Storm Arwen lessons show enhanced asset monitoring is a ‘win-win’ for ED2

Electricity North West's Steve Cox sets out the barriers and opportunities around enhanced LV network monitoring.

Ofgem’s objectives broadly reflect both the needs of customers and the direction set out in the government’s recent Ten Point Energy Plan to accelerate net zero during ED2 – but at a price that customers can afford.

While those are the two primary dimensions, however, a third I would add is supply reliability. Of the 93,000 properties that lost power in the North West due to Storm Arwen, we restored 18,000 within three minutes and 90% within 48 hours. That still left a number of customers in rural areas off for significantly longer.

These are three – hopefully complimentary but sometimes conflicting – vectors rolled into a really interesting challenge.

Ofgem, to their credit, has provided £500 million in innovation funding across ED1. That is really starting to show in network business investment plans – with that funding paying more than several times over in cost reductions, and with customers seeing very significant increases in supply and reliability.

The frequency of supply interruptions on Electricity North West’s network has halved over the last eight years, with duration dropping by around 60%. A lot of that has come about through investment in technology.

However, it’s not through simply replacing assets that you deliver such performance – it’s through sensing and monitoring.

When deployed at scale, these technologies can yield benefits not only in terms of reliability, but in terms of replacing assets less frequently, extending lifespan, refurbishing them, and also boosting capacity en route to net zero.

Yet, while network businesses know a lot about assets above the ground, they currently know very little about what’s beneath their feet.

Replacement models suggest that low voltage cables – which represent approximately 60% of DNO-controlled assets – only need to be replaced every 1,000 years. This suggests they are being managed reactively and are not subject to more advanced and efficient asset management techniques.

What will happen when we start to increase the load on them? How will that affect reliability? What we’ve found is that advanced sensing gives you an insight into the health of those assets as well as their capacity for load and renewable generation, as well as improving the reliability. Deploying monitoring and sensing technology is a real win-win.

Electricity North West’s network visibility strategy

When people talk about net zero, they talk about opening up networks so that customers can connect low carbon technologies. However, there are a number of potential barriers.

One of them is power quality – effectively how clean, in a technical sense rather than a ‘green’ sense, the electricity is. If electricity is not clean enough, appliances won’t run properly. That can act as an early barrier to connection.

Additionally, there are both thermal barriers – a cable becoming too hot because of the amount of power – and voltage barriers – insufficient or excessive voltage on the cable causing appliances to shut down. The latter has been one of the real challenges with photovoltaics, for example, with excess voltage on the network causing it to shut down.

As technologies increasing the amount of power flowing through the network are deployed, you’ll hit one of these barriers, then another, then another – and they’ll swap positions in the stack. You need to measure each parameter to offer true network visibility and gauge where headroom exists. Very low-cost sensors will, for example, only accurately measure thermal performance rather than power quality or voltage.

Come the end of ED1, Electricity North West will have fully covered 40% of all customers. Our ED2 strategy is to ensure that 95% of customers are covered via sensing that spans power quality, capacity, and voltage.

Monitoring capacity

The sensors have been designed to allow us to efficiently touch the network – just once – to solve problems of today, tomorrow, and those we’re set to face in the coming decades.

As well as monitoring power quality, voltage and thermal capacity, the sensors we’ve chosen also detect cable faults before they cause a customer power outage.

If you can accurately measure that effect, you can not only detect that the cable is going to fail in a matter of days, but pinpoint where it will happen. That fundamentally changes our response to faults – from digging up holes in the middle of the night, to being able to intervene and fix the cable before it turns everybody’s lights out.

That is effectively the technology Electricity North West has developed with Kelvatek to deploy on the low voltage network at huge scale. Electricity North West has around 100,000 separate LV feeders. If we are to invest in those, which do we replace, which feeders are approaching end of life, and which are approaching capacity limits?

How do you combine those different investment drivers to choose the most efficient programme to keep costs as low as possible for customers? Our strategy with monitoring is to think about the full range of problems and invest efficiently.

A selective sensor rollout

We see the adoption of two low carbon technologies concentrated in urban and semi-urban areas. Therefore, our focus in the past few years have been Greater Manchester and large population centers in Lancashire investing to unlock capacity now for those customers who are adopting now – and less in rural areas where EV adoption is slower.

If we look at Greater Manchester, for example, the Greater Manchester Combined Authority has a very strong decarbonisation strategy. They’re investing heavily in social housing decarbonisation and are really pushing the clean air agenda through making Manchester an EV friendly city. They have the political drive, and our role is to facilitate in terms of network capacity.

Once our analysis reveals where technologies will cluster, and which customers will adopt first. This guides out sensor roll out program and focuses on urban, and semi-urban areas first. We expect by the end of ED2 only the 5% of customers living in predominantly remote rural areas will not have sensors fitted. In such areas LCTs are unlikely to cluster and the customer benefits from sensing are much lower.

Steve Cox is distribution system operation director at Electricity North West

This article is an extract from a new report by Utility Week, in association with Kelvatek, titled Sensing underground assets: LV network monitoring in ED2.