Analysis on heat loss characteristics of a 10 kV HTS power substation

• A 10 kV High Temperature Superconducting power substation was developed.
• Analysis of four types of heat losses was fulfilled, it is the basement for the refrigeration system design.
• The principle and basis for analysis of the heat losses of HTS apparatus are discussed.
• The main apparatus and its heat load are calculated and analyzed, which agree well with the test result.
• The refrigeration system design was finished based on the heat losses analysis.

A 10 kV High Temperature Superconducting power substation (10 kV HTS substation), supported by Chinese State 863 projects, was developed and has been running to supply power for several factories for more than two years at an industrial park of Baiyin, Gansu province in Northwest China. The system of the 10 kV HTS substation compositions, including a HTS cable, a HTS transformer, a SFCL, and a SMES, are introduced. The SMES works at liquid helium temperature and the other three apparatus operates under liquid nitrogen condition. There are mainly four types of heat losses existing in each HTS apparatus of the 10 kV HTS substation, including AC loss, Joule heat loss, conductive heat, and leak-in heat from cryostat. A small quantity of AC loss still exists due to the harmonic component of the current when it carries DC for HTS apparatus. The principle and basis for analysis of the heat losses are introduced and the total heat loss of each apparatus are calculated or estimated, which agree well with the test result. The analysis and result presented are of importance for the design of the refrigeration system.