The power must flow
Written by: Sam Fenwick | Published:

Wireless comms play a huge and increasing role in the neverending battle to keep the lights on, as Sam Fenwick discovers in this piece on the utility industry

Richard Luke, chief operating officer (COO), at the Joint Radio Company (JRC), says its priority, and that of some of the other focus groups in the utility industry, this year “is very much about making government and regulators aware that the changes they are demanding (such as the shift to smart grid and low carbon generation) requires a magnitude of change in wireless communications”.

He adds that the shift from centralised to distributed generation, given the rise of renewable power sources such as solar cells and wind turbines has transformed the electricity grid’s operating model as, prior to their adoption, electricity flowed in a single direction. This change is requiring distribution network operators (DNOs) to become distribution system operators (DSOs), which Luke says have a much bigger role to play, and he adds that the increased complexity of the system requires real-time data links.

“Radio is perfect for that application. Running smart grids over the air requires an absolute minimum of 2 X 3MHz TDD LTE in UHF, and a lot of our focus is on obtaining this.”

He explains that utilities tend to focus on 400-500MHz, given the way in which the amount of infrastructure required increases exponentially as you go up in frequency, and utilities’ focus on optimising cost rather than maximising download speeds. Luke also highlights the fact that the need to be able to monitor multiple points on an asset increases the amount of operational data that is generated, which is dwarfed by IP packetisation and security overheads, and this is another driver behind the utility industry’s need for more spectrum.

“If we don’t get that, they can forget about achieving the transition to the smart grid and meeting our low-carbon targets,” he warns. Part of the problem could well be due to the sector’s own success – the electricity supply is so reliable that people can be forgiven for assuming that on any given day, the sun will rise, the lights will turn on when they try to turn their smartphone’s alarm off and there will be plenty of hot water waiting for them when they take a shower.

A rude awakening

That said, a recent incident has served as a sharp reminder that this mundane miracle relies on a hugely complex system that cannot be taken for granted. I am speaking here of the events that took place on 9 August when five per cent of the UK’s power demand (some 1.1 million customers) was cut to preserve the integrity of the system when a lightning strike, which reduced some distributed generation, coincided with a drop in supply from the Hornsea off-shore windfarm and the Little Barford gas power station. Ofgem is investigating the incident, partly to ensure that “the industry learns the relevant lessons”.

Luke adds that he is seeing some hope in the increasing interest in spectrum sharing (it is worth noting Ofcom’s decision to enable shared spectrum access for local use and applications to use spectrum that is held by mobile operators but is not being used or planned to be used in typically remote areas). He also explains that given the inefficiencies created by hand-offs and multiple interfaces, it would be better to have a single system for all utilities, which would be built to deal with a worst-case scenario.

Speaking of which, Luke says Black Start (the process of bringing the national electricity transmission system back online following a total or partial shutdown) is being heavily reviewed at the moment as it relies on bringing back large central power sources online, “but as we shift to distributed generation, that may not be possible”.

Private LTE

“From a wireless perspective, I expect that the next 5-10 years will see continued roll-out of narrowband solutions for monitoring the high- and medium-value items on a distribution grid in a highly resilient way, but at the same time I expect that there will be significant innovations to allow the monitoring, capturing, leveraging and control of the new sources of data that are out there,” says Jamie Bishop, general manager – transport at Tait Communications. “There has to be a way of [connecting] these devices, which is potentially broadband, but utilities need to have a certain degree of control and management over it.”

Luke highlights the private LTE trial that was initiated by Western Power Distribution (WPD) two years ago in Avonmouth, which is still running. He adds that WPD brought JRC on board to work out how this approach could be expanded across its entire operational area, “We did a study that looked into spectrum, coverage, throughput, and we defined a system that could be scaled up to their full area. While most people draw circles on a map for coverage, and that was our starting point, we very quickly moved beyond that, given that LTE connectivity is driven by propagation and received signal strength and utilities need minimum guaranteed bandwidth. Our model accounts for propagation and throughput.”

Bishop says that Tait is looking to provide broadband network cores, also known as evolved packet cores (EPCs), to utilities so that they could run their own dedicated private networks or a network that is integrated with public networks. He explains that Tait is looking to provide this as part of a collaboration, and there is some sharing of intellectual property rights (IPR) – “we’re not developing from the ground up,” he adds. Bishop says Tait will be coming to market with this solution (which will be able to support hundreds or low thousands of sites) very soon and the company will focus on offering the flexibility required to meet utilities’ business models rather than competing head-on with the big mobile infrastructure providers.

He expects the challenge with the private broadband network approach from a utility perspective will be around spectrum, business case and return on investment (ROI). However, “I think the ROI will stack up because having the connectivity will provide significantly better management of the grid, which will become essential given the disruption caused by distributed generation and electric vehicles.”

Bishop says Tait will be speaking with JRC members about this approach at a meeting after the FCS BR ’19 event, along with “integrating it into an IoT platform and standards-based IoT sensors, as well as the distribution network management platforms that we traditionally work and interface with”.

Cheap and cheerful sensors

Turning to the Internet of Things (IoT), JRC’s Luke says “there is definitely a place for it [in the utility sector]”, but notes its limitations when it comes to mission-critical applications.

It may therefore come as no surprise that The Critical Communications Association (TCCA)’s SCADA, Smartgrid and Telemetry Group recently published a white paper (https://bit.ly/36fal2y) that looks at ‘Emerging IoT Bearers for non-Mission Critical SCADA’.

Nick Smye, the Group’s chair and principal consultant with Mason Advisory, says a trial that Scottish and Southern Energy Networks (SSEN) has performed on the Isle of Skye is an interesting example of this approach. The Isle “has very rugged terrain, which is subject to the full force of the Atlantic. The Island has one main transmission line, which runs across it. If that fails, a lot of people lose their supply and it could take a long time to find the break and repair it. As it is a remote location, there is little cellular coverage, so SSEN was looking for some way of measuring condition of the line.”

SSEN therefore worked to develop a remote monitoring system with EkkoSense, and this was installed on the 809 poles that carry the line and cover an area of more than 1,000 sq km on the Isle.

“The line is made up of wooden poles that can rot,” adds Smye. “Traditionally you’d do a line inspection every few years, physically check every pole and assess its physical strength. SSEN carried out a LoRa trial with an accelerometer sensor on each pole. This allowed them to measure the deflection of the pole, so when a storm comes in, if there’s some structural weakness, you may see one pole bending a lot more than the others. The sensors are so sensitive that they can detect a sheep rubbing against the pole. That’s a really interesting approach. I heard about it six to nine months ago and SSEN was getting a huge amount of data from it.”

He adds that one thing that needs to be considered is that while in this trial, interference is unlikely to be an issue, given its remote location, the same might not be true of an urban environment. As Sigfox, LoRa and Wi-Sun use licence-exempt spectrum, they offer no protection against interference, in contrast to 3GPP LPWA technologies such as NB-IoT and LTE-M.

JRC’s Luke says he is aware of a number of trials where remote sensors have been used to monitor the temperature of transformers, as there is a tight correlation between this and their performance and failure rate. He adds that this is a good example where “cheap and cheerful sensors can have significant impact on an asset that costs hundreds or thousands of pounds”. However, Luke warns that “IoT is being marketed as the fix-all for automation challenges; it’s not, it’s just one tool in the toolbox and it needs to be used appropriately”.

Tait’s Bishop adds that the UK’s power sector operates in seven-year cycles and utilities are currently putting their business plans together for the 2023-2030 period with the goal of submitting them to Ofgem (the sector’s regulator) for approval in late 2021/early 2022. “They’re therefore spending innovation funds to work out which of the next-generation solutions they’ll be needing to procure in 2023-2030, and at the same time they’re also making their investments from the last spending cycle – we’re in the middle of that now.” He explains that the latter is “essentially the narrowband projects that can be practically delivered under current regulatory structures, eg, Ofcom frequencies being available whether it be for voice or grid automation – the latter is driving the business cases, as it has by far the biggest impact on their KPIs as service providers”.

Luke says MPT 1327, the trunked analogue two-way radio technology used by most of the UK’s utilities, is increasingly becoming obsolete, so there is lot of interest in IP-based communications technology packetised media. He adds that JRC is working with a couple of utilities that are interested in LTE/DMR packetised voice as a value-added service.

Bishop says he is expecting utilities to move away from “traditional grid standards and toward the IoT environment” in the next period of funding. One potential application for IoT that he sees is allowing distribution companies to monitor power generation from roof-mounted solar panels or micro wind turbines at the individual property level rather than “relying on more traditional points on a medium voltage grid, such as a substation”. While doing this on a small scale wouldn’t add much value, a large-scale approach, combined with greater adoption of distributed generation, would give the distribution company much greater visibility from a data perspective.

From what we have heard it is an interesting time for the UK’s electricity sector and its wireless comms vendors. Given the challenges ahead, it is clear that our politicians need to realise that Brexit is not the only issue of huge significance to our country’s future.


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