Industry background:

The main load of the steel rolling power distribution system is the DC motor. The working voltage is 0.4KV, 0.66KV, 0.75KV, etc. The characteristics are short working cycle, fast speed, large load impact change, and a large amount of harmonics and reactive power generated during operation. The DC motor adopts thyristor rectification technology, with low power factor and high harmonic content, which reduces the effective load of the transformer, generates heat, increases losses, causes some relays to malfunction, and affects the operation of other equipment.

Site description: 

       The project is a steel rolling production line with the following loads: 3 units of 500 flat rolling machines Z710-6B type 1350KW 660V; 11 units of 500 flat rolling machines Z560-4B type 1000KW 660V; 6 units of 550 flat rolling machines Z560-3B type 630kw 660V.

The harmonics generated by the single-side winding of the rolling mill rectifier transformer are mainly 5th, 7th, 11th and 13th harmonics. The low-voltage side is a double-winding y △ connection method, and the high voltage shows 11th and 13th harmonics. The power factor is 0.6-0.7, and the transformer has a low effective load. The power quality problem is prominent. Our company designed according to the load data and determined the following solutions:

Solution:

 Install a dynamic filter compensation XHTSF device on the 660V bus side with a design capacity of 10,000kvar. Use high-performance, high-power thyristor dynamic switching to control harmonics and quickly compensate for reactive power. The power factor is increased to above 0.95, which increases the effective load of the transformer and stabilizes production.

Eliminate some characteristic harmonics such as 5th, 7th, 11th, and 13th harmonics, and the filtering effect is obvious; increase the effective load of the distribution transformer, reduce the transformer temperature and noise, and increase the transformer life. Reduce voltage fluctuations and suppress voltage flicker, improve voltage stability, and improve voltage quality; reduce user line losses and improve production efficiency. It has a complete control system, short-circuit protection, overvoltage protection, overcurrent protection, reliable operation, and intelligent operation.

Scope of application: Metallurgical industry steel rolling, plate rolling, galvanizing production line, oil drilling platform, mining hoist, etc.; Voltage: 400V, 600V, 660V, 690V, 750V, 800V, etc.