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Ignition of discharges in macroscopic isolated voids and first electron availability

pubblicazioni - Articolo

Ignition of discharges in macroscopic isolated voids and first electron availability

Si discute un modello di innesco di scarica per effetto Schottky tale da migliorare la qualità della simulazione delle scariche parziali.

Internal partial discharges and electrical treeing are some of the main aging mechanisms of all the polymeric insulating materials present in the power net. A better understanding of this process calls for the development of more sophisticated simulation tools based on the numerical solution of first principles equations i.e. a set of partial differential equations. The accuracy of the predictions of these models heavily relies on the quality of the set of physical parameters used as, for example, the swarm parameters. A key aspect is the correct representation of the first electron availability which triggers the discharge.

These electrons are mainly injected into the gas from the interface between the gas itself and the solid polymeric matrix by means of the Schottky effect. The work function is a very relevant parameter in defining this effect and so the entire quality of the simulation process depends on it. In this work we both estimate the value of the work function using ab-initio quantumelectronic structure simulations and we perform some parametric analyses to show how the discharge simulations are affected by the variation of this quantity. In particular we assume that the polymeric material is polyethylene which is used extensively in the electric power delivery industry. The discharge simulations produce also some relevant data that can be compared against experimental data for validation purposes.

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