Ultra high‐voltage gas‐insulated switchgear – a technology milestone

Abstract

SUMMARYChina is in urgent need of electrical power. Huge power plants are built all over the country and the enormous flow of electrical power to the large megacities has to cross several thousand kilometres from the source to the end user. At those dimensions, losses of the power lines can be significant. The State Grid Corporation of China (SGCC) is thus aiming for 1100 kV as the voltage level for AC transmission to keep losses as low as possible, a step into a new area of electrical grids. Asea Brown Boveri (ABB), together with its partners and suppliers, has developed the heart of such a system -a gas-insulated switchgear (GIS) design -that could pass all the tests with this groundbreaking technology. Many years of experience at voltage levels of up to 800 kV are available as the basis for developing GIS for 1100 kV. Nevertheless, the individual components such as circuit-breakers (CB) and disconnectors differ greatly from the known designs. As regards the CB, for instance, it emerges that a design with the closing resistor in a parallel tank is advantageous. The very fast transient overvoltages become more important for the disconnector design.

Multi-spark modeling of very fast transient overvoltages for the purposes of developing HV and UHV gas-insulated switchgear and of conducting insulation co-ordination studies

“…This leads to the highest number of associated breakdown flashovers occurring in the disconnector contact system during the disconnector opening and closing operations. Figure 1 shows an example of the GIS pole layout, as piloted in the Jingmen 1100 kV station in China [10], where the "breaker-and-a-half" configuration of the GIS pole was used.…”

“…1. "Breaker-and-a-half" configuration of a GIS pole as piloted in the Jingmen 1100 kV AIS-GIS hybrid substation [10] Fig. 1.…”

“…s to the highest number of the associated n flashovers occurring in the disconnector stem during the disconnector opening and closing . shows example of the GIS pole layout, as piloted n 1100 kV station in China [10], where the nd-a-half" configuration of the GIS pole was FTO generation process is determined by voltage on the source-and on the load-side of the tor contact system, on characteristics of the eakdowns in the disconnector contact gap (the so rks), and on the parameters characterizing the onents that the disconnector is connected to. The nditions primarily determine the instances of the contact system primarily determines high frequency nature of the VFTO waveforms.…”

“…1. "Breaker-and-a-half" configuration of a GIS pole as piloted in Jingmen 1100 kV AIS-GIS hybrid substation [10]: DS -disconnector operated, CB -Circuit Breaker; S -source-side 50/60 Hz voltage, Lload side voltage on the GIS busbar between disconnector DS and circuitbreaker CB.…”

“…Several papers have been published based on this work, addressing different aspects of VFTO measurements and simulations. As an example, in [9] the impact of the disconnectors moving contact speed on the variety of VFTO parameters is analyzed.Also in the previous works conducted by ABB, the VFTO have been investigated to support design work of the 1100 kV disconnector [10,11] and to analyze the impact of the VFTO on selection of the VFTO damping solutions [6]. These works utilized the so-called multi-spark approach [4,12] for modeling the entire process of disconnector operation and to analyze distributions of the VFTO, along with other parameters, such as trapped charge voltage distributions, arcing time and number of sparks -and the mutual effect of these qualities and the GIS disconnector design.…”