Predischarge models in dielectric liquids

This study presents self-consistent models of streamer growth using an equivalent electrical network, the only input data being the electrode geometry and the applied voltage waveform. The growth of filamentary and bushlike discharge structures are simulated. The initiation and the development of streamers are taken into account using field criteria. The streamer instantaneous propagation velocity is obtained using a model based on energetic considerations. In the case of filamentary streamers, each branch is assumed to be a cylindrical channel represented by an RC cell (R and C an, respectively, the resistance and the capacitance associated with each branch). The hazardous discharge propagation is also taken into account. hi the case of bush-like structures, the envelope of streamers is assumed to be approximately spherical. For given experimental conditions (such as applied voltage and electrode geometry), we determine the streamer characteristics such as the shape and amplitude of the streamer current, the electrical charge, the velocity, power and energy injected in the gap. The developed models also enable the simulation of an image converter working in streak or frame mode and the Streamer trajectory plotted in real time. An estimate of the pressure within bushlike streamer envelope is given. A good agreement between computed and experimental results has been obtained.