Ultra-high voltage(UHV)transmission lines are an important part of China’s power grid and are often surrounded by a complex electromagnetic environment.The ground total electric field is considered a main electromagn...Ultra-high voltage(UHV)transmission lines are an important part of China’s power grid and are often surrounded by a complex electromagnetic environment.The ground total electric field is considered a main electromagnetic environment indicator of UHV transmission lines and is currently employed for reliable long-term operation of the power grid.Yet,the accurate prediction of the ground total electric field remains a technical challenge.In this work,we collected the total electric field data from the Ningdong-Zhejiang±800 kV UHVDC transmission project,as of the Ling Shao line,and perform an outlier analysis of the total electric field data.We show that the Local Outlier Factor(LOF)elimination algorithm has a small average difference and overcomes the performance of Density-Based Spatial Clustering of Applications with Noise(DBSCAN)and Isolated Forest elimination algorithms.Moreover,the Stacking algorithm has been found to have superior prediction accuracy than a variety of similar prediction algorithms,including the traditional finite element.The low prediction error of the Stacking algorithm highlights the superior ability to accurately forecast the ground total electric field of UHVDC transmission lines.展开更多
:A new accurate algorithms based on mathematical modeling of two parallel transmissions lines system(TPTLS)as influenced by the mutual effect to determine the fault location is discussed in this work.The distance rela...:A new accurate algorithms based on mathematical modeling of two parallel transmissions lines system(TPTLS)as influenced by the mutual effect to determine the fault location is discussed in this work.The distance relay measures the impedance to the fault location which is the positive-sequence.The principle of summation the positive-,negative-,and zero-sequence voltages which equal zero is used to determine the fault location on the TPTLS.Also,the impedance of the transmission line to the fault location is determined.These algorithms are applied to single-line-to-ground(SLG)and double-line-to-ground(DLG)faults.To detect the fault location along the transmission line,its impedance as seen by the distance relay is determined to indicate if the fault is within the relay’s reach area.TPTLS under study are fed from one-and both-ends.A schematic diagrams are obtained for the impedance relays to determine the fault location with high accuracy.展开更多
Audible noise from high voltage transmission lines’ corona discharge has become one of the decisive factors affecting design of high voltage transmission lines, thus it is very important to study the spatial propagat...Audible noise from high voltage transmission lines’ corona discharge has become one of the decisive factors affecting design of high voltage transmission lines, thus it is very important to study the spatial propagation characteristics of audible noise for its accurate pre- diction. A calculation model for the propagation of audible noise is presented in this paper, which is based on the basic equation of the sound wave and can involve the influences of the atmosphere absorption and ground effects. The effects of different ground impedances and the atmospheric attenuation on the distribution of sound pressure level are discussed in this paper. The results show that the atmospheric absorp- tion may increase the attenuation of the audible noise, and the ground surface affects both the amplitude and phase of the sound. The spatial distribution fluctuates considering the ground effects. The atmospheric attenuation and the ground effect are closely related to the frequency of the noise. In the frequency range of the audible noise, the influence of atmospheric attenuation on the spatial propagation characteristics is more obvious in high frequency while ground has significant influences in low frequency.展开更多
The amplitude of switching overvoltages is a key factor for designing the insulation of UHV equipment. The effect of different arresters needs to be studied, since installing arresters is an important way to suppress ...The amplitude of switching overvoltages is a key factor for designing the insulation of UHV equipment. The effect of different arresters needs to be studied, since installing arresters is an important way to suppress switching overvoltages in UHV transmission lines. Switching overvoltages on the 1000 kV Huainan-Huxi double-circuit transmission line were simulated for different operating modes and different arrester designs using the electromagnetic transient program PSCAD/EMTDC. With parallel resistors, the switching overvoltages are less than 1.70 p.u. （1.0 p.u.=1100×√ 2 /√3 kV）. If the arrestors are better, the switching overvoltages can be reduced even lower to 1.55 p.u. Without parallel resistors, the arresters can reduce three-phase energizing overvoltages to 1.70 p.u, while the single-phase reclosing overvoltages still exceed the limit. The results show that the parallel resistors cannot be eliminated if the arresters are only installed at each end of the transmission line. Also, better quality arresters significantly lower the switching overvoltages.展开更多
The analytical model of voltage-controlled MOS capacitance of tapered through silicon via （TSV） is derived. To capture the frequency-dependent behavior of tapered TSV, the conventional analytical equations of RLCG f...The analytical model of voltage-controlled MOS capacitance of tapered through silicon via （TSV） is derived. To capture the frequency-dependent behavior of tapered TSV, the conventional analytical equations of RLCG for two-wire transmission lines are revised. With the adoption of MOS capacitance model and the revised RLCG analytical equations, a transmission line-type electrical model for tapered TSV is proposed finally. All the proposed models are validated by simulation tools, and a good correlation is obtained between the proposed models and simulations up to 100 GHz. With the proposed model, both the semiconductor phenomenon and frequency- dependent behavior of tapered TSV can be fully captured at high frequency, and the performance of tapered TSV can be evaluated accurately and conveniently prior to 3D IC design.展开更多
基金funded by a science and technology project of State Grid Corporation of China“Comparative Analysis of Long-Term Measurement and Prediction of the Ground Synthetic Electric Field of±800 kV DC Transmission Line”(GYW11201907738)Paulo R.F.Rocha acknowledges the support and funding from the European Research Council(ERC)under the European Union’s Horizon 2020 Research and Innovation Program(Grant Agreement No.947897).
文摘Ultra-high voltage(UHV)transmission lines are an important part of China’s power grid and are often surrounded by a complex electromagnetic environment.The ground total electric field is considered a main electromagnetic environment indicator of UHV transmission lines and is currently employed for reliable long-term operation of the power grid.Yet,the accurate prediction of the ground total electric field remains a technical challenge.In this work,we collected the total electric field data from the Ningdong-Zhejiang±800 kV UHVDC transmission project,as of the Ling Shao line,and perform an outlier analysis of the total electric field data.We show that the Local Outlier Factor(LOF)elimination algorithm has a small average difference and overcomes the performance of Density-Based Spatial Clustering of Applications with Noise(DBSCAN)and Isolated Forest elimination algorithms.Moreover,the Stacking algorithm has been found to have superior prediction accuracy than a variety of similar prediction algorithms,including the traditional finite element.The low prediction error of the Stacking algorithm highlights the superior ability to accurately forecast the ground total electric field of UHVDC transmission lines.
文摘:A new accurate algorithms based on mathematical modeling of two parallel transmissions lines system(TPTLS)as influenced by the mutual effect to determine the fault location is discussed in this work.The distance relay measures the impedance to the fault location which is the positive-sequence.The principle of summation the positive-,negative-,and zero-sequence voltages which equal zero is used to determine the fault location on the TPTLS.Also,the impedance of the transmission line to the fault location is determined.These algorithms are applied to single-line-to-ground(SLG)and double-line-to-ground(DLG)faults.To detect the fault location along the transmission line,its impedance as seen by the distance relay is determined to indicate if the fault is within the relay’s reach area.TPTLS under study are fed from one-and both-ends.A schematic diagrams are obtained for the impedance relays to determine the fault location with high accuracy.
基金Project supported by National Basic Research Program of China (973 Program) (2011 CB209402)Fundamental Research Funds for the Central Universities(13XS07)
文摘Audible noise from high voltage transmission lines’ corona discharge has become one of the decisive factors affecting design of high voltage transmission lines, thus it is very important to study the spatial propagation characteristics of audible noise for its accurate pre- diction. A calculation model for the propagation of audible noise is presented in this paper, which is based on the basic equation of the sound wave and can involve the influences of the atmosphere absorption and ground effects. The effects of different ground impedances and the atmospheric attenuation on the distribution of sound pressure level are discussed in this paper. The results show that the atmospheric absorp- tion may increase the attenuation of the audible noise, and the ground surface affects both the amplitude and phase of the sound. The spatial distribution fluctuates considering the ground effects. The atmospheric attenuation and the ground effect are closely related to the frequency of the noise. In the frequency range of the audible noise, the influence of atmospheric attenuation on the spatial propagation characteristics is more obvious in high frequency while ground has significant influences in low frequency.
基金Supported by the National Natural Science Foundation of China(No. 50737001)
文摘The amplitude of switching overvoltages is a key factor for designing the insulation of UHV equipment. The effect of different arresters needs to be studied, since installing arresters is an important way to suppress switching overvoltages in UHV transmission lines. Switching overvoltages on the 1000 kV Huainan-Huxi double-circuit transmission line were simulated for different operating modes and different arrester designs using the electromagnetic transient program PSCAD/EMTDC. With parallel resistors, the switching overvoltages are less than 1.70 p.u. （1.0 p.u.=1100×√ 2 /√3 kV）. If the arrestors are better, the switching overvoltages can be reduced even lower to 1.55 p.u. Without parallel resistors, the arresters can reduce three-phase energizing overvoltages to 1.70 p.u, while the single-phase reclosing overvoltages still exceed the limit. The results show that the parallel resistors cannot be eliminated if the arresters are only installed at each end of the transmission line. Also, better quality arresters significantly lower the switching overvoltages.
基金Project supported by the National Defense Basic Scientific Research Program of China(No.A0320132012)
文摘The analytical model of voltage-controlled MOS capacitance of tapered through silicon via （TSV） is derived. To capture the frequency-dependent behavior of tapered TSV, the conventional analytical equations of RLCG for two-wire transmission lines are revised. With the adoption of MOS capacitance model and the revised RLCG analytical equations, a transmission line-type electrical model for tapered TSV is proposed finally. All the proposed models are validated by simulation tools, and a good correlation is obtained between the proposed models and simulations up to 100 GHz. With the proposed model, both the semiconductor phenomenon and frequency- dependent behavior of tapered TSV can be fully captured at high frequency, and the performance of tapered TSV can be evaluated accurately and conveniently prior to 3D IC design.
