Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound w...Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.展开更多
针对某220 k V变电站35 k V母线电压互感器高压熔丝频繁熔断现象,结合变电站的系统运行方式,通过对统计数据进行分析,逐步排除了二次消谐装置异常、熔丝过热等一系列因素;通过在35k VⅡ段母线加装电压电流监视装置,对电压电流信号进行...针对某220 k V变电站35 k V母线电压互感器高压熔丝频繁熔断现象,结合变电站的系统运行方式,通过对统计数据进行分析,逐步排除了二次消谐装置异常、熔丝过热等一系列因素;通过在35k VⅡ段母线加装电压电流监视装置,对电压电流信号进行录波分析,发现由于电压互感器抗饱和特性裕度不足,额定电流0.5 A熔丝抗电流扰动性能较差,导致熔丝频繁承受脉动过电压和脉动冲击电流,进而引起熔丝逐步受损熔断。最后结合研究结果提出合理的建议及改造方案,并通过试验验证了改造方案的可行性。展开更多
文摘Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.
基金a grant from National Natural Science Foundation of China (10671072)Doctoral Program Foundation of the Ministry of Education of China (20060269016)+1 种基金the National Basic Research Program (973 Program,2007CB814904) of Chinathe NSF of Anhui Educational Bureau (KJ2008B243)
文摘针对某220 k V变电站35 k V母线电压互感器高压熔丝频繁熔断现象,结合变电站的系统运行方式,通过对统计数据进行分析,逐步排除了二次消谐装置异常、熔丝过热等一系列因素;通过在35k VⅡ段母线加装电压电流监视装置,对电压电流信号进行录波分析,发现由于电压互感器抗饱和特性裕度不足,额定电流0.5 A熔丝抗电流扰动性能较差,导致熔丝频繁承受脉动过电压和脉动冲击电流,进而引起熔丝逐步受损熔断。最后结合研究结果提出合理的建议及改造方案,并通过试验验证了改造方案的可行性。
