ABB’s new medium-voltage circuit breaker boosts steel plant performance and equipment life

VD4-AF is an all-in-one compact device with synchronization, continuous monitoring and precise control of its own mechanical and electrical performances.


Boosting steel industry management by increasing the lifetime of assets and reducing operating costs, the newly released VD4-AF1 is the first medium-voltage (MV) circuit breaker with servomotors, enabling precise drive control and true inrush free transformer switching for applications up to 38kV.  

It also improves asset protection and maximizes output by extending equipment life by more than 10 percent over three years and allows up to 5-to-10-times higher endurance than the market standard.  

Steelmaking is one of the most severe applications for any circuit breaker, due to the rigors and extreme processes in an electric arc furnace. Such extremes can impact the health of the transformer and the assets of the plant, causing costly maintenance, downtime and reduced plant efficiency.  

The new all-in-one compact device means that the equipment previously required to resolve the challenges of the environment are no longer needed, leading to significant cost and space savings in plants that usually suffer from heavy equipment costs. 

“With a firm focus on designing safety into our products, the new features of VD4-AF1 reduce the risk of equipment failure and protect site operators. Smart monitoring and diagnostic features will also enable customers to benefit from improved analytics that provide our customers with visibility into the health status of their circuit breaker. These are just some of the features we introduce to ensure that we improve customer experience through safe, smart and sustainable solutions”, said Matteo Caiti, Global Product Group Manager, Control and Protection Products and Services for ABB. 

The VD4-AF1 solution protects the transformer by eliminating current and voltage transients (negative events that harm the electrical circuit) which can happen during transformer switching, through an embedded sensor. As such, the VD4-AF1 offers continuous predictive health indication and accurate synchronization with network voltage, to control accuracy and precision of the electrical current passing through the furnace while reducing risk of component failure and enhancing safety. 

In addition to the technical capabilities, the VD4-AF1 is designed with a draw-out, roll-on-floor construction, to be combined, if required, with ABB indoor enclosures, allowing a faster and easier integration or replacement operation in the steel industry 

Detailed information about VD4-AF1 circuit breaker, its advantages and main features can be found on the ABB website 

ABB (ABBN: SIX Swiss Ex) is a leading global technology company that energizes the transformation of society and industry to achieve a more productive, sustainable future. By connecting software to its electrification, robotics, automation and motion portfolio, ABB pushes the boundaries of technology to drive performance to new levels. With a history of excellence stretching back more than 130 years, ABB’s success is driven by about 105,000 talented employees in over 100 countries. 

ABB’s Electrification Business Area is a global leader in electrical products and solutions, operating in more than 100 countries, with over 200 manufacturing sites. Our 50,000+ employees are dedicated to delivering safe, smart and sustainable electrification. With ABB AbilityTM enabled digital solutions at its core, our portfolio protects, connects and optimizes the flow of electrical energy for smarter electricity distribution for utilities, industry, buildings, infrastructure and mobility. For more information visit 


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