通过直接估计输电线路电阻实现配电网电线网损评估功能,存在难以精准把握的问题,因而提出了将配电网输电线最高允许温度转化为有功功率损耗的限制,从而确立输电线短期热定值的方法。以输电线路热平衡方程中环境参量作为状态变量,根据输...通过直接估计输电线路电阻实现配电网电线网损评估功能,存在难以精准把握的问题,因而提出了将配电网输电线最高允许温度转化为有功功率损耗的限制,从而确立输电线短期热定值的方法。以输电线路热平衡方程中环境参量作为状态变量,根据输电线有功功率损耗与电阻、温度的耦合关系,推导出输电线有功功率损耗变化的微分方程,以此建立系统的量测方程;同时,考虑热平衡方程式参数变化的迟缓性,建立状态变量空间表达式;继而,依据输电线有功功率损耗变化率,采用卡尔曼滤波的方法,实现对状态变量的估计。由此,完成了配电网电线网损评估的功能,为配电网输电线短期最大电流运行方式是否可行提供了解决依据。以贵州省凯里某地区220 k V电网输电线的实测数据为例,验证了该方法的可行性与有效性。展开更多
Considering the defects of low accuracy and slow speed existing in traditional flood loss assessment, firstly, the technical route of flood loss assessment was presented based on the neural network ensemble. Secondly,...Considering the defects of low accuracy and slow speed existing in traditional flood loss assessment, firstly, the technical route of flood loss assessment was presented based on the neural network ensemble. Secondly, through the study of certain country of Poyang Lake district, the flood loss assessment indicators of the test area were analyzed and extracted by utilizing analytic hierarchy process (AHP), and the weights of the impact factors were assigned. Subsequently, the approaches to generate individuals and conclusions of neural network ensemble model were also investigated. In the platform of C# language and neural network library under AForge.NET open source, a flood loss assessment program which could rapidly build neural network ensemble models was developed. Finally, the proposed method was tested and verified. The comparison results between the assessment results of the proposed method and the actual statistical flood loss proved the feasibility of this method, thus a new approach for flood loss assessment was provided.展开更多
A real case of a steel lattice shell suffering a fire was studied. Based on the theory of field modeling, fire dynamic simulator (FDS) was used to identify the temperature field. The damage mechanism of the structure ...A real case of a steel lattice shell suffering a fire was studied. Based on the theory of field modeling, fire dynamic simulator (FDS) was used to identify the temperature field. The damage mechanism of the structure was determined by FEM analysis. After damage assessment, the shell was repaired with the pipe-encasement method. Finally, field test was employed to check the capacity of the structure after repair. The numerical study results indicate that the damage assessment agrees well with field inspection, verifying the accuracy of fire numerical simulation and FEM analysis. The field test results prove that the pipe-encasement method is secure and reasonable, and the repaired shell is safe.展开更多
文摘通过直接估计输电线路电阻实现配电网电线网损评估功能,存在难以精准把握的问题,因而提出了将配电网输电线最高允许温度转化为有功功率损耗的限制,从而确立输电线短期热定值的方法。以输电线路热平衡方程中环境参量作为状态变量,根据输电线有功功率损耗与电阻、温度的耦合关系,推导出输电线有功功率损耗变化的微分方程,以此建立系统的量测方程;同时,考虑热平衡方程式参数变化的迟缓性,建立状态变量空间表达式;继而,依据输电线有功功率损耗变化率,采用卡尔曼滤波的方法,实现对状态变量的估计。由此,完成了配电网电线网损评估的功能,为配电网输电线短期最大电流运行方式是否可行提供了解决依据。以贵州省凯里某地区220 k V电网输电线的实测数据为例,验证了该方法的可行性与有效性。
基金Project(41061041)supported by the National Natural Science Foundation of ChinaProject(2010gzs0084)supported by the Natural Science Foundation of Jiangxi Province,China
文摘Considering the defects of low accuracy and slow speed existing in traditional flood loss assessment, firstly, the technical route of flood loss assessment was presented based on the neural network ensemble. Secondly, through the study of certain country of Poyang Lake district, the flood loss assessment indicators of the test area were analyzed and extracted by utilizing analytic hierarchy process (AHP), and the weights of the impact factors were assigned. Subsequently, the approaches to generate individuals and conclusions of neural network ensemble model were also investigated. In the platform of C# language and neural network library under AForge.NET open source, a flood loss assessment program which could rapidly build neural network ensemble models was developed. Finally, the proposed method was tested and verified. The comparison results between the assessment results of the proposed method and the actual statistical flood loss proved the feasibility of this method, thus a new approach for flood loss assessment was provided.
基金Supported by National Natural Science Foundation of China (No. 50778122)
文摘A real case of a steel lattice shell suffering a fire was studied. Based on the theory of field modeling, fire dynamic simulator (FDS) was used to identify the temperature field. The damage mechanism of the structure was determined by FEM analysis. After damage assessment, the shell was repaired with the pipe-encasement method. Finally, field test was employed to check the capacity of the structure after repair. The numerical study results indicate that the damage assessment agrees well with field inspection, verifying the accuracy of fire numerical simulation and FEM analysis. The field test results prove that the pipe-encasement method is secure and reasonable, and the repaired shell is safe.
