Tianjin Electric Research Institute, a subsidiary of Sinomach, has independently developed a high-power three-level AC-DC-AC frequency converter, which passed a test run in the high roller mill modification project of Taiyuan Iron & Steel Group Co (TISCO).
It marks the first application of a domestic medium-voltage frequency conversion system in the Sendzimir mill and fills in the gap in the application of domestic products in high-end stainless cold rolling mills.
The original automation and transmission system of the unit in the TISCO Stainless Steel Cold Rolling Mill was supplied by a foreign producer in 2002.
It has current problems such as ageing, a high failure rate and lack of spare parts. As a result, the stable and normal operation of the unit could not be guaranteed.
After an in-depth study of the characteristics of the original unit, Tianjin Electric Research Institute took the lead in proposing a matching solution with the original automation system, and verified its feasibility on site.
The institute’s technicians carefully recorded and analyzed hundreds of data items on transmission and automation in operation of the original system, making sure that each index of the new system was not lower than that of the original one.
According to the collected data, the research and development personnel have optimized the control and algorithm of the frequency converter in the process of independent development.
The project team completed the modification five days ahead of schedule and returned the unit to its normal production level on the first day of application of the new system, with the control accuracy increased from 0.2 percent to 0.1 percent.
Meanwhile, the process data acquisition device developed by the institute also passed field trials.
The institute also successfully replaced the imported frequency converter with the independently developed medium-voltage three-level TMV1 active rectifier and inverter, marking great breakthroughs in domestic technical equipment.