AKL Hot Water Ripple 14June

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Nate001

638 posts

Ultimate Geek

#319919 14-Jun-2025 12:18

Noticed today our HWC Ripple has been controlled aggressively today vs usually nothing. Transpowers live load data shows a dip shedding Auckland GZ2 every hour for up to 20 minutes. Loads don't appear to be high, anyone know if theres a fault limiting usage?

Our HWC monitoring:

geek3001

63 posts

Master Geek

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#3383946 14-Jun-2025 16:32

Ah, so I'm not going silly...

I noticed my hot water power in Auckland was off by ripple control this morning just after 7am. I'm on Vector ripple control.

When I checked, the spot market power price was reported by https://www1.electricityinfo.co.nz/ as being below one dollar per MW / less than a cent per kW.

The same thing happened a few mornings ago too, when it was off and on several times.

Nate001

638 posts

Ultimate Geek

#3384134 14-Jun-2025 19:29

Ongoing since 7am. Your retailer may load shed for high spot prices, but vector only does to manage load. Their capacity must be limited today, eg maintenance.

Hamilton for comparison.

geek3001

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#3384163 15-Jun-2025 07:34

I was of the understanding that in Auckland, only the lines company (Vector in my case) has ripple plant at Transpower grid exit points or elsewhere within their own network to inject ripple control signals to control ripple switches at customer premises.

In previous comms I have had with my retailer (Mercury) they were adamant that they don't ripple control, that is up to Vector.

Counties Energy in the southern parts of Auckland might be different.

My interpretation of what I'm seeing...

Looking at the zone load graph after expanding it on the time axis, it looks a lot like ripple control signals have been progressively sent around the top of each hour, every hour for many hours, to switch controlled load off. There is a fairly fast drop in load over five minutes or so, followed by a slower resumption of load over the next ten to twenty minutes.

My hot water has been going off around the top of the hour, but has come back on within that half hour trading period, per the usual randomization built in to the electronic ripple switches Vector use, ie: when the ripple switch receives an ON signal, its relay remains off for a random number of minutes before being set to on again. This observed behavior tends to match the zone load graph.

I wonder if they are testing to see how the load changes, or perhaps there is or has been a fault somewhere in the signalling.

halper86

547 posts

Ultimate Geek

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#3384279 15-Jun-2025 11:02

Makes for a very interesting load graph via TP website. Looks to be a good 100MW+ difference too.