耐雷水平低、结构复杂的配网线路是电网防雷的薄弱环节,直击雷与感应雷极易导致雷电过电压,造成电气设备损坏与线路跳闸等恶性后果。近年来,新型防雷措施层出不穷,却存在着或使雷击跳闸率增加;或装置动作寿命短;或工程应用困难等诸多问...耐雷水平低、结构复杂的配网线路是电网防雷的薄弱环节,直击雷与感应雷极易导致雷电过电压,造成电气设备损坏与线路跳闸等恶性后果。近年来,新型防雷措施层出不穷,却存在着或使雷击跳闸率增加;或装置动作寿命短;或工程应用困难等诸多问题。笔者通过研究游离电弧在多细管制约条件下的质、能流量变化特性,发现压缩效应产生的自膨胀气流能加速高温电弧去游离,快速切断短路电弧,通过仿真与实验验证,分析了灭弧装置在实际线路的运行效果。得出结论:压缩效应能积聚大量自膨胀气流;实验与仿真电弧都在1000μs内可靠熄灭;灭弧装置在10 k V线路运行效果优异,雷击跳闸率大幅降低。展开更多
为分析多间隙纵吹灭弧系统（MGS）灭弧效果,通过建立纵吹气流耦合电弧的数学模型,分析计算了灭弧管道中温度、电流、压力等参数。为了验证计算结果的正确性及此系统的续流猝灭效率,选取了幅值2 k A的工频电流电弧、灭弧管道个数为20的...为分析多间隙纵吹灭弧系统（MGS）灭弧效果,通过建立纵吹气流耦合电弧的数学模型,分析计算了灭弧管道中温度、电流、压力等参数。为了验证计算结果的正确性及此系统的续流猝灭效率,选取了幅值2 k A的工频电流电弧、灭弧管道个数为20的灭弧装置进行试验验证。计算结果证明：弧柱能量分段及自膨胀灭弧气流的叠加作用对工频续流电弧暂态发展有深度抑制效果,在50μs左右电弧电流衰减至最低值10 A。试验结果表明：MGS能够促使工频电弧在130μs内基本完成衰减,重燃率几乎为零,证明了该自能式灭弧的有效性与可靠性。展开更多
The present study examines the results of the researches related to the gob bulking factor carried out at home and abroad.A mathematical function of a three-dimensional gob bulking factor is described based on a three...The present study examines the results of the researches related to the gob bulking factor carried out at home and abroad.A mathematical function of a three-dimensional gob bulking factor is described based on a three-dimensional gob model.The method of taking value for interstice and permeability ratios is also proposed.The law of air leakage of fully mechanized top coal is researched in this study.The results show that the speed of air flow near the upper and lower crossheadings is higher than that in the central section of the gob at the same distance from the working face.When the amount of air at the working face exceeds a critical amount,the width of the spontaneous combustion zone in the upper and lower crossheadings is also larger than that in the central section.In this situation,the key is preventing the coal left in the upper and lower crossheadings from self-igniting.Reducing the amount of air at the working face can decrease the width of the spontaneous combustion zone,especially the width near the upper and lower crossheadings.This also moves the spontaneous combustion zone in the direction of the working face.It can prevent the coal in the gob from self-igniting by making the coal left in the crossheadings to be inert and by effectively controlling the amount of air at the working face.展开更多
配网输电线路没有避雷线的保护,因此雷击造成感应过电压幅值大、作用范围广、雷击闪络概率高。为了改善配网线路雷击跳闸频繁的现状,设计出一种能连续、多次动作并长期运行的压缩灭弧间隙,对其产生自膨胀气流灭弧机理进行研究。设计并...配网输电线路没有避雷线的保护,因此雷击造成感应过电压幅值大、作用范围广、雷击闪络概率高。为了改善配网线路雷击跳闸频繁的现状,设计出一种能连续、多次动作并长期运行的压缩灭弧间隙,对其产生自膨胀气流灭弧机理进行研究。设计并完成了冲击电弧和工频电弧叠加作用下的灭弧实验。电弧的熄灭过程借助高速摄像机和示波器监测。结果表明,该灭弧间隙能在冲击电弧暂态发展初期对其能量分段,并于1.2 ms左右熄灭2 k A的工频电弧。该装置已应用于10kV配网线路上,验证了该装置的实用性。展开更多
文摘耐雷水平低、结构复杂的配网线路是电网防雷的薄弱环节,直击雷与感应雷极易导致雷电过电压,造成电气设备损坏与线路跳闸等恶性后果。近年来,新型防雷措施层出不穷,却存在着或使雷击跳闸率增加;或装置动作寿命短;或工程应用困难等诸多问题。笔者通过研究游离电弧在多细管制约条件下的质、能流量变化特性,发现压缩效应产生的自膨胀气流能加速高温电弧去游离,快速切断短路电弧,通过仿真与实验验证,分析了灭弧装置在实际线路的运行效果。得出结论:压缩效应能积聚大量自膨胀气流;实验与仿真电弧都在1000μs内可靠熄灭;灭弧装置在10 k V线路运行效果优异,雷击跳闸率大幅降低。
文摘为分析多间隙纵吹灭弧系统（MGS）灭弧效果,通过建立纵吹气流耦合电弧的数学模型,分析计算了灭弧管道中温度、电流、压力等参数。为了验证计算结果的正确性及此系统的续流猝灭效率,选取了幅值2 k A的工频电流电弧、灭弧管道个数为20的灭弧装置进行试验验证。计算结果证明：弧柱能量分段及自膨胀灭弧气流的叠加作用对工频续流电弧暂态发展有深度抑制效果,在50μs左右电弧电流衰减至最低值10 A。试验结果表明：MGS能够促使工频电弧在130μs内基本完成衰减,重燃率几乎为零,证明了该自能式灭弧的有效性与可靠性。
基金Financial support for this work was obtained from the National Natural Science Foundation of China(No.51074059)
文摘The present study examines the results of the researches related to the gob bulking factor carried out at home and abroad.A mathematical function of a three-dimensional gob bulking factor is described based on a three-dimensional gob model.The method of taking value for interstice and permeability ratios is also proposed.The law of air leakage of fully mechanized top coal is researched in this study.The results show that the speed of air flow near the upper and lower crossheadings is higher than that in the central section of the gob at the same distance from the working face.When the amount of air at the working face exceeds a critical amount,the width of the spontaneous combustion zone in the upper and lower crossheadings is also larger than that in the central section.In this situation,the key is preventing the coal left in the upper and lower crossheadings from self-igniting.Reducing the amount of air at the working face can decrease the width of the spontaneous combustion zone,especially the width near the upper and lower crossheadings.This also moves the spontaneous combustion zone in the direction of the working face.It can prevent the coal in the gob from self-igniting by making the coal left in the crossheadings to be inert and by effectively controlling the amount of air at the working face.
文摘配网输电线路没有避雷线的保护,因此雷击造成感应过电压幅值大、作用范围广、雷击闪络概率高。为了改善配网线路雷击跳闸频繁的现状,设计出一种能连续、多次动作并长期运行的压缩灭弧间隙,对其产生自膨胀气流灭弧机理进行研究。设计并完成了冲击电弧和工频电弧叠加作用下的灭弧实验。电弧的熄灭过程借助高速摄像机和示波器监测。结果表明,该灭弧间隙能在冲击电弧暂态发展初期对其能量分段,并于1.2 ms左右熄灭2 k A的工频电弧。该装置已应用于10kV配网线路上,验证了该装置的实用性。
