Wellington Electricity Network - Ripple Load Control Failing to Turn Off

Forums › Home Workshop DIY › Wellington Electricity Network - Ripple Load Control Failing to Turn Off - Request for Half Hour Meter Data

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273 posts

Ultimate Geek

#3234576 25-May-2024 13:57

From: https://www.southaucklandplumbing.co.nz/blog/hot-water-cylinder-overflow-explained/

"When water is heated it expands. That’s what we mean by thermal expansion. When the water in your cylinder is heated from cold, the volume can increase by as much as 3%; in a hot water cylinder with a capacity of 180 litres, that is as much as 5.4 litres. That extra water has to go somewhere! Hot water cylinders are manufactured to relieve this expanded hot water through an open vent pipe on the roof, or via a relief valve and pipe to an outside wall or drain."

We'd get less than 5 litres in 24 hours. As its questioned I'll measure it!

If its a mains pressure tank I'd be worried if no water was coming out, might be a warning of bad things to come!

Jase2985

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#3234625 25-May-2024 14:20

that contradicts your previous post which say the cold water expansion valve "does all the day to day reliving of pressure"

The pressure and volume you are talking about would be from the cylinder being cold, not from 55-60 degrees when it's routinely heating after either cooldown or the addition of cold water.

5L is a lot, that's likely the volume of hot water in a sink to do a load of dishes. Maybe for me, but my wife can stand hotter water than i can.

I'll see if I can fit a pipe to the outlet from the tank, but it's under the house in a galley trap which is not easily accessible.

From my calculations we are using about 90-150 minutes of a day of hot water heating, which is 4.5-7.5kWh of power.

Hinko

273 posts

Ultimate Geek

#3234668 25-May-2024 19:48

For anyone unsure about requesting data from their power retailer the Electricity Authority gives https://www.ea.govt.nz/industry/consumer-data/

Hinko

273 posts

Ultimate Geek

#3234740 26-May-2024 09:51

Jase2985:

From my calculations we are using about 90-150 minutes of a day of hot water heating, which is 4.5-7.5kWh of power.

Interesting. Is that based on a separately metered hot water cylinder? Or?

To be confirmed power was on thermostat 23:00 and off at 07:00.

Overnight 2.85 litres came out of the two relief valves from one cylinder. I understand that's normal and to be expected. Anyone else?

Hinko

273 posts

Ultimate Geek

#3234755 26-May-2024 11:03

nova:

How can you be sure that there weren't other factors that caused different total consumption on these days? Heating / oven use etc.

Because the Hot water cylinders (2) are on their own separately metered circuit. That data was downloaded and added up for different days. Easy to do. The conclusion is the same. Our use of hot water was not different to the extent of the increased energy consumption.

I've copied the actual metered data into the below table.

The difference between these two days is significant, we were billed (and paid) for an extra 10.286 kWh that we had not authorised or agreed to use or pay for.

Nor did anyone come back to us and say sorry you were overcharged and here is your refund.

This an example of the data one can receive from your power retailer should you have a smart meter and should you request the data.

SomeoneSomewhere

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#3234765 26-May-2024 12:14

95% of hot water cylinders are either on 24/7 or on something like the 19+ hours/day ripple plans. If you're burning 8kWh/day extra because your HWC is on longer, then you have a faulty HWC and it's not exactly the power company's fault.

Have you averaged this across a month or so? One extra shower is a few kWh.

I need to sit down properly and write some responses to your previous posts, but I'll leave you with this image for the intended purpose of the D16/N8 channel:

Hinko

273 posts

Ultimate Geek

#3234770 26-May-2024 12:36

SomeoneSomewhere:

95% of hot water cylinders are either on 24/7 or on something like the 19+ hours/day ripple plans....

While I've not checked your 95% figure, if it were correct that would mean there are 5% of consumers who are not on those systems, and are therefore most likely on "Night Boost" (10 hours on) or "Night Only" (8 hours on) controlled systems.

"Night Boost" or "Night Only" are the current official descriptors for these (!).

Those 5% of customers are also entitled to power to specification - or are you saying they are not?

Whether we have no faults or huge faults is irrelevant. The power is supposed to be off when it is supposed to be off. Game over.

Fwiw if we had a fault wouldn't it show up before and after - or are you saying we had a fault just on the day?

There was a fault. The ripple control devices failed to turn off. While it could have been a fault in our ripple receiver / relay the evidence is the faults were across the network.

The question I raise is how much of the network was affected? That is the focus of this thread and people will have access to the data that clarifies.

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Hinko

273 posts

Ultimate Geek

#3234773 26-May-2024 12:42

SomeoneSomewhere:

If you're burning 8kWh/day extra because your HWC is on longer, then you have a faulty HWC and it's not exactly the power company's fault.

Yes we pay for power we use over 23:00 and 07:00 all power consumption faults included and accepted.

Outside those times the power should be off. End of. OFF. Not on. Meter not clicking over.

Those things are 100% the power retailer and its commercially associated entities responsibility.

The meter and load control devices are sealed and outside my reach and control.

0% my responsibility.

I say it is 100% the power companies (plural) fault.

As consumers in New Zealand we can use as much or as little hot water we like. Where are you coming from? Who do you work for?

SomeoneSomewhere

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#3234775 26-May-2024 12:57

While I've not checked your 95% figure, if it were correct that would mean there are 5% of consumers who are not on those systems, and are therefore most likely on "Night Boost" (10 hours on) or "Night Only" (8 hours on) controlled systems.

[...]

Fwiw if we had a fault wouldn't it show up before and after - or are you saying we had a fault just on the day?

No, most of those 5% will be on custom time switches, PLCs, solar diverters, building automation etc. 8 or 10 hour (or others) ripple controls for HWCs are not lines company accepted solutions (at least in the WE region and I think nationwide) and should not have been installed as such.

My point is that if your hot water cylinder is consuming double the power when on for triple the time, the hot water cylinder is faulty. Because it's the same cylinder as those intended to be run 24/7. Ripple control does not reduce energy use in HWCs; it merely shifts it. For the record, our HWC spent 39 minutes on yesterday with negligible usage - that's about 2kWh.

Usage above this is because hot water was used or leaked.

The question I raise is how much of the network was affected? That is the focus of this thread and people will have access to the data that clarifies.

The 100+50 (D16/C8) ripple contacts in our switchboard (off Tawa zone sub) seem to be switching as intended 0700-2300. They're no longer switching anything because we don't have a mechanical day/night meter that needs to be told which rate to use, but the relay is receiving the signal.

The focus to this thread seems to have shifted to a lack of understanding of the metering and billing systems.

I'm not currently in the power industry; I'm in NZ, I've done some automation work on stuff like this and I know a fair bit about metering.

RunningMan

8954 posts

Uber Geek

#3234783 26-May-2024 13:47

I think this thread has run its course and is going in circles now.

To summarise:

1) The OP has a fault with their ripple control not switching at the correct time. They've requested people in the same geographical area check their usage for a similar fault and there has been no replies to this request. The fault might be just the OP, or it could be more widespread. It probably needs to be reported through the energy retailer for followup. It could be as simple as a faulty ripple reciever at the OP's location. The OP shouldn't be seeing usage on their bill in time slots where their contract with the retailer says the ripple controlled circuit is inactive.

2) It is probable there is a seperate fault with one or both of the OP's HWC installations given the seemingly excessive idle energy usage.

3) Ripple control is older technology, and being displaced with more modern alternatives like smart meters that can switch a seperate HWC circuit. Some retailers are already offering this sort of service, with the right meter. There's a good overview of NZ ripple control here, dated 2020.

Hinko

273 posts

Ultimate Geek

#3234804 26-May-2024 14:36

RunningMan:

I think this thread has run its course and is going in circles now.

To summarise:

Yeah thanks for taking interest, but nah. I consider you should be able to accurately refer to information in the OP and accurately include it in your summary and properly analyse that before you suggest the thread "has run its course".

Also being able to reply to real information provided such as the number of potentially affected ICP's (over 60,000) which is based on actual Electricity Authority data - and not some pie in the sky I think its 95%....

It can take well over 5 working days for retailers to provide customer use data for anyone wanting to check the dates and whether they were affected too.

We understand you are unable to check whether the signal issue affected you, maybe its time to run on to your next thread, and let the other 60,000 potentially affected consumers have a fair opportunity to consider the matter for themselves.

SomeoneSomewhere

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#3234820 26-May-2024 14:54

Also being able to reply to real information provided such as the number of potentially affected ICP's (over 60,000) which is based on actual Electricity Authority data - and not some pie in the sky I think its 95%....

And where does the pie-in-the-sky 60k figure for those with ripple relays on the wrong channel come from?

Jase2985

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#3234821 26-May-2024 15:05

You provide contradicting information, pick and choose what you reply to and generally ignore suggestions.

Your mind is set on the answer and you just want someone to verify it for you

so with that im out

Hinko

273 posts

Ultimate Geek

#3234824 26-May-2024 15:08

SomeoneSomewhere:

Also being able to reply to real information provided such as the number of potentially affected ICP's (over 60,000) which is based on actual Electricity Authority data - and not some pie in the sky I think its 95%....

And where does the pie-in-the-sky 60k figure for those with ripple relays on the wrong channel come from?

I thought I'd written Electricity Authority.....

In anticipation of the next question, the data is available here: https://www.emi.ea.govt.nz/Retail/Datasets/MarketStructure/ICPandMeteringDetails

SomeoneSomewhere

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#3234840 26-May-2024 15:57

Hinko:

SomeoneSomewhere:

And where does the pie-in-the-sky 60k figure for those with ripple relays on the wrong channel come from?

I thought I'd written Electricity Authority.....

In anticipation of the next question, the data is available here: https://www.emi.ea.govt.nz/Retail/Datasets/MarketStructure/ICPandMeteringDetails

I don't see a 60K figure there. These are dense CSVs, so presumably you did some wading through data.

Wellington Electricity seems to have roughly 93 ICPs with a CN-8 register, indicating controlled load, 8 hours.

Note that this is not the same as an N-8 register, indicating uncontrolled load, meter reading for the 8 night hours, must be paired with a D-16 register code.

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