A high temperature superconductor （HTS） cable system of both a length of 4 metre and a normal current of 2 KA with terminations and a cooling system has been built up and tested. The cable conductor was made of Bi-2...A high temperature superconductor （HTS） cable system of both a length of 4 metre and a normal current of 2 KA with terminations and a cooling system has been built up and tested. The cable conductor was made of Bi-2223 tape. A space maintained vacuum between two corrugated stainless steel tubes functions as the cryostat surrounding the superconductor. A series of tests were carried out to verify the functions of the system. The important data obtained can be used to make longer HTS cable systems.展开更多
The installation of 10kV distribution network line transformation and distribution project is a systematic and complicated work, which has high requirements for each detail in the implementation process. As an importa...The installation of 10kV distribution network line transformation and distribution project is a systematic and complicated work, which has high requirements for each detail in the implementation process. As an important part of the cable line construction, not only the relevant personnel need to be able to master the line installation skills, but also the line materials, line protection and other aspects need to do a good job in details, so as to better ensure the development of 10kV distribution network line transformation and distribution project installation.展开更多
In recent years, with the continuous construction and development of China's construction projects, especially the increasing number of high-rise buildings, there is a higher requirement for risk management. In th...In recent years, with the continuous construction and development of China's construction projects, especially the increasing number of high-rise buildings, there is a higher requirement for risk management. In the current construction work of building power projects, relevant managers should pay attention to the analysis of actual construction problems based on the actual situation, constantly change the situation of construction personnel, equipment used and the surrounding environment, identify, analyze and evaluate the safety risks in the actual construction of power cable projects in building power projects, formulate a construction strategy that meets the actual situation, solve various problems in the actual construction of power cable projects in building power projects, drive the good improvement of China's economic construction, and promote social progress in China.展开更多
With the support of the National Center for R&D on Superconductivity, a 6m high T_c superconducting (HTS) power cable has cartied a current of 1473 A successfully at the Institute of Electrical Engineering (IEE), ...With the support of the National Center for R&D on Superconductivity, a 6m high T_c superconducting (HTS) power cable has cartied a current of 1473 A successfully at the Institute of Electrical Engineering (IEE), CAS. In 1998, a one-meter-long, 1000A HTS power cable prototype was developed successfully by展开更多
With the rapid development of offshore wind farms, the usage and quantity of offshore wind power ca- bles have increased significantly. However, the existing research on offshore wind power cables still can- not meet ...With the rapid development of offshore wind farms, the usage and quantity of offshore wind power ca- bles have increased significantly. However, the existing research on offshore wind power cables still can- not meet the stringent requirements of deep-sea environments. Therefore, improving the understanding of the mechanical performance of offshore wind power cables and their influencing factors holds pro- found implications. This paper provides an overview of existing numerical and experimental researches on mechanical performance of offshore wind power cables. The relationship between various mechanical properties of offshore wind power cables and their complex cross-sectional structural forms are system- atically elaborated. The limitations of these researches are analyzed. And a prospective outlook on future research directions is provided, aiming to guide reliable engineering applications of offshore wind power cables in complex marine environments.展开更多
This paper constructs a model of the internal cross-sectional temperature field of power cables based on the multiphysics coupling simulation software,Comsol,to conduct an in-depth analysis of internal defects in powe...This paper constructs a model of the internal cross-sectional temperature field of power cables based on the multiphysics coupling simulation software,Comsol,to conduct an in-depth analysis of internal defects in power cables.First,a temperature field coupling model for power cables was built,and the accuracy of the simulation model was verified through mesh and boundary condition analysis.Subsequently,the distribution patterns of the internal temperature field of power cables were investigated under normal operating conditions and typical fault conditions(eccentric defects,internal water tree defects).The simulation results reveal that the presence of faults affects the insulation capability of the cable’s insulation layer,causing an imbalance in internal heat conduction and thus impacting the temperature distribution within the power cable.Additionally,this paper compares the internal temperature field distribution of power cables under different conditions(changing coil current and heat transfer coefficient)during normal operation.The results indicate that the temperature rise of power cables is closely related to the current carrying capacity and the heat transfer coefficient.Through an in-depth study of the temperature field distribution in power cables,this research provides a more precise,efficient,and economical reference solution for fault detection and repair in power systems,thereby enhancing the stability and safety of power cables and promoting the sustainable development of power cable technology.展开更多
The paper presents the application of Finite Element Method in thermal analysis of underground power cable system. The computations were performed for power cables buried in-line in the ground at a depth of 2 meters. ...The paper presents the application of Finite Element Method in thermal analysis of underground power cable system. The computations were performed for power cables buried in-line in the ground at a depth of 2 meters. The developed mathematical model allows determining the two-dimensional temperature distribution in the soil, thermal backfill and power cables. The simulations studied the effect of soil and cable backfill thermal conductivity on the maximum temperature of the cable conductor. Also, the effect of cable diameter on the temperature of cable core was studied. Numerical analyses were performed based on a program written in MATLAB.展开更多
The aging characteristics of the XLPE insulation of 110 kV power cables in the initial stage of operation are studied in this paper.The XLPE insulation from cables with different running time was tested by using elect...The aging characteristics of the XLPE insulation of 110 kV power cables in the initial stage of operation are studied in this paper.The XLPE insulation from cables with different running time was tested by using electrical and physicochemical methods,from which the degradation state of XLPE under multiple stresses during operation was derived.The broadband dielectric spectrum test taken from 10–1 to 10^(6) Hz showed that the dielectric constant and dielectric loss of the XLPE insulation first decrease and then increase with the increase of cable running time,which show obvious variation until 10 years of operation.The AC breakdown strengths of the XLPE insulation of operated cables with the service year no longer than 10 years were higher than that of new cables.The mechanical properties of the XLPE insulation showed no dependence with the cable running time.The crystallinity and perfection of the crystallization area were found to be enhanced during operation and the polar functional groups inside the XLPE insulation were found to be determined not only by the cross-linking by-products but also by the oxidation process during cable operation.The experimental results in this paper are important for improving the operation reliability and reducing the maintenance costs of the cables.展开更多
Due to the increasing demand of replacing large capacity overhead lines with underground cables in Korea, KEPCO （Korea Electric Power Corporation） and LS Cable （LS Cable ＆ System） have developed 345 kV optical fi...Due to the increasing demand of replacing large capacity overhead lines with underground cables in Korea, KEPCO （Korea Electric Power Corporation） and LS Cable （LS Cable ＆ System） have developed 345 kV optical fiber composite XLPE （cross-linked polyethylene） 2,500 mm2 cable system. This system has been installed in Cheongna district of Incheon city. KEPCO and LS Cable are also planning to build the cooling system in a tunnel in order to reduce the ambient temperature caused by currents. In this paper, the process of development, field installation, and final inspection test of the complete system will be described.展开更多
In modern power transmission systems,AC cables are increasingly integrated with overhead lines,forming hybrid networks.These cables are frequently exposed to repeated impulse voltages from the overhead lines.While sur...In modern power transmission systems,AC cables are increasingly integrated with overhead lines,forming hybrid networks.These cables are frequently exposed to repeated impulse voltages from the overhead lines.While surge arresters offer partial protection,the long-term effects of these impulses on polypropylene(PP)insulation remain unclear.This study systematically investigates the cumulative degradation of the electrical breakdown properties of PP insulation under repeated impulse voltage stress.The 50%impulse breakdown voltage(U_(50))was first determined,and a series of impulse tests were conducted at varying voltage levels to assess the number of impulses required for elec-trical breakdown,leading to the construction of an amplitude of impulse voltage(U)and the number of times required for breakdown(N),which is U-N curve.To evaluate the cumulative degradation,impulse voltage at 0.8 U_(50)was applied for 50,100,and 200 cycles,with the electrical conductivity current measured before and after each series of impulses.The results indicate significant degradation in the insulating properties of PP under repeated impulse stress.Mechanisms of cumulative degradation under impulse stress were further explored using isothermal relaxation current and space charge measurements.These findings provide critical insights into the performance of PP in hybrid transmission systems and offer valuable data to inform improved insulation design and protection strategies.展开更多
An analysis of underground power cables is performed using Fourier analysis with the objective of detecting fault and average life of the cables.Three types of cables are used in this experiment:a normal cable,a short...An analysis of underground power cables is performed using Fourier analysis with the objective of detecting fault and average life of the cables.Three types of cables are used in this experiment:a normal cable,a shorted cable, and a cable with holes.The impedance in each case is computed and Fourier transformation is applied so that the resulting impedance magnitude and impedance phase can be examined in the frequency domain.Various windowing techniques are applied to the experimental data to eliminate any interference.Fourier analysis is then applied to the impedance data calculated from both the sending end voltage and differential voltage.This analysis reveals differences in the frequency response of the three different types of a cable and can eventually be used as a measure for fault detection. Preliminary results reveal the differences in the frequency response.Accordingly,Fourier type methods can be effectively used as low cost and viable solutions to identify and detect faults in underground cables.展开更多
Recently,radiated electromagnetic interference(EMI)has become a research hotspot in power electronics systems,as the switching frequencies of power electronics systems have increased significantly with the adoption of...Recently,radiated electromagnetic interference(EMI)has become a research hotspot in power electronics systems,as the switching frequencies of power electronics systems have increased significantly with the adoption of wide-bandgap devices.In this article,a generalized radiated EMI model for power electronics converters with power cables is first reviewed.The radiated EMI model is then developed for a flyback power converter with critical ground impedance included.Based on the developed model,accurate high-frequency parameter extraction techniques and a radiated EMI prediction technique are developed and experimentally validated.Finally,essential measurement techniques are identified and developed to accurately extract parameters for accurate EMI prediction.The effects of the resolution bandwidth of the spectrum analyzer and critical PCB ground impedance on the radiated EMI are experimentally validated.PCB’s impact on the common-mode(CM)choke’s impedance and the radiated EMI is further validated.Techniques for minimizing the undesired near-field couplings in parameter extraction are discussed.The predicted EMI properly agreed with the measured EMI in the range of 30-230 MHz based on the EN550323 m class B standard.展开更多
The main purpose of the work presented here is to evaluate different methods for quality control of polymeric insulated HVDC cables.The insight gained can be used to evaluate proposed test methods for quality assuranc...The main purpose of the work presented here is to evaluate different methods for quality control of polymeric insulated HVDC cables.The insight gained can be used to evaluate proposed test methods for quality assurance of long lengths of polymer insulated power cables.Laboratory experiments were performed using both Rogowski shaped test objects and model cables,insulated with XLPE containing imbedded spherically shaped particles.Tests were performed by stressing the test object with AC(50 Hz),VLF(0.1 Hz) and DC voltages and measuring time to breakdown at the different voltages.The slope of the voltage-time curve for 0.1 and 50 Hz were found to be parallel showing higher breakdown strength for 0.1 Hz than 50 Hz.The number of periods to breakdown is somewhat higher for 0.1 Hz than for 50 Hz.The breakdown strength for DC was much higher than for both AC 50 Hz and 0.1 Hz.The results indicate that the VLF test voltage needs to be 2 to 3 times higher than at 50 Hz power frequency in order to eliminate the same defects within a comparable time.展开更多
Power cables play a very important role in urban development.On the other hand,the integrity and the safe operation of power cables are crucial as even a minor potential mishap can result in serious loss of life and p...Power cables play a very important role in urban development.On the other hand,the integrity and the safe operation of power cables are crucial as even a minor potential mishap can result in serious loss of life and property.Hence,early diagnosis and warning of cable faults are imperative.Addressing the current lack of practical detection technologies,this study proposes a non-destructive testing method based on electromagnetic field principles.Through scanning the power-on power cables with probes,the electric field intensity around the cables can be measured,and the weak anomaly caused by structural and material defects can be detected using Superlets transformation.Additionally,to gain a better characterization of the faults,a digital post-processing approach consisting of imaging and sonification algorithms is developed to aid in pinpointing the location of the faults.Both numerical simulation and experimental test indicate that the proposed non-destructive detection method is feasible and can achieve good accuracy in locating cable faults.With image and audio characterization,the present method has great potential applications in ensuring the safety of power cables.展开更多
This research seeks to evaluate the economic benefits to be gained by installing a small-scale wind turbine for a customer with a three-phase electrical supply requirement. The evidence for the claims made in this pap...This research seeks to evaluate the economic benefits to be gained by installing a small-scale wind turbine for a customer with a three-phase electrical supply requirement. The evidence for the claims made in this paper is obtained by using actual data obtained from the installed equipment over a three year period. The objective is to accurately appraise the financial investment using real data. There appears to be limited studies conducted into this type of research, possibly because the renewable energy sector is in the infancy stage in the host country, Ireland. There are some wind energy installations with financial appraisal techniques based on modeled data, which may, or may not, be accurate. The study concludes by claiming that the financial benefits of the wind energy turbine installation had disappointing results when compared to predicted benefits based on modeled data.展开更多
Despite the many submarine telecommunications and power cables laid world-wide there are fewer than ten published studies of their environmental effects in the refereed literature.This paper describes an investigation...Despite the many submarine telecommunications and power cables laid world-wide there are fewer than ten published studies of their environmental effects in the refereed literature.This paper describes an investigation into the effects of laying and operating the Basslink High Voltage Direct Current(HVDC)cable and its associated metallic return cable across Bass Strait in South East Australia.Over more than 95%of its length the cable was directly laid into a wet jetted trench given the predominantly soft sediments encountered.Underwater remote video investigations found that within two years all visible evidence of the cable and trench was gone at over a third of the transects at six deep water sites(32-72 m deep).At other deep water transects the residual trench trapped drift material providing habitat for the generally sparsely distributed benthic community.Diver surveys at both of the near shore sites(<15 m deep)on the northern side of the Strait also found the cable route was undetectable after a year.On the southern side,where the cable traversed hard basalt rock near shore,it was encased in a protective cast iron half shell.Ecological studies by divers over 3.5 years demonstrated the colonization of the hard shell by similar species occupying hard substrates elsewhere on the basalt reef.Magnetic field strengths associated with the operating cable were found to be within 0.8%of those predicted from theory with strength dropping rapidly with distance from the cable.Beyond 20 m the field was indistinguishable from background.展开更多
The ocean holds abundant petroleum,natural gas,and mineral resources that form an essential material foundation for the sustainable development of modern society.The safe and efficient exploitation of these resources ...The ocean holds abundant petroleum,natural gas,and mineral resources that form an essential material foundation for the sustainable development of modern society.The safe and efficient exploitation of these resources depends heavily on various slender,composite,flexible structures,including umbilical cables,dynamic power cables for offshore wind turbines,petroleum pipelines(both bonded and unbonded),deep-sea mining risers,and LNG cryogenic flexible hoses.These structures feature highly complex configurations and incur substantial design and manufacturing costs,while operating in environments far more severe and variable than those of onshore pipelines.They must withstand multisource stochastic loads generated by the combined action of wind,waves,currents,and tides,and maintain robustness under extreme conditions such as typhoons,earthquakes,and explosions.展开更多
文摘A high temperature superconductor （HTS） cable system of both a length of 4 metre and a normal current of 2 KA with terminations and a cooling system has been built up and tested. The cable conductor was made of Bi-2223 tape. A space maintained vacuum between two corrugated stainless steel tubes functions as the cryostat surrounding the superconductor. A series of tests were carried out to verify the functions of the system. The important data obtained can be used to make longer HTS cable systems.
文摘The installation of 10kV distribution network line transformation and distribution project is a systematic and complicated work, which has high requirements for each detail in the implementation process. As an important part of the cable line construction, not only the relevant personnel need to be able to master the line installation skills, but also the line materials, line protection and other aspects need to do a good job in details, so as to better ensure the development of 10kV distribution network line transformation and distribution project installation.
文摘In recent years, with the continuous construction and development of China's construction projects, especially the increasing number of high-rise buildings, there is a higher requirement for risk management. In the current construction work of building power projects, relevant managers should pay attention to the analysis of actual construction problems based on the actual situation, constantly change the situation of construction personnel, equipment used and the surrounding environment, identify, analyze and evaluate the safety risks in the actual construction of power cable projects in building power projects, formulate a construction strategy that meets the actual situation, solve various problems in the actual construction of power cable projects in building power projects, drive the good improvement of China's economic construction, and promote social progress in China.
文摘With the support of the National Center for R&D on Superconductivity, a 6m high T_c superconducting (HTS) power cable has cartied a current of 1473 A successfully at the Institute of Electrical Engineering (IEE), CAS. In 1998, a one-meter-long, 1000A HTS power cable prototype was developed successfully by
基金National Natural Science Foundation of China(grant no.52088102)Young Elite Scien-tists Sponsorship Program by CAST(grant no.2020QNRC001)+3 种基金Na-tional Key R&D Program of China(grant no.2023YFC2811600)Chenguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(grant no.21CGA15)The Science and Technology Commission of Shanghai Municipality(22ZR1434100)the Fundamental Research Funds for the Central Universities.
文摘With the rapid development of offshore wind farms, the usage and quantity of offshore wind power ca- bles have increased significantly. However, the existing research on offshore wind power cables still can- not meet the stringent requirements of deep-sea environments. Therefore, improving the understanding of the mechanical performance of offshore wind power cables and their influencing factors holds pro- found implications. This paper provides an overview of existing numerical and experimental researches on mechanical performance of offshore wind power cables. The relationship between various mechanical properties of offshore wind power cables and their complex cross-sectional structural forms are system- atically elaborated. The limitations of these researches are analyzed. And a prospective outlook on future research directions is provided, aiming to guide reliable engineering applications of offshore wind power cables in complex marine environments.
文摘This paper constructs a model of the internal cross-sectional temperature field of power cables based on the multiphysics coupling simulation software,Comsol,to conduct an in-depth analysis of internal defects in power cables.First,a temperature field coupling model for power cables was built,and the accuracy of the simulation model was verified through mesh and boundary condition analysis.Subsequently,the distribution patterns of the internal temperature field of power cables were investigated under normal operating conditions and typical fault conditions(eccentric defects,internal water tree defects).The simulation results reveal that the presence of faults affects the insulation capability of the cable’s insulation layer,causing an imbalance in internal heat conduction and thus impacting the temperature distribution within the power cable.Additionally,this paper compares the internal temperature field distribution of power cables under different conditions(changing coil current and heat transfer coefficient)during normal operation.The results indicate that the temperature rise of power cables is closely related to the current carrying capacity and the heat transfer coefficient.Through an in-depth study of the temperature field distribution in power cables,this research provides a more precise,efficient,and economical reference solution for fault detection and repair in power systems,thereby enhancing the stability and safety of power cables and promoting the sustainable development of power cable technology.
文摘The paper presents the application of Finite Element Method in thermal analysis of underground power cable system. The computations were performed for power cables buried in-line in the ground at a depth of 2 meters. The developed mathematical model allows determining the two-dimensional temperature distribution in the soil, thermal backfill and power cables. The simulations studied the effect of soil and cable backfill thermal conductivity on the maximum temperature of the cable conductor. Also, the effect of cable diameter on the temperature of cable core was studied. Numerical analyses were performed based on a program written in MATLAB.
文摘The aging characteristics of the XLPE insulation of 110 kV power cables in the initial stage of operation are studied in this paper.The XLPE insulation from cables with different running time was tested by using electrical and physicochemical methods,from which the degradation state of XLPE under multiple stresses during operation was derived.The broadband dielectric spectrum test taken from 10–1 to 10^(6) Hz showed that the dielectric constant and dielectric loss of the XLPE insulation first decrease and then increase with the increase of cable running time,which show obvious variation until 10 years of operation.The AC breakdown strengths of the XLPE insulation of operated cables with the service year no longer than 10 years were higher than that of new cables.The mechanical properties of the XLPE insulation showed no dependence with the cable running time.The crystallinity and perfection of the crystallization area were found to be enhanced during operation and the polar functional groups inside the XLPE insulation were found to be determined not only by the cross-linking by-products but also by the oxidation process during cable operation.The experimental results in this paper are important for improving the operation reliability and reducing the maintenance costs of the cables.
文摘Due to the increasing demand of replacing large capacity overhead lines with underground cables in Korea, KEPCO （Korea Electric Power Corporation） and LS Cable （LS Cable ＆ System） have developed 345 kV optical fiber composite XLPE （cross-linked polyethylene） 2,500 mm2 cable system. This system has been installed in Cheongna district of Incheon city. KEPCO and LS Cable are also planning to build the cooling system in a tunnel in order to reduce the ambient temperature caused by currents. In this paper, the process of development, field installation, and final inspection test of the complete system will be described.
基金China Southern Power Grid Company Limited,Grant/Award Number:ZBKJXM20220101National Natural Science Foundation of China,Grant/Award Number:52107019。
文摘In modern power transmission systems,AC cables are increasingly integrated with overhead lines,forming hybrid networks.These cables are frequently exposed to repeated impulse voltages from the overhead lines.While surge arresters offer partial protection,the long-term effects of these impulses on polypropylene(PP)insulation remain unclear.This study systematically investigates the cumulative degradation of the electrical breakdown properties of PP insulation under repeated impulse voltage stress.The 50%impulse breakdown voltage(U_(50))was first determined,and a series of impulse tests were conducted at varying voltage levels to assess the number of impulses required for elec-trical breakdown,leading to the construction of an amplitude of impulse voltage(U)and the number of times required for breakdown(N),which is U-N curve.To evaluate the cumulative degradation,impulse voltage at 0.8 U_(50)was applied for 50,100,and 200 cycles,with the electrical conductivity current measured before and after each series of impulses.The results indicate significant degradation in the insulating properties of PP under repeated impulse stress.Mechanisms of cumulative degradation under impulse stress were further explored using isothermal relaxation current and space charge measurements.These findings provide critical insights into the performance of PP in hybrid transmission systems and offer valuable data to inform improved insulation design and protection strategies.
文摘An analysis of underground power cables is performed using Fourier analysis with the objective of detecting fault and average life of the cables.Three types of cables are used in this experiment:a normal cable,a shorted cable, and a cable with holes.The impedance in each case is computed and Fourier transformation is applied so that the resulting impedance magnitude and impedance phase can be examined in the frequency domain.Various windowing techniques are applied to the experimental data to eliminate any interference.Fourier analysis is then applied to the impedance data calculated from both the sending end voltage and differential voltage.This analysis reveals differences in the frequency response of the three different types of a cable and can eventually be used as a measure for fault detection. Preliminary results reveal the differences in the frequency response.Accordingly,Fourier type methods can be effectively used as low cost and viable solutions to identify and detect faults in underground cables.
文摘Recently,radiated electromagnetic interference(EMI)has become a research hotspot in power electronics systems,as the switching frequencies of power electronics systems have increased significantly with the adoption of wide-bandgap devices.In this article,a generalized radiated EMI model for power electronics converters with power cables is first reviewed.The radiated EMI model is then developed for a flyback power converter with critical ground impedance included.Based on the developed model,accurate high-frequency parameter extraction techniques and a radiated EMI prediction technique are developed and experimentally validated.Finally,essential measurement techniques are identified and developed to accurately extract parameters for accurate EMI prediction.The effects of the resolution bandwidth of the spectrum analyzer and critical PCB ground impedance on the radiated EMI are experimentally validated.PCB’s impact on the common-mode(CM)choke’s impedance and the radiated EMI is further validated.Techniques for minimizing the undesired near-field couplings in parameter extraction are discussed.The predicted EMI properly agreed with the measured EMI in the range of 30-230 MHz based on the EN550323 m class B standard.
文摘The main purpose of the work presented here is to evaluate different methods for quality control of polymeric insulated HVDC cables.The insight gained can be used to evaluate proposed test methods for quality assurance of long lengths of polymer insulated power cables.Laboratory experiments were performed using both Rogowski shaped test objects and model cables,insulated with XLPE containing imbedded spherically shaped particles.Tests were performed by stressing the test object with AC(50 Hz),VLF(0.1 Hz) and DC voltages and measuring time to breakdown at the different voltages.The slope of the voltage-time curve for 0.1 and 50 Hz were found to be parallel showing higher breakdown strength for 0.1 Hz than 50 Hz.The number of periods to breakdown is somewhat higher for 0.1 Hz than for 50 Hz.The breakdown strength for DC was much higher than for both AC 50 Hz and 0.1 Hz.The results indicate that the VLF test voltage needs to be 2 to 3 times higher than at 50 Hz power frequency in order to eliminate the same defects within a comparable time.
基金National Natural Science Foundation of China(Grant No.12072300).
文摘Power cables play a very important role in urban development.On the other hand,the integrity and the safe operation of power cables are crucial as even a minor potential mishap can result in serious loss of life and property.Hence,early diagnosis and warning of cable faults are imperative.Addressing the current lack of practical detection technologies,this study proposes a non-destructive testing method based on electromagnetic field principles.Through scanning the power-on power cables with probes,the electric field intensity around the cables can be measured,and the weak anomaly caused by structural and material defects can be detected using Superlets transformation.Additionally,to gain a better characterization of the faults,a digital post-processing approach consisting of imaging and sonification algorithms is developed to aid in pinpointing the location of the faults.Both numerical simulation and experimental test indicate that the proposed non-destructive detection method is feasible and can achieve good accuracy in locating cable faults.With image and audio characterization,the present method has great potential applications in ensuring the safety of power cables.
文摘This research seeks to evaluate the economic benefits to be gained by installing a small-scale wind turbine for a customer with a three-phase electrical supply requirement. The evidence for the claims made in this paper is obtained by using actual data obtained from the installed equipment over a three year period. The objective is to accurately appraise the financial investment using real data. There appears to be limited studies conducted into this type of research, possibly because the renewable energy sector is in the infancy stage in the host country, Ireland. There are some wind energy installations with financial appraisal techniques based on modeled data, which may, or may not, be accurate. The study concludes by claiming that the financial benefits of the wind energy turbine installation had disappointing results when compared to predicted benefits based on modeled data.
文摘Despite the many submarine telecommunications and power cables laid world-wide there are fewer than ten published studies of their environmental effects in the refereed literature.This paper describes an investigation into the effects of laying and operating the Basslink High Voltage Direct Current(HVDC)cable and its associated metallic return cable across Bass Strait in South East Australia.Over more than 95%of its length the cable was directly laid into a wet jetted trench given the predominantly soft sediments encountered.Underwater remote video investigations found that within two years all visible evidence of the cable and trench was gone at over a third of the transects at six deep water sites(32-72 m deep).At other deep water transects the residual trench trapped drift material providing habitat for the generally sparsely distributed benthic community.Diver surveys at both of the near shore sites(<15 m deep)on the northern side of the Strait also found the cable route was undetectable after a year.On the southern side,where the cable traversed hard basalt rock near shore,it was encased in a protective cast iron half shell.Ecological studies by divers over 3.5 years demonstrated the colonization of the hard shell by similar species occupying hard substrates elsewhere on the basalt reef.Magnetic field strengths associated with the operating cable were found to be within 0.8%of those predicted from theory with strength dropping rapidly with distance from the cable.Beyond 20 m the field was indistinguishable from background.
文摘The ocean holds abundant petroleum,natural gas,and mineral resources that form an essential material foundation for the sustainable development of modern society.The safe and efficient exploitation of these resources depends heavily on various slender,composite,flexible structures,including umbilical cables,dynamic power cables for offshore wind turbines,petroleum pipelines(both bonded and unbonded),deep-sea mining risers,and LNG cryogenic flexible hoses.These structures feature highly complex configurations and incur substantial design and manufacturing costs,while operating in environments far more severe and variable than those of onshore pipelines.They must withstand multisource stochastic loads generated by the combined action of wind,waves,currents,and tides,and maintain robustness under extreme conditions such as typhoons,earthquakes,and explosions.
