Development of Online Monitoring and Controlling System for the 630 kVA Three-Phase High Temperature Superconducting Transformer

The 630 kVA three-phase high temperature superconducting (HTS) transformer is one of the key parts of the superconducting power substation, which has been successfully developed and put into operation in live grid for the first time around the world in 2011. The real-time monitoring system ensures the safe operation of HTS transformer and superconducting power substation. The system measures those signals pertaining to the operation of HTS transformer, such as voltage, current, liquid level, and an automatic supply of liquid nitrogen is achieved. This paper introduces the structure and testing features of 630kVA/10.5kV HTS transformer, and illustrates the influences on the testing procedures, as well as solutions, while the system runs in adverse magnetic environment. The project covers schematic design, structure design, function implementation and system integration. The data collected for liquid nitrogen loss is also analyzed and discussed. The successful development of 630kVA three-phase HTS real-time monitoring system is a foundation for the normal operation of superconducting power substation. Consequently, the experiences gained from this project will certainly benefit the development of high-capacity and high voltage superconducting transformer in the future.