Does OVO have plans to offer a 3 Phase smart meter for supplies larger than "100A per phase” connections (CT-type meters), and “vector sum” compliant?

Thanks for that news @SeanS.

Have a look at this other Topic about 3-phase metering where we specifically discussed the requirement for “vector sum metering”.

I’ve just looked at the Spec sheet on the SGM 1430 series from Aclara and I can’t see any reference to vector sum. I think they’d be claiming such functionality if it was present, don’t you?

I can’t see many domestic customers clamoring for a 3-phase meter which provides no ability to cope with exporting on one or two phases whilst importing on the third.

What do you think?

Hi @Transparent I just scanned the Aclara data sheet of this model and they do not use the phrase “vector sum metering”, however it does note “Class B Active, Import and Export, Class 2/3 Reactive 3 x”. This to me suggests that this meter is capable of calculating both import and export energy. Now whether the meter presumably does this *correctly* (one would hope) taking into account the net import and export energy across ALL of the phases, and accounting for the possible variations in the net apparent/real/reactive power per phase (presumably the definition for ‘vector sum’) only Aclara would be able to say for certain.  

Interestingly in the press release blurb from the Good Energy blog, their customer, Emmanuel Obubuafo, is noted as having a 12 kW solar array on his house. Presumably this chap would want his net energy import taking into account his solar export to be correctly metered…if I was in his position I certainly would expect it.

It’s also worth noting that this 3-phase meter from Aclara might be OK for larger domestic 3-phase connections, but that only covers the “entry level” shall we say of 3-phase connections - that is those typically under 100A per phase. Though to be fair such direct-current meters would adequately cover the expected connection sizes of the vast majority of OVO customers I’d reckon.

However there still is no SMETS2 solution right now for larger single customer 3-phase connections (admittedly we’re now veering into the territory of extra large “domestic” connections and really into medium to larger commercial and industrial connections, so not really your typical OVO customer base!) that require smart metering for > 100A per phase supplies and these use CT-type (rather than direct-current) 3-phase metering. To my knowledge no energy supplier or meter supplier has officially announced anything for these bigger connections, although both Drax and EDMI have teased with this…a “trial of polyphase SMETS 2 smart meters aimed at giving Drax’s larger business customers better control of their power use, making them more sustainable...”

A close look at the photo shows a development (direct current measurement) EDMI ES-30B meter with “export” shown on the display….though that meter in itself is not really capable for “larger” businesses I would have said. Note also that the EDMI ES-30B data sheet does not mention “vector sum” but the measured values lists are what you would expect to see for a meter that reports import and export energy.

Personally my motivations for wanting 3-phase “smart” metering are rather more prosaic - (a) the ability to have “smart” meters that don’t become instantly “dumb” (as the present 3-phase remote-read AMR type meters do) when changing from supplier X to supplier Y and (b) the capability of working with ‘smart’ gas meters to give an err integrated metering and energy monitoring solution. Presumably both are the raison d’etre of SMETS2 over earlier SMETS1 (and AMR type remote meter read) standards. Proper energy import/export when using micro-generation metering would be nice to have, but its not strictly needed (right now) for any of my 3-phase connections.

Well I’m largely in agreement with you @SeanS. Just a few points to pick up:

a: If Good Energy’s customer has a 12kW array on his house, then I think we must assume that this is a nominal 4kW per phase to comply with G98 export certification limit of 16A/phase. That being so, he wouldn’t be concerned about vector-sum metering because his export will be balanced across the 3 phases.

b: I’m intrigued that Aclara have inbuilt a Zigbee transceiver in the SGM1400 series meters. That means it could be installed on a site where the Comms Hub is remote rather than being physically connected to the IHCI. The SGM1400 display also has status indication for a gas meter - presumably to avoid needing to view the Comms Hub LEDs.

c: I’m sending a PM to an OVO Techie to see if we can glean any better insight into the “Class B Active, Import and Export, Class 2/3 Reactive 3 x” part of the specification.

d: I have a new estate being built near me where such a meter might be required. The housing developer has installed gas combi-boilers with a shower running off this. However, the larger houses have a master-bed en-suite bathroom, and I can’t see how the second shower could be run from the same boiler. That suggests it will have to be electric (40A). All these houses have a feed to support an EV charger (32A) and an electric double-oven. That 100A Service Fuse is going to be too close for comfort.

I’m sorry I simply can’t see the word Drax as a manufacturer without imagining this:

@Transparent a quick email to both Aclara and EDMI Europe directly may elicit a more (hopefully) thorough answer as to “meter capability”, perhaps that even OVO technical folks are not aware of. I guess this falls somewhere between “meter capability” (the meter manufacturer) and “meter configuration” (combination of meter manufacturer and energy supplier).

This “issue” around imbalanced energy import/export across phases is not a new one. Here is a relatively old (2013)  document from the Association of Meter Operators that describes it quite well. Quote from that document in Section 3.5 (Future):

“The government policy requiring the installation of smart meters by 2020 will result in these older meters designs being replaced. So this issue is a time limited issue whose impact will decline more rapidly during the roll-out of smart meters. As at August 2013, the SMETS smart meter specification will correctly meter import and export energy by whole current meters, although it does currently replicate the issue described above for twin element meters.”

So yeah here we are in 2020! One would hope and presume that this new generation of 3-phase electronic SMETS2 compliant meters released quite recently, as the Aclara SGM1400 series (2019) and the forthcoming EDMI ES-30B meter (2020) both would account for this in their design and measurement capability. It would be quite astounding if they didn't.

I would also be astounded if this isn't something the DCC check when they certify a meter for use as part of the SMETS2 compliance procedures….then again.

Again, I substantially agree with what you write, @SeanS

I opted to message an OVO Engineer first because:

• it was he who told me about the code that OVO themselves download into the SMETS2 Meters whilst we were discussing software faults in their R&D lab at Bristol. The meter doesn’t just use code written by the manufacturer.
• To implement the vector-sum functionality, there must also be matching algorithms in the Billing Software.

So we could yet find a meter manufacturer saying that vector-sum is possible for a given model of meter, whilst failing to tell us that it would require several months of software development from an Energy Supplier!

I’ve looked at how OVO’s Billing System has support for half-hour variable costings, despite the fact that they don’t yet offer a Time Of Use tariff.

So I’d really hope they’ve also built in the hooks to permit data inputs from a vector-sum meter whilst they were designing it.

We might find that a Moderator could ask this question directly to a Product Manager in the Billing Software Team, based in London. @Amy_OVO - are you up for that?

Yes thanks for initiating the messaging with the OVO tech folk @Transparent and agreed the meter needs to firstly support this (hopefully all these new SMETS2 compliant polyphase ones do) + whatever configuration needed from the energy supplier.

However, it then begs the question, IF there is loads of “customisation” required by the energy supplier to make a given smart meter work properly (for import/export energy measurement) with their billing back-end - how will interoperability work when a customer shifts from Supplier X to Supplier Y - one would presume that this would be reasonably seamless in SMETS2 land. Otherwise it’s deja vu...a ”dumb” meter in another form.

Hopefully some insight here from OVO soon, on what their plans are.

 @Transparent and @SeanS - This discussion is really insightful, thank you! I’m going to be honest with you though, there’s a some points of discussion that are a bit beyond my understanding.

I can certainly raise this with the relevant department, but I wanna make sure I’m asking the right questions!

Would you like me to ask them whether SMETS2 installations on a 3-phase supply rely on vector sum metering? Apologies if this is way off the mark, I’m struggling to get my head around all this technical jargon!

Many thanks @Ed_OVO

A couple of things would be good to know.

1. When will OVO support SMETS2 metering for 3-phase supplies?
2. Furthermore will this be an “up to 100A per phase” solution only (direct-current / whole current type meters) or will there be metering solutions that can also consider “larger than 100A per phase” connections (CT-type meters)?
3. Will the metering solution solution be “vector sum” compliant - that is correctly account for differing import and export energy across the phases and measuring the true energy, where for example a customer may have their own (solar or other) micro-generation that exports unevenly on perhaps one or two phases?
4. Will the 3-phase SMETS2 solution presumably interoperate with SMETS2 gas meters and also when changing supplier

Yes please @Ed_OVO - bounce this to the relevant techies.

I PM’d Ben coz he’s got access to the SMETS R&D lab, but no response yet.

We’re not going to get answers from just one Department. The issue straddles the SMETS Engineers and the programmers developing the new Billing System.

To some extent it’s possible that you also need to check with Utilita because you use the BOL from uSmart to connect to DCC. But that shouldn’t interfere with the contents of your data packets, and therefore shouldn’t be an issue.

I think I can already surmise the answer to Question 4 from @SeanS 

The SMETS2 commands are completely interoperable if a user switches Energy Supplier. The issue is whether the billing software can handle different rates across the phases being used for import and export.

Ultimately that comes down to the Tariff they offer.

And @Ed_OVO the pace of the technical advances in the energy sector are clearly going beyond the background comprehension of the Moderators. I have previously suggested that your team members should take an occasional day-out, just as a school teacher would have “in-service training”.

You actually need to visit a substation, a hydro-electric generation plant and a wind-turbine facility with energy storage.

Been doing some digging on the Smart Energy Code (SEC) Company website…found this within the recesses of the subsidiary documents of the SEC. If anyone is having trouble sleeping tonight I recommend perusing this website! 

In terms of meeting the SMETS2 technical standard for the meters themselves, for three-phase (or more inclusively polyphase meters), SEC Schedule 9 - Smart Metering Equipment Technical Specifications 2 v4.2 (4 July 2019). Under Part C (Polyphase Electricity Metering Equipment), section 5.17, we have spec as follows.

Note the terminology “vector sum” isn’t actually used, however the functional description of energy measurement is effectively that:

5.17 Functional Requirements

ESME shall be capable of calculating Active Power Import, Consumption, Reactive Energy Import, Active Energy Export and Reactive Energy Export values as follows:

1. Active Power Import shall be the sum of the Active Power Import on the importing measuring element(s) of its Electricity Meter less the sum of the Active Power Export on the exporting measuring element(s) of its Electricity Meter;
2. Consumption shall be the sum of the cumulative Active Energy Imported on the importing measuring element(s) of its Electricity Meter less the sum of the cumulative Active Energy Exported on the exporting measuring element(s) of its Electricity Meter;
3. Reactive Energy Import shall be the sum of the cumulative Reactive Energy Import on the importing measuring element(s) of its Electricity Meter less the sum of the cumulative Reactive Energy Export on the exporting measuring element(s) of its Electricity Meter;
4. Active Energy Export shall be the sum of the cumulative Active Energy Export on the exporting measuring element(s) of its Electricity Meter less the sum of the cumulative Active Energy Import on the importing measuring element(s) of its Electricity Meter; and
5. Reactive Energy Export shall be the sum of the cumulative Reactive Energy Export on the exporting measuring element(s) of its Electricity Meter less the sum of the cumulative Reactive Energy Import on the importing measuring element(s) of its Electricity Meter.

If the result of any of the calculations (i) to (v) is negative then it shall be deemed to be zero.

So that’s the 3-phase (sorry sir Polyphase) SMETS2 meters themselves covered.