CSG “Electrifies” the World’s First 160kV DC SFCL

CSG engineers adjust the lines for the bushing monitoring device of the 160kV DC SFCL.

Shantou, Guangdong - July 9, 2002 - The world’s first 160kV DC SFCL was placed on line which “electrified” the site of the Nan’ao VSC-MTDC Pilot Project located here as this super project entered its key stage of field tests.
The DC SFCL, known as the direct current superconducting fault current limiter, is a device to limit the fault current. When there is a fault in VSC-HVDC system, the DC SFCL lowers the short circuit current to help the circuit breaker easily cut power on time.
“The characteristics of short-circuit fault in VSC-HVDC systems are totally different from that in FACTS, and there was no worldwide precedent to follow, which means the design and development of the 160kV DC SFCL have to be done through indigenous innovation,” said Sheng Chao, lead manager of the China Southern Power Grid project.
The primary challenge of the design was simulating the fault current of VSC-HVDC systems, which, however, related closely to the design parameter of DC SFCL.
To solve these issues, the project team spent one full year in building a multi-field coupling design for DC SFCL based on thermal equivalent analysis and another half year in developing several experimental facility sets for simulating fault current of VSC-HVDC systems and impulse power discharge, providing a massive amount of data for the design of DC SFCL.
One of the core issues during DC SFCL design was which superconductor material should be chosen.
The R&D team independently fully explored the material and conducted thousands of sample experiments, exploring the proper crafts, compositions and parameters for the superconductors and analyzing the deficiencies of different materials.
Finally, CSG engineers successfully developed a high-performance HTS tape (YBCO tape) for the resistance DC SFCL by the end of 2018 and put it in mass production.
By the end of July, the integrated test and artificial short circuit experiment is expected to be finished and a six-month trial run will begin.