Automatic Optimization of Gas Insulated Components Based on the Streamer Inception Criterion

Abstract

Gas insulated transmission lines (GILs) are used in electrical systems mainly for power transmission and High Voltage substation interconnection. In this paper, we focus on the development of complex numerical tools for the optimization of gas insulated HVDC components by the estimation of realistic electric field distribution and the voltage holding of the designed geometry. In particular, the paper aims at describing the correct modelling approach suitable to study high voltage components in DC, considering the nonlinear behaviour characterizing the electrical conductivity of solid and gas insulators. The simulated field distribution is then adopted to estimate the voltage holding of the dielectric gas, with a convenient engineering technique, based on the streamer criterion. These two tools are integrated in an automatic optimization package developed in COMSOL® and MATLAB®, with the purpose of adjusting the critical geometry features, suffering from excessive electrical stress and possibly giving rise to electrical breakdown, in order to guide the designer towards a robust solution.

Development of HVDC Gas-Insulated Components for the Power Supply of Neutral Beam Injectors

“…Model ( 6)-( 7) is realized in the Transport of Diluted Species (TDS) physics, while the electric field is evaluated by the Electric Currents module, assigning σ G = 0 S/m to the gas and coupling the two analysis with a boundary current source given by the TDS [53]. The boundary and initial conditions for the model ( 6)-( 7) are described in [14].…”

“…In order to homogenize and thus reduce the field in the surface layer, different solutions were proposed. One approach consists in modifying the geometry by using the shape optimization approach [13], [14], another take advantage of particular materials such as the surface functional graded materials (SFGM) [15]. When dealing with nonlinear resistive field grading materials (FGM), for electric fields below the switching value E 1 kV/mm the material behaves as dielectric, while for stresses E > E 1 the material become conductive and consequently a significant increase of Joule heating takes place.…”

“…The critical reduced electric field (E/N ) 0 correspond to the value for which ᾱ = 0. Once the trend of ᾱ is known for the insulating gas adopted, for example from experimental fittings or by solving the collisional Boltzmann equation as stated in [14], the streamer criterion can be used in symbiosis with an optimization algorithm which allow to automatically redesign the critical parts of the geometry.…”

Study of Breakdown Voltage Stability of Gas-Filled Surge Arresters in the Presence of Gamma Radiation

“…[13,14]. It should be noted that similar research with gaseous components was conducted, for example, with HVDC components estimating the distribution of the electric field and the voltage holding of the designed geometry [15]. Ref.…”

“…Ref. [15] also describes the research that concerns the correct modeling approach suitable to study high-voltage components in DC. Moreover, the investigations of the implementation and design of real-time breakdown voltage and temperature monitored system for single avalanche diodes are published in Ref.…”