多端柔性直流系统在分布式能源和直流负荷接入、网络柔性互联、电能质量等方面具有显著优势,成为未来电网的重要发展趋势。为了保证多端柔性直流系统安全稳定可靠运行,需要能够在数毫秒内开断故障电流的直流断路器。本文面向张北±5...多端柔性直流系统在分布式能源和直流负荷接入、网络柔性互联、电能质量等方面具有显著优势,成为未来电网的重要发展趋势。为了保证多端柔性直流系统安全稳定可靠运行,需要能够在数毫秒内开断故障电流的直流断路器。本文面向张北±500 k V柔性直流电网示范工程的应用需求,开展了500 k V直流断路器原理研究与样机研制。首先,提出500 k V耦合负压换流型混合式直流断路器系统方案,给出其拓扑结构、工作原理和控制逻辑;进而,设计基于电磁斥力操动机构和电磁缓冲机构的快速机械开关、基于二极管和复合被动保护支路的交叉桥式电力电子开关和基于耦合负压电路的换流装置等;最后,研制500 k V耦合负压换流型混合式直流断路器工程样机进行实验验证。研究结果表明,研制的100 k V混合式直流断路器能够在3 ms开断25 k A短路电流,具有低损耗、低成本、高可靠性等特点,相关成果已经过实验验证。展开更多
There were differences between real boundary and blast hole controlling boundary of irregular mined-out area in underground metal mines. There were errors in numerical analysis of stability for goaf, if it was analyze...There were differences between real boundary and blast hole controlling boundary of irregular mined-out area in underground metal mines. There were errors in numerical analysis of stability for goaf, if it was analyzed as regular 3D mined-out area and the influence of coupling stress-seepage-disturbance was not considered adequately. Taking a lead zinc mine as the background, the model was built by the coupling of Surpac and Midas-Gts based on the goaf model precisely measured by CMS.According to seepage stress fundamental equations based on the equivalent continuum mechanical and the theory about equivalent load of dynamic disturbance in deep-hole blasting, the stability of mined-out area under multi-field coupling of stress-seepage-dynamic disturbance was numerically analyzed. The results show that it is more consistent between the numerical analysis model based on the real model of irregular 3D shape goaf and the real situation, which could faithfully reappear the change rule of stress–strain about the surrounding rock under synthetic action of blasting dynamic loading and the seepage pressure. The mined-out area multi-field coupling formed by blasting excavation is stable. Based on combination of the advantages of the CMS,Surpac and Midas-Gts, and fully consideration of the effects of multi-field coupling, the accurate and effective way could be provided for numerical analysis of stability for mined-out area.展开更多
The model of pressure solution for granular aggregate was introduced into the FEM code for analysis of thermo-hydro- mechanical （T-H-M） coupling in porous medium. Aiming at a hypothetical nuclear waste repository in...The model of pressure solution for granular aggregate was introduced into the FEM code for analysis of thermo-hydro- mechanical （T-H-M） coupling in porous medium. Aiming at a hypothetical nuclear waste repository in an unsaturated quartz rock mass, two computation conditions were designed： 1） the porosity and the permeability of rock mass are fimctions of pressure solution; 2） the porosity and the permeability are constants. Then the corresponding numerical simulations for a disposal period of 4 a were carried out, and the states of temperatures, porosities and permeabilities, pore pressures, flow velocities and stresses in the rock mass were investigated. The results show that at the end of the calculation in Case 1, pressure solution makes the porosities and the permeabilities decrease to 10%-45% and 0.05%-1.4% of their initial values, respectively. Under the action of the release heat of nuclear waste, the negative pore pressures both in Case 1 and Case 2 are 1.2-1.4 and 1.01-l.06 times of the initial values, respectively. So, the former represents an obvious effect of pressure solution. The magnitudes and distributions of stresses within the rock mass in the two calculation cases are the same.展开更多
文摘多端柔性直流系统在分布式能源和直流负荷接入、网络柔性互联、电能质量等方面具有显著优势,成为未来电网的重要发展趋势。为了保证多端柔性直流系统安全稳定可靠运行,需要能够在数毫秒内开断故障电流的直流断路器。本文面向张北±500 k V柔性直流电网示范工程的应用需求,开展了500 k V直流断路器原理研究与样机研制。首先,提出500 k V耦合负压换流型混合式直流断路器系统方案,给出其拓扑结构、工作原理和控制逻辑;进而,设计基于电磁斥力操动机构和电磁缓冲机构的快速机械开关、基于二极管和复合被动保护支路的交叉桥式电力电子开关和基于耦合负压电路的换流装置等;最后,研制500 k V耦合负压换流型混合式直流断路器工程样机进行实验验证。研究结果表明,研制的100 k V混合式直流断路器能够在3 ms开断25 k A短路电流,具有低损耗、低成本、高可靠性等特点,相关成果已经过实验验证。
基金Project(2012BAK09B02-05)supported by the National"Twelfth Five"Science and Technology Support Program,ChinaProject(51274250)supported by the National Natural Science Foundation of China+2 种基金Project(2013zzts057)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(11KF02)supported by the Research Fund of the State Key Laboratory of Coal Resources and Mine safety,CUMT,ChinaProject(2012M511417)supported by China Postdoctoral Science Foundation
文摘There were differences between real boundary and blast hole controlling boundary of irregular mined-out area in underground metal mines. There were errors in numerical analysis of stability for goaf, if it was analyzed as regular 3D mined-out area and the influence of coupling stress-seepage-disturbance was not considered adequately. Taking a lead zinc mine as the background, the model was built by the coupling of Surpac and Midas-Gts based on the goaf model precisely measured by CMS.According to seepage stress fundamental equations based on the equivalent continuum mechanical and the theory about equivalent load of dynamic disturbance in deep-hole blasting, the stability of mined-out area under multi-field coupling of stress-seepage-dynamic disturbance was numerically analyzed. The results show that it is more consistent between the numerical analysis model based on the real model of irregular 3D shape goaf and the real situation, which could faithfully reappear the change rule of stress–strain about the surrounding rock under synthetic action of blasting dynamic loading and the seepage pressure. The mined-out area multi-field coupling formed by blasting excavation is stable. Based on combination of the advantages of the CMS,Surpac and Midas-Gts, and fully consideration of the effects of multi-field coupling, the accurate and effective way could be provided for numerical analysis of stability for mined-out area.
基金Project(2010CB732101) supported by the National Basic Research Program of ChinaProject(51079145) supported by the National Natural Science Foundation of ChinaProject(2009BAK53B03) supported by the National Key Technology R&D Program of China
文摘The model of pressure solution for granular aggregate was introduced into the FEM code for analysis of thermo-hydro- mechanical （T-H-M） coupling in porous medium. Aiming at a hypothetical nuclear waste repository in an unsaturated quartz rock mass, two computation conditions were designed： 1） the porosity and the permeability of rock mass are fimctions of pressure solution; 2） the porosity and the permeability are constants. Then the corresponding numerical simulations for a disposal period of 4 a were carried out, and the states of temperatures, porosities and permeabilities, pore pressures, flow velocities and stresses in the rock mass were investigated. The results show that at the end of the calculation in Case 1, pressure solution makes the porosities and the permeabilities decrease to 10%-45% and 0.05%-1.4% of their initial values, respectively. Under the action of the release heat of nuclear waste, the negative pore pressures both in Case 1 and Case 2 are 1.2-1.4 and 1.01-l.06 times of the initial values, respectively. So, the former represents an obvious effect of pressure solution. The magnitudes and distributions of stresses within the rock mass in the two calculation cases are the same.
