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In the ground wire-clamp system, aluminum armor tape (AAT) or armor rod (AR) is commonly adopted to avoid the wear damage of ground wire. While under the short-circuit current, damage or even breakage of ground wire in suspension clamp due to overheat may occur. However, there still lacks attention on the investigation about this type of damage. In this paper, a finite element (FE) modeling method of the ground wire-clamp system, which was applicable to two cases with AAT and AR, was proposed to discuss the transient thermal and mechanical behaviors. In the modeling of contact points, an improved contact bridge model considering the contact shape characteristics was proposed. The transient temperature rise experiments for ground wire-clamp systems with AAT and AR were carried out to verify the accuracy of models. The results shows that the improved contact bridge model is conducive to obtaining the accurate calculation results. For the analysis of this type of damage, the generated thermal stress cannot be ignored. In engineering, the ground wire twinned by AAT is at risk of overheat or even breakage under the short-circuit current, while using AR can prevent the ground wire in the suspension clamp from damage of overheat.
Gang Liu; Wencheng Zheng; Deming Guo; Ruidong Peng; Xuan Lin; Meishan Zhong. Numerical modeling and analysis of thermal and mechanical behavior for ground wire-clamp system under short-circuit current. Electric Power Systems Research 2021, 201, 107497 .
AMA StyleGang Liu, Wencheng Zheng, Deming Guo, Ruidong Peng, Xuan Lin, Meishan Zhong. Numerical modeling and analysis of thermal and mechanical behavior for ground wire-clamp system under short-circuit current. Electric Power Systems Research. 2021; 201 ():107497.
Chicago/Turabian StyleGang Liu; Wencheng Zheng; Deming Guo; Ruidong Peng; Xuan Lin; Meishan Zhong. 2021. "Numerical modeling and analysis of thermal and mechanical behavior for ground wire-clamp system under short-circuit current." Electric Power Systems Research 201, no. : 107497.
With the extensive integration of renewable energy sources in power system, the fluctuation characteristics of transmission and distribution network load have been further strengthened. However, for the power cable widely used in power system, its dynamic thermal behavior under continuously fluctuant load cannot be well modeled by the IEC method. It has not been sufficiently addressed in the literatures either. In this paper, the variation of the time-dependent Van Wormer coefficient and the error cumulative phenomenon of adopting the constant Van Wormer coefficient in conventional methods (including the IEC 60853-2 and the classical thermo-electric equivalent method) under continuously fluctuant cable load are discussed. Moreover, several different modification ways on the lumped thermal model of cable insulation to mitigate the possible error cumulative phenomenon are presented. The superiority of the modified methods compared with the conventional methods is verified by the real cable experiments. The results show that the modified methods can better reflect the cable's real thermal behavior under continuously fluctuant load. The modified methods are instructive for maximizing cable utilization while still ensuring cable reliability, which can be easy to be integrated into the existing real-time cable thermal rating system.
Pengyu Wang; Longyun Kang; Zhifeng Xu; Wenqing Zhou; Shuzhen Bao; Zhiheng Wu; Yanpeng Hao; Gang Liu. Dynamic thermal analysis for underground cables under continuously fluctuant load considering time-varying van wormer coefficient. Electric Power Systems Research 2021, 199, 107395 .
AMA StylePengyu Wang, Longyun Kang, Zhifeng Xu, Wenqing Zhou, Shuzhen Bao, Zhiheng Wu, Yanpeng Hao, Gang Liu. Dynamic thermal analysis for underground cables under continuously fluctuant load considering time-varying van wormer coefficient. Electric Power Systems Research. 2021; 199 ():107395.
Chicago/Turabian StylePengyu Wang; Longyun Kang; Zhifeng Xu; Wenqing Zhou; Shuzhen Bao; Zhiheng Wu; Yanpeng Hao; Gang Liu. 2021. "Dynamic thermal analysis for underground cables under continuously fluctuant load considering time-varying van wormer coefficient." Electric Power Systems Research 199, no. : 107395.
This paper proposes a risk-based contingency-constrained optimal power flow (OPF) model by leveraging the methods of both adjustable uncertainty set and distributionally robust optimization. In the proposed model, an adjustable uncertainty set of wind power is developed with network contingencies explicitly incorporated. Based on this uncertainty set, the proposed model is capable of securing the network against both wind power fluctuations and contingencies in a probabilistic manner with the optimal balance between operation cost and risk. Meanwhile, a data-driven L1-norm-based ambiguity set is employed so that the proposed model is distributionally robust to the ambiguous wind power distribution and applicable to cases where the exact wind distribution is not available. A decomposition-based algorithm is also derived so that the proposed model is solvable by off-the-shelf solvers. Numerical studies on IEEE 14- and 118-bus systems are conducted to verify the effectiveness of the proposed model.
Lei You; Hui Ma; Tapan Saha; G Liu. Risk-based Contingency-constrained Optimal Power Flow With Adjustable Uncertainty Set of Wind Power. IEEE Transactions on Industrial Informatics 2021, PP, 1 -1.
AMA StyleLei You, Hui Ma, Tapan Saha, G Liu. Risk-based Contingency-constrained Optimal Power Flow With Adjustable Uncertainty Set of Wind Power. IEEE Transactions on Industrial Informatics. 2021; PP (99):1-1.
Chicago/Turabian StyleLei You; Hui Ma; Tapan Saha; G Liu. 2021. "Risk-based Contingency-constrained Optimal Power Flow With Adjustable Uncertainty Set of Wind Power." IEEE Transactions on Industrial Informatics PP, no. 99: 1-1.
Long-distance high voltage alternating current (AC) submarine cables are widely used to connect offshore wind farms and land power grids. However, the transmission capacity of the submarine cable is limited by the capacitive charging current. This paper analyzes the impacts of reactive power compensation in different positions on the current distribution on long-distance submarine cable transmission lines, and tests the rationality of the existing reactive power compensation schemes based on electrothermal coordination (ETC). Research shows that compensation at the sending end has obvious impacts on current distribution along the cable, and the maximum current occurs at the sending or receiving end. Moreover, the reactive power compensation at sending end will reduce the current at receiving end of the line. On the contrary, it will increase the current at sending end. Compared with the directly buried laying method of the submarine cable in the landing section, the cable trench laying method can increase the cable ampacity of the landing section and reduce the reactive power compensation capacity at the sending end. The ampacity is the current representation of the thermal limits of the cable. ETC exploits the cable ampacity to coordinate current distribution on transmission lines under existing reactive power compensation schemes, thus optimizing the reactive power compensation schemes and avoiding the bottleneck point of cable ampacity.
Gang Liu; Mingming Fan; Pengyu Wang; Ming Zheng. Study on Reactive Power Compensation Strategies for Long Distance Submarine Cables Considering Electrothermal Coordination. Journal of Marine Science and Engineering 2021, 9, 90 .
AMA StyleGang Liu, Mingming Fan, Pengyu Wang, Ming Zheng. Study on Reactive Power Compensation Strategies for Long Distance Submarine Cables Considering Electrothermal Coordination. Journal of Marine Science and Engineering. 2021; 9 (1):90.
Chicago/Turabian StyleGang Liu; Mingming Fan; Pengyu Wang; Ming Zheng. 2021. "Study on Reactive Power Compensation Strategies for Long Distance Submarine Cables Considering Electrothermal Coordination." Journal of Marine Science and Engineering 9, no. 1: 90.
The silicone rubber is subjected to either the mechanical stress or the pulse voltage, making it is easier for initiation and development of electrical tree, which is the main reason for breakdown failure of cable joint. Studying the effect of electrical tree for breakdown failure of cable joint is the valid way to ensure the safety and stability of the cable system. In this paper, a breakdown failure case of 220 kV integral prefabricated silicone rubber cable joint with large expanding rate under closing overvoltage is discussed. Through dissection, it was found that there were electric trees inside the cable joint produced by factory C. Based on the failure characteristics, the mechanical stress model of the cable joint and the closing overvoltage model of the system were established to analyze the influencing factors of electric trees. Furthermore, some sample tests were carried out to discuss the relationship between material performance and electrical tree, including carbon black test, gel content test, thermogravimetric test, tensile test and volume resistivity. The results showed that the large circumferential stress would destroy the physical crosslinking of silicone rubber, leading to a decrease in tensile strength and volume resistivity. This was the main factor affecting the growth of electrical trees. Meanwhile the overvoltage and the poor material characteristics of cable joint would accelerate the growth rate of electrical trees. Eventually the breakdown failure of cable joint occurred when the electric trees running through both polarities. The analytical method and conclusions proposed in this paper can provide suggestions and guidance for the analysis of similar breakdown accidents in the future.
Yanqun Liao; Shuzhen Bao; Yue Xie; Yifeng Zhao; Pengyu Wang; Gang Liu; Baojun Hui; Yang Xu. Breakdown failure analysis of 220 kV cable joint with large expanding rate under closing overvoltage. Engineering Failure Analysis 2020, 120, 105086 .
AMA StyleYanqun Liao, Shuzhen Bao, Yue Xie, Yifeng Zhao, Pengyu Wang, Gang Liu, Baojun Hui, Yang Xu. Breakdown failure analysis of 220 kV cable joint with large expanding rate under closing overvoltage. Engineering Failure Analysis. 2020; 120 ():105086.
Chicago/Turabian StyleYanqun Liao; Shuzhen Bao; Yue Xie; Yifeng Zhao; Pengyu Wang; Gang Liu; Baojun Hui; Yang Xu. 2020. "Breakdown failure analysis of 220 kV cable joint with large expanding rate under closing overvoltage." Engineering Failure Analysis 120, no. : 105086.
With the increase in electricity demand, the ampacity calculation based on the dynamic thermal rating (DTR) technology is increasingly significant for assessing and improving the power transfer capacity of the existing overhead conductors. However, the DTR models now available present some inadequacies in measurement techniques related to wind speed. Therefore, it is essential to propose a new model instead of wind speed measuring in DTR technology. In this paper, the influence analysis of various weather parameters on the conductor ampacity is carried out by using the real weather data. Based on the analysis, it is confirmed that the impact of wind speed is significant, especially in the case of the low wind speed. Moreover, an equivalent heat transfer (EHT) model for DTR technology is proposed instead of wind speed measuring. For this EHT model, the calculation of conductor ampacity is realized through investigating the correlation of heat losses between the heating aluminum (Al) ball and conductor. Finally, combined with the finite element method (FEM), the EHT model proposed in this paper is verified by the Institute of Electrical and Electronic Engineers (IEEE) standard. The results indicate that the error of the EHT model is less than 6% when employing the steady thermal behavior of the Al ball to calculate the ampacity. The EHT model is useful in the real-time thermal rating of overhead conductors. It can increase the utilization of overhead conductors while also avoiding the limitation of the existing measurement techniques related to wind speed.
Zhao Liu; Honglei Deng; Ruidong Peng; Xiangyang Peng; Rui Wang; Wencheng Zheng; Pengyu Wang; Deming Guo; Gang Liu. An Equivalent Heat Transfer Model Instead of Wind Speed Measuring for Dynamic Thermal Rating of Transmission Lines. Energies 2020, 13, 4679 .
AMA StyleZhao Liu, Honglei Deng, Ruidong Peng, Xiangyang Peng, Rui Wang, Wencheng Zheng, Pengyu Wang, Deming Guo, Gang Liu. An Equivalent Heat Transfer Model Instead of Wind Speed Measuring for Dynamic Thermal Rating of Transmission Lines. Energies. 2020; 13 (18):4679.
Chicago/Turabian StyleZhao Liu; Honglei Deng; Ruidong Peng; Xiangyang Peng; Rui Wang; Wencheng Zheng; Pengyu Wang; Deming Guo; Gang Liu. 2020. "An Equivalent Heat Transfer Model Instead of Wind Speed Measuring for Dynamic Thermal Rating of Transmission Lines." Energies 13, no. 18: 4679.
In urban underground environment, a short-conduit is commonly used to provide mechanical protection for the cable. The cable section buried in the short-conduit may experience excessive thermal stresses. However, the thermal rating for the cable in the short-conduit is not specialized in the IEC 60287. It has not been sufficiently addressed in the literature either. This paper proposes a quasi-three-dimensional thermal model for the cable installed in the short-conduit. A simplified model for efficiently and effectively solving the proposed model is then developed. Based on the simplified thermal model, an improved method for assessing the real-time ampacity of the cable installed in the short-conduit is implemented. The performance of the improved method with respect to the IEC method on thermal rating for the cable installed in the short-conduit is verified by the Finite Element Analysis (FEA). The results show that the improved method outperforms the IEC method when the conduit length is less than five meters. The method is useful in real-time thermal rating of the short-conduit cables and paves a way to increase the utilization of cables installed in short-conduits while still ensuring their reliability.
Gang Liu; Zhifeng Xu; Hui Ma; Yanpeng Hao; Pengyu Wang; Wenbo Wu; Yue Xie; Deming Guo. An improved analytical thermal rating method for cables installed in short-conduits. International Journal of Electrical Power & Energy Systems 2020, 123, 106223 .
AMA StyleGang Liu, Zhifeng Xu, Hui Ma, Yanpeng Hao, Pengyu Wang, Wenbo Wu, Yue Xie, Deming Guo. An improved analytical thermal rating method for cables installed in short-conduits. International Journal of Electrical Power & Energy Systems. 2020; 123 ():106223.
Chicago/Turabian StyleGang Liu; Zhifeng Xu; Hui Ma; Yanpeng Hao; Pengyu Wang; Wenbo Wu; Yue Xie; Deming Guo. 2020. "An improved analytical thermal rating method for cables installed in short-conduits." International Journal of Electrical Power & Energy Systems 123, no. : 106223.
Vacuum circuit breakers may cause severe reignition overvoltage when switching off inductive loads, which may cause damage to other equipment connected with them, especially in the offshore wind farm power collection system. In order to study this process, a 35 kV electrical system was built in a laboratory platform, and the reignition overvoltage was recorded and analyzed. The measurements were used to improve the vacuum circuit breaker model. The parameters of dielectric strength of a 40.5 kV vacuum circuit breaker model were discussed in this publication. Then, a simulation model based on the experimental system was established using PSCAD/EMTDC. The reignition breakdown voltage across vacuum circuit breakers and the voltage at the high-voltage side of the connected transformer were equal, and the reason was explained according to the theory of wave propagation. Surge arresters and RC snubber are often used for overvoltage suppression, and the different configurations of them were evaluated. Finally, the efficiency of overvoltage suppression was compared both in the time domain and energy spectral density based on the simulation results.
Yaxun Guo; Xiaofeng Jiang; Yun Chen; Ming Zheng; Gang Liu; Xiaohua Li; Wenhu Tang. Reignition overvoltages induced by vacuum circuit breakers and its suppression in offshore wind farms. International Journal of Electrical Power & Energy Systems 2020, 122, 106227 .
AMA StyleYaxun Guo, Xiaofeng Jiang, Yun Chen, Ming Zheng, Gang Liu, Xiaohua Li, Wenhu Tang. Reignition overvoltages induced by vacuum circuit breakers and its suppression in offshore wind farms. International Journal of Electrical Power & Energy Systems. 2020; 122 ():106227.
Chicago/Turabian StyleYaxun Guo; Xiaofeng Jiang; Yun Chen; Ming Zheng; Gang Liu; Xiaohua Li; Wenhu Tang. 2020. "Reignition overvoltages induced by vacuum circuit breakers and its suppression in offshore wind farms." International Journal of Electrical Power & Energy Systems 122, no. : 106227.
A metal oxide arrester (MOA) accident occurred in a tropical coastal area is studied in this paper. The control test and disassembly analysis for the MOAs in the accident group and the control group were conducted. It was considered that the varistors of the MOA were deteriorating. Although the performance of the zinc oxide (ZnO) varistor is qualified, its side insulation glaze has defects. The leakage current under U1mA and 0.75 U1mA have exceeded the standard requirements due to the decrease of insulation performance. An electrothermal model of the MOA was constructed. The root-mean-square (RMS) value of the voltage across the varistor column and the RMS of leakage current flowing through the varistor were obtained through simulation. The heating power was calculated as the heat source input of the thermal circuit model to calculate the temperature of the varistor. It was verified that the electrolyte deposited on the surface of the porcelain house due to salt spray formed a dry area after being affected by moisture, because of the uneven potential distribution, the radial current flowing to the varistors through the coupling capacitor on the surface of the porcelain house increased sharply, and it caused the varistor to generate a large amount of heat in extreme condition. The side insulation glaze of the varistor was damaged by frequent heating effect. Eventually, the internal flashover occurred in the MOA, and the internal pressure rose sharply then broke through the explosion-proof film, causing an accident.
Qian Li; Zikai Zhou; Wenqing Zhou; Juntao Wei; Kai Wang; Gang Liu; Honglei Deng; Peng Wang; Jian Shu. A case study on an explosion accident of a 110 kV porcelain housed MOA. Engineering Failure Analysis 2020, 115, 104665 .
AMA StyleQian Li, Zikai Zhou, Wenqing Zhou, Juntao Wei, Kai Wang, Gang Liu, Honglei Deng, Peng Wang, Jian Shu. A case study on an explosion accident of a 110 kV porcelain housed MOA. Engineering Failure Analysis. 2020; 115 ():104665.
Chicago/Turabian StyleQian Li; Zikai Zhou; Wenqing Zhou; Juntao Wei; Kai Wang; Gang Liu; Honglei Deng; Peng Wang; Jian Shu. 2020. "A case study on an explosion accident of a 110 kV porcelain housed MOA." Engineering Failure Analysis 115, no. : 104665.
To extend the cable service life, the feasibility of cable rejuvenation on two retired cables through heat treatment was investigated in this study. First, two retired 110 kV AC cables without overheated record were annealed at four temperatures of 90, 95, 100, and 105 °C by simulating the cable operation. Second, the insulation layer of the annealed cables was peeled, and the peels near the inner conductor were selected as test samples. Then, differential scanning calorimetry was performed, and the DC conduction current and dielectric breakdown strength E B were measured. The results showed that the heat treatment of simulating cable operation could be a feasible method to rejuvenate retired cables and 95 °C was determined to be the optimum annealing temperature for the two cables.
Yue Xie; Yifeng Zhao; Xinghui Fan; Zhuozhan Han; Pengyu Wang; Gang Liu; Yanpeng Hao; Licheng Li. Experimental study on cable rejuvenation via simulated cable operation. IEEE Transactions on Dielectrics and Electrical Insulation 2020, 27, 708 -711.
AMA StyleYue Xie, Yifeng Zhao, Xinghui Fan, Zhuozhan Han, Pengyu Wang, Gang Liu, Yanpeng Hao, Licheng Li. Experimental study on cable rejuvenation via simulated cable operation. IEEE Transactions on Dielectrics and Electrical Insulation. 2020; 27 (2):708-711.
Chicago/Turabian StyleYue Xie; Yifeng Zhao; Xinghui Fan; Zhuozhan Han; Pengyu Wang; Gang Liu; Yanpeng Hao; Licheng Li. 2020. "Experimental study on cable rejuvenation via simulated cable operation." IEEE Transactions on Dielectrics and Electrical Insulation 27, no. 2: 708-711.
This paper reveals a correlation between morphology and thermal parameters on cross-linked polyethylene (XLPE) cable with different insulating states. Several cables were selected to detect the physicochemical and thermal parameters of the XLPE. The results show that the cable ampacity is determined by the thermal parameters, which are deeply subjected to the morphology of the XLPE. The molecular chain and crystal structure of the XLPE have a close connection with the thermal resistivity. The physicochemical parameters of carbonyl index (CI) and unsaturated band index (UBI) from Fourier transform infrared spectrum (FTIR) and melting range (Rm) from differential scanning calorimetry (DSC) can be the indicator to evaluate the diversity of the thermal resistivity. The change of thermal capacity is governed by the crystal distribution of the XLPE. The physicochemical parameters of crystallinity (χ) and lamellar thickness (L) from DSC can be the indicator to evaluate the change of the thermal capacity. In addition, FWHM of the crystallization peak ΔW, crystalline rate index (T0-TP) and cross-linking degree (G) can also be the indicator of the thermal parameters. Finally, this paper proposes a more accurate on-line monitoring method for electric power industry by detecting thermal parameters to diagnose the operating cables in the practical application.
Yifeng Zhao; Zhuozhan Han; Yue Xie; Xinghui Fan; Yangyang Nie; Pengyu Wang; Gang Liu; Yanpeng Hao; Jiasheng Huang; Wenwei Zhu. Correlation Between Thermal Parameters and Morphology of Cross-Linked Polyethylene. IEEE Access 2020, 8, 19726 -19736.
AMA StyleYifeng Zhao, Zhuozhan Han, Yue Xie, Xinghui Fan, Yangyang Nie, Pengyu Wang, Gang Liu, Yanpeng Hao, Jiasheng Huang, Wenwei Zhu. Correlation Between Thermal Parameters and Morphology of Cross-Linked Polyethylene. IEEE Access. 2020; 8 (99):19726-19736.
Chicago/Turabian StyleYifeng Zhao; Zhuozhan Han; Yue Xie; Xinghui Fan; Yangyang Nie; Pengyu Wang; Gang Liu; Yanpeng Hao; Jiasheng Huang; Wenwei Zhu. 2020. "Correlation Between Thermal Parameters and Morphology of Cross-Linked Polyethylene." IEEE Access 8, no. 99: 19726-19736.
In this work, heat treatment was performed on three retired 110 kV AC cables with service years of 0, 15 and 30, and the effects on the thermal and electrical performance of the cable insulation were investigated. First, each cable with a length approximately of 5 m was prepared and cut into five equal segments. Four segments of each cable were annealed at a temperature of 90, 95, 100, or 105 °C by building a small circuit to simulate cable operation. Then, a section at the middle of each segment was cut out, and the insulation layer was peeled away. The peeled-off layers from the inner, middle and outer positions were selected as the test samples. Subsequently, Fourier transform infrared spectrometry (FTIR), and differential scanning calorimetry (DSC) were performed, and the DC conduction current and dielectric breakdown strength were measured. The best thermal properties of the highest melting point, crystallinity, and smallest melting range were found when the cables were annealed at 100, 105, and 105 °C for the inner, middle, and outer positions, respectively. The highest dielectric breakdown strength and lowest electrical conductivity were found at temperatures of 95 or 100 °C for the inner and middle positions, respectively, and at 105 °C for the outer position. The FTIR results showed that thermal annealing for hundreds of hours did not adversely affect the molecular chains. It is found that this type of heat treatment could be a feasible method to rejuvenate retired cables, and a conservative temperature of 95 °C is regarded as the optimum annealing temperature.
Yue Xie; Yifeng Zhao; Shuzhen Bao; Pengyu Wang; Jiasheng Huang; Gang Liu; Yanpeng Hao; Licheng Li. Rejuvenation of Retired Power Cables by Heat Treatment: Experimental Simulation in Lab. IEEE Access 2020, 8, 5635 -5643.
AMA StyleYue Xie, Yifeng Zhao, Shuzhen Bao, Pengyu Wang, Jiasheng Huang, Gang Liu, Yanpeng Hao, Licheng Li. Rejuvenation of Retired Power Cables by Heat Treatment: Experimental Simulation in Lab. IEEE Access. 2020; 8 (99):5635-5643.
Chicago/Turabian StyleYue Xie; Yifeng Zhao; Shuzhen Bao; Pengyu Wang; Jiasheng Huang; Gang Liu; Yanpeng Hao; Licheng Li. 2020. "Rejuvenation of Retired Power Cables by Heat Treatment: Experimental Simulation in Lab." IEEE Access 8, no. 99: 5635-5643.
Further research on retired cable rejuvenation via heat treatment was investigated in this paper. Three retired cables with service year of 7, 15 and 30 years were used and annealed at different temperatures following two different heat treatment methods. In the first test, two short cables with a length of 5 m were prepared and cut into five equal segments. Four segments of each cable were annealed at 90, 95, 100, and 105 ℃ to simulate the cable operation. Then, the cross-linked polyethylene (XLPE) from the cable insulation was peeled, and the peels from the inner, middle and outer positions were selected and subjected to the differential scanning calorimetry (DSC), DC conduction current, and dielectric breakdown strength measurements. The thermal and electrical performance of these samples were analyzed, and the optimum annealing temperature was determined. In the second test, three identical long cables were connected to a transformer, joints, and terminals to build two experimental circuits. The cables were annealed at the optimum temperature determined in the first test. The same measurements were performed on XLPE samples taken from the same positions as those in the first test. The results showed that the short cables exhibited the best thermal and electrical performance when annealed at 95 ℃. The three long cables annealed at 95 ℃ verified that the thermal and electrical properties of the cable insulation were significantly improved. The results of the two different annealing methods, which closely represent the actual cable operations, verified the feasibility that old cables without overheating history could be rejuvenated via heat treatment.
Yue Xie; Yifeng Zhao; Shuzhen Bao; Pengyu Wang; Jiasheng Huang; Gang Liu; Yanpeng Hao; Licheng Li. Investigation on Cable Rejuvenation by Simulating Cable Operation. IEEE Access 2020, 8, 6295 -6303.
AMA StyleYue Xie, Yifeng Zhao, Shuzhen Bao, Pengyu Wang, Jiasheng Huang, Gang Liu, Yanpeng Hao, Licheng Li. Investigation on Cable Rejuvenation by Simulating Cable Operation. IEEE Access. 2020; 8 (99):6295-6303.
Chicago/Turabian StyleYue Xie; Yifeng Zhao; Shuzhen Bao; Pengyu Wang; Jiasheng Huang; Gang Liu; Yanpeng Hao; Licheng Li. 2020. "Investigation on Cable Rejuvenation by Simulating Cable Operation." IEEE Access 8, no. 99: 6295-6303.
Qingbo Lai; Jie Chen; Libin Hu; Jingying Cao; Yue Xie; Deming Guo; Gang Liu; Pengyu Wang; Ningxi Zhu. Investigation of tail pipe breakdown incident for 110 kV cable termination and proposal of fault prevention. Engineering Failure Analysis 2020, 108, 1 .
AMA StyleQingbo Lai, Jie Chen, Libin Hu, Jingying Cao, Yue Xie, Deming Guo, Gang Liu, Pengyu Wang, Ningxi Zhu. Investigation of tail pipe breakdown incident for 110 kV cable termination and proposal of fault prevention. Engineering Failure Analysis. 2020; 108 ():1.
Chicago/Turabian StyleQingbo Lai; Jie Chen; Libin Hu; Jingying Cao; Yue Xie; Deming Guo; Gang Liu; Pengyu Wang; Ningxi Zhu. 2020. "Investigation of tail pipe breakdown incident for 110 kV cable termination and proposal of fault prevention." Engineering Failure Analysis 108, no. : 1.
Rupture accidents of overhead conductors may occur due to its complex operating environment. If wires rupture happens, the overhead conductors can be repaired by full-tension splice (FTS) in practical engineering to restore the mechanical strength and ampacity required. However, with time increases, ageing will occur on the overhead conductors. There may exist potential of rupture in the repaired segment of the conductor. Once the conductor is broken, the reliability of transmission line will be seriously destroyed. Therefore, it is of great importance to investigate the rupture reason and process of conductor repaired by FTS. In this paper, a rupture accident of 110 kV overhead conductor repaired by FTS is discussed. Firstly, the fractography analysis for the conductor sample is conducted, and the rupture reason is preliminarily inferred according to the rupture feature of the sample. Then, the current density distributions in the repaired segment of new conductor and aged conductor are compared by a finite element analysis (FEA) model of electromagnetic field. Also, the reason of high temperature produced in the conductor sample during rupture process is determined. Subsequently, to analyze the relationship between temperature and equivalent plastic strain, a FEA model of structure field for the steel core of conductor is established. Finally, combined with the fractography test results and simulation results, the rupture mechanism of conductor repaired by FTS is summarized in detail. The analytical method and conclusions proposed in this paper can provide references and suggestions for the study of similar conductor rupture accident and optimization of repaired process.
Tao Zhang; Wencheng Zheng; Yue Xie; Junjian Yuan; Tao Xu; Pengyu Wang; Gang Liu; Deming Guo; Gengbin Zhang; Yongchun Liang. A case study of rupture in 110 kV overhead conductor repaired by full-tension splice. Engineering Failure Analysis 2019, 108, 104349 .
AMA StyleTao Zhang, Wencheng Zheng, Yue Xie, Junjian Yuan, Tao Xu, Pengyu Wang, Gang Liu, Deming Guo, Gengbin Zhang, Yongchun Liang. A case study of rupture in 110 kV overhead conductor repaired by full-tension splice. Engineering Failure Analysis. 2019; 108 ():104349.
Chicago/Turabian StyleTao Zhang; Wencheng Zheng; Yue Xie; Junjian Yuan; Tao Xu; Pengyu Wang; Gang Liu; Deming Guo; Gengbin Zhang; Yongchun Liang. 2019. "A case study of rupture in 110 kV overhead conductor repaired by full-tension splice." Engineering Failure Analysis 108, no. : 104349.
For the study of transient overvoltage (TOV) in an offshore wind farm (OWF) collector system caused by switching off vacuum circuit breakers (VCBs), a simplified experimental platform of OWF medium-voltage (MV) cable collector system was established in this paper to conduct switching operation tests of VCB and obtain the characteristic parameters for VCB, especially dielectric strength parameters; also, the effectiveness of the VCB reignition model was verified. Then, PSCAD/EMTDC was used to construct the MV collector system of the OWF, and the effects of normal switching and fault switching on TOV amplitude, steepness, and the total number of reignition of the VCB were studied, respectively, with the experimental parameters and traditional parameters of dielectric strength of the VCB. The simulation results show that when the VCB is at the tower bottom, the overvoltage amplitude generated by the normal switching is the largest, which is 1.83 p.u., and the overvoltage steepness of the fault switching is the largest, up to 142 kV/μs. The overvoltage amplitude and steepness caused by switching off VCB at the tower bottom faultily with traditional parameters are about 2 and 1.5 times of the experimental parameters under the same operating condition.
Zikai Zhou; Yaxun Guo; Xiaofeng Jiang; Gang Liu; Wenhu Tang; Honglei Deng; Xiaohua Li; Ming Zheng. Study on Transient Overvoltage of Offshore Wind Farm Considering Different Electrical Characteristics of Vacuum Circuit Breaker. Journal of Marine Science and Engineering 2019, 7, 415 .
AMA StyleZikai Zhou, Yaxun Guo, Xiaofeng Jiang, Gang Liu, Wenhu Tang, Honglei Deng, Xiaohua Li, Ming Zheng. Study on Transient Overvoltage of Offshore Wind Farm Considering Different Electrical Characteristics of Vacuum Circuit Breaker. Journal of Marine Science and Engineering. 2019; 7 (11):415.
Chicago/Turabian StyleZikai Zhou; Yaxun Guo; Xiaofeng Jiang; Gang Liu; Wenhu Tang; Honglei Deng; Xiaohua Li; Ming Zheng. 2019. "Study on Transient Overvoltage of Offshore Wind Farm Considering Different Electrical Characteristics of Vacuum Circuit Breaker." Journal of Marine Science and Engineering 7, no. 11: 415.
This paper verifies the fluctuation on thermal parameters and ampacity of the high-voltage cross-linked polyethylene (XLPE) cables with different insulation conditions and describes the results of a thermal aging experiment on the XLPE insulation with different operating years in different laying modes guided by Comsol Multiphysics modeling software. The thermal parameters of the cables applied on the models are detected by thermal parameter detection control platform and differential scanning calorimetry (DSC) measurement to assure the effectivity of the simulation. Several diagnostic measurements including Fourier infrared spectroscopy (FTIR), DSC, X-ray diffraction (XRD), and breakdown field strength were conducted on the treated and untreated specimens in order to reveal the changes of properties and the relationship between the thermal effect and the cable ampacity. Moreover, a new estimation on cable ampacity from the perspective on XLPE insulation itself has been proposed in this paper, which is also a possible way to judge the insulation condition of the cable with specific aging degree in specific laying mode for a period of time.
Zhu; Yifeng Zhao; Zhuozhan Han; Wang; Gang Liu; Yue Xie; Wenwei Zhu; Xiangbing Wang; Yanfeng Wang; Ningxi Zhu; Zhao; Han; Liu; Xie. Thermal Effect of Different Laying Modes on Cross-Linked Polyethylene (XLPE) Insulation and a New Estimation on Cable Ampacity. Energies 2019, 12, 2994 .
AMA StyleZhu, Yifeng Zhao, Zhuozhan Han, Wang, Gang Liu, Yue Xie, Wenwei Zhu, Xiangbing Wang, Yanfeng Wang, Ningxi Zhu, Zhao, Han, Liu, Xie. Thermal Effect of Different Laying Modes on Cross-Linked Polyethylene (XLPE) Insulation and a New Estimation on Cable Ampacity. Energies. 2019; 12 (15):2994.
Chicago/Turabian StyleZhu; Yifeng Zhao; Zhuozhan Han; Wang; Gang Liu; Yue Xie; Wenwei Zhu; Xiangbing Wang; Yanfeng Wang; Ningxi Zhu; Zhao; Han; Liu; Xie. 2019. "Thermal Effect of Different Laying Modes on Cross-Linked Polyethylene (XLPE) Insulation and a New Estimation on Cable Ampacity." Energies 12, no. 15: 2994.
In this paper, the performance of several annealing methods on three retired cables and the annealing effects on the improvement in the thermal and electrical properties of cross-linked polyethylene (XLPE) insulation were discussed. The cable insulation layer was peeled, and the peels near the inner semi-conductive layer were used as the test samples. Isothermal treatment and heat recycling treatment were performed at temperatures of 85, 90, 95, and 100 °C, and the temperatures were held in the heat recycling treatment for 8, 16, and 24 h, respectively. Each heat recycling treatment was repeated 20 times, and the duration of the isothermal treatment was the same as that for the heat recycling treatment with a 24 h temperature holding hour. Then, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were performed, and the dielectric spectrum, DC conduction current, and dielectric breakdown strength EB were measured. The results showed that damage involving molecular changes is linearly related to the cable service year. As the annealing temperature increases, the melting range and electrical conductivity decrease; the melting point, crystallinity, lamellar thickness, and dielectric breakdown strength increase; and the optimal values appear for the samples annealed at 95 °C. With an increased temperature holding hour, the peels annealed at 95 °C exhibit a decreased melting range and electrical conductivity and an increased crystallinity, melting point, lamellar thickness, and dielectric breakdown strength. As a result, the two different treatments are verified to effectively improve the thermal and electrical properties for the XLPE as early research on cable rejuvenation by heat treatment.
Yue Xie; Yifeng Zhao; Gang Liu; Jiasheng Huang; Licheng Li. Annealing Effects on XLPE Insulation of Retired High-Voltage Cable. IEEE Access 2019, 7, 104344 -104353.
AMA StyleYue Xie, Yifeng Zhao, Gang Liu, Jiasheng Huang, Licheng Li. Annealing Effects on XLPE Insulation of Retired High-Voltage Cable. IEEE Access. 2019; 7 ():104344-104353.
Chicago/Turabian StyleYue Xie; Yifeng Zhao; Gang Liu; Jiasheng Huang; Licheng Li. 2019. "Annealing Effects on XLPE Insulation of Retired High-Voltage Cable." IEEE Access 7, no. : 104344-104353.
The rupture accident of overhead ground wire (OGW) may happen when the overhead transmission line gets struck by lightning, especially in the case of a large lightning current. This may trigger a short-circuit fault of the overhead transmission line and cause serious harm to the safety and stable operation of the power grid. The Lightning samples are very limited and it is difficult to simulate the actual lightning current in the laboratory accurately. Besides, the standard are short of the consideration to the thermo-mechanical properties of OGW under lightning current. Therefore, it is of considerable significance to study the reason and process of rupture accident of OGW caused by lightning strike. In this paper, a rupture accident of 220 kV OGW happened in Qingyuan, Guangdong Province due to a large lightning strike (475.9kA) is investigated. Firstly, the rupture process of OGW is preliminarily inferred through the fractography analysis of the broken OGW samples. Then, a three-dimensional thermoelectric coupling simulation model of OGW is established, and the melting area and average temperature of each wire of OGW under a lightning strike are calculated. Based on the fractography analysis results and the simulation results of the OGW samples, and taking the correlation between the temperature and the tensile strength of metal material into consideration, a more detailed discussion on the rupture process of OGW is conducted. Finally, the rationality of wire diameter selection for OGW is demonstrated by calculating the residual tensile strength of each wire of OGW under different lightning current. The method for analyzing the rupture accident of OGW caused by lightning strike presented in this paper, which is based on various influencing factors, can provide reference and suggestions for the investigation and solution in similar cases.
Gang Liu; Xiangyang Peng; Meishan Zhong; Rui Wang; Pengyu Wang; Deming Guo; Qi Qi. A case study of ruptures in overhead ground wire under a large lightning over 400kA. Engineering Failure Analysis 2019, 104, 1211 -1233.
AMA StyleGang Liu, Xiangyang Peng, Meishan Zhong, Rui Wang, Pengyu Wang, Deming Guo, Qi Qi. A case study of ruptures in overhead ground wire under a large lightning over 400kA. Engineering Failure Analysis. 2019; 104 ():1211-1233.
Chicago/Turabian StyleGang Liu; Xiangyang Peng; Meishan Zhong; Rui Wang; Pengyu Wang; Deming Guo; Qi Qi. 2019. "A case study of ruptures in overhead ground wire under a large lightning over 400kA." Engineering Failure Analysis 104, no. : 1211-1233.
This paper investigates the impact factors of switching transient overvoltage (SOV) in an offshore wind farm (OWF) by analyzing multiple ignitions of a vacuum circuit breaker. The statistical features of transient overvoltages, which occur under real switching operation scenarios, are analyzed based on measurements in a laboratory platform, which is built according to the configuration of an actual OWF. Next, an OWF simulation transient model is established considering high frequency characteristics of circuit breakers, which is verified to be able to calculate the SOV accurately. Based on the developed OWF simulation model, the occurrence mechanism of SOV is discussed in detail by studying characteristics of transient voltage and current during multiple ignitions within a vacuum circuit breaker, when it is switched off. Then, key impact factors of switching-off induced overvoltage are identified, which include the inter-phase capacitance of cable in a windmill tower, the actual operating capacity of a wind turbine generator, and the single-phase inlet capacitance in terminals of a wind turbine transformer. Finally, the recommended configurations are given for transient mitigation in an OWF.
Jiujiang Zhou; Yanli Xin; Wenhu Tang; Gang Liu; Qinghua Wu. Impact Factor Identification for Switching Overvoltage in an Offshore Wind Farm by Analyzing Multiple Ignition Transients. IEEE Access 2019, 7, 64651 -64662.
AMA StyleJiujiang Zhou, Yanli Xin, Wenhu Tang, Gang Liu, Qinghua Wu. Impact Factor Identification for Switching Overvoltage in an Offshore Wind Farm by Analyzing Multiple Ignition Transients. IEEE Access. 2019; 7 (99):64651-64662.
Chicago/Turabian StyleJiujiang Zhou; Yanli Xin; Wenhu Tang; Gang Liu; Qinghua Wu. 2019. "Impact Factor Identification for Switching Overvoltage in an Offshore Wind Farm by Analyzing Multiple Ignition Transients." IEEE Access 7, no. 99: 64651-64662.