Beijing, China, Mar. 4 - The low-voltage terminal of Southern Hami Converter Station Pole II was successfully re-commissioned on Feb. 12 after a 168-hour trial run. This is the first time China has used its own valve technology to refurbish oversea supplier’s, which marks another technological progress in the field of HVDC converter valve.

A5000 type UHVDC converter valve technology was jointly developed by SGRI and C-EPRI in 2011. So far, A5000 has been employed in three ±800kV UHVDC projects, including Jinping-Sunan project, Xiluodu-Zhejiang project, and Southern Hami-Zhengzhou project, all with well proven performance.

The refurbishment was carried out by replacing key valve components supplied by another manufacturer, like damping resistor and TTM unit, yet without changing the valve structure.

After detailed calculations of electromagnetic distribution, electrical stresses, and thermal stresses, the refurbished valve managed to bring down the temperature of DC grading resistor from 100℃ to below 62℃, and hence contribute to improved equipment reliability. All the valves passed type tests in SGRI’s power system power electronics laboratory at the end of 2014.