Preventing breakdown by direct optimization approach

The ultimate goal when designing the HV apparatus is to prevent the breakdown appearance during the operational conditions. In this paper we present the modeling approach for the optimal design of HV devices. Here we combine several tools that in an automatic iterative loop converge to the final, breakdown-free design. The integrated framework contains the module for BEM-based field computation, the tool for free-form optimization of the real-world problems and the controlling tool for breakdown criteria evaluation. In each iteration step after calculating the field distribution, the new instance of the possible final design is proposed by the module for the free-form optimization and checked by tool for the automatic control of the breakdown appearance. The brief description of the techniques used within the integrated framework (simulation / optimization / controlling) is given. Special attention is paid to the optimization approach. Here we use the gradient-less free-form optimization approach for both direct (sensitivity-less) and indirect (simple sensitivity-based) optimization. The procedure is illustrated by some examples of the optimization of the real-world apparatus (switches, circuit breakers). The optimal design proposed by the simulation is verified by the laboratory tests.