This paper is devoted to predict AC loss of cable in conduit conductor （CICC） which is of importance in the design of conductors. The consideration for the conductor＇s design and main parameters for the magnets are...This paper is devoted to predict AC loss of cable in conduit conductor （CICC） which is of importance in the design of conductors. The consideration for the conductor＇s design and main parameters for the magnets are introduced. In order to attain a good accuracy in the calculation of AC losses, the field distribution within superconducting outsert should be considered. Calculation of the AC losses, including hysteresis losses and coupling losses, is conducted. An emphasis is put on the hysteresis loss during the ramp up of the current to the operational current （15.3 kA） and the coupling loss of the conductor in a power-down condition for insert. The results are obtained to be 74.9 kJ and 950 J for 40 T hybrid magnets, respectively. Based on the calculation, a brief analysis of losses effect on the conductor design and the operation of magnet is given for the purpose that the capacity of the cryogenertor can be evaluated and the stability regime can be improved in our future work on the hybrid magnets.展开更多
Insulated underground cables have the potential to reduce power outages, maintenance costs, and transmission losses compared to overhead lines.</span><span style="font-family:""> </span&g...Insulated underground cables have the potential to reduce power outages, maintenance costs, and transmission losses compared to overhead lines.</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">On the other hand, they are exposed to several risks and physical damages, since they are buried in the ground. Though the cables are armoured in order to provide mec</span><span style="font-family:Verdana;">hanical protection and achieve tensile strength, and also to provide effective conductance of earth fault currents.</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">The main purpose of this paper is to introduce insulated underground cables, armouring process, and to analyze the induced currents in metallic parts such as sheath and armour </span><span style="font-family:Verdana;">that causeohmic losses which are categorized mainly in two groups as circulating current and eddy current. This paper presents a review on analytical techniques used to analyze the effect of magnetic fields, andcalculate the losses in </span><span style="font-family:Verdana;">the armour of the cables,</span><span style="font-family:""> </span><span style="font-family:Verdana;">besides providing the strategies and solutions used for armour loss reduction.展开更多
We investigated the magnetocaloric effect in commercial Er_(2)O_(3) powders which presents almost no hysteresis losses at low temperature.At a magnetic field change of 5 T,it displays large magnetic entropy change(-Δ...We investigated the magnetocaloric effect in commercial Er_(2)O_(3) powders which presents almost no hysteresis losses at low temperature.At a magnetic field change of 5 T,it displays large magnetic entropy change(-ΔSM)max of 15.02 J/(kg·K)and a refrigerant capacity(RC)of 311 J/K at Neel temperature TN=3.32 K.The magnetic transition was found to be of a second-order.The maximum values of adiabatic temperature change(ΔTad)max reach 0.70 K for a magnetic field change of 1 T.The large value,of(-ASM)max as well as no hysteresis loss,makes Er_(2)O_(3) a promising material as a magnetic refrigerant at low temperature.展开更多
Total losses per cycle vs. frequency curves measured by some investigators for various metallic soft magnetic alloys exhibit obviously non-linearity below 500Hz, and have a considerable large anormalous loss. This is ...Total losses per cycle vs. frequency curves measured by some investigators for various metallic soft magnetic alloys exhibit obviously non-linearity below 500Hz, and have a considerable large anormalous loss. This is a common character of various soft magnetic alloys. Most of the investigators have thought that the origin of the non-展开更多
准确、快速地计算磁性材料在非正弦激励下的损耗是变压器、电机等电力设备优化设计的关键环节,特别是当其包含偏置小磁滞回环的情况。然而,在现有的文献中还没有高效系统地考虑偏置小磁滞回环的非正弦激励下磁性材料损耗的算法。从主磁...准确、快速地计算磁性材料在非正弦激励下的损耗是变压器、电机等电力设备优化设计的关键环节,特别是当其包含偏置小磁滞回环的情况。然而,在现有的文献中还没有高效系统地考虑偏置小磁滞回环的非正弦激励下磁性材料损耗的算法。从主磁滞回环与其内部偏置小磁滞回环相互独立的角度出发,分别计算这两种环对应的磁滞损耗与剩余损耗分量,并基于简化静态Preisach模型推导磁滞损耗的通用算式;针对损耗统计理论(statistical theory of losses,STL)剩余损耗统计参数提取较为繁琐的问题,利用简化动态Preisach模型与STL剩余损耗算式之间的函数关系,推导剩余损耗统计参数的通用辨识公式,继而提出一种考虑偏置小磁滞回环的磁性材料非正弦激励损耗算法。利用所提算法,仅需少量传统正弦激励下的数据即可辨识模型所有参数。最后,通过实验及仿真验证所提算法的准确性与实用性。展开更多
We have investigated the magnetic transition and magnetocaloric effects of Mn1＋xCo1-xGe alloys by tuning the ratio of Mn/Co. With increasing Mn content, a series of first-order magnetostructural transitions from ferr...We have investigated the magnetic transition and magnetocaloric effects of Mn1＋xCo1-xGe alloys by tuning the ratio of Mn/Co. With increasing Mn content, a series of first-order magnetostructural transitions from ferromagnetic to paramagnetic states with large changes of magnetization are observed at room temperature. Further increasing the content of Mn （x = 0.11） gives rise to a single second-order magnetic transition. Interestingly, large low-field magnetic entropy changes with almost zero magnetic hysteresis are observed in these alloys. The effects of Mn/Co ratio on magnetic transition and magnetocaloric effects are discussed in this paper.展开更多
文摘This paper is devoted to predict AC loss of cable in conduit conductor （CICC） which is of importance in the design of conductors. The consideration for the conductor＇s design and main parameters for the magnets are introduced. In order to attain a good accuracy in the calculation of AC losses, the field distribution within superconducting outsert should be considered. Calculation of the AC losses, including hysteresis losses and coupling losses, is conducted. An emphasis is put on the hysteresis loss during the ramp up of the current to the operational current （15.3 kA） and the coupling loss of the conductor in a power-down condition for insert. The results are obtained to be 74.9 kJ and 950 J for 40 T hybrid magnets, respectively. Based on the calculation, a brief analysis of losses effect on the conductor design and the operation of magnet is given for the purpose that the capacity of the cryogenertor can be evaluated and the stability regime can be improved in our future work on the hybrid magnets.
文摘Insulated underground cables have the potential to reduce power outages, maintenance costs, and transmission losses compared to overhead lines.</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">On the other hand, they are exposed to several risks and physical damages, since they are buried in the ground. Though the cables are armoured in order to provide mec</span><span style="font-family:Verdana;">hanical protection and achieve tensile strength, and also to provide effective conductance of earth fault currents.</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">The main purpose of this paper is to introduce insulated underground cables, armouring process, and to analyze the induced currents in metallic parts such as sheath and armour </span><span style="font-family:Verdana;">that causeohmic losses which are categorized mainly in two groups as circulating current and eddy current. This paper presents a review on analytical techniques used to analyze the effect of magnetic fields, andcalculate the losses in </span><span style="font-family:Verdana;">the armour of the cables,</span><span style="font-family:""> </span><span style="font-family:Verdana;">besides providing the strategies and solutions used for armour loss reduction.
文摘We investigated the magnetocaloric effect in commercial Er_(2)O_(3) powders which presents almost no hysteresis losses at low temperature.At a magnetic field change of 5 T,it displays large magnetic entropy change(-ΔSM)max of 15.02 J/(kg·K)and a refrigerant capacity(RC)of 311 J/K at Neel temperature TN=3.32 K.The magnetic transition was found to be of a second-order.The maximum values of adiabatic temperature change(ΔTad)max reach 0.70 K for a magnetic field change of 1 T.The large value,of(-ASM)max as well as no hysteresis loss,makes Er_(2)O_(3) a promising material as a magnetic refrigerant at low temperature.
文摘Total losses per cycle vs. frequency curves measured by some investigators for various metallic soft magnetic alloys exhibit obviously non-linearity below 500Hz, and have a considerable large anormalous loss. This is a common character of various soft magnetic alloys. Most of the investigators have thought that the origin of the non-
文摘准确、快速地计算磁性材料在非正弦激励下的损耗是变压器、电机等电力设备优化设计的关键环节,特别是当其包含偏置小磁滞回环的情况。然而,在现有的文献中还没有高效系统地考虑偏置小磁滞回环的非正弦激励下磁性材料损耗的算法。从主磁滞回环与其内部偏置小磁滞回环相互独立的角度出发,分别计算这两种环对应的磁滞损耗与剩余损耗分量,并基于简化静态Preisach模型推导磁滞损耗的通用算式;针对损耗统计理论(statistical theory of losses,STL)剩余损耗统计参数提取较为繁琐的问题,利用简化动态Preisach模型与STL剩余损耗算式之间的函数关系,推导剩余损耗统计参数的通用辨识公式,继而提出一种考虑偏置小磁滞回环的磁性材料非正弦激励损耗算法。利用所提算法,仅需少量传统正弦激励下的数据即可辨识模型所有参数。最后,通过实验及仿真验证所提算法的准确性与实用性。
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 50701022,51001019,and 50831006)the Program for New Century Excellent Talents of China (Grant No. NCET-08-0278)
文摘We have investigated the magnetic transition and magnetocaloric effects of Mn1＋xCo1-xGe alloys by tuning the ratio of Mn/Co. With increasing Mn content, a series of first-order magnetostructural transitions from ferromagnetic to paramagnetic states with large changes of magnetization are observed at room temperature. Further increasing the content of Mn （x = 0.11） gives rise to a single second-order magnetic transition. Interestingly, large low-field magnetic entropy changes with almost zero magnetic hysteresis are observed in these alloys. The effects of Mn/Co ratio on magnetic transition and magnetocaloric effects are discussed in this paper.
