The prompt extinction of the secondary arc is critical to the single-phase reclosing of AC transmission lines, including half-wavelength power transmission lines. In this paper, a low- voltage physical experimental pl...The prompt extinction of the secondary arc is critical to the single-phase reclosing of AC transmission lines, including half-wavelength power transmission lines. In this paper, a low- voltage physical experimental platform was established and the motion process of the secondary arc was recorded by a high-speed camera. It was found that the arcing time of the secondary arc rendered a close relationship with its arc length. Through the input and output power energy analysis of the secondary arc, a new critical length criterion for the arcing time was proposed. The arc chain model was then adopted to calculate the arcing time with both the traditional and the proposed critical length criteria, and the simulation results were compared with the experimental data. The study showed that the arcing time calculated from the new critical length criterion gave more accurate results, which can provide a reliable criterion in term of arcing time for modeling and simulation of the secondary arc related with power transmission lines.展开更多
In this study, the transmission capacity of VANETs in a highway scenario is analysed on the basis of a 1D line model and the carrier sense multiple access with collision avoidance(CSMA/CA) protocol. We describe the CS...In this study, the transmission capacity of VANETs in a highway scenario is analysed on the basis of a 1D line model and the carrier sense multiple access with collision avoidance(CSMA/CA) protocol. We describe the CSMA/CA protocol used in IEEE802.11 p from the perspective of the geometric relationship amongst simultaneous transmitters. The desired channel and interfering channels are assumed to experience the same amount of path-loss and Rayleigh fading. On the basis of the proposed model, we analyse the attempted transmission probability of each road segment and the maximum intensity of active transmitters, including their theoretical values. Then, we employ the physical model to obtain the outage probability and derive the upper bound of the transmission capacity of a VANET, which is defined as the average spatial density of successful transmissions in the network. Simulation results indicate that the theoretical value offers a good bound on network capacity.展开更多
We present a time domain hybrid method to realize the fast coupling analysis of transmission lines excited by space electromagnetic fields, in which parallel finite-difference time-domain (FDTD) method, interpolation ...We present a time domain hybrid method to realize the fast coupling analysis of transmission lines excited by space electromagnetic fields, in which parallel finite-difference time-domain (FDTD) method, interpolation scheme, and Agrawal model-based transmission line (TL) equations are organically integrated together. Specifically, the Agrawal model is employed to establish the TL equations to describe the coupling effects of space electromagnetic fields on transmission lines. Then, the excitation fields functioning as distribution sources in TL equations are calculated by the parallel FDTD method through using the message passing interface (MPI) library scheme and interpolation scheme. Finally, the TL equations are discretized by the central difference scheme of FDTD and assigned to multiple processors to obtain the transient responses on the terminal loads of these lines. The significant feature of the presented method is embodied in its parallel and synchronous calculations of the space electromagnetic fields and transient responses on the lines. Numerical simulations of ambient wave acting on multi-conductor transmission lines (MTLs), which are located on the PEC ground and in the shielded cavity respectively, are implemented to verify the accuracy and efficiency of the presented method.展开更多
Output-pulse shaping capability of a linear transformer driver （LTD） module under different conditions is studied, by conducting the whole circuit model simulation by using the PSPICE code. Results indicate that a h...Output-pulse shaping capability of a linear transformer driver （LTD） module under different conditions is studied, by conducting the whole circuit model simulation by using the PSPICE code. Results indicate that a higher impedance profile of the internal transmission line would lead to a wider adjustment range for the output current rise time and a narrower adjustment range for the current peak. The number of cavities in series has a positive effect on the output- pulse shaping capability of LTD. Such an improvement in the output-pulse shaping capability can primarily be ascribed to the increment in the axial electric length of LTD. For a triggering time interval longer than the time taken by a pulse to propagate through the length of one cavity, the output parameters of LTD could be improved significantly. The present insulating capability of gas switches and other elements in the LTD cavities may only tolerate a slightly longer deviation in the triggering time interval. It is feasible for the LTD module to reduce the output current rise time, though it is not useful to improve the peak power effectively.展开更多
A whole circuit model of a linear transformer drivers （LTD） module composed of 60 cavities in series was developed in the software PSPICE to study the influence of switching jitter on the operational performances of...A whole circuit model of a linear transformer drivers （LTD） module composed of 60 cavities in series was developed in the software PSPICE to study the influence of switching jitter on the operational performances of LTDs. In the model, each brick in each cavity is capable of operating with jitter in its switch. Additionally, the manner of triggering cables entering into cavities was considered. The performances of the LTD module operating with three typical cavity-triggering sequences were simulated and the simulation results indicate that switching jitter affects slightly the peak and starting time of the output current pulse. However, the enhancement in switching jitter would significantly lengthen the rise time of the output current pulse. Without considering other factors, a jitter lower than 10 ns may be necessary for the switches in the LTD module to provide output current parameters with an acceptable deviation.展开更多
通信网络是输电线路在线监测系统的重要组成部分,关系到监测数据的完整性和安全性。由于现行通信网络在实际监测中的数据通信效果并不理想,吞吐量较低且丢包率较高,通信网络性能存在一定缺陷。为解决这一问题,文章提出基于5G的输电线路...通信网络是输电线路在线监测系统的重要组成部分,关系到监测数据的完整性和安全性。由于现行通信网络在实际监测中的数据通信效果并不理想,吞吐量较低且丢包率较高,通信网络性能存在一定缺陷。为解决这一问题,文章提出基于5G的输电线路在线监测通信网络设计。利用5G技术来设计输电线路在线监测的通信网络模型和信道,同时基于开放式系统互连(Open System Interconnect,OSI)参考模型来设计通信网络协议,从而完成基于5G的输电线路在线监测通信网络的整体设计。经实验验证,所设计的通信网络吞吐性能良好,丢包率在1%以下,输电线路在线监测通信效果良好。展开更多
基金supported by National Natural Science Foundation of China(Nos.51277061 and 51420105011)
文摘The prompt extinction of the secondary arc is critical to the single-phase reclosing of AC transmission lines, including half-wavelength power transmission lines. In this paper, a low- voltage physical experimental platform was established and the motion process of the secondary arc was recorded by a high-speed camera. It was found that the arcing time of the secondary arc rendered a close relationship with its arc length. Through the input and output power energy analysis of the secondary arc, a new critical length criterion for the arcing time was proposed. The arc chain model was then adopted to calculate the arcing time with both the traditional and the proposed critical length criteria, and the simulation results were compared with the experimental data. The study showed that the arcing time calculated from the new critical length criterion gave more accurate results, which can provide a reliable criterion in term of arcing time for modeling and simulation of the secondary arc related with power transmission lines.
基金supported in part by the National Natural Science Foundation of China under Grant No.61271184 and 61571065
文摘In this study, the transmission capacity of VANETs in a highway scenario is analysed on the basis of a 1D line model and the carrier sense multiple access with collision avoidance(CSMA/CA) protocol. We describe the CSMA/CA protocol used in IEEE802.11 p from the perspective of the geometric relationship amongst simultaneous transmitters. The desired channel and interfering channels are assumed to experience the same amount of path-loss and Rayleigh fading. On the basis of the proposed model, we analyse the attempted transmission probability of each road segment and the maximum intensity of active transmitters, including their theoretical values. Then, we employ the physical model to obtain the outage probability and derive the upper bound of the transmission capacity of a VANET, which is defined as the average spatial density of successful transmissions in the network. Simulation results indicate that the theoretical value offers a good bound on network capacity.
基金Project supported by the National Natural Science Foundation of China(Grant No.61701057)the Chongqing Research Program of Basic Research and Frontier Technology,China(Grant No.cstc2017jcyjAX0345).
文摘We present a time domain hybrid method to realize the fast coupling analysis of transmission lines excited by space electromagnetic fields, in which parallel finite-difference time-domain (FDTD) method, interpolation scheme, and Agrawal model-based transmission line (TL) equations are organically integrated together. Specifically, the Agrawal model is employed to establish the TL equations to describe the coupling effects of space electromagnetic fields on transmission lines. Then, the excitation fields functioning as distribution sources in TL equations are calculated by the parallel FDTD method through using the message passing interface (MPI) library scheme and interpolation scheme. Finally, the TL equations are discretized by the central difference scheme of FDTD and assigned to multiple processors to obtain the transient responses on the terminal loads of these lines. The significant feature of the presented method is embodied in its parallel and synchronous calculations of the space electromagnetic fields and transient responses on the lines. Numerical simulations of ambient wave acting on multi-conductor transmission lines (MTLs), which are located on the PEC ground and in the shielded cavity respectively, are implemented to verify the accuracy and efficiency of the presented method.
基金supported by National Natural Science Foundation of China (Nos. 50637010, 51077111)the State Key Laboratory of Electrical Insulation and Power Equipment of Xi'an Jiaotong University of China (EIPE 09207)
文摘Output-pulse shaping capability of a linear transformer driver （LTD） module under different conditions is studied, by conducting the whole circuit model simulation by using the PSPICE code. Results indicate that a higher impedance profile of the internal transmission line would lead to a wider adjustment range for the output current rise time and a narrower adjustment range for the current peak. The number of cavities in series has a positive effect on the output- pulse shaping capability of LTD. Such an improvement in the output-pulse shaping capability can primarily be ascribed to the increment in the axial electric length of LTD. For a triggering time interval longer than the time taken by a pulse to propagate through the length of one cavity, the output parameters of LTD could be improved significantly. The present insulating capability of gas switches and other elements in the LTD cavities may only tolerate a slightly longer deviation in the triggering time interval. It is feasible for the LTD module to reduce the output current rise time, though it is not useful to improve the peak power effectively.
基金supported partly by National Natural Science Foundation of China(Nos.50637010,51077111)partly by the State Key Laboratory of Electrical Insulation and Power Equipment of Xi'an Jiaotong University of China(EIPE09207)
文摘A whole circuit model of a linear transformer drivers （LTD） module composed of 60 cavities in series was developed in the software PSPICE to study the influence of switching jitter on the operational performances of LTDs. In the model, each brick in each cavity is capable of operating with jitter in its switch. Additionally, the manner of triggering cables entering into cavities was considered. The performances of the LTD module operating with three typical cavity-triggering sequences were simulated and the simulation results indicate that switching jitter affects slightly the peak and starting time of the output current pulse. However, the enhancement in switching jitter would significantly lengthen the rise time of the output current pulse. Without considering other factors, a jitter lower than 10 ns may be necessary for the switches in the LTD module to provide output current parameters with an acceptable deviation.
基金国家自然科学基金(52076013)北京市自然科学基金(3212024)2023年度中韩青年科学家交流计划,the Government of the Republicof Korea(Ministry of Science and ICT),and the National Research Foundation of Korea in 2023。
文摘通信网络是输电线路在线监测系统的重要组成部分,关系到监测数据的完整性和安全性。由于现行通信网络在实际监测中的数据通信效果并不理想,吞吐量较低且丢包率较高,通信网络性能存在一定缺陷。为解决这一问题,文章提出基于5G的输电线路在线监测通信网络设计。利用5G技术来设计输电线路在线监测的通信网络模型和信道,同时基于开放式系统互连(Open System Interconnect,OSI)参考模型来设计通信网络协议,从而完成基于5G的输电线路在线监测通信网络的整体设计。经实验验证,所设计的通信网络吞吐性能良好,丢包率在1%以下,输电线路在线监测通信效果良好。
