Smart meter - could it control my energy?

YBR

This is probably a stupid question, but do smart meters have a function to control electricity/gas (essentially can I be cut off remotely) or does it only report usage?

I realise that there would be a legal process to go through, and I'm in credit with my supplier so I'm not in the firing line, but mistakes can be made!

Swipe

Yes, smart meters have the ability to remotely cut off supply to a premises

matelodave

However if you've got paygo or token meter - if you dont top them up then they cutoff the gas or leccy gets cut off until you put so credit back on them. 

Although there's all the scaremongering about smart meters bing able to control the suplly, I've not yet heard of anyone being remotely cut-off although I've heard a lot of whinging from those who's paygo meter has run out and they have been been left in the dark or cold until they've got it sorted.

(I've no doubt there will be those who know of a friend's, husband's wife's girlfriend'd uncle etc to whom it has happened)

[Deleted User]

There is logic to having smart meters with remote disconnection facilities built in, but I accept that these come with some small risk. Some countries offer cheap tariffs based on the maximum power (kWs) drawn from the Grid at certain times of the day. If this limit is exceeded, the supplier will send out messages to the IHD; by text et al to warn that the agreed KW limit is being exceeded. As a last resort, the supply will be disconnected from the Grid. The consumer than phones a dedicated line to restore power. Frequent breaches result in a change of tariff. In this situation, use of the on/off switch is by mutual consent.

The very small risk is of disconnection by a remote actor. GCHQ which has provided the layered security built into our smart meter system believes that the risk is minimal.

YBR

Thanks for all your replies. 
I'm sure the cyber-security aspects are much more robust than some other household smart devices, and they're not particularly vulnerable to malicious third party actors. 
I'm not on pay-meter so that's fine.
I'd heard scare-mongering about suppliers cutting you off in error, and know that there are instances of energy companies entering premises to cut them off in error. Of course it would be even easier for an error to cut off the wrong house if all it takes is pressing the wrong button! So wanted to check at least one truth with you knowledgeable people.

[Deleted User]

YBR said:

Thanks for all your replies. 
I'm sure the cyber-security aspects are much more robust than some other household smart devices, and they're not particularly vulnerable to malicious third party actors. 
I'm not on pay-meter so that's fine.
I'd heard scare-mongering about suppliers cutting you off in error, and know that there are instances of energy companies entering premises to cut them off in error. Of course it would be even easier for an error to cut off the wrong house if all it takes is pressing the wrong button! So wanted to check at least one truth with you knowledgeable people.

Let us put the above comment into context. The last published Ofgem figures that I can find are as follows:

In 2018, suppliers in Great Britain disconnected just six electricity disconnections for debt (there were no disconnections in Scotland or Wales) and, for the first time since we started recording data on disconnections, there have been no gas disconnections for debt.

The default position these days is that suppliers fit prepayment meters which are usually smart. Even fitting a prepayment meter requires the supplier to obtain a Warrant of Entry. No one is, as you put it, going to press the wrong button. Even pressing the button (if there is such a thing which there isn't) will require the supplier to obtain a Court Order UNLESS there is a Maximum Demand contract in place where the customer agrees to limit demand.

If scare-mongering is going on then why are you repeating the claims? 

QrizB

If you've ever wondered what's inside a smart meter (including the fabled remote disconnection contactor) you might enjoy this video by Big Clive:

https://www.youtube.com/watch?v=G32NYQpvy8Q
Edited for typos.

[Deleted User]

Spain, like many countries, has just got on and rolled out mandatory smart meters which include remote disconnection for power exceedances (instant kWs) which is now built into many tariffs. The more consumers restrict their demand the less they pay.

Intelligent meter technology

The E450 PRIME smart electricity meters delivered to Iberdrola include advanced functionality to provide the utility much more than just near real time consumption figures for billing purposes. Besides consumption, energy generated can also be measured. The E450 meter enables power disconnection and connection, which supports the contract management processes within the utility and can be used to empower the gathering of billing receivables. Thresholds can also be set to disconnect the power if the preset limit is exceeded.

If consumers willing sign up to this type of tariff, they really cannot complain when they turn on their shower whilst charging their EV in a restricted/high demand period, if the power goes off. 

Jeff_Dee

That's an interesting video QrizB. What Clive missed was the fact that there is actually a microphone inside, it's just disguised as a capacitor.*

A purely technical and non-conspiracy question about the 'off switch', which is a smallish relay inside the smart meter. 

Is this rated to break a large load? For example under a worst case scenario when the oven and shower are on and a lot of current is being drawn at the time of switch-off. Or maybe it can do the switch at near zero-crossing to reduce the arc across the contacts.

* Not really true, sorry for being flippant.

QrizB

Jeff_Dee said:

That's an interesting video QrizB. What Clive missed was the fact that there is actually a microphone inside, it's just disguised as a capacitor.*

* Not really true, sorry for being flippant.

Jeff_Dee said:

A purely technical and non-conspiracy question about the 'off switch', which is a smallish relay inside the smart meter. 

Is this rated to break a large load? For example under a worst case scenario when the oven and shower are on and a lot of current is being drawn at the time of switch-off. Or maybe it can do the switch at near zero-crossing to reduce the arc across the contacts.

I've wondered the same, and made the same assumption that the system can switch at or near the zero point. It is only an assumption and it would be interesting to know more.

[Deleted User]

Jeff_Dee said:

A purely technical and non-conspiracy question about the 'off switch', which is a smallish relay inside the smart meter. 

Is this rated to break a large load? For example under a worst case scenario when the oven and shower are on and a lot of current is being drawn at the time of switch-off. Or maybe it can do the switch at near zero-crossing to reduce the arc across the contacts.

Yes it is, check the data sheet for type 723 as shown in Clive's video.

https://www.gruner.de/relais/produktfinder

Rated to break 120 amps which is more than enough for a domestic supply.

As for doing the switch at near zero crossing, well it isn't so simple with AC circuits, just because voltage is at the zero crossing it doesn't mean current is at zero, they lag / lead when using capacitive / inductive loads so they will never be an exact moment where current and voltage are both zero.

Even if there was a 100% resistive load only, the voltage is at zero 100 times as second - so it changes from zero to full and back to zero in just 10ms. The above relay is rated at 15ms actions time, so the voltage will have been zero twice and back to full voltage twice in that time period it takes to complete the disconnection.

In other words, not worth bothering with trying to disconnect at the zero point, just build a relay capable of handling the arc and suppressing it as quick as possible.

At 343 volts (240v RMS) the spark distance in air is 7.5 micrometers (0.0075mm). The relay opens to 8mm so the arc is suppressed very quickly.