电工技术学报2024，Vol.39Issue(13)：4139-4152,14.DOI:10.19595/j.cnki.1000-6753.tces.230608
2/3匝线圈式纵磁触头大开距真空断路器分闸速度设计
Design of Opening Velocities for Large-Gap Vacuum Circuit Breakers with 2/3 Coil-Type Axial Magnetic Field Contacts
摘要
Abstract
The development of vacuum circuit breakers(VCBs)towards transmission voltage is an effective alternative of SF6 CBs on background of carbon dioxide emission and carbon neutrality nowadays.In the VCBs,the axial magnetic field(AMF)contacts have been widely mounted tends to promote the breaking capability of circuit breakers.The vacuum arc plasma can be constrained by the axial magnetic field lines to counteract the pinch force of conducting current,which always concentrate the arc plasma at local anode surface to generate an anode spot in high current interruption process.In this case,a rational design of opening velocities for the VCBs with coil-type AMF contacts could effectively regulate the flux density of the axial magnetic field imposed on the electrode space.However,there is still a lack of quantitative design method for a full stroke opening velocities of the VCB with coil-type AMF contacts. This paper experimentally investigates the influence of arcing current and opening velocities on evolution of vacuum arc anode discharging modes.Couples of coil-type AMF contacts,tending to be applied in a 126 kV single-break vacuum circuit breaker,were mounted in a demountable vacuum chamber to investigate the influence of opening velocities on transitions of vacuum arc anode discharging mode.A high charge coupled device(CCD)was used to photograph these transitions.Two kinds of opening velocities,v1 and v2,were used to define an opening travel-curve:v1 is an initial opening velocity,which defines as an average velocity over 1/3 contact stroke,d,of 60 mm;while,v2 is an average velocity over 2d/3.In the experiment,v1 varied from 1.8 m/s to 2.4 m/s and 2.7 m/s,respectively.Correspondingly,v2 varied from 2.4 m/s to 2.7 m/s and 3.0 m/s.The arcing current was set to rise from 4 kA to 40 kA,stepped by 4 kA.Test result shows that v1 has significant impact on the transition of intense arc mode into diffuse arc mode in the first arcing current loop,while v2 significantly influences the formation of both footpoint mode and anode spot mode in the rest arcing current loop. The design of v1 should higher than the threshold velocity of 3.5 m/s,which corresponds to a peak critical contact gap for the transitions of intense arc mode into diffuse arc mode.While,v2 should not exceed the threshold velocity of 3.0 m/s,which corresponds to a maximum critical contact gap for the formation of footpoint mode and anode spot mode.In this case,the high current vacuum arc could quickly transit from the intense arc mode into diffuse arc mode in short arcing time high current interruption.Meanwhile,the formation of anode spot could be effectively avoided in long arcing time high current interruption.In addition,the transition of anode discharging mode for the test AMF contact could be predicted by comparing the actual axial magnetic flux density,Baxial,with the critical quantities,Bcri intense and Bcri anode These critical axial magnetic flux densities were experimentally determined for the transitions of intense arc mode to diffuse arc mode,and diffuse arc mode to footpoint mode and anode spot mode,respectively.The above v1 and v2 were applied on a 126 kV single-break VCB,and proved to be effectiveness by passing series of short-circuit current breaking type test.The result could provide reference and foundation for VCBs developing towards transmission voltage level.关键词
纵向磁场/大开距/真空断路器/阳极放电模式/分闸速度Key words
Axial magnetic field/large-gap/vacuum circuit breakers/anode discharge mode/opening velocity分类
信息技术与安全科学引用本文复制引用
马飞越,姚晓飞,刘志远,孙尚鹏,白涛..2/3匝线圈式纵磁触头大开距真空断路器分闸速度设计[J].电工技术学报,2024,39(13):4139-4152,14.基金项目
宁夏回族自治区重点研发计划项目(2022BDE93011)和国网宁夏电力有限公司科技项目(5229DK22000B)资助. （2022BDE93011）
