阻断式直流开断中狭缝电弧行为特性及其与器壁材料相互作用机理研究

In order to meet the requirement of fast and reliable breaking of large fault current in millisecond time in medium and low voltage DC system. A arc-blocking DC breaking method based on narrow slot arc is proposed in this project. The behavior of narrow slot arc and its interaction with the wall of slot are studied. Firstly, by observing the wall erosion behavior under arc in the narrow slot, the influencing factors and mechanism of wall erosion are analyzed. The mathematical model of wall erosion is established. By the model, the relationship between arc energy and erosion quantity of wall materials are obtained. Then, the interaction between narrow slot arc and wall material is studied. The energy transfer mechanism of narrow slot arc and the influence of wall erosion on the transport characteristics of arc plasma are analyzed. The mathematical model of narrow slot arc considering wall erosion is established. The intrinsic mechanism and law of influence on the behavior of narrow slot arc are obtained. Finally, based on the arc model combined with the test of breaking characteristics, the main factors and laws affecting the characteristics of arc motion are analysed. The control method and adaptability of narrow slot arc are put forward. It can provide theoretical basis for the application of arc-blocking DC breaking method. And according to the breaking requirements of typical DC system, the specific control measures of narrow slot arc are put forward by optimizing the design parameters. A principle DC breaker prototype of arc-blocking breaking is developed.

为了满足中低压直流系统毫秒级时间内快速可靠分断大容量短路故障的要求，本项目提出了基于狭缝灭弧的阻断式直流快速开断方法，并围绕狭缝电弧行为特性及其与绝缘器壁相互作用机理开展研究。首先，通过对狭缝电弧作用下绝缘器壁侵蚀行为的观测，分析器壁侵蚀的机理和影响因素，并建立器壁侵蚀数学模型，获得电弧能量与器壁材料侵蚀量的内在关系；然后，研究狭缝电弧与器壁材料的相互作用过程，分析狭缝电弧的能量传递机制和器壁侵蚀对狭缝电弧等离子体输运特性的影响，建立考虑器壁侵蚀的狭缝电弧数学模型，获得影响电弧行为特性的内在机理和规律。最后，基于狭缝电弧模型结合开断特性的测试，分析影响电弧运动特性的主要因素和规律，提出狭缝电弧调控的方法及适应性，为阻断式直流开断方法的应用提供理论依据。并针对典型直流系统的开断要求，通过参数的优化提出狭缝电弧调控的具体措施，研制阻断式直流开断原理样机。

国防重大装备、民用关键设施以及新能源系统的快速发展，使得中低压直流配电系统的容量持续增长，短路故障电流等级也急剧增加。现有的直流开断方法难以满足快速可靠大容量开断的需求，直流断路器的快速分断技术成为制约直流配电系统快速发展的一大瓶颈。为了满足中低压直流系统毫秒级时间内快速可靠开断大容量直流短路故障的要求，本项目提出基于狭缝电弧的阻断式直流快速开断方法，并围绕狭缝电弧电气特性及其与绝缘器壁相互作用机理开展研究。首先，研究了狭缝空气电弧电气特性的测试方法，测试获得狭缝电弧电气特性的变化规律以及狭缝尺寸、器壁材料等因素对狭缝电弧伏安特性的影响规律。在此基础上，建立了狭缝电弧伏安特性的数学模型。然后，分析了狭缝电弧的能量传递机制，研究获得了狭缝截面尺寸、壁面材料、以及开断电流等因素对壁面烧蚀质量和狭缝峰值气压的影响及规律，建立了壁面烧蚀质量和狭缝内峰值气压的数学模型。最后，分析了利用狭缝快速挤压拉弧过程动态电弧的特性，提出了阻断式开断方法和实现手段，设计研制了直流开断实验样机，测试获得不同电流和开断速度下的开断特性及影响规律，确定了阻断式原理样机单元的设计参数，该样机单元实现了500V/22kA/5ms的可靠开断。