There are the application scope limits for single differential-mode current injection test method, so in order to carry out injection susceptibility test for two-pieces equipment interconnected with both ends of a cab...There are the application scope limits for single differential-mode current injection test method, so in order to carry out injection susceptibility test for two-pieces equipment interconnected with both ends of a cable simultaneously, a double differential-mode current in- jection test method (DDMCI) is proposed. The method adopted the equivalence source wave theorem and Baum-Liu-Tesche(BLT) equation as its theory foundation. The equivalent corresponding relation between injection voltage and radiation electric field intensity is derived, and the phase relation between the two injection voltage sources is confirmed. The results indicate that the amplitude and phase of the equivalent injection voltage source is closely related to the S parameter of directional coupling device, the transmission line length, and the source vector in BLT equation, but has nothing to do with the reflection coefficient between the two equipment pieces. Therefore, by choosing the right amplitude and phase of the double injection voltage sources, the DDMCI test is equivalent to the radiation test for two interconnected equipment of a system.展开更多
The paper addresses the first eddy current benchmark problem proposed by the World Federation of Nondestructive Evaluation Centers (WFNDEC). The problem simulates the eddy current response to the presence of an axisym...The paper addresses the first eddy current benchmark problem proposed by the World Federation of Nondestructive Evaluation Centers (WFNDEC). The problem simulates the eddy current response to the presence of an axisymmetric circumferential defect in an Inconel-600 tube. All simulations employ the axisymmetric code of the electromagnetic field simulator Finite Element Method Magnetics. For three different frequencies of excitation, it is explained how the displacement of the detecting coil inside the tube leads to a variation in the impedance of the eddy current coil. Variations of the resistive and inductive components of the impedance with distance from the defect region are used to build the impedance trajectory for each frequency of analysis.展开更多
[目的]核电厂汽水管线一般在管道外壁加装保温层,从而提高换热效率。目前对于铁磁性管道的检测手段主要为常规超声及超声导波,检测前需要将管道外壁保温层拆除,导致检测工期延长,人力成本增加,无法达到核电厂高质量发展的要求。核电厂...[目的]核电厂汽水管线一般在管道外壁加装保温层,从而提高换热效率。目前对于铁磁性管道的检测手段主要为常规超声及超声导波,检测前需要将管道外壁保温层拆除,导致检测工期延长,人力成本增加,无法达到核电厂高质量发展的要求。核电厂脉冲涡流技术的应用可以省去保温层的拆装,实现不停机在线筛查。检测线圈的放置方式对缺陷的检出能力是脉冲涡流技术重要指标。[方法]文章利用ANSYS中的Maxwell模块进行管件建模及仿真,分别设计同轴式与垂直式检测线圈,保持提离距离、材料一致及其他条件一致下,模拟脉冲涡流对平底缺陷的检测能力。选取核电厂样管进行同轴式与垂直式脉冲涡流测试,将脉冲涡流(Pulsed Eddy Current Testing,PECT)测试结果与超声测厚进行复核,对比两种线圈放置方式对脉冲涡流检测的影响。[结果]研究表明:垂直式线圈相对于同轴式线圈对缺陷检出效果更佳。[结论]核电厂脉冲涡流技术的应用对脉冲涡流技术在核电领域实施具有重要意义。展开更多
This paper analyzes characteristics of multi type current transformers hybrid operation for each branch of the bus and their effects on differential protection of the bus. By theoretically analyzing transmission chara...This paper analyzes characteristics of multi type current transformers hybrid operation for each branch of the bus and their effects on differential protection of the bus. By theoretically analyzing transmission characteristics of multi type current transformers and their influence factors, we study the dynamic model testing method of multi type current transformers for the bus, and design 3 kinds of testing schemes by making the equivalent model based on the field of P-level current transformer, TPY-level current transformer and electronic current transformer, and build the hybrid operation testing platform of multi type current transformers. Finally, we compare and analyze the transmission characteristics difference of multi type current transformers on the same branch and the characteristics difference of hybrid operation in two successive external faults, analyze the cause behind the differences, and put forward the corresponding improvement measures.展开更多
基金Project supported by Arm Pre-research Program （51333040101）, National Defense 973 Program （6131380301 ）, National Natural Science Foundation of China （61040003）.
文摘There are the application scope limits for single differential-mode current injection test method, so in order to carry out injection susceptibility test for two-pieces equipment interconnected with both ends of a cable simultaneously, a double differential-mode current in- jection test method (DDMCI) is proposed. The method adopted the equivalence source wave theorem and Baum-Liu-Tesche(BLT) equation as its theory foundation. The equivalent corresponding relation between injection voltage and radiation electric field intensity is derived, and the phase relation between the two injection voltage sources is confirmed. The results indicate that the amplitude and phase of the equivalent injection voltage source is closely related to the S parameter of directional coupling device, the transmission line length, and the source vector in BLT equation, but has nothing to do with the reflection coefficient between the two equipment pieces. Therefore, by choosing the right amplitude and phase of the double injection voltage sources, the DDMCI test is equivalent to the radiation test for two interconnected equipment of a system.
文摘The paper addresses the first eddy current benchmark problem proposed by the World Federation of Nondestructive Evaluation Centers (WFNDEC). The problem simulates the eddy current response to the presence of an axisymmetric circumferential defect in an Inconel-600 tube. All simulations employ the axisymmetric code of the electromagnetic field simulator Finite Element Method Magnetics. For three different frequencies of excitation, it is explained how the displacement of the detecting coil inside the tube leads to a variation in the impedance of the eddy current coil. Variations of the resistive and inductive components of the impedance with distance from the defect region are used to build the impedance trajectory for each frequency of analysis.
文摘[目的]核电厂汽水管线一般在管道外壁加装保温层,从而提高换热效率。目前对于铁磁性管道的检测手段主要为常规超声及超声导波,检测前需要将管道外壁保温层拆除,导致检测工期延长,人力成本增加,无法达到核电厂高质量发展的要求。核电厂脉冲涡流技术的应用可以省去保温层的拆装,实现不停机在线筛查。检测线圈的放置方式对缺陷的检出能力是脉冲涡流技术重要指标。[方法]文章利用ANSYS中的Maxwell模块进行管件建模及仿真,分别设计同轴式与垂直式检测线圈,保持提离距离、材料一致及其他条件一致下,模拟脉冲涡流对平底缺陷的检测能力。选取核电厂样管进行同轴式与垂直式脉冲涡流测试,将脉冲涡流(Pulsed Eddy Current Testing,PECT)测试结果与超声测厚进行复核,对比两种线圈放置方式对脉冲涡流检测的影响。[结果]研究表明:垂直式线圈相对于同轴式线圈对缺陷检出效果更佳。[结论]核电厂脉冲涡流技术的应用对脉冲涡流技术在核电领域实施具有重要意义。
文摘This paper analyzes characteristics of multi type current transformers hybrid operation for each branch of the bus and their effects on differential protection of the bus. By theoretically analyzing transmission characteristics of multi type current transformers and their influence factors, we study the dynamic model testing method of multi type current transformers for the bus, and design 3 kinds of testing schemes by making the equivalent model based on the field of P-level current transformer, TPY-level current transformer and electronic current transformer, and build the hybrid operation testing platform of multi type current transformers. Finally, we compare and analyze the transmission characteristics difference of multi type current transformers on the same branch and the characteristics difference of hybrid operation in two successive external faults, analyze the cause behind the differences, and put forward the corresponding improvement measures.
