To the Evaluation of the Insulation State Based on the Analysis of Partial Discharges

The existing partial discharge models, their diagnostic value, and application area are analyzed in the article. The models are considered from the point of view of their improvement or the possibility of creating new diagnostic methods for electrical equipment based on the characteristics of partial discharges. As an example of the implementation of a new approach to partial discharge modeling, a quasi-deterministic model is considered, which makes it possible to obtain information on the real number of cavities in the insulation of high-voltage equipment.

Discharge modeling of a DC magnetron

A two-dimensional simulation of a glow discharge of a dc magnetron operating in an argon is performed in this work. The “Plasm” and “Magnetic Fields/No Currents” modules of the COMSOL Multiphysics software package were used for modeling. All models are constructed within the framework of a stationary problem. Obtained results correspond to the physical concepts of the glow discharge of a balanced magnetron

Progress in modeling streamer and leader discharges­­­

<p>We present recent progress in pulsed discharge modeling in Amsterdam that is motivated by high voltage and plasma engineering and by lightning.</p><p>We perform streamer simulations with adaptive mesh refinement in 2D and 3D using PIC particle models and fluid models, where we now can include complex electrode shapes and dielectric boundaries. For the longer time evolution, we also have added Ohmic heating, gas expansion, and the relevant ­­­plasma chemistry for air and methane-air mixtures.</p><p>Results relevant for lightning physics include</p><ul><li>Validation and verification of streamer propagation models (with S. Dijcks and S. Nijdam for the experimental counterpart)</li> <li>Simulations of streamer branching and comparison with experiments</li> <li>Parameter studies for long non-branching streamers that can accelerate or decelerate, and vary largely in velocity, radius and inner electron density, depending on the electric field</li> <li>Different stagnation behavior of positive and negative streamers in low electric fields</li> <li>Positive streamers in air that can continue to propagate as isolated patches of positive charge, without a conducting channel behind the streamer head</li> <li>Repetitive discharges, heating, and plasma-chemistry</li> </ul>