基于压控材料与真空电弧协同驱使的电流转移特性研究

In recent years, the demand for the rapidity and reliability of current commutation is more and more urgent in the high current parallel breaking, the fault commutation current limiting and the hybrid DC breaking. The essence of current commutation is the voltage competition between parallel branches. The traditional method of relying on mechanical fracture or power electronic commutation is more difficult to satisfy both the flow-through ability and the rapid commutation. In this study, a method based on pressure-controlled material co-operating with a vacuum interrupter to drive the current commutation will be used. The resistance of the material will rapidly increase under mechanical pressure control, and the branch voltage will increase so current can be rapidly driven. The vacuum fracture acts breaking current and withstanding voltage after arc extinguishes. The project intends to study the pressure-resistance characteristics, temperature characteristics and breakdown characteristics of the materials. Through the establishment of models such as pressure-controlled module and commutation arc, the cascaded pressure-controlled module groups and the operation sequence with the vacuum interrupters, the parallel branch impedance characteristics and other factors in the commutation process will be simulated and analyzed. The commutation strategy will be optimized by the collection and analysis of the commutation arc image and the measurement of the post-arc dielectric recovery strength. Finally, by setting up the experimental platform of the whole equipment, the feasibility of the overall scheme is verified, the commutation arc model will be modified, and the current commutation mechanism under synergistic operation will be explored, which can give guidance for the practical research in current commutation.

近年来电力系统中，大电流并联开断、故障转移限流、混合式直流开断等场合对电流转移的快速性及可靠性需求越来越迫切。电流转移的本质是并联支路间的电压竞争。传统依靠机械断口或电力电子器件转移电流的方法较难同时满足通流能力和转移快速性。本研究提出一种基于压控材料协同真空电弧驱使电流转移的方法，通过机械方式使压控材料的电阻迅速提升，进而提高支路电压来加快电流转移速度，并由真空断口配合完成电流开断及弧后耐压。项目拟对材料的压阻特性、温度特性、击穿特性等进行研究，通过建立压控模块及转移电弧等模型，仿真分析级联压控模块组以及与真空断口间的动作时序、并联支路的阻抗特性等因素对转移过程的影响。通过转移电弧图像采集分析及弧后介质恢复强度的测量对转移策略进行优化。最终通过搭建整机实验平台，验证整体方案的可行性，对转移电弧模型进行修正，探索出协同操作下的电流转移机理，为多领域电流转移场合的实用化研究给出指导。

随着我国经济发展，电网容量不断增大，大电流并联开断、故障转移限流、混合式直流开断等场合对电流转移的快速性及可靠性需求越来越迫切。本课题对一种压控材料与电弧协同进行电流转移的应用进行了研究，利用压控材料电阻在压力作用下快速发生变化的特点实现阻抗快速切换，并与电弧协同配合促进电流转移快速可靠完成。首先对压控材料的电气特性进行了研究，总结了各种因素对压控材料电阻影响的规律，通过试验研究了压控材料的通流耐压特性，设计了基于压控材料的可变电阻模块。然后基于试验数据建立了压控材料和开关电弧的数学模型，对二者之间的协同配合情况进行了仿真，研究了压控模块与不同并联支路下的电流转移情况，得到了不同类型并联支路对转移过程的影响。设计制作了用于控制压控材料的混合式操动机构，并对机构的合闸保持力和分闸速度进行了优化。对电弧图像进行了采集，分析了电弧的燃弧过程，通过试验研究了压控材料对电弧的影响情况及压控材料对开关介质恢复的影响情况，并对二者之间的动作时序进行了讨论。最后搭建了整体试验平台，对压控材料与电弧串联下的转移限流特性进行了研究，分析了压控材料对电弧特性的影响规律，并最终确定了压控材料与电弧协同配合的转移限流方案，对压控材料在电力系统中的限流应用给出了指导方案。