基于米氏散射理论,建立了光学元件基板不同疵病等级光学元件的散射模型,进而定量分析了元件表面存在粒子污染时的基板缺陷复制引起的表面散射特性。在此基础上,以R-C光学系统为例,利用ASAP(Advanced System Analysis Program)光学分析软...基于米氏散射理论,建立了光学元件基板不同疵病等级光学元件的散射模型,进而定量分析了元件表面存在粒子污染时的基板缺陷复制引起的表面散射特性。在此基础上,以R-C光学系统为例,利用ASAP(Advanced System Analysis Program)光学分析软件,针对主镜表面存在粒子污染的情况,仿真计算和分析系统主镜基板不同疵病等级的杂散辐射特性,并根据信噪比的计算方法,对系统信噪比进行了计算和分析。结果表明:当天空背景辐射温度不变时,随着主镜基板疵病等级的增加,系统信噪比明显减小。当主镜基板疵病等级不变时,随着天空背景辐射温度的升高,主镜基板不同疵病等级对信噪比的影响逐渐减小。当天空背景温度为200 K时,对于主镜表面粒子污染为300等级(粒子表面覆盖率为0.03%),且其基板疵病等级分别为Ⅰ-10、Ⅰ-20、Ⅰ-30、Ⅱ和Ⅲ五种情况,计算得到系统相对信噪比(相对于理想主镜)分别为0.932、0.920、0.906、0.832和0.807。由此可见,当元件光学特性变差时,为保证微弱信号的有效探测,必须将疵病等级严格控制在Ⅱ级以内。展开更多
Transient over voltages due to lightning and switching surges cause steep build-up of voltage on transmission lines and other electrical apparatus,like circuit breakers,transformers,insulators etc.Therefore it is nece...Transient over voltages due to lightning and switching surges cause steep build-up of voltage on transmission lines and other electrical apparatus,like circuit breakers,transformers,insulators etc.Therefore it is necessary for the GIS also to withstand such voltages without breakdown of Insulation.The system has to be tested under these conditions.Usually the GIS system operates on power frequency.Lightning Impulse Voltage of 1050 kV and Switching Impulse Voltage of 750 kV superimposed on Power frequency voltages of 75 kV,100 kV and 132 kV are applied to Single Phase Gas Insulated Busduct and the maximum movement of Aluminum,Copper and Silver particles is determined.The movement patterns are also determined with and without Monte Carlo Simulation for movement of particle in axial and radial directions.The results show that there is a sudden jump in the movement at the application of impulse on sine wave.This is because of high magnitude voltage of 1050 kV during 1.2/50 μs.Similar movement patterns of reduced maximum movement is observed for Switching Impulse superimposed on sine wave.The results are presented and analyzed.展开更多
文摘基于米氏散射理论,建立了光学元件基板不同疵病等级光学元件的散射模型,进而定量分析了元件表面存在粒子污染时的基板缺陷复制引起的表面散射特性。在此基础上,以R-C光学系统为例,利用ASAP(Advanced System Analysis Program)光学分析软件,针对主镜表面存在粒子污染的情况,仿真计算和分析系统主镜基板不同疵病等级的杂散辐射特性,并根据信噪比的计算方法,对系统信噪比进行了计算和分析。结果表明:当天空背景辐射温度不变时,随着主镜基板疵病等级的增加,系统信噪比明显减小。当主镜基板疵病等级不变时,随着天空背景辐射温度的升高,主镜基板不同疵病等级对信噪比的影响逐渐减小。当天空背景温度为200 K时,对于主镜表面粒子污染为300等级(粒子表面覆盖率为0.03%),且其基板疵病等级分别为Ⅰ-10、Ⅰ-20、Ⅰ-30、Ⅱ和Ⅲ五种情况,计算得到系统相对信噪比(相对于理想主镜)分别为0.932、0.920、0.906、0.832和0.807。由此可见,当元件光学特性变差时,为保证微弱信号的有效探测,必须将疵病等级严格控制在Ⅱ级以内。
文摘Transient over voltages due to lightning and switching surges cause steep build-up of voltage on transmission lines and other electrical apparatus,like circuit breakers,transformers,insulators etc.Therefore it is necessary for the GIS also to withstand such voltages without breakdown of Insulation.The system has to be tested under these conditions.Usually the GIS system operates on power frequency.Lightning Impulse Voltage of 1050 kV and Switching Impulse Voltage of 750 kV superimposed on Power frequency voltages of 75 kV,100 kV and 132 kV are applied to Single Phase Gas Insulated Busduct and the maximum movement of Aluminum,Copper and Silver particles is determined.The movement patterns are also determined with and without Monte Carlo Simulation for movement of particle in axial and radial directions.The results show that there is a sudden jump in the movement at the application of impulse on sine wave.This is because of high magnitude voltage of 1050 kV during 1.2/50 μs.Similar movement patterns of reduced maximum movement is observed for Switching Impulse superimposed on sine wave.The results are presented and analyzed.
