Modernising a London Data Centre: Converting DRUPS to Standby Power

DRUPS (Diesel Rotary Uninterruptible Power Supplies) systems are an industry legacy – they ensure reliable, uninterrupted power when the national power grid fails. 

DRUPS systems combine a diesel engine with a flywheel-based UPS, and our Special Projects team have begun converting these systems into fully operational standby generators.

Since 2020, our team have been proudly working on the UK’s first DRUPS-conversion project in the industry.

Our client needed to future-proof their infrastructure without losing resilience. As one of the largest data centre operators in London Docklands, our client’s brief requested the conversion of legacy DRUPS systems. The decision to convert rather than replace is based on four key reasons.  

• Significant financial savings
• Reduces environmental impact
• Minimises disruptions to site
• Lowers maintenance time

Laying the groundwork

Phase One began in 2020, when we were contracted to convert six DRUPS to HV standby generators. The client’s trust and confidence in AVK allowed us to provide the turnkey solution.  Our Special Projects team:

• Assessed and removed the original DRUPS infrastructure.
• Retained the existing DRUPS bedframe and modified it to accommodate a new Nidec alternator, thus converting it to a generating set.
• Conducted torsional vibration analysis to confirm the characteristics of the flexible coupling and AVMs, ensuring mechanical integrity.
• Integrated a new control system, installed the high-voltage (HV) switch gear and provided a distributed power station allowing the client’s load to connect directly to our upgraded system.

Phase One provided us with a multitude of learning opportunities, encountering time constraints and methodology issues. Our ‘lessons learnt’ allow us to streamline our processes and delivery in challenging environments.

This project has been acknowledged by our client as a landmark achievement for our industry, setting a new standard of excellence. In recognition of the outstanding quality delivered, AVK was subsequently awarded the contract for Phase Two.

Scaling up and optimising delivery

Phase Two has so far consisted of the conversion of 11 units, and AVK is now preparing to convert 10 more. An element of Phase Two involves a different DRUPS variant, requiring significant design alterations, and a new execution methodology to accommodate.

This second phase also includes ‘ring topology’ switchgear, so that every generator has its own switchboard. This presented new challenges for us to overcome with space constraints and significant additional HV cabling in a busy switchroom, along with additional synchronising control requirements.

“Integrating and commissioning new, critical systems in a live data centre environment is the most challenging aspect of Special Projects. We must plan and execute our work stringently to ensure we don’t affect the client’s resilience.”

John Beesley – VP of Special Projects

By completion in 2026, we will have converted 26 DRUPS systems and integrated three functioning generators to develop a total of 4no. power stations. This includes 29 generator synchronising switchboards, 29 GCPs, 29 SCPs, 26 NERs, 8 MCPs and the repurpose of 25 VCBs to make up distribution switchgear. Alongside this, 26 engine overhauls and the installation of 3370m of HV cable.

A service built on trust

Our proven ability to execute complex work with the utmost safety, efficiency and minimal disruption has transformed what began as a one-off project into a long-term collaboration. From the exterior, one would never know the magnitude or intricacy of the work taking place within – an approach which we consider essential as the industry continues to evolve.

What’s next?

A new energy centre is due to be constructed on-site as part of a wider power intensification programme. AVK has been invited to tender for this next phase and if selected, we will be ready to deliver again.