局部放电产生的脉冲电流宽度为纳秒级和亚纳秒级,而特高频（UHF）传感器接收的信号持续时间达到微秒级,因而接收信号出现失真现象。经理论分析,得出UHF传感器的群延迟不平坦和相位中心不稳定引起UHF信号的失真。以自行设计的Vivaldi天...局部放电产生的脉冲电流宽度为纳秒级和亚纳秒级,而特高频（UHF）传感器接收的信号持续时间达到微秒级,因而接收信号出现失真现象。经理论分析,得出UHF传感器的群延迟不平坦和相位中心不稳定引起UHF信号的失真。以自行设计的Vivaldi天线和微带天线作为样本,通过脉冲响应仿真和试验对以上两因素进行验证。并对110 k V预制故障的套管进行实验,研究不同UHF天线获得的信号与视在放电量的对应关系。结果表明：群延迟不平坦导致UHF信号的相位失真,相位中心不稳定导致幅度失真。利用群延迟平坦相位中心稳定的传感器获得的UHF信号与视在放电量的拟合优度从0.647提升至0.862。群延迟和相位中心可作为有效高度的补充参数对UHF传感器失真程度进行评价,为UHF传感器的设计和选型提供依据。展开更多
The instability of the pillar was discussed based on the potential energy principle and the cusp catastrophe theory, and a simplified mechanical model of the pillar was established considering the mining effect. The n...The instability of the pillar was discussed based on the potential energy principle and the cusp catastrophe theory, and a simplified mechanical model of the pillar was established considering the mining effect. The necessary-sufficient conditions, the jump value of displacement of pillar and the released energy expressions were deduced. The results show that the instability of the pillar is related to the properties of the rock, the external force and the relative stiffness of the elastic area to the plastic area. The instability of system is like to occur with the enlarging of the softening area or the decreasing of E/λ. The calculation done shows that the estimated results correspond to practical experience.展开更多
文摘局部放电产生的脉冲电流宽度为纳秒级和亚纳秒级,而特高频（UHF）传感器接收的信号持续时间达到微秒级,因而接收信号出现失真现象。经理论分析,得出UHF传感器的群延迟不平坦和相位中心不稳定引起UHF信号的失真。以自行设计的Vivaldi天线和微带天线作为样本,通过脉冲响应仿真和试验对以上两因素进行验证。并对110 k V预制故障的套管进行实验,研究不同UHF天线获得的信号与视在放电量的对应关系。结果表明：群延迟不平坦导致UHF信号的相位失真,相位中心不稳定导致幅度失真。利用群延迟平坦相位中心稳定的传感器获得的UHF信号与视在放电量的拟合优度从0.647提升至0.862。群延迟和相位中心可作为有效高度的补充参数对UHF传感器失真程度进行评价,为UHF传感器的设计和选型提供依据。
基金Project(50274074) supported by the National Natural Science Foundation of China
文摘The instability of the pillar was discussed based on the potential energy principle and the cusp catastrophe theory, and a simplified mechanical model of the pillar was established considering the mining effect. The necessary-sufficient conditions, the jump value of displacement of pillar and the released energy expressions were deduced. The results show that the instability of the pillar is related to the properties of the rock, the external force and the relative stiffness of the elastic area to the plastic area. The instability of system is like to occur with the enlarging of the softening area or the decreasing of E/λ. The calculation done shows that the estimated results correspond to practical experience.
