故障电弧诱发电气线路火灾的电热耦合作用机制与发展规律研究

The electrical arcing conditions including safe or unintentional arcs occur regularly in many electrical circuits. Arc-fault is defined as an unintentional arcing condition in a circuit to distinguish from the arcs by normal operation. The continuous luminous discharge of the arc-fault and complex coupling effects between electrical and thermal parameters would raise the potential fire risk. This research work mainly focused on the combustion dynamics of the electrical fire induced by arc-fault, which would be experimentally and theoretically studied in detail. Firstly, the interaction mechanisms and developing characteristics of the arc-fault will be investigated to establish a systematic dynamical model for arc-fault circuit. Secondly, the process of heat and mass transfer of typical cable cover materials under the heating effect of arc-fault will be further studied with different electrical conditions. Then we will reveal the dynamical mechanisms and transition critical rules of flaming electrical fire induced by arc-fault. Based on the electro-thermal coupling dynamical model of arc-fault, a theoretical model on the special burning behavior of electrical circuit fire will be developed. Finally, a new early detection method of arc-fault for complex electrical conditions will be developed based on the above experimental and theoretical works. It would be helpful to enrich the scientific understandings on the mechanisms of arc-fault electrical fires from the works in this project. In addition, some important scientific support and application guidance could be provided for the early detection of arc-fault electrical fires.

电气线路中故障电弧的持续电热耦合作用易诱发电缆包层材料起火，形成高能弧柱激励下的特殊线路燃烧和火蔓延行为，对设备或人员安全均构成重大威胁。本项目针对当前故障电弧电气线路火灾研究中的薄弱环节，首先从故障电弧电、热特征参量的相互作用机制入手，系统研究故障电弧热效应参量与回路电气特征参量的关联反馈机制，建立故障电弧非稳态耦合发展动力学模型。然后，进一步研究典型线缆包层材料在故障电弧热作用下的复杂传热传质过程，从理论上揭示故障电弧诱发电缆明火的动力学机制和转捩临界条件。基于所建立的故障电弧电热耦合发展动力学模型，研究电缆包层在故障电弧作用下的特殊火蔓延行为，建立故障电弧电气线路火灾的系统动力学模型。最后，挖掘提炼该过程中的相关探测参量新特征，发展能够有效应对多种复杂电气环境的故障电弧综合探测方法。本项目有助于丰富对故障电弧电气线路火灾致灾机制的科学认识，并为此类火灾的早期识别、预警提供科学支撑。

项目研究围绕电气线路火灾中的故障电弧这一特殊现象，以故障电弧电、热特征参量相互作用机制为核心，通过自主设计研发的综合实验测试平台和理论分析，揭示了故障电弧热效应与电气特征参量的关联反馈机制，建立了故障电弧及由此产生的电气线缆火蔓延非稳态耦合发展动力学模型。以此为基础和指导，成功发展了基于高维特征空间广义闭区域的故障电弧诊断新方法，并大幅优化了电弧多参数早期识别算法，从而较好地解决了故障电弧诱发电气线路火灾在致灾机制、早期探测和防治方法上的一些关键科学技术问题。通过开展本项目，我们获得了以下重要结果：（1）利用自主研发测试平台，分别对故障电弧物理图像特征变化、电热特征参量发展趋势、电极表面特征温升、电芯轴向温度与径向环境梯度演化等开展了系统实验研究，探明了故障电弧早期电热特征参量耦合发展趋势。（2）针对电弧发生后引发的电气线缆包层复杂火蔓延，研究了回路强载流及电弧激励条件下的电缆材料熔融滴落复杂火蔓延行为，建立了热塑性包层材料熔滴燃烧动力学模型。（3）研究了热效应参量与回路电气特征参量关联反馈作用下故障电弧的双谱非线性动态特征，且初步给出了基于高维特征空间广义闭区域的故障电弧特征提取与诊断方法。（4）在实验平台基础上，通过进一步对电压源、负载等的多样性扩展，针对电弧早期探测与识别进行了算法优化，在大幅提高准确率的同时，有效克服了屏蔽作用和串扰现象的影响。总体而言，本项目研究较好地完成了预期目标，加深了对故障电弧电气线路火灾致灾机制的科学认识，其成果可为此类火灾的早期识别和预警提供科学支撑，具有重要的实际应用价值。