基于Pockels效应的光学电压传感器(Optical Voltage Transducer,OVT),运行中不可避免地存在震动、元器件连接的老化与热胀冷缩等问题,导致光学器件的相互位置产生偏移,进而影响电光晶体的内电场分布。文中以基于会聚偏光干涉原理的110 ...基于Pockels效应的光学电压传感器(Optical Voltage Transducer,OVT),运行中不可避免地存在震动、元器件连接的老化与热胀冷缩等问题,导致光学器件的相互位置产生偏移,进而影响电光晶体的内电场分布。文中以基于会聚偏光干涉原理的110 k V纵向调制的OVT为例,进行了仿真分析与实验研究,发现当入射光发生±0.5°的偏移或电光晶体发生±1°的偏移时,分别引入约0.107%和0.124%的电场积分误差。由于OVT必须满足0.2%的准确度要求,上述影响不容忽视。为此提出了介质包裹法,将Al2O3陶瓷包裹在电光晶体外部,使电场积分误差分别降低至0.001%和0.003%。实验与应用的情况表明,介质包裹法简单、实用、有效。展开更多
介绍光学电压互感器(optical voltage transducer,OVT)的原理,提出基于横向调制的110 kV电压等级OVT的初步结构设计,利用有限元电磁场软件对其内电场进行仿真。仿真结果表明,OVT内部某些部位的电场分布较为集中,影响晶体内电场的均匀性...介绍光学电压互感器(optical voltage transducer,OVT)的原理,提出基于横向调制的110 kV电压等级OVT的初步结构设计,利用有限元电磁场软件对其内电场进行仿真。仿真结果表明,OVT内部某些部位的电场分布较为集中,影响晶体内电场的均匀性。合理配置均压环和充入SF6绝缘气体可以减小场聚集效应,降低电场强度,改善晶体内电场的均匀性。最后,根据一系列仿真数据,设计了满足0.1级准确度,内电场最大电场强度仅为22.1 kV/cm的OVT结构,为下一步原理样机的研制提供参考。展开更多
光学电压互感器(Optical Voltage Transducer,OVT)是重要的电力系统测量设备。在使用过程中,因碰撞、连接不稳定或温度变化等问题,会导致传感光路或内部锗酸铋(BGO)晶体发生微小偏移。当偏移为0.5°时,所引起的最大积分电压误差可达...光学电压互感器(Optical Voltage Transducer,OVT)是重要的电力系统测量设备。在使用过程中,因碰撞、连接不稳定或温度变化等问题,会导致传感光路或内部锗酸铋(BGO)晶体发生微小偏移。当偏移为0.5°时,所引起的最大积分电压误差可达0.1%,这对于0.2%的标准要求而言是不可接受的。为了减小偏移带来的误差,并改善BGO晶体内电场的均匀性,文中针对110 kV纵向调制型OVT提出了一种方解石介质分层和氮化铝包裹法,两端采用Φ10 mm×75 mm的方解石对BGO晶体进行分压,并覆盖一层0.5 mm厚的氮化铝来避免与SF6气体直接接触。该结构模型成功解决了其他方法无法解决的晶体或者光路偏移导致的积分电压误差问题。根据仿真结果可知,其偏移误差降低至0.008%以下,并且通过实验所得到图像的标准差提高了35%以上,光强的分布均匀性得到了提高。仿真和实验结果均表明,这种优化改进方案显著提升了OVT的性能和稳定性,为电力系统的精准测量提供了可靠保障。展开更多
Covalent organic frameworks(COFs)are promising materials for converting solar energy into green hydrogen.However,limited charge separation and transport in COFs impede their application in the photocatalytic hydrogen ...Covalent organic frameworks(COFs)are promising materials for converting solar energy into green hydrogen.However,limited charge separation and transport in COFs impede their application in the photocatalytic hydrogen evolution reaction(HER).In this study,the intrinsically tunable internal bond electric field(IBEF)at the imine bonds of COFs was manipulated to cooperate with the internal molecular electric field(IMEF)induced by the donor-acceptor(D-A)structure for an efficient HER.The aligned orientation of IBEF and IMEF resulted in a remarkable H_(2) evolution rate of 57.3 mmol·g^(-1)·h^(-1)on TNCA,which was approximately 520 times higher than that of TCNA(0.11 mmol·g^(-1)·h^(-1))with the opposing electric field orientation.The superposition of the dual electric fields enables the IBEF to function as an accelerating field for electron transfer,kinetically facilitat-ing the migration of photogenerated electrons from D to A.Furthermore,theoretical calculations indicate that the inhomogeneous charge distribution at the C and N atoms in TNCA not only pro-vides a strong driving force for carrier transfer but also effectively hinders the return of free elec-trons to the valence band,improving the utilization of photoelectrons.This strategy of fabricating dual electric fields in COFs offers a novel approach to designing photocatalysts for clean energy synthesis.展开更多
基金jointly supported by the NNSF of China(60906042 and 61178003)the Yangchen Scholar Project(10B010D)+1 种基金the STPAA(10B001)of Guangzhou City,STP of Panyu Region(2010-D-09-1103004)Project of Academic Innovation Group of Guangzhou City(13C17)
文摘基于Pockels效应的光学电压传感器(Optical Voltage Transducer,OVT),运行中不可避免地存在震动、元器件连接的老化与热胀冷缩等问题,导致光学器件的相互位置产生偏移,进而影响电光晶体的内电场分布。文中以基于会聚偏光干涉原理的110 k V纵向调制的OVT为例,进行了仿真分析与实验研究,发现当入射光发生±0.5°的偏移或电光晶体发生±1°的偏移时,分别引入约0.107%和0.124%的电场积分误差。由于OVT必须满足0.2%的准确度要求,上述影响不容忽视。为此提出了介质包裹法,将Al2O3陶瓷包裹在电光晶体外部,使电场积分误差分别降低至0.001%和0.003%。实验与应用的情况表明,介质包裹法简单、实用、有效。
文摘介绍光学电压互感器(optical voltage transducer,OVT)的原理,提出基于横向调制的110 kV电压等级OVT的初步结构设计,利用有限元电磁场软件对其内电场进行仿真。仿真结果表明,OVT内部某些部位的电场分布较为集中,影响晶体内电场的均匀性。合理配置均压环和充入SF6绝缘气体可以减小场聚集效应,降低电场强度,改善晶体内电场的均匀性。最后,根据一系列仿真数据,设计了满足0.1级准确度,内电场最大电场强度仅为22.1 kV/cm的OVT结构,为下一步原理样机的研制提供参考。
文摘Covalent organic frameworks(COFs)are promising materials for converting solar energy into green hydrogen.However,limited charge separation and transport in COFs impede their application in the photocatalytic hydrogen evolution reaction(HER).In this study,the intrinsically tunable internal bond electric field(IBEF)at the imine bonds of COFs was manipulated to cooperate with the internal molecular electric field(IMEF)induced by the donor-acceptor(D-A)structure for an efficient HER.The aligned orientation of IBEF and IMEF resulted in a remarkable H_(2) evolution rate of 57.3 mmol·g^(-1)·h^(-1)on TNCA,which was approximately 520 times higher than that of TCNA(0.11 mmol·g^(-1)·h^(-1))with the opposing electric field orientation.The superposition of the dual electric fields enables the IBEF to function as an accelerating field for electron transfer,kinetically facilitat-ing the migration of photogenerated electrons from D to A.Furthermore,theoretical calculations indicate that the inhomogeneous charge distribution at the C and N atoms in TNCA not only pro-vides a strong driving force for carrier transfer but also effectively hinders the return of free elec-trons to the valence band,improving the utilization of photoelectrons.This strategy of fabricating dual electric fields in COFs offers a novel approach to designing photocatalysts for clean energy synthesis.
