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Xin J.-B.,Jiangxi Electric Power Research Institute | Xin J.-B.,Nanchang University | Wan J.-B.,Jiangxi Electric Power Research Institute | Hu J.,Jiangxi Electric Power Research Institute | Li Q.-P.,Jiangxi Provincial Electrical Power Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2013

In practical power system, the safety assessment bases mainly on the "N-1" or "N-2" criterions. These criterions are somehow deterministic and thus may not reveal the underlying risk of the system in time and protect the system from large scale black out. It is therefore significant to carry out uncertainty based security risks assessment for power system short-term operation in a way that can practically support the power system maintenance and operation mode planning. This paper proposes a framework of short-term risk assessment system for the provincial power system, risk assessment models and methods are proposed considering the uncertainty of the health status and the external environment of power grid equipment, load fluctuations, and generation unit forced outages. Detailed functional designs of the system are described including the data management, risk assessment and identification of weak link. It provides technical support for decision making and optimization of provincial power grid mid/short term operation.

Yan J.-W.,Nanchang Institute of Technology | Luo L.,Nanchang Hangkong University | Zhang C.-S.,Nanchang Institute of Technology | Li Q.-P.,Jiangxi Provincial Electrical Power Company | And 3 more authors.
Gongneng Cailiao yu Qijian Xuebao/Journal of Functional Materials and Devices | Year: 2012

In recent years, as a kind of very potential application value of the new type of magnetostrictive materials, Fe-Ga alloy caused the people's extensive concern due to its excellent comprehensive performance. This paper summarized the research development of the Fe-Ga alloy composition, microstructure and properties. It is pointed out that the research focus and development direction.

Liu S.,Hubei Engineering University | Ruan J.,Hubei Engineering University | Peng Y.,Hubei Electric Power Company | Zhang Y.,Hubei Engineering University | Zhang Y.,Jiangxi Provincial Electrical Power Company
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010

This paper improved current filament method (CFM) which is commonly used in coil gun's circuit simulation. In the modified CFM, each excitation coil was divided into small sub-coils to improve calculation precision of inductance in equivalent electric network. In order to check the effect of the modification and analyze electromagnetic transient in coil gun launch, the field-circuit method for induction coil gun was introduced. The field model is built based on 3D composite grid method (CGM), CGM uses two sets of mutual independent grids to discretize solution region, the coarse grids discretize the global region and the fine grids discretize the moving part. In every time step, instead of remeshing it is only necessary to change the coordinates of nodes in fine girds. A three-stage coil gun's field-circuit model was built, by comparing the results of field-circuit model before and after the improvement of CFM, the validity of modification is proved. © 2010 Chinese Society for Electrical Engineering.

Liu S.-B.,Hubei Engineering University | Ruan J.-J.,Hubei Engineering University | Zhang Y.,Jiangxi Provincial Electrical Power Company | Du Z.-Y.,Hubei Engineering University | Huang D.-C.,Hubei Engineering University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010

Finite element governing equations of the conductor region and source current region were deduced based on magnetic vector potential/electric scalar potential formulations using the Coulomb gauge. Boundary element equations of free space were built on direct method. By introducing interface condition, the finite element and boundary element coupling method (FE-BECM) was realized in which boundary element matrix was equivalent to finite element matrix. In order to prove the validity of FE-BECM in eddy current problem and study modeling principle of the method, it was used to solve TEAM-7 problem. In the application of FE-BECM in moving conductor eddy current problem (MCEC), the source regions and moving components was discredited by finite elements, boundary elements were used to discretize the free space and associate finite element regions. When the position of moving components changed, it was only need to change the coordinate of nodes in moving region and all elements' shape kept invariant. The trouble of remeshing in normal finite element technique based on one set of grid was overcome in FE-BECM. The dynamic characteristics of a 3D coil gun model were calculated by FE-BECM. Numerical results obtained were compared with experimental data and results of 3D composite grid method (CGM), reasonable agreement was achieved and the efficiency of FE-BECM for such kind of problems was displayed. ©2010 Chin.Soc.for Elec.Eng.

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