Development of Large-Capacity Gas-Insulated Transformer

Detection in Spacer of Gas-Insulated Switchgears

With the increasing demand for precise condition monitoring and diagnosis of 11 gas-insulated switchgears (GIS), it has become a challenge to improve the detection sensitivity of 12 partial discharge (PD) induced in the GIS spacer. This paper deals with the elimination of the 13 capacitive component from the phase resolved partial discharge (PRPD) signal generated in GIS 14 spacer based on the ...

New 550-kV Gas-insulated Switchgear

OVERVIEW: Hitachi has developed smaller and more reliable gas-insulated switchgear (GIS) in response to demands for lower costs and stable power supplies. Reliability of this GIS was improved and the enclosure diameter was reduced in order to minimize the installation space by using new analysis techniques and rationalization in insulation design and in temperature rise criteria. Furthermore, t...

Development of Large Capacity CO2 Scroll Compressor

CO2 refrigerant with a high operating pressure has a large difference between the suction and discharge pressures in compressors. Because of a load increase, the high performance and high reliability of compressors are required. Compared to the scroll compressor employing the conventional refrigerant, the thrust load increases in the CO2 scroll compressor. Therefore the design of thrust bearing...

Development of Large Capacity Photonic Network Technologies

Analysis of effective factors on transient ground potential rise in gas insulated substations

This study presents the manner in which transient modeling concepts, which are fully analyzed in the referred standards, are implemented, for the purpose of evaluating the Transient Ground Potential Rise (TGPR). This is a phenomenon of 10–100kV voltages with up to 10μs duration on the grounded enclosure of Gas Insulated Substations (GIS), which may cause concern for personnel safety and problem...