Investigation on the spatial arc resistance distribution of switching arcs in gas filled high voltage circuit breakers

在高压断路器领域，填充六氟化硫(SF6)的自爆式断路器是最先进的。用于高压供电系统的电路开关。由于这些断路器作为保护元件，它们需要在故障情况下切断额定电流和短路电流。由于SF6具有较高的全球变暖潜力，人们正在研究替代气体，以期获得经济和生态优势。一种可能的替代品是二氧化碳(CO2)。有必要研究这种替代品是否可以使用，以及是否必须改变SF6断路器的设计，以使CO2断路器具有最佳的开关性能。为了在这种开发过程的密集实验测试中节省时间和成本，需要对可以应用于不同气体的物理过程和数学模型有深入的了解。这有助于改进最初针对SF6和替代气体进行优化的断路器的设计。用于断路器开发和设计的最先进的模拟工具是为研究具有传统几何组件的SF6断路器而设计的。由于它们是通过实验的事后视图进行配置的，因此它们不能应用于替代组件和气体。因此，在第一个项目中开发的测量系统将用于研究不同气体和流动条件下的引弧行为。这些信息可以用来导出合适的仿真模型。这些型号尤其应能够促进使用SF6替代品的断路器的开发。到目前为止，最先进的模拟工具还不能计算出与SF6不同的二氧化碳冷却机制。除了模型对不同气体替代品的适用性外，针对淬火气体的断路器几何形状的定制也是至关重要的。利用前面的研究以及开发的测量系统作为进一步参数变化的基础，可以更好地理解断路器合闸过程中的物理过程。因此，这种理解可以在数值模型中实现。除了喷嘴几何形状和淬火气体压力的变化外，主要关注的是吹气的变化。例如，应使用SF6、二氧化碳和空气进行调查。所建立的仿真模型必须适用于非SF6断路器的开发。

In the field of high voltage circuit breakers self-blast circuit breakers filled with sulphur hexa fluoride (SF6) are state of the art. They are used for switching electric circuits of the high voltage power supply systems. As these breakers serve as protective components, they are required tointerrupt nominal currents as well as short circuit currents in case of a failure.Due to the high global warming potential of SF6, alternative gases are investigated aiming for economic and ecologic advantages. One possible substitute is carbon dioxide (CO2). It is necessary to investigate, if this substitute can be used and whether the design of a SF6 circuit breaker has to be changed for an optimal switching performance of a CO2 circuit breaker. A deep understanding of both the physical processes and the mathematical models, which can be applied on different gases,are required in order to save time and costduring intensive experimental tests of such a development process. This helps to improve the design of circuit breakers, which were initially optimized for SF6,for alternative gases.State of the art simulation tools for circuit breaker development and design are designed for investigating SF6 breakers with conventional geometric assemblies. As they are configured via an ex-post view on experiments they cannot be applied to alternative assemblies and gases. Hence the measurement system, which has been developed in the first project, shall be used for investigating the arcing behaviour for different gases and flow conditions. This information can be used to derive suitable simulation models. These models shall in particular be able to enhance the development of circuit breakers with SF6 substitutes. Up to now state of the art simulation tools are not able to calculate the different cooling mechanisms of CO2 in contrast to the mechanisms of SF6. In addition to the applicability of the models for different gas alternatives, the customization of breaker geometry for the quenching gas is of vital importance.Using the previous investigations as well as the developed measurement system as a basis for further parameter variations, the physical processes during the switching process of a circuit breaker can be better understood. Hence this understanding can be implemented in numerical models. Next to the variation of the nozzle-geometry and the quenching gas pressure the main focus is on the variation of the blowing gas. For instance the gases SF6, CO2 and air shall be used for the investigations. The derived simulation models are required to be applicable for the development of non-SF6 circuit breakers.