A Turnkey Solution for Computing the Static Breakdown Voltage in HVDC Applications Utilising Atmospheric Parameters

Reducing the distances between components that carry voltage and the grounding electrodes is essential for cost optimization when designing and sizing systems for high-voltage applications like transformer stations, converter stations, and high-voltage laboratories. The insulating medium in this example is atmospheric air. In order to avoid electrical breakdowns or so-called flashovers, the air gaps must be designed appropriately as part of the isolation coordination. The conventional calculation of air gaps is based on empirically determined equations with correction factors for climatic conditions and the used geometries. However, before complete electrical breakdown occurs, phenomena such as Townsend and Streamer discharges occur. In weakly homogeneous and homogeneous electrode arrangements, these discharges lead directly to a complete breakdown due to the sufficiently high electric field strength over the entire stroke width. In a previous publication, an innovative method was used to design air gaps for DC voltage stresses. However, the gas composition and especially the atmospheric parameters such as humidity and temperature have an influence on the dielectric strength. The aim of this publication is therefore to extend the innovative model for calculating the static breakdown voltage to also take into account the influence of humidity and temperature. The result is a method for the numerical calculation of the breakdown voltage on the basis of gas-physical processes, apart from empirical equations. The geometry is also arbitrarily complex.