Forging great savings in South Wales

A steel company in South Wales carried out the UK’s largest construction project for 2012, with the important rebuild of its blast furnace. Part of the project involved the design, manufacture, supply, installation and commissioning of the transformer, drives, motors and control systems for the combustion air fans, cooling tower fans and fume extraction fans.

Replacing the existing Direct-On-Line motor starters with state-of-the-art low harmonic variable speed drives, along with new transformers and motors, would provide both cost and energy savings.

 

Our Solution

The combustion air fans comprised three variable speed drives, with the speed determined by duty cycle and combustion air demand. They operate as two duty and one standby, or together at a reduced speed. Each system consisted of:

• 1 – 3,300V/690V supply transformer
• 1 – 600kW ACS800 low harmonic variable speed drive
• 1 – local operator stations at the drive, transformer and motor

The existing fixed speed motor control systems for the watercooling towers were upgraded with three new variable speed drives each rated at 90KW, to maintain the set delivery water temperature. The Form 4 MCC consists of:

• 3 – ACS800 low harmonic 90KW VSDs
• 5 – 3P+N switch fuse supplies
• 3 – local operator stations located at each motor

The two fume extract fans driven by ‘Syncdrive’ variable speed drive systems were replaced with new motors inclusive of a new bed plate and half coupling. Each system consists of:

• 1 – 11,000V/690V Supply Transformer
• 1 – 2.7MW ACS800 Variable Speed Drive
• 1 – 2.7MW Motor including bedplate, coupling and guard
• 1 – local operator stations

The control and speed set point(s) for the above systems are derived from an ABB AC800 PLC via a high speed communications network.

Drives were housed in a bespoke IP54 steel container designed specifically for this application to include internal ducting, removing in excess of 50kW of dissipated heat.

Results

• Complete upgrade of old and obsolete equipment
• Reduced costs
• Increased energy savings

 

At the time of print, it’s believed these are the largest low voltage air cooled drives in the UK.