It is important for the safety of transmission system to accurately calculate single-phase earth fault current distribution.Features of double sided elimination method were illustrated.Quantitative calculation of sing...It is important for the safety of transmission system to accurately calculate single-phase earth fault current distribution.Features of double sided elimination method were illustrated.Quantitative calculation of single-phase earth fault current distribution and case verification were accomplished by using the loop method.Influences of some factors,such as single-phase earth fault location and ground resistance of poles,on short-circuit current distribution were discussed.Results show that:1) results of the loop method conform to those of double sided elimination method;2) the fault location hardly influences macro-distribution of short-circuit current.However,current near fault location is evidently influenced;and 3) the short-circuit current distribution is not so sensitive to the ground resistance of poles.展开更多
Electric field measurement holds immense significance in various domains.The power supply and signal acquisition units of the sensor may be coupled with ground wire interference,which could result in reduced measureme...Electric field measurement holds immense significance in various domains.The power supply and signal acquisition units of the sensor may be coupled with ground wire interference,which could result in reduced measurement accuracy.Moreover,this problem is often ignored by researchers.This paper investigated the origin of ground coupling interference in electric field sensors and its impact on measurement accuracy.A miniature undistorted electric field sensor with wireless transmission was compared with existing D-dot,microelectromechanical systems(MEMS),and optical sensors.The results indicate that MEMS and D-dot exhibit diminished accuracy in measuring electric fields under uniform conditions,owing to interference from ground wires.In the case of transmission lines with non-uniform conditions,the wireless sensor exhibited a measurement error of 5%,whereas the optical sensor showed an error rate of approximately 8%.However,the D-dot sensor displayed a measurement error exceeding 50%,whereas the MEMS sensor yielded an error as high as 150%.This means that the wireless sensor isolates the ground-coupled interference signal and realizes the distortion-free measurement of the electric field.The wireless sensors will find extensive applications in new power systems for intelligent equipment status perception,fault warning,and other scenarios.展开更多
Today the entire globe is shrouded in an inefficient three-phase system. There is however an efficient single-wire system. To use the single wire method, three phase systems can be converted to triple one wire systems.
针对架空输电线路接地线挂拆作业中人工登塔风险高、效率低的问题,该文提出了一种基于无人机的自动挂拆接地线方法,设计了重力自锁式导线夹紧机构与按压式弹性自锁接地装置,采用轻量化的结构设计,完成了装置与无人机的系统适配。试验结...针对架空输电线路接地线挂拆作业中人工登塔风险高、效率低的问题,该文提出了一种基于无人机的自动挂拆接地线方法,设计了重力自锁式导线夹紧机构与按压式弹性自锁接地装置,采用轻量化的结构设计,完成了装置与无人机的系统适配。试验结果表明,该装置在5.03 k A短路电流(0.5096 s)及40.021 kg负载21次循环工况下均未发生脱落,挂取可靠、锁止稳定,实现了安全高效的免登塔挂接地线作业目标。展开更多
文摘It is important for the safety of transmission system to accurately calculate single-phase earth fault current distribution.Features of double sided elimination method were illustrated.Quantitative calculation of single-phase earth fault current distribution and case verification were accomplished by using the loop method.Influences of some factors,such as single-phase earth fault location and ground resistance of poles,on short-circuit current distribution were discussed.Results show that:1) results of the loop method conform to those of double sided elimination method;2) the fault location hardly influences macro-distribution of short-circuit current.However,current near fault location is evidently influenced;and 3) the short-circuit current distribution is not so sensitive to the ground resistance of poles.
基金supported in part by the National Key Research and Development Program of China under Grant 2022YFB3206800in part by the National Natural Science Foundation of China under Grant 52125703.
文摘Electric field measurement holds immense significance in various domains.The power supply and signal acquisition units of the sensor may be coupled with ground wire interference,which could result in reduced measurement accuracy.Moreover,this problem is often ignored by researchers.This paper investigated the origin of ground coupling interference in electric field sensors and its impact on measurement accuracy.A miniature undistorted electric field sensor with wireless transmission was compared with existing D-dot,microelectromechanical systems(MEMS),and optical sensors.The results indicate that MEMS and D-dot exhibit diminished accuracy in measuring electric fields under uniform conditions,owing to interference from ground wires.In the case of transmission lines with non-uniform conditions,the wireless sensor exhibited a measurement error of 5%,whereas the optical sensor showed an error rate of approximately 8%.However,the D-dot sensor displayed a measurement error exceeding 50%,whereas the MEMS sensor yielded an error as high as 150%.This means that the wireless sensor isolates the ground-coupled interference signal and realizes the distortion-free measurement of the electric field.The wireless sensors will find extensive applications in new power systems for intelligent equipment status perception,fault warning,and other scenarios.
文摘Today the entire globe is shrouded in an inefficient three-phase system. There is however an efficient single-wire system. To use the single wire method, three phase systems can be converted to triple one wire systems.
文摘针对架空输电线路接地线挂拆作业中人工登塔风险高、效率低的问题,该文提出了一种基于无人机的自动挂拆接地线方法,设计了重力自锁式导线夹紧机构与按压式弹性自锁接地装置,采用轻量化的结构设计,完成了装置与无人机的系统适配。试验结果表明,该装置在5.03 k A短路电流(0.5096 s)及40.021 kg负载21次循环工况下均未发生脱落,挂取可靠、锁止稳定,实现了安全高效的免登塔挂接地线作业目标。
