“Energy savings were promised, and the results so far have exceeded our expectations with a massive 40 – 45% reduction of electricity used in our NZ Steel crane operation. The ABB regenerative drives are showing themselves to be reliable and have been installed with little difficulty. ABB NZ has provided technical support throughout the project to ensure a smooth and successful delivery.” says Dion Cassidy, NZ Steel Plant Maintenance Superintendent.
Recently New Zealand Steel tasked the New Zealand ABB team with the modernisation of one of its large casting bay gantry cranes with ABB regenerative drives.
New Zealand Steel is a subsidiary of global leader BlueScope that makes and supplies steel for the building and construction industries, providing vital components for houses, buildings, structures, vehicles and more.
They are also New Zealand’s sole producer of flat rolled steel products operating a fully integrated steel mill. The process uses locally sourced iron sand to produce around 670,000 tonnes of steel a year.
The facility has a collection of four cranes in the Steel Plant referred to as Group 1, two of these are the West 125 Tonne (W125T) cranes found in the casting bay. Their primary task is to take ladles with 80 tonnes of molten steel from the steel making process and transfer them to the slab and billet casting machines.
Historically, New Zealand Steel has been installing ABB drives across a variety of different applications since 1999 when its automation engineers sought a VSD crane solution and ABB was the only manufacturer with dedicated crane firmware (with torque proving).
Gayomurd Desai, ABB Global Application Manager for Deck & Offshore Machinery says, “Since the first ABB crane drive install at New Zealand Steel which the ABB NZ team worked on with support from our Helsinki factory, New Zealand Steel has preferred having ABB drives on all their cranes. ABB’s product features, its reliability, and continuous technical support provided over many years have allowed us to build a longstanding trusted partnership with New Zealand Steel.”
Modernisation helps ensure process reliability
Since all four Group 1 cranes had ABB drives that were installed approximately 20 years ago with ABB NZ’s support, New Zealand Steel recognised the need to replace the drives on one of their W125T casting bay cranes with modern ones to make it more reliable and equipped with the latest technology.
Operations in the casting bay can continue for a short time with one crane non-operational, but if both cranes were to fail then the slab and billet production would cease at great cost to New Zealand Steel.
Regenerative drives help save energy and improve sustainability
Another key project consideration was that NZ Steel wished to reduce their energy consumption so they could make significant savings on their electricity costs and in doing so also have a more sustainable solution.
They also wanted to remove the brake resistors from the cranes and consequently eliminate the monthly maintenance associated with looking after them, plus reduce a potential point of failure.
Steel plants are dusty environments, hence blowing the dust off the brake resistors is one of the planned monthly maintenance tasks to prevent resistors from overheating and potentially failing.
The project faced logistical challenges due to the height at which the equipment needed to be installed on the crane which was 23 metres above ground. This was further complicated as the equipment needed to also fit through the small hatch opening in the crane roof.
ABB were selected to carry out this modernisation project because of their established track record of excellence in the field of industrial motor controls and longstanding relationship with New Zealand Steel.
New Zealand Steel decided to fit out the casting bay crane with five modern ABB ACS880 regenerative drives because of the expected energy savings and the opportunity to remove the braking resistors from the cranes.
In the first month of the W125T crane operating with all regenerative drives, there was a 40 – 45% reduction in the electricity used.
Removal of brake resistors reduces maintenance and provides operational savings
Removing the brake resistors has eliminated a laborious monthly maintenance task saving New Zealand Steel time, human resource and money, whilst reducing a point of failure.
Additionally, there were eight brake resistor cabinets on top of the crane which were removed after the regenerative drive installation. This also eliminated all the heavy electrical cables between the drive and resistor cabinets.
The project has been carried out on time and to budget with no mechanical faults despite the challenging work environment consisting of constricted spaces and working at height.
Glenn Cloutman, Steel Plant Automation Engineer for NZ Steel said, “The ABB drives we have used on our cranes have been exceptionally reliable. The ABB Drive Composer commissioning tool for drives is intuitive and easy to use. The support provided by ABB has been invaluable since our first installation in 1999.
We now have a crane equipped with modern ABB drives making it more reliable, that not only saves us a large amount of energy but makes our operation a lot more sustainable.”
