Application of electronic secondary technologies to 1000 kV gas-insulated switchgear and transformers

To achieve the target of starting operation at the beginning of the twenty-first century, 1000 kV GIS and transformer were developed. From the viewpoint of enhancement of reliability and rationalization of operation and maintenance, not only the primary equipment but also the secondary equipment such as electronic current and voltage transformer and monitoring sensors for 1000 kV equipment are the key technologies. 1000 kV GIS and transformers, which are subjected to long-term tests in a UHV Equipment Test Site, have special structures. With an on-line monitoring system using several sensors suitable for 1000 kV equipment, we have collected testing data and monitored the functionality. For the voltage transformer, we have introduced an optical potential device. Throughout the long-term field test, we have verified the performance and the reliability. It has been found that the electronic secondary devices and systems for 1000 kV substation operated properly and these technologies are mentioned to be applicable for the future 1000 kV substations.