Extending life of old assets is key to grid sustainability

Grid sustainability has two meanings, each closely linked. It means keeping networks running with the resources available – both physical and financial; and equipping them to enable the transition to a net zero carbon future. New technologies are critical for both aspects of sustainability. But so is keeping older assets running, to extend their performance way beyond their original design lives.

Fundamentals works at both ends of the spectrum, specifically in voltage control, which is increasingly vital as the grid adapts to historic changes in the ways electricity is generated and consumed: from intermittent supplies from renewables, to fast-changing demand from customers who need to power their electrified homes and vehicles.

New meets old in voltage control

In the new tech arena, our SuperTAPP SG smart grid automatic voltage controller is widely used as a plug-in unit, adding advanced automation and communications to distribution substations. Our latest development is software-only AVC packages, working on multiple platforms as part of the move towards highly automated, fully digital substations.

At the old tech end of the spectrum, we support a vast range of electro-mechanical tapchangers in more than 30 countries, including Ferranti, Metropolitan Vickers, AEI and English Electric, because they remain the core voltage control assets on many grids worldwide, as well as in the UK. Many have been operating efficiently for more than 60 years and have decades of life left in them, with regular maintenance and upgrades – a textbook example of getting the most out of older assets, to maximise the value of original investments and reduce the need for new costs.

100+ year asset life?

I have lost count of the conversations I have had with newer generations of grid engineers who, knowing Fundamentals for our new tech AVC expertise, are amazed that we can help keep tapchangers working that were installed long before they were born. Let me give you an example:

We were recently called to a 132/11/11kV transformer with a tapchanger that was starting to give problems after more than six decades of operation. The site engineers were considering a complete transformer and tapchanger replacement at a cost of £2 million. They were astonished when we told them we had the parts, factory manuals and know-how to restore its performance to 100% – and doubly amazed when we said that, with basic maintenance, it would last at least another 35-40 years and probably reach its 100th birthday.

Among the advantages of old electro-mechanical units is that many were robustly engineered, with parts such as contacts and switches that are accessible and relatively easy to replace. With basic mechanical maintenance, plus monitoring of oil levels and condition, their life expectancy is effectively infinite.

From dumb to smart

The biggest limitation of older assets is that they are dumb, because they were designed before the current demand for communications, automation and control. Transforming them into smart members of modern digital platforms is being addressed with new products under the IEC 61850 international standard. This defines the protocols which enable communication between different equipment located in a substation, such as protection, control, and measurement equipment, as well as intelligent electronic devices (IEDs). Modern controller interfaces equip them to be fully integrated with DNO management systems, greatly reducing the need for physical interventions.

In addition to communications functionality, tapchangers and transformers can be modernised with a range of upgrades, including digital probes for monitoring temperatures and the latest breathers for controlling moisture. But the essential engineering of electro-mechanical assets remains as fit for purpose as ever.

Repair and re-use

Even the best old assets will eventually need replacing. But redundant tapchangers, for example, still have value. So we buy them in, strip down some for re-usable components, refurbish some to good-as-new condition and supply them with a full five year warranty. Yet another way grid operators can align with the sustainability mantra of ‘repair and re-use’.

At Fundamentals, we see no disparity between working at the cutting edge of digital substation technology and keeping legacy electro-mechanical assets running for decades to come. Both are aspects of Total Voltage Control and are essential for the sustainability of the grid – and its ability to deliver clean, green electricity for a sustainable future.