航空故障电弧形成机理、特征及保护特性的研究

Fault arcs occurring in aeronautic electrical circuits may have a catastrophic effect. In order to recognize fault arcs without delay and control their consequences. The proposed project will focus on the key science and fundamental issue of fault arcs occurring in aeronautic cables for theoretical exploration and technological innovation in the view of mathematic model established, simulation and experiment of the fault arc. A fault arc model will be established based on the magneto-hydrodynamic modeling considering the effects of arc energy, cable ablation, flow and Lorents force. And the physical experimental platforms will be designed and made up in order to creating the fault arcs. The interaction mechanism of fault arcs with the surrounding electromagnetic and fluid fields and cable will be explored for evolution laws that govern the fault arcs' ignition, development, extinction and re-ignition. The arc characteristic will be presented through analyzing the relationship between the physics parameters and the electrical transient parameters of fault arcs. The time domain and frequency domain characteristics of fault arcs will be researched by adopting various methods such as FFT and wavelet packet for recognize the fault arcs. The protection characteristics of fault arcs will be proposed with the help of the relations of ablation of cables with the arc energy and arc movement. These results of this project will lay a theoretical foundation and offer a technological support for detection of fault arcs and heath management of the electrical system of modern aircraft.

航空电缆故障电弧是引发空难事故的原因之一。为了能及时发现故障电弧，减轻其带来的危害，本项目针对航空故障电弧的关键科学与基础性问题，从数学建模、数字仿真与实验的角度，进行理论探索与技术创新研究。建立考虑故障电弧能量交换、电缆烧蚀、气流、洛伦兹力等相互作用的磁流体动力学故障电弧模型，构建模拟实验平台，研究故障电弧放电过程及其与电磁场、流场和电缆相互作用机理，揭示故障电弧的产生、发展、熄灭以及重燃的演化规律；分析故障电弧物理参量和电气参量暂态特征及影响因素，研究故障电弧动态特性；采用快速傅立叶变换、小波变换等方法，研究故障电弧的时域、频域特征，提出辨识故障电弧的特征参数；分析故障电弧能量、电弧运动特性与电缆烧蚀规律的关系，研究故障电弧保护特性。本项目的研究成果，为现代飞机的故障电弧检测技术奠定理论基础和电气系统综合控制与健康管理提供技术支撑。

航空电缆故障电弧是引发空难事故的主要原因之一。为了能及时发现故障电弧，提高现代飞机供配电系统运行的安全性，迫切需要研究故障电弧的特性、识别与保护方法等关键科学问题。本项目从试验、仿真及诊断的角度开展研究，构建直流28V、270V和交流115V /400Hz电源下串联和并联故障电弧实验平台，研究了考虑多种负载、振动和环境压力等因素的故障电弧演化规律，得到了故障电弧的动态特性及影响规律。分别采用小波包分解和集合经验模态分解方法研究直流和交流故障电弧特征参数，对于直流故障电弧，采用了coif1小波包分解基函数确定故障特征频率段为1562.5Hz—7812.5Hz，选取相应频率段节点2、3、4、5的能量熵作为故障特征量。对于交流故障电弧，采用第2、3、4本征模态分量的能量熵作为故障特征量。建立了磁流体动力学的故障电弧仿真模型及建立仿真平台，计算了300-30000K混合蒸气电弧等离子体热力学参数和输运参数，并仿真了燃弧过程，分析故障电弧能量扩散。建立了电缆绝缘的烧蚀模型，计算了电弧能量与电缆烧蚀的关系，当电弧能量通量小于10^9W/m^2时，应考虑烧蚀时间，且该时间随电弧能量通量变化较大。采用LM算法优化的BP神经网络，直流和交流故障电弧的识别正确率分别达95%和90%以上。分析给出了以采样周期10ms连续十个周期来识别直流故障电弧，以采样周期5ms连续十个周期来识别交流故障电弧的诊断方法；通过计算故障电弧作用下电缆绝缘达到热解温度所需要时间，给出了反时限保护规律。结合故障电弧的识别、诊断和烧蚀研究，认为持续并联故障电弧主要依靠电气系统的过电流保护来防止故障电弧，间歇性或较大阻抗短路引起的并联故障电弧以及串联故障电弧需要依靠故障电弧的识别和诊断来完成保护。本项目的研究成果可为现代飞机的故障电弧检测技术研究和电气系统综合控制与健康管理提供技术支撑。