one correspondence with the three types of influencing factors, and the probability distribution is determined. Posterior probabilistic and sensitivity analyses are carried out, and the results show that the main influencing factors obtained by the two methods are basically the same. The constructed dynamic risk assessment model is most affected by the objective factor rating and monitoring factor rating, followed by the subjective factor rating. The dynamic risk rating is mainly affected by the surrounding rock level among the objective factors, construction management among the subjective factors, and arch crown convergence and side wall displacement among the monitoring factors. The dynamic risk assessment method based on the Bayesian network is applied to the No. 3 inclined shaft of the Humaling tunnel. According to the adjustment of the monitoring data and geological conditions, the dynamic risk rating probability of level I greatly decreased from 81.7% to 33.8%, the probability of level II significantly increased from 12.3% to 34.0%, and the probability of level III increased from 5.95% to 32.2%, which indicates that the risk level has risen sharply. The results show that this method can effectively predict the risk level during tunnel construction.

scholarly journals Dynamic Risk Assessment of Ultra-Shallow-Buried and Large-Span Double-Arch Tunnel Construction

2021 ◽  
Vol 11 (24) ◽  
pp. 11721
Author(s):  
Jianxiu Wang ◽  
Ansheng Cao ◽  
Zhao Wu ◽  
Zhipeng Sun ◽  
Xiao Lin ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Risk Evaluation ◽  
Assessment Method ◽  
Risk Level ◽  
Tunnel Excavation ◽  
Rock Reinforcement ◽  
Large Span ◽  
Dynamic Risk ◽  
Dynamic Risk Assessment ◽  
Assessment Result

Ultra-shallow-buried and large-span double-arch tunnels face complex risks during construction. The risk sources are hidden, complicated, and diverse. The dynamic risk assessment problem cannot be solved satisfactorily by using the static method as an insufficient amount of research has been conducted. The land part of the Xiamen Haicang double-arch tunnel was selected as the background for the dynamic risk assessment of ultra-shallow-buried and large-span double-arch tunnel construction. The construction process was divided into five stages: pre-construction preparation; ground and surrounding rock reinforcement; pilot tunnel excavation; and the single-and the double-tunnel excavations of the main tunnel. Through consultation with tunnel experts, six first-level and thirty second-level risk evaluation indexes were proposed. The benchmark weight of the dynamic risk assessment index was determined by using the analytic hierarchy process. The weight of the risk evaluation index was revised according to the monitoring data and the construction stage. The fuzzy evaluation matrix of the construction risk membership degree was obtained by using the fuzzy comprehensive assessment method, and the calculation results were analyzed using the subsection assignment method. Control measures were suggested according to the risk assessment results. The risk assessment result of the double tunnel excavation stage of the main tunnel was level II, and the risk level was the highest among the five construction stages. The risk assessment result of the ground and surrounding rock reinforcement stage was level IV, and the risk level was the lowest. The dynamic construction safety risk assessment based on the fuzzy comprehensive assessment method is more timely, accurate, and reasonable than the traditional assessment method. The method can be adopted in similar engineering projects.

scholarly journals The Risk Assessment of Debris Flow Hazards in Banshanmen Gully Based on the Entropy Weight-Normal Cloud Method

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
X. B. Gu ◽  
S. T. Wu ◽  
X. J. Ji ◽  
Y. H. Zhu
Keyword(s):  
Risk Assessment ◽  
Debris Flow ◽  
Cloud Model ◽  
Risk Estimation ◽  
Assessment Method ◽  
Risk Level ◽  
Entropy Weight ◽  
Entropy Weight Method ◽  
Weight Method ◽  
Index Weight

The debris flow is one of the geological hazards; its occurrence is complex, fuzzy, and random. And it is affected by many indices; a new multi-index assessment method is proposed to analyze the risk level of debris flow based on the entropy weight-normal cloud model in Banshanmen gully. The index weight is calculated by using the entropy weight method. Then, the certainty degree of each index belonging to the corresponding cloud is obtained by using the cloud model. The final risk level of debris flow is determined according to the synthetic certainty degree. The conclusions are drawn that the method is feasible and accurate rate of risk estimation for debris flow is very high, so a new method and thoughts for the risk assessment of debris flow can be provided in the future.

scholarly journals Study on Risk Assessment and Early Warning of Flood-Affected Areas when a Dam Break Occurs in a Mountain River

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1369 ◽  
Author(s):  
Qiang Fan ◽  
Zhong Tian ◽  
Wei Wang
Keyword(s):  
Risk Assessment ◽  
Early Warning ◽  
Assessment Method ◽  
Research Literature ◽  
Dam Break ◽  
Hydropower Station ◽  
Risk Level ◽  
Mountain River ◽  
Flood Level ◽  
Study Results

Under the influence of extreme weather conditions or other unfavorable factors, if a dam break occurs in a mountain river, it will cause a great number of casualties and property losses in the affected downstream areas. Usually, early warning of the affected areas downstream of the dam depends mainly on qualitative evaluation and cannot be quantitatively evaluated. Based on the authors’ calculation of floods for many years, this study presents a quantitative assessment method for flood risk. The Ertan Hydropower Station in Southwest China and the flood-affected areas were chosen as the object of this study. Based on field surveys, research literature data, and the authors’ calculations, the basic data of the Ertan Hydropower Station and the calculation results of the dam break were obtained, and 35 representative flood-affected areas were selected to study risk assessment and early warning. The fuzzy analytic hierarchy process (FAHP) was used to build a mathematical model for quantitative analysis. The population, flood arrival time, flood level, evacuation time, and local GDP (Gross Domestic Product) were selected as five typical evaluation factors. Finally, this study calculated and counted the risk level of 35 representative flood-affected areas, and the study results were applied to Quxue and Guanmaozhou Hydropower Station.

ANALISIS PENERAPAN KESELAMATAN KERJA DALAM UPAYA PENGENDALIAN KECELAKAAN KERJA DI PT. BUDI DWIYASA PERKASA

2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Farah Alhamid ◽  
Keyword(s):  
Risk Assessment ◽  
Hazard Analysis ◽  
Assessment Method ◽  
Hazard Identification ◽  
Risk Level ◽  
Protective Equipment ◽  
Risk Assessment Method ◽  
Accident Data ◽  
Plantation Company ◽  
Work Done

Abstract In conducting activities, many found workers who did not use personal protective equipment, do not pay attention to safety in work and work done like without procedure. PT. Budi Dwiyasa Perkasais a plantation company palm oil. Based on accident data obtained work, there are 14 case of accident in April until June 2016 in PT. Budi Dwiyasa Perkasa. A major factor cause of the accident is unsafe actions and unsafe conditions. Hazard analysis needs to be done in order to prevent the accident of work. Hazard identification done with using the risk assessment method. This analysis of the technique used to determine the level of the risk of a job is a combination of between the possibility of the harms caused by the severity of the caused. The result of hazard identification with this method is used in a kind of work to have a high risk level and need to address special in order to prevent the accident.

Risk Assessment of Reservoir by Fuzzy Comprehensive Evaluation Method Based on Information Entropy

2013 ◽  
Vol 438-439 ◽  
pp. 1612-1618
Author(s):  
Yong Jia Song ◽  
Cong Cong Jin ◽  
Xian Cai Zhang ◽  
Jing Li
Keyword(s):  
Risk Assessment ◽  
Information Entropy ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Assessment Method ◽  
Assessment Model ◽  
Risk Level ◽  
Entropy Weight ◽  
Weighting Method

This paper proposes a new risk assessment model on account of the fuzziness and uncertainty of risk factors in the reservoir after earthquake. The paper adopts methods of information entropy and fuzzy mathematics to assess risk level of the model. After analyzing the statistical data of earthquake-damaged reservoirs, we present comprehensive weight composed of importance and improved entropy weight. Base on comprehensive weight, we can adopt membership function to establish single factor evaluation of the model. Moreover, we combine fuzzy weighting method to assess risk level of a reservoir after earthquake. The result shows that risk level of the reservoir is high-risk. The case study verifies the practicability and rationality of the risk assessment method. Therefore, the method could be applied in the emergency rescue and reinforcement for reservoir after earthquake.

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