多电飞机断路器电弧机理及灭弧技术研究综述

Overview of the arc mechanism and extinguishing in the circuit breaker of a more-electric aircraft

多电飞机指次级功率从机械能、液压能、气压能等传统的多能源体制统一为电能体制的飞机,具有系统结构简单、可靠性高、可维护性高和能源利用率高等优点,其电力系统最先进的架构为360~800 Hz变频交流电源和270 V直流电源,目前已在空客A380、波音B787、F-22等多电飞机中应用.但随着用电功率的增加,多电飞机的配电、用电网络以及线缆布局将变得更复杂,发生短路等电气故障的概率明显加大.故障电流产生的电弧不仅严重影响线缆和用电设备的寿命、可靠性和安全性,还将限制航空电力系统扩容和飞行性能提升.多电飞机断路器是灭弧的关键器件,通过分析断路器中电弧放电过程的复杂机理,可有助于提升其灭弧性能.为深入推进多电飞机电力系统中断路器电弧理论与灭弧技术研究的开展,首先分析了民用和军用多电飞机电力系统的结构以及电气故障保护的难点,然后分别归纳了航空变频交流断路器和270 V直流断路器中电弧理论与灭弧技术的研究现状,最后预测了未来航空保护电器灭弧技术的发展趋势.

A more-electric aircraft refers to an aircraft whose secondary power is unified from the traditional multi-energy,such as mechanical energy,hydraulic energy,and pneumatic energy,to the electrical energy,which has the advantages of a simple system structure,high reliability,high maintainability,and high energy efficiency.The most advanced architecture of its power system is the 360–800 Hz variable frequency AC power supply and the 270 V high-voltage DC power supply,which have been applied in the Airbus A380,Boeing B787,F-22,and other more-electric aircraft.As power consumption increases,the power distribution,power network,and cable layout in a more-electric aircraft become more complex,and the probability of electrical faults such as short circuits increases.The arc generated by fault current not only severely affects the life,reliability,and safety of cable and electrical equipment but also limits the capacity expansion of an aviation power system and the improvement of flight performance.The circuit breaker in a more-electric aircraft is a key device for arc extinguishing.Analyzing the complex mechanism of the arc-discharging process in a circuit breaker helps improve the arc-extinguishing performance.To further promote research on the arc mechanism and extinguishing technology of circuit breakers in more-electric aircraft power systems,in this paper,the structure of civilian and military more-electric aircraft power systems and the difficulties in the electrical fault and protection are first analyzed.Then,the research status of the arc-extinguishing technology of the aviation variable frequency AC circuit breaker and the 270 V high-voltage DC circuit breaker are summarized.For an intermediate-frequency vacuum arc,the instantaneous input power inside the gap and at the anode increases with the current frequency,which indicates that the half-wave input power increases with the frequency and proves that the transition state arc is an important source of anode ablation during intermediate-frequency arcing.Under the same current condition,the frequency increases.On the one hand,when the value of di/dt increases,the arc-extinguishing ability decreases with increasing frequency.On the other hand,intensifying the skin effect leads to an increase in the arc center pressure,arc contraction,and magnetic field hysteresis,which is not conducive to arc extinguishing.In addition,the metal vapor density vaporized by droplets reduces the recovery strength of the dielectric after the current zero,which is not conducive to arc extinguishing.For the 270 V DC arc,air,nitrogen,helium,hydrogen,and other gas are presently used in aviation power systems,among which hydrogen is the research hotspot.Finally,future research trends of arc extinguishing technology for aviation circuit breakers are predicted.