大容量静态无功补偿装置(static var compensator,SVC)相控电抗器对站用低压直流电源影响问题特殊且严重。为深入了解SVC对厂站低压直流电源的影响,对某变电站SVC现场设备进行实测,进而对SVC及附近区域建立三维电磁场仿真模型。通过与...大容量静态无功补偿装置(static var compensator,SVC)相控电抗器对站用低压直流电源影响问题特殊且严重。为深入了解SVC对厂站低压直流电源的影响,对某变电站SVC现场设备进行实测,进而对SVC及附近区域建立三维电磁场仿真模型。通过与现场的实测值进行对比,并在实验室建立等比例模型验证仿真的等效性,在此基础上分析在电抗器敷设不同的屏蔽材料对直流电源电能质量改善情况以及带来的衍生问题。结果表明:大型SVC相控电抗器对厂站低压直流电源的影响已超过规程允许值,而敷设硅钢片、铝板、铁板均可有效降低干扰,并且带来的电感变化、发热等情况在可接受范围内。展开更多
Large amount of groundwater discharging from tunnel is likely to cause destruction of the ecological environment in the vicinity of the tunnel, thus an appropriate drainage criterion should be established to balance t...Large amount of groundwater discharging from tunnel is likely to cause destruction of the ecological environment in the vicinity of the tunnel, thus an appropriate drainage criterion should be established to balance the tunnel construction and groundwater.To assess the related problems, an limiting drainage standard ranging from 0.5 to 2.0 m3/(m·d) was suggested for mountain tunnels based on survey and comparative analysis. After that, for the purpose of verifying the rationality of the standard, a calculated formula for dewatering funnel volume caused by drainage was deduced on the basis of the groundwater dynamics and experience method.Furthermore, the equation about the relationship between water discharge and drawdown of groundwater table was presented. The permeability coefficient, specific yield and groundwater table value were introduced, and then combined with the above equation, the drawdown of groundwater table under the proposed limiting drainage criterion was calculated. It is shown that the proposed drainage standard can reach the purpose of protecting ecological environment under the following two conditions. One is the permeability coefficient ranges from 10-4 to 10-5 m/s and the specific yield ranges from 0.1 to 0.001. The other is the permeability coefficient varies from 10-6 to 10-8 m/s and the specific yield varies from 0.1 to 0.01. In addition, a majority of common geotechnical layers are involved in the above ranges. Thus, the proposed limiting drainage standard which ranges from 0.5 to 2.0 m3/(m·d) for mountain tunnel is reasonable.展开更多
文摘大容量静态无功补偿装置(static var compensator,SVC)相控电抗器对站用低压直流电源影响问题特殊且严重。为深入了解SVC对厂站低压直流电源的影响,对某变电站SVC现场设备进行实测,进而对SVC及附近区域建立三维电磁场仿真模型。通过与现场的实测值进行对比,并在实验室建立等比例模型验证仿真的等效性,在此基础上分析在电抗器敷设不同的屏蔽材料对直流电源电能质量改善情况以及带来的衍生问题。结果表明:大型SVC相控电抗器对厂站低压直流电源的影响已超过规程允许值,而敷设硅钢片、铝板、铁板均可有效降低干扰,并且带来的电感变化、发热等情况在可接受范围内。
基金Projects(51078359,51208522,51208523)supported by the National Natural Science Foundation of ChinaProject(2010-122-009)supported by the Traffic Science and Technology Fund of Guizhou Province,ChinaProject(CX2011B098)supported by the Postgraduate Research Innovation Fund of Hunan Province,China
文摘Large amount of groundwater discharging from tunnel is likely to cause destruction of the ecological environment in the vicinity of the tunnel, thus an appropriate drainage criterion should be established to balance the tunnel construction and groundwater.To assess the related problems, an limiting drainage standard ranging from 0.5 to 2.0 m3/(m·d) was suggested for mountain tunnels based on survey and comparative analysis. After that, for the purpose of verifying the rationality of the standard, a calculated formula for dewatering funnel volume caused by drainage was deduced on the basis of the groundwater dynamics and experience method.Furthermore, the equation about the relationship between water discharge and drawdown of groundwater table was presented. The permeability coefficient, specific yield and groundwater table value were introduced, and then combined with the above equation, the drawdown of groundwater table under the proposed limiting drainage criterion was calculated. It is shown that the proposed drainage standard can reach the purpose of protecting ecological environment under the following two conditions. One is the permeability coefficient ranges from 10-4 to 10-5 m/s and the specific yield ranges from 0.1 to 0.001. The other is the permeability coefficient varies from 10-6 to 10-8 m/s and the specific yield varies from 0.1 to 0.01. In addition, a majority of common geotechnical layers are involved in the above ranges. Thus, the proposed limiting drainage standard which ranges from 0.5 to 2.0 m3/(m·d) for mountain tunnel is reasonable.
