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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1802 posts

Uber Geek

Lifetime subscriber

#3234370 24-May-2024 18:13

Hinko:

michaelmurfy:

... and having hot water won't cost you any more on a regular plan when it is supposed to be off.

That's the thing here, when the hot water load control fails to turn off, the meter keeps clicking over and the consumer IS charged for the unintended extra power consumed.

Flick charged me for the unauthorized power consumption. A refund is being discussed.

While Flick might deserve some adverse publicity in relation to this matter I'll keep it balanced and on point.

Did any power retailer advise any Wellington N8 or CN10 power consumer they'd been overcharged and were getting a refund? Not that I am aware of.

For that to happen the retailer would need to become aware of the issue. Complaints is one avenue, but I don't plan to discuss that here beyond observing staff would need adequate training to competently handle this issue.

The preferable route would be for Wellington Electricity to advise the retailers of the details of the issue, so that the retailer could then analyse their data and provide appropriate advice and refunds to their consumers. "Smart" meters do measure the power used on a half hourly basis so unintended use can be calculated.

But Wellington Electricity would need to have systems that alert them to the issue, and act on them. I am not aware Wellington Electricity have alerted any retailer of Ripple Off Failures on their network in the last year.

It seems likely some people have paid extra and don't know otherwise - and like michaelmurfy do not have the possibility of being overcharged on their radars. (No disrespect implied or intended, its very understandable)

If your hot water was on a dedicated meter (e.g. RSUTOU-NITE or -CTRL), you would be charged the special rate regardless of what time it ran at.

If your hot water was on a suitable ripple relay on an all inclusive rate (RSUTOU-AICO 2.82c) (not metered separately), then you get a discount on all your power for having the HWC controllable, regardless of what time the HWC is actually run at.

There is a hole if you are on an all-inclusive peak/off peak rate, (-P-AI 7.49c and -OP-AI 0.69c) as the consumption could move into peak territory.

Remember that HWCs do not use extra power when turned on longer - it just means that the same amount of power is used at sub-optimal times.

Bear in mind that HWCs aren't actually supposed to be on the -NITE (NB10) rates; they should be on -CTRL which may operate during peak times anyway. If you're not happy with this you can install your own time switch. People with genuine night-store heaters and pool heaters might have a reason to be upset as running those for longer would imply more energy usage, and those channels aren't supposed to run during peak. They are, however, very rare.

Hinko

273 posts

Ultimate Geek

#3234396 24-May-2024 19:44

SomeoneSomewhere:

It would help if you used the specific rate codes in the document. I think you are misreading the rate codes and I'm really not understanding what you're trying to argue. I'm going to restrict myself to the RSUTOU codes so we don't talk about everything twice. That's Residential Standard User (not low user) with Time of Use metering (half-hourly smart meter fitted).

Yeah nah. I pondered noting the codes, as it seems it will help I've added them here:

A low user with a controlled night meter I understand WE is charging the retailer on behalf of a low user the uncontrolled rate of 6.73 cents (RLU-24UC) for metered power used at a very controlled over 8 night hours, yet the longer 10 hour "night boost" rate is .... really, yes its 1.90 cents (RLU-NITE).

To my nose that's the 354% odour of a cash cow. Quite a stink that somehow slipped under the Commerce Commissions (blocked?) nose.

And a standard user with a controlled night meter I understand WE is charging the retailer on behalf of the user the uncontrolled rate of 3.76 cents (RSU-24UC) when the power used is very controlled over 8 night hours, yet the 10 hour night boost rate is .... really, yes its 0.90 cents (RSU-NITE).

At 411% premium the cost is a real pong that comcom staff must have been hospitalised with covid to have missed that olfactory alert!

Other lines companies are not doing this, they are charging a lower rate for N8 that is LESS than CN10.

I used the charges in the middle "Residential" table to keep it simpler. As there remain low and standard users on the network I consider them all relevant cases to exemplify the cash cow issues.

I remind you that Bung earlier pointed out:

Bung:

The PDF you reference has a Note 3 that says Wellington Electricity does not offer Day/Night pricing.

I understand that means the retailers are charged the 24UC rates by Wellington Electricity for N8 metered connections.

I understand Wellington Electricity have confirmed this to me.

Flick advised me if I shift my hot water ripple relay LCD from a N8 to a NB10 (CN10) basis Flick will only then be charged discounted rates by Wellington Electricity for that register.

Using this excess charging model retailers are being economically encouraged to move their consumers customers from N8 to CN10 ripple control.

Are consumers advised this issue applies in Wellington - but not other places in New Zealand?

Lets be clear here, strictly that is a matter between Flick (and the other retailers) and Wellington Electricity. But as its been put on my desk, it does not seem right to me, so I am calling it out.

Hinko

273 posts

Ultimate Geek

#3234410 24-May-2024 20:06

SomeoneSomewhere:

"Day/Night" metering is where you had two meter registers, Day, and Night. Note that it is listed in the decabit tables as 'two-rate metering', not as load control. It is essentially providing a time-switch service to allow the meters to switch which was recording usage."

Yeah...respectfully nah!

Care of Orion the middle circuit below is the more recent Day/Night ripple control configuration that uses ONE meter register. (They use the word "Dual" but show one meter register. Go figure?!) Whatever rate(s) can be applied (statistically based) to the summed power measured as used by the ONE meter register in half hourly increments.

The bottom circuit is (for simplistic illustrative purposes here) the dual meter circuit we are using uses a ripple controlled relay that also switches the load as N8 despite the LCD slot being labelled as Day/Night. It shows the use of two meter registers that accurately measure the power used by the two loads separately.

The ambiguity of Day/Night labeling is illustrated.

Hinko

273 posts

Ultimate Geek

#3234412 24-May-2024 20:13

SomeoneSomewhere: #3234367 24-May-2024 18:05

I believe you're looking at the RSUTOU-UC (Uncontrolled) code....

Yeah...nah, not on its own. I've not replied to the remainder of the incorrect assumptions in this post, particularly as it started off course with incorrect assumptions. If you want a reply to a point please raise the point again - following reviewing my subsequent clarifications, particularly the codes.

Hinko

273 posts

Ultimate Geek

#3234418 24-May-2024 20:35

SomeoneSomewhere:

Remember that HWCs do not use extra power when turned on longer - it just means that the same amount of power is used at sub-optimal times.

Sorry I do not remember that, and more to the point by failing to turn off the ripple control on a few days the actual power use is measured when we did not know of the fault, we just kept on going about our lives with our standard hot water use patterns.

Review of the power use measured in this serendipitous controlled manner conclusively shows more power is used as we have both scenarios to compare!

Anyone with similar dual metered CN10 or CN8 register with OFF failures will be able to check their own half hour use data and draw their own conclusions too.

I would welcome the opportunity to review any such data - the point of this thread!

In case I am greeted with skepticism, think about it like this. When the power is connected to the Hot Water cylinder the thermostat works to maintain the hot water temperature. Wash your hands, trigger the thermostat and more power is drawn to raise the temperature back to the set temp. Every time during the day hot water is drawn more power is used to re-heat the water. It takes MORE power to repeatedly heat and maintain the tank temperature than it does with the night scenario. The night alternative is there is a burst of power drawn from 11 pm until the set water temperature is reached, we don't use much (usually none!) hot water between 23:00 and 07:00 so all the thermostat is doing is maintaining the water temperature just from tank heat losses. It takes less power to do this.

This is confirmed with the ironic consequence of ripple OFF failures!

RunningMan

8953 posts

Uber Geek

#3234421 24-May-2024 20:44

@Hinko you are confusing energy and power.

Think of it like this. The energy required to change the temperature of a given volume of water from the input temperature to the storage temperture remains the same, regardless of whether it is done in one go, or several. Multiple short bursts or one long one will use the same energy.

Additionally, the thermostat will not immediately turn the element on every single time you use the hot tap. It's a hysteresis loop and will only turn on once the temp has dropped by the appropriate amount, not every time there is cold incoming to the cylinder.

Hinko

273 posts

Ultimate Geek

#3234428 24-May-2024 20:48

Hey runningman, I note your logic, and before I had the data I had wondered what the position would be. However the measured data is clear that more power is used. Show me actual data to the contrary.

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RunningMan

8953 posts

Uber Geek

#3234432 24-May-2024 20:54

The power will remain the same for a given water heater element. It cannot change.

The only reason energy usage would change would be the average temp of the cylinder over time. A cylinder that does not maintain temp over time may have a lower average temp across the day therfore a lower energy use because the losses through the cylinder wall will be slightly less. You could acomplish the same energy saving by reducing the thermostat temperature though.

Hinko

273 posts

Ultimate Geek

#3234440 24-May-2024 21:11

RunningMan:

@Hinko you are confusing energy and power.

Think of it like this. The energy required to change the temperature of a given volume of water from the input temperature to the storage temperture remains the same, regardless of whether it is done in one go, or several. Multiple short bursts or one long one will use the same energy.

The power will remain the same for a given water heater element. It cannot change.

The only reason energy usage would change would be the average temp of the cylinder over time. A cylinder that does not maintain temp over time may have a lower average temp across the day therfore a lower energy use because the losses through the cylinder wall will be slightly less. You could acomplish the same energy saving by reducing the thermostat temperature though.

I respectfully note your theoretical points. Here is exemplary data c\o Flick's graphing (no longer available like this :-( )

We have morning showers and cook with power at typical times. Note the power use shown graphed is the two registers summed, but the difference is so significant and the use patterns so clear it does not matter, there can only be one conclusion. More energy and more power is used.!

The top graph shows our power use pattern and "energy" use when the ripple control behaves to specification, that is turns off at 07:00 and on again at 23:00.

The bottom graph shows power use resulting when the ripple OFF fails to run, that is Hot Water continues to draw power and energy.

The separately measured registers also confirm increased energy use, but I don't have presentation standard of those to hand.

Show me data that proves your theory. In the absence of better data from you I am unlikely to change my conclusion. I am open to being persuaded otherwise, bring it on!

Hinko

273 posts

Ultimate Geek

#3234444 24-May-2024 21:24

PS Depending on the retail plan in place it might cost even more because the post shower water energy surge may be drawn during the high peak time of use period rather than the off peak night period!

nova

250 posts

Master Geek

Trusted

#3234483 25-May-2024 07:52

RunningMan is absolutely correct, the impact on your total kWH consumption for water heating should be minimal, the main impact to you is that you pay an increased price for that kWh usage if it happens during the day rather than overnight.

How can you be sure that there weren't other factors that caused different total consumption on these days? Heating / oven use etc. For example the graph looks a bit different in the midnight to 6am section between these days, and ripple control not turning off should have zero impact on this portion of the graph.

Jase2985

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#3234484 25-May-2024 08:03

Unless you have a device controlling the power into your HWC, the element is either on or off. so its using the full or nothing. You would see big spikes in your graph.

Here is a daily graph with no HWC Ripple control, all the big spikes are the HWC Heating, first one is morning showers, then the other small ~3kW spikes are it doing a small 10 min top-up approximately every 5-7 hours due to standing heat losses.

I think you are hunting for something that doesn't exist, or you have an inefficient cylinder or a hot water leak

Hinko

273 posts

Ultimate Geek

#3234499 25-May-2024 08:30

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:

hinko:

The separately measured registers also confirm increased energy use, but I don't have presentation standard of those to hand.

That is 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.

Hinko

273 posts

Ultimate Geek

#3234503 25-May-2024 08:45

Jase2985:

Unless you have a device controlling the power into your HWC, the element is either on or off. so its using the full or nothing.

Thanks for your interesting post. To this point I agree with you entirely.

Jase2985:

You would see big spikes in your graph.

This is not entirely true. While you do not say I think your interesting (thank you) graphs are close to real time data, possibly from a home energy system, maybe sampled every 30 or 60 seconds I am guessing?

My data (and the Flick graphs) is limited to the half hour increments of total power used in that period as the smart meters upload.

If an element is on for 10 minutes and off for 20 minutes of the period the spike height is a third of what it would be of on for the whole 30 minutes. This is effectively happening throughout the day which is why you generally do not see the high spikes, except the post shower morning spike where the elements will run for the full 30 minute period(s). A 6 KW load over an hour drops to 3KW over half an hour.

Hinko

273 posts

Ultimate Geek

#3234508 25-May-2024 09:14

Jase2985:

....or you have an inefficient cylinder or a hot water leak

You are onto something here. Its an interesting and fair point, thank you.

We have two mains pressure hot water (replacement) cylinders each made circa 2013 each with 3KW elements.

They DO leak during normal operation due to the pressure release valves letting water out as a safety mechanism to stop the cylinders from (otherwise) exploding.

As we've had a water crisis we had a bucket under the relief valve outlet of one to collect the water that was otherwise wasted. Water collected this way was used in the garden. The cylinders are believed to be functioning normally. The pattern of water leakage has been observed.

Buts here's the thing which I think you've helped advance our understanding. When the Ripple control and element are both on there is a continuous stream of drips from the pressure relief valve. So we do have a leak which will explain some of the lost energy.

When the ripple control is off the element is also off, and we observe minimal water leakage.

With a Night Only pattern of cycling of 8 hours on, 16 hours off there are 16 hours when we don't lose much water.

Change that to 24 hours on, we lose more water (as expected) and use more total energy.

Actually anyone with a mains pressure cylinder could test what I am saying by turning off their switch to the heater element at 07:00, and turning it back on at 23:00, and see what results they get. But depending on how much water you use and the size of your cylinder(s) this might not be an acceptable test for all people in your house(!).

But people with the downloaded data sought by this thread have unwittingly already got independent test results (!) which might involve less effort.

Anyone willing to share their independent "test" data? Privacy can and will be respected as one would expect, the only thing that needs to be said is whether the ripple control failed to turn off on said days in a suburb.

Wellington Electricity would probably appreciate knowing the ICP for confirmation of the extent of their problem, but that would be up to you whether you wanted that released or not.

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