摘要
高原轨道交通和电工产业转型对起关键保护作用的大容量直流空气断路器(LC-DCCB)提出了更高要求,但现有产品在高海拔地区的开断仍存在一定问题。该文以轨道交通用LC-DCCB为研究对象,首先基于磁流体动力学(MHD)理论,考虑湍流效应的影响,对其在高海拔环境下开断18 kA短路电流进行仿真;然后对电弧形态及灭弧室内温度场、电磁场、气流场进行分析,得出高海拔地区空气电弧开断困难的主要原因;最后根据仿真与理论分析,考虑采用合理数量和布局的间插式U型栅片改善电弧开断特性。结果表明:随着海拔的升高,电弧前期运动速度加快,但断路器的灭弧性能降低;在高海拔环境下电弧存在严重的弧根粘滞和弧根拖尾现象,弧根拖尾畸变空间电场,不利于熄弧;同时,在不同海拔环境下,电弧会产生不同程度的反向运动现象,易导致弧后重燃。该研究深入揭示了高海拔环境下LC-DCCB电弧演变过程及复杂开断现象背后的物理本质,可为该类产品研发提供理论指导。
In Recent years,with the rapid development of urban rail transit at plateau and transformation and booming of the electrotechnical industry in China,it has put higher requirements for large-capacity DC air circuit breaker(LC-DCCB)which plays a significant role in protection.But when the short-circuit current is interrupted in LC-DCCB at plateau,the probability of interrupting failure increase,which is harmful to the urban rail transit sustain its stability and reliability.So how to extinguish the arc in which generated between the contacts when the contacts opening in LC-DCCB at plateau quickly and reliably remains a critical issue to be resolved.This paper established a transient magnetohydrodynamics(MHD)arc model of LC-DCCB at plateau considering the turbulence effect,the dynamic characteristics and the key behavior of the arc during short-circuit current interrupted at different altitudes were studied,and the primary courses of difficulty of arc interruption in LC-DCCB at plateau were concluded.An improved model with interleaved U-shaped splitter plates was proposed combined with theoretical analysis which can improve the interruption performance of LC-DCCB at plateau.This study can provide a theoretical basis for design and improvement of LC-DCCB at plateau.Through simulation results we can see that different altitudes can cause different environmental parameters and physical properties of air,which effects the arc behavior in LC-DCCB significantly.At 0 km altitude,the arc can extinguish successfully.At 2 km and 3 km altitudes,although the arc extinguish successfully,nevertheless,the arc will re-strike after a few milliseconds.At 4 km and 5 km altitudes,the arc can not extinguish.The physical parameters of air change with the altitude rases,which lead the arc enters the splitter plates in advance.One can found that the arc root viscous and trailing phenomena in LC-DCCB will appear during the full-dynamic arc simulation.When the arc root moves at the horizontal arc runner to a certain point,the movement speed of the arc root will decrease,and then the arc root will stop its moving or even move in reverse direction,while the high temperature gas adjacent to the arc root will cause the electric field distortion at the entrance of the arc chamber.The characteristics of arc root movement are different with altitude raise.Meanwhile,under the joint action of electromagnetic and airflow field,the reverse phenomenon of arc roots on both sides of the center line in the arc chamber will appear,the arc presents multi-peak shape.The reverse phenomenon of the arc between the splitter plates varies with the altitude,which is a key factor leading to the post-arc re-strike.An improved structure with interleaved U-shaped splitter plates in the arc chamber can restrain the arc reverse movement between splitter plates effectively.Through simulation and analysis in this paper come to the following conclusions:(1)Arc re-strike will occur during LC-DCCB interrupts short-circuit current at plateau,which will lead to the difficulty of interruption.(2)The arc root viscous and trailing phenomena will intensify with the altitude raise.(3)The arc reverse movement in LC-DCCB is a key factor for post-arc re-strike.(4)The interleaved U-shaped splitter plates can restrain the arc reverse movement between splitter plates effectively,which improve the arc extinguishing performance at plateau of LC-DCCB to some extent.
作者
李静
易晨曦
彭世东
曹云东
于龙滨
Li Jing;Yi Chenxi;Peng Shidong;Cao Yundong;Yu Longbin(Key Lab of Special Electric Machine and High Voltage Apparatus Shenyang University of Technology,Shenyang 110870,China;Electric Power Research Institute of Liaoning Electric Power Limited Company,Shenyang 110006,China)
出处
《电工技术学报》
EI
CSCD
北大核心
2024年第3期863-874,共12页
Transactions of China Electrotechnical Society
基金
国家自然科学基金项目(51977132)
辽宁省重大科技专项(2020JH1/10100012)
辽宁省教育厅面上项目(LJKZ0126)资助。
关键词
高海拔
大容量直流空气断路器
弧根拖尾
电弧反向
弧后重燃
High altitude
large-capacity DC air circuit breaker(LC-DCCB)
arc root trailing
arc reverse movement
post-arc re-strike
