Cable-in-conduit conductor (CICC) conductor sample of the PF2 coil for ITER was tested in the SULTAN facility. According to the test results, the CICC conductor sample exhibited a stable performance regarding the cu...Cable-in-conduit conductor (CICC) conductor sample of the PF2 coil for ITER was tested in the SULTAN facility. According to the test results, the CICC conductor sample exhibited a stable performance regarding the current sharing temperature. Under the typical operational conditions of a current of 45 kA, a magnetic field of 4 T and a temperature of 5 K for PF2, the test result for the conductor current sharing temperature is 6.71 K, with a temperature margin of 1.71 K. For a comparison thermal-hydraulic analysis of the PF2 conductor was carried out using GANDALF code in a 1-D model, and the result is consistent with the test one.展开更多
Corona discharge suppression for high-voltage direct-current(HVDC)transmission lines at line terminals such as converter stations is a subject that requires attention.In this paper,a method based on a conductor covere...Corona discharge suppression for high-voltage direct-current(HVDC)transmission lines at line terminals such as converter stations is a subject that requires attention.In this paper,a method based on a conductor covered with dielectric film is proposed and implemented through a bench-scale setup.Compared with the bare conductor,the corona discharge suppression effect of the dielectric-film-covered conductor under positive polarity is studied from the composite field strength and ion current density using a line-plate experimental device.The influences of film thickness and film material on the corona discharge suppression effect are investigated.The charge accumulation and dissipation characteristics of different film materials are also studied.The results show that the conductor covered with dielectric film has excellent ability to inhibit corona discharge.The ground-level composite field strength of the conductor covered with dielectric film is lower than its nominal field strength,and its ion current density is at the nA m^(−2) level.The corona threshold voltage can be promoted by increasing the film thickness,but the ability to inhibit corona discharge becomes weak.The larger the surface electric field strength,the more charge accumulated,but the faster the charge dissipation rate.Compared with polyvinyl chloride film,cross-linked polyethylene film has stronger charge accumulation ability and slower charge dissipation rate,which can better restrain the corona discharge of HVDC transmission lines.展开更多
In the flamework of the ITER qualification tests, the first China TF conductor sample (CNTF1) was tested at the SULTAN facility. The sample was made of two TF conductor sections manufactured from identical internal ...In the flamework of the ITER qualification tests, the first China TF conductor sample (CNTF1) was tested at the SULTAN facility. The sample was made of two TF conductor sections manufactured from identical internal stannum strands provided by the Oxford ~upercon- cluctlng technology company (OST). In order to evaluate the conductor performance, the current sharing temperature (Tcs) was measured at specified electromagnetic load cycling steps. Both conductor sections of the CNTF1 sample showed identical performance. Tcs was 7.2 K before cycling loading, and 6.9 K even after 950 cycles, without significant degradation, which substan- tially exceeds the ITER requirement of 5.7 K. The tests of the CNTF1 conductor sample showed that the electromagnetic cyclic load exhibited a negligible effect on the conductor performance. The coupling time constant 0 for AC loss was 214 ms and 71.52 nrs before and after the cycling load. respectively. The test results of the sample are compared with the strand performance and parameter model analysis.展开更多
Based on conventional static line rating method, the actual current carrying capability of overhead conductors cannot be judged. Due to continuous increment in electricity demand and the difficulties associated with n...Based on conventional static line rating method, the actual current carrying capability of overhead conductors cannot be judged. Due to continuous increment in electricity demand and the difficulties associated with new line constructions, the overhead lines are therefore required to be rated based on a method that should establish their real-time capability in terms of electricity transmission. The method used to determine the real-time ampacity of overhead conductors not only can enhance their transmission capacity but can also help in allowing excessive renewable generation in the electricity network. In this research work, the issues related to analyzing an impact of wind power on periodical loading of overhead line as well as finding its static and dynamic ampacities with line current are investigated in detail. Moreover, the investigation related to finding a suitable location for the construction of a 60 MW wind farm is taken on board. Thereafter, the wind park is integrated with a regional grid, owned by Fortum Distribution AB. In addition to that, the electricity generated from the wind park is also calculated in this project. Later on, the work is devoted to finding the static and dynamic line ratings for “VL3” overhead conductor by using IEEE-738-2006 standard. Furthermore, the project also deals with finding the line current and making its comparison with maximum capacity of overhead conductor (VL3) for loading it in such a way that no any violation of safe ground clearance requirements is observed at all. Besides, the line current, knowing the conductor temperature when it transmits the required electricity in the presence of wind power generation is also an important factor to be taken into consideration. Therefore, based on real-time ambient conditions with actual line loading and with the help of IEEE-738-2006 standard, the conductor temperature is also calculated in this project. At the end, an economic analysis is performed to evaluate the financial advantages related to applying the dynamic line ratings approach in place of traditional static line ratings technique across an overhead conductor (VL3) and to know how much beneficial it is to temporarily postpone the rebuilding and/or construction of a new transmission line. Furthermore, an economic analysis related to wind power system is taken into consideration as well to get familiar with the costs related to building and connecting a 60 MW wind farm with the regional grid.展开更多
The research of LTS/HTS hybrid conductor is a more recent topic in superconducting domain,and the current-sharing temperature is a key parameter to identify the characteristic of superconducting material.In this paper...The research of LTS/HTS hybrid conductor is a more recent topic in superconducting domain,and the current-sharing temperature is a key parameter to identify the characteristic of superconducting material.In this paper,based on the power-law model,the current-sharing temperatures for LTS and HTS were calculated respectively,and the calculated results have a good agreement with the existing equation results.The current-sharing temperature of a LTS/HTS hybrid superconducting conductor was numerically calculated.The calculated result of hybrid conductor shows that its current-sharing temperature can increase at least 0.2 K compared with typical LTS conductor with the same normalized transport current,so that the stability of this hybrid conductor is better than typical LTS supercondutor.It indicates that this LTS/HTS hybrid conductor as the substitutes of low-temperature superconductor,will have a wide application prospect and talent commercial value.展开更多
基金supported by the Priority Base Research Development Project of China (No. 0559730532)
文摘Cable-in-conduit conductor (CICC) conductor sample of the PF2 coil for ITER was tested in the SULTAN facility. According to the test results, the CICC conductor sample exhibited a stable performance regarding the current sharing temperature. Under the typical operational conditions of a current of 45 kA, a magnetic field of 4 T and a temperature of 5 K for PF2, the test result for the conductor current sharing temperature is 6.71 K, with a temperature margin of 1.71 K. For a comparison thermal-hydraulic analysis of the PF2 conductor was carried out using GANDALF code in a 1-D model, and the result is consistent with the test one.
基金by State Grid Shandong Electric Power Company(52062618001M)。
文摘Corona discharge suppression for high-voltage direct-current(HVDC)transmission lines at line terminals such as converter stations is a subject that requires attention.In this paper,a method based on a conductor covered with dielectric film is proposed and implemented through a bench-scale setup.Compared with the bare conductor,the corona discharge suppression effect of the dielectric-film-covered conductor under positive polarity is studied from the composite field strength and ion current density using a line-plate experimental device.The influences of film thickness and film material on the corona discharge suppression effect are investigated.The charge accumulation and dissipation characteristics of different film materials are also studied.The results show that the conductor covered with dielectric film has excellent ability to inhibit corona discharge.The ground-level composite field strength of the conductor covered with dielectric film is lower than its nominal field strength,and its ion current density is at the nA m^(−2) level.The corona threshold voltage can be promoted by increasing the film thickness,but the ability to inhibit corona discharge becomes weak.The larger the surface electric field strength,the more charge accumulated,but the faster the charge dissipation rate.Compared with polyvinyl chloride film,cross-linked polyethylene film has stronger charge accumulation ability and slower charge dissipation rate,which can better restrain the corona discharge of HVDC transmission lines.
文摘架空导线运行温度是电网系统的重要监测参数。文章提出一种基于鲸鱼优化算法(whaleoptimization algorithm,WOA)的架空导线温度计算方法。将架空导线温度值作为鲸鱼位置,利用IEEE标准计算对应的载流量,将其和额定载流量的差值作为适应度函数,通过迭代求解最优鲸鱼位置,作为最终的温度值计算结果。利用IEEE标准所提供的计算样例对所提方法进行有效性验证。实验对比WOA、粒子群优化算法(particleswarm optimization,PSO)和灰狼优化算法(grey wolf optimizer,GWO)3种启发式算法的性能,结果表明WOA算法的准确率相比PSO和GWO更高,对100组温度值计算结果的平均误差仅为0.00001℃,误差和仅为0.000982℃;同时WOA算法的运行时间更短,综合性能最优。
基金supported by the Major State Basic R,esearch Development, Program of China (973 program) (No. 0559730532)
文摘In the flamework of the ITER qualification tests, the first China TF conductor sample (CNTF1) was tested at the SULTAN facility. The sample was made of two TF conductor sections manufactured from identical internal stannum strands provided by the Oxford ~upercon- cluctlng technology company (OST). In order to evaluate the conductor performance, the current sharing temperature (Tcs) was measured at specified electromagnetic load cycling steps. Both conductor sections of the CNTF1 sample showed identical performance. Tcs was 7.2 K before cycling loading, and 6.9 K even after 950 cycles, without significant degradation, which substan- tially exceeds the ITER requirement of 5.7 K. The tests of the CNTF1 conductor sample showed that the electromagnetic cyclic load exhibited a negligible effect on the conductor performance. The coupling time constant 0 for AC loss was 214 ms and 71.52 nrs before and after the cycling load. respectively. The test results of the sample are compared with the strand performance and parameter model analysis.
文摘Based on conventional static line rating method, the actual current carrying capability of overhead conductors cannot be judged. Due to continuous increment in electricity demand and the difficulties associated with new line constructions, the overhead lines are therefore required to be rated based on a method that should establish their real-time capability in terms of electricity transmission. The method used to determine the real-time ampacity of overhead conductors not only can enhance their transmission capacity but can also help in allowing excessive renewable generation in the electricity network. In this research work, the issues related to analyzing an impact of wind power on periodical loading of overhead line as well as finding its static and dynamic ampacities with line current are investigated in detail. Moreover, the investigation related to finding a suitable location for the construction of a 60 MW wind farm is taken on board. Thereafter, the wind park is integrated with a regional grid, owned by Fortum Distribution AB. In addition to that, the electricity generated from the wind park is also calculated in this project. Later on, the work is devoted to finding the static and dynamic line ratings for “VL3” overhead conductor by using IEEE-738-2006 standard. Furthermore, the project also deals with finding the line current and making its comparison with maximum capacity of overhead conductor (VL3) for loading it in such a way that no any violation of safe ground clearance requirements is observed at all. Besides, the line current, knowing the conductor temperature when it transmits the required electricity in the presence of wind power generation is also an important factor to be taken into consideration. Therefore, based on real-time ambient conditions with actual line loading and with the help of IEEE-738-2006 standard, the conductor temperature is also calculated in this project. At the end, an economic analysis is performed to evaluate the financial advantages related to applying the dynamic line ratings approach in place of traditional static line ratings technique across an overhead conductor (VL3) and to know how much beneficial it is to temporarily postpone the rebuilding and/or construction of a new transmission line. Furthermore, an economic analysis related to wind power system is taken into consideration as well to get familiar with the costs related to building and connecting a 60 MW wind farm with the regional grid.
基金supported by the National Natural Science Foundation of China (51077051)the Specialized Research Fund for the Doctoral Program of Higher Education (D00033)the Doctoral Research Fund of North China Electric Power University (10QL27)
文摘The research of LTS/HTS hybrid conductor is a more recent topic in superconducting domain,and the current-sharing temperature is a key parameter to identify the characteristic of superconducting material.In this paper,based on the power-law model,the current-sharing temperatures for LTS and HTS were calculated respectively,and the calculated results have a good agreement with the existing equation results.The current-sharing temperature of a LTS/HTS hybrid superconducting conductor was numerically calculated.The calculated result of hybrid conductor shows that its current-sharing temperature can increase at least 0.2 K compared with typical LTS conductor with the same normalized transport current,so that the stability of this hybrid conductor is better than typical LTS supercondutor.It indicates that this LTS/HTS hybrid conductor as the substitutes of low-temperature superconductor,will have a wide application prospect and talent commercial value.