Offshore structures will encounter serious environmental load, so it is important to study the structural system reliability and to evaluate the structural component safety rank. In this paper, the bracnch-and-bound m...Offshore structures will encounter serious environmental load, so it is important to study the structural system reliability and to evaluate the structural component safety rank. In this paper, the bracnch-and-bound method is adopted to search the main failure path, and the Ditlevsen bound method is used to calculate the system failure probability. The structure is then assessed by the fuzzy comprehensive assessment method, which evaluates the structural component safety rank. The ultimate equation of the tubular cross- section is analyzed on the basis of ultimate stregnth analysis. The influence of effect coefficients on the structural system failure probability is investigated, and basic results are obtained. A general program for spatial frame structures by means of the above method is developed, and verified by the numerical examples.展开更多
This paper proposes an assessment framework for branch parameter estimation of power systems,based on which the estimation accuracy can be improved and the estimation reliability can be ensured.The proposed framework ...This paper proposes an assessment framework for branch parameter estimation of power systems,based on which the estimation accuracy can be improved and the estimation reliability can be ensured.The proposed framework comprises three parts:1) Parameter credibility assessment to evaluate the credibility of original parameters in the case that their true values are unknown;2) estimation accuracy assessment to provide quantitative information about the validity of the estimation;3) parameter dominance assessment to find out the key parameters for the estimation.This framework can be incorporated into the conventional parameter estimation process easily such that the accuracy and reliability of the estimation are improved.The implementation problems are addressed in details.Tests are carried out on the IEEE 14-bus system,IEEE 30-bus system,and IEEE 300-bus system to show the correctness and effectiveness of the proposed assessment framework.展开更多
This paper proposes a branch-independence-based reliability assessment approach for transmission systems.The approach consists of branch decoupling and state-space partition techniques.By integrating an impact-increme...This paper proposes a branch-independence-based reliability assessment approach for transmission systems.The approach consists of branch decoupling and state-space partition techniques.By integrating an impact-increment-based reliability index calculation model and the proposed branch decoupling technique,a proportion of sampled contingency states no longer need to be analyzed using the time-consuming optimal power flow(OPF)algorithm.In this way,the technique speeds up the calculation of reliability indices.Since first-order contingency states have a high probability of being sampled,we propose a state-space partition technique to replace first-order contingency state simulation with first-order contingency state enumeration.Consequently,the calculation of reliability indices is further accelerated by avoiding a large amount of repetitive OPF analyses during simulation process without affecting reliability index accuracy.The validity and applicability of our approach are verified using the IEEE 118-bus and IEEE 145-bus systems.Numerical results indicate that the proposed approach can improve computational efficiency without decreasing accuracy.展开更多
文摘Offshore structures will encounter serious environmental load, so it is important to study the structural system reliability and to evaluate the structural component safety rank. In this paper, the bracnch-and-bound method is adopted to search the main failure path, and the Ditlevsen bound method is used to calculate the system failure probability. The structure is then assessed by the fuzzy comprehensive assessment method, which evaluates the structural component safety rank. The ultimate equation of the tubular cross- section is analyzed on the basis of ultimate stregnth analysis. The influence of effect coefficients on the structural system failure probability is investigated, and basic results are obtained. A general program for spatial frame structures by means of the above method is developed, and verified by the numerical examples.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50977047,51007041)
文摘This paper proposes an assessment framework for branch parameter estimation of power systems,based on which the estimation accuracy can be improved and the estimation reliability can be ensured.The proposed framework comprises three parts:1) Parameter credibility assessment to evaluate the credibility of original parameters in the case that their true values are unknown;2) estimation accuracy assessment to provide quantitative information about the validity of the estimation;3) parameter dominance assessment to find out the key parameters for the estimation.This framework can be incorporated into the conventional parameter estimation process easily such that the accuracy and reliability of the estimation are improved.The implementation problems are addressed in details.Tests are carried out on the IEEE 14-bus system,IEEE 30-bus system,and IEEE 300-bus system to show the correctness and effectiveness of the proposed assessment framework.
基金supported by the China Postdoctoral Science Foundation (No.2020TQ0222)。
文摘This paper proposes a branch-independence-based reliability assessment approach for transmission systems.The approach consists of branch decoupling and state-space partition techniques.By integrating an impact-increment-based reliability index calculation model and the proposed branch decoupling technique,a proportion of sampled contingency states no longer need to be analyzed using the time-consuming optimal power flow(OPF)algorithm.In this way,the technique speeds up the calculation of reliability indices.Since first-order contingency states have a high probability of being sampled,we propose a state-space partition technique to replace first-order contingency state simulation with first-order contingency state enumeration.Consequently,the calculation of reliability indices is further accelerated by avoiding a large amount of repetitive OPF analyses during simulation process without affecting reliability index accuracy.The validity and applicability of our approach are verified using the IEEE 118-bus and IEEE 145-bus systems.Numerical results indicate that the proposed approach can improve computational efficiency without decreasing accuracy.
