Decision of Maintenance Priority of Power System Using an Improved Risk Priority Number Methodology Based on Fuzzy Theory

Author(s):  
Sung-Hun Lee ◽  
Byeong-Chan Oh ◽  
Sung-Yul Kim
2020 ◽  
Vol 12 (11) ◽  
pp. 168781402096692
Author(s):  
Po-Tuan Chen ◽  
Cheng-Jung Yang ◽  
K David Huang

A fuzzy control strategy is developed in this study to manage the parallel hybrid power system of internal combustion engine (ICE) and electric motor (EM) for hybrid vehicles. The rules established for the fuzzy logic are based on the conditions of vehicle pedal position, vehicle velocity, and the state of charge to control the throttle position of the ICE and the switch position of EM in low-, mid-, and high-power cruising. The optimization of the control strategy can make vehicles achieving ECE 40 driving pattern. In addition, the ICE can work in an optimal operation range, thus reducing carbon emission. The EM may provide power according to the demand, such that the torque output of the output shaft of the power split device is twice of the input of the two power sources separately.


Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xiaojun Wu ◽  
Jing Wu

The risk priority number (RPN) calculation method is one of the critical subjects of failure mode and effects analysis (FMEA) research. Recently, RPN research under a fuzzy uncertainty environment has become a hot topic. Accordingly, increasing studies have ignored the important impact of the random sampling uncertainty in the FMEA assessment. In this study, a fuzzy beta-binomial RPN evaluation method is proposed by integrating fuzzy theory, Bayesian statistical inference, and the beta-binomial distribution. This model can effectively realize real-time, dynamic, and long-term evaluation of RPN under the condition of continuous knowledge accumulation. The major contribution of the proposed model is to use the random uncertainty and fuzzy uncertainty in an integrated model and provide a Markov Chain Monte Carlo (MCMC) method to solve the complex integrated model. The study presented a case study, which presented how to apply this model in practice and indicated the significant influence on the measurement error caused by ignoring the random uncertainty caused by expert evaluation in RPN calculations.


2014 ◽  
Vol 1 (1) ◽  
pp. 5
Author(s):  
Gehao Sheng ◽  
Guangyu Tu ◽  
Yi Luo

<p>As one of the important constituents of power system automation, reactive power/voltage control possesses inherent characteristics of complexity, nonlinearity, inaccuracy and high requirement for control speed, parts of which are hard to be described by the traditional mathematical models or to be realized by routine control methods. The artificial intelligence (AI) techniques have intelligence feature which traditional method does not bear, so special attentions are paid to the application of AI techniques in reactive voltage control and a lot of results in this field are obtained. In this paper the main results and methods of applying the AI techniques, such as Expert System (ES), Artificial Neural Network (ANN), Fuzzy Theory (FT), Genetic Algorithm (GA) and Multi-Agent System (MAS), etc., to reactive voltage control in power systems are summarized, the respective application features of these techniques are analyzed and compared and some problems to be solved are pointed out.</p>


2013 ◽  
Vol 837 ◽  
pp. 16-21
Author(s):  
Nadia Belu ◽  
Daniel Constantin Anghel ◽  
Nicoleta Rachieru

Failure Mode and Effects Analysis is a methodology to evaluate a system, design, process, machine or service for possible ways in which failures (problems, errors, risks and concerns) can occur and it has been used in a wide range of industries. Traditional method uses a Risk Priority Number to evaluate the risk level of a component or process. This is obtained by finding the multiplication of three factors, which are the severity of the failure (S), the probability/occurrence of the failure (O), and the probability of not detecting the failure (D). There are significant efforts which have been made in FMEA literature to overcome the shortcomings of the crisp RPN calculation. Fuzzy logic appears to be a powerful tool for performing a criticality analysis on a system design and prioritizing failure identified in analisys FMEA for corrective actions. In this paper we present a parallel between the typical and the fuzzy computation of RPNs, in order to assess and rank risks associated to failure modes that could appear in the functioning of control equipment.


2016 ◽  
Vol 9 (2) ◽  
pp. 73-84
Author(s):  
He Tao ◽  
Liang Zhidong ◽  
Pang Jihong ◽  
Ye Xianquan ◽  
Yuan Jinxin

2014 ◽  
Vol 496-500 ◽  
pp. 2733-2736
Author(s):  
Fu Chao Zhang ◽  
Jia Dong Huang

This paper makes a grading of the probability of cascading failures using the theory of fuzzy C-means clustering to implement the level of risk assessment. Then from the perspective of power system transient security, use the specific severity functions to grade the probability of cascading failures, and the synthetical severity is graded by fuzzy theory. Finally, synthesizing the probability of cascading failures with the severity of failure, and the level of risk assessment is determined according to the principle of the maximum membership. Finally, taking IEEE 39 system for example, to assess the level of the risk of cascading failures in power grid, thus the rationality and effectiveness of the proposed algorithm are verified.


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