How do street lights work?

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#923830 29-Oct-2013 21:45

On the old united network on the shore it is all done with a pilot wire, which runs a few dozen streetlights then goes into a big relay to pass it on to the next few dozen. Means when one packs it in everything downstream of it is dark. Same ghetto old method controls the hot water relay, with a whole separate wire from the house back to the power pole for that.

Fixing this primitive way of controlling things gets second place to total outages, so every winter when there is a bit of a blow that stuffs up the vintage overground network, as well as power outages we get a day or 2 with no hotwater quite often.

even better, they have no telemetry on the state of this pilot wire, so the only way they know its broken is when people start to report no streetlights or hot water faults and for hot water they expect you to call a sparky first. Usually ends up getting fixed without doing that so I guess after they get enough calls they bother going to have a look at it.

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#924425 30-Oct-2013 21:28

Problem is, The ripple control method (at least in the AECT area) is not much better reliability wise. The plumbing company I work for once had 20 calls all for no hot water, on the same day. And all were electric hot water (We also fix gas hot water systems). Normally we would only get 1 or 2 calls (if that) per day for no hot water faults.

One of my mates used to work for Vector and he said that alot of the ripple control equipment dates back to the 60s. Therefore it is beginning to fail. (AFAIK he is referring to the equipment that injects the ripple signals into the network. Not the upstream control equipment).

Definitely time for the networks to invest in a load management system that was designed in this century. They missed a golden opportunity to roll out a new system with the [not so] smart meters. I live on the Shore as well and whenever it gets a bit windy the pilot wire goes down. Even though it is very unusual for the power to go out completely where I live. Glad that electric hot water is only a backup for me instead of my main system. Element has only been switched on for 1 week approx over the previous year to date.

cleggy2

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#924446 30-Oct-2013 22:16

This is how street lights work

The first electric street lighting in one Nelson suburb was powered by a small hydroelectric generator in the hills above the city. To switch the lights on and off, a chicken run was added to the power plant. At dusk every night the hens would go inside their coop and roost on a special hinged perch. This sank under their weight and connected a switch which turned on the street lights. At first light the hens would leave the coop, the spring-loaded perch swung back and the lights went out again.

farcus

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#924503 31-Oct-2013 05:01

forgive my ignorance - but if streetlights are triggered by ripple control - what triggers the ripple?
Does this mean there actually is a man (or woman) sitting in an office somewhere looking out the window and when they deem it dark enough they send the ripple signal down the pipe?

edit: oops - ignore my post.
I missed wasabi2k's post which seems pretty comprehensive.

kiwifidget

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#924552 31-Oct-2013 08:32

In Pukekohe the street lights are controlled by a light sensor located at the local lines company. I know this because I used to work there, and one day we were moving gear around in the control room to make more space for new equipment when we unknowingly disconnected the sensor (unmarked, unlabeled, undocumented). That night, the town was dark.

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#924595 31-Oct-2013 09:33

This sounds like the beginning of a noir novel:

kiwifidget: In Pukekohe ... [t]hat night, the town was dark.

DUN DUN DUUUUUUUUN!

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k14

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#924603 31-Oct-2013 09:54

farcus: forgive my ignorance - but if streetlights are triggered by ripple control - what triggers the ripple?
Does this mean there actually is a man (or woman) sitting in an office somewhere looking out the window and when they deem it dark enough they send the ripple signal down the pipe?

edit: oops - ignore my post.
I missed wasabi2k's post which seems pretty comprehensive.

The ripple control will be done by the local distribution network operator. I believe in most cases it will be manually done from the control room by the guy sitting at a computer controlling/monitoring the network via SCADA. Usually the criteria for this is when the load at the grid exit point (where the power gets off Transpowers 220/110kv system and gets onto the local 33/11kv etc system) gets near a predetermined threshold. The network has to pay Transpower a fee based on the maximum off take during the peak demand, so the network can avoid some costs by chopping the peak off when it load gets high (in theory passing these savings onto the customers via reduced line tariffs). Although some of the networks do have different systems in place, some use the ripple system to provide instantaneous reserve to the wholesale electricity market so that when a generator trips (for instance Huntly) and the frequency drops below a certain threshold the ripple signal will be sent out so that some load can be instantly reduced to try and alleviate the loss of generation. In this case the system is fully automated with no human input to the ripple signal being sent.

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Geektastic

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#924606 31-Oct-2013 10:04

Aredwood: Problem is, The ripple control method (at least in the AECT area) is not much better reliability wise. The plumbing company I work for once had 20 calls all for no hot water, on the same day. And all were electric hot water (We also fix gas hot water systems). Normally we would only get 1 or 2 calls (if that) per day for no hot water faults.

One of my mates used to work for Vector and he said that alot of the ripple control equipment dates back to the 60s. Therefore it is beginning to fail. (AFAIK he is referring to the equipment that injects the ripple signals into the network. Not the upstream control equipment).

Definitely time for the networks to invest in a load management system that was designed in this century. They missed a golden opportunity to roll out a new system with the [not so] smart meters. I live on the Shore as well and whenever it gets a bit windy the pilot wire goes down. Even though it is very unusual for the power to go out completely where I live. Glad that electric hot water is only a backup for me instead of my main system. Element has only been switched on for 1 week approx over the previous year to date.

Yes I have always thought it odd that they don't just abandon the control idea and either use a separate meter for cheap rate electricity or make it all cheap rate outside peak times.

To actually require control like this seems needlessly complex. Of course the advent of smart metering and remote metering should make it more simple.

Here in the Wairarapa I would settle for a line network that did not fall over every time the wind got above 10kms!

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#924638 31-Oct-2013 10:29

cleggy2: This is how street lights work

The first electric street lighting in one Nelson suburb was powered by a small hydroelectric generator in the hills above the city. To switch the lights on and off, a chicken run was added to the power plant. At dusk every night the hens would go inside their coop and roost on a special hinged perch. This sank under their weight and connected a switch which turned on the street lights. At first light the hens would leave the coop, the spring-loaded perch swung back and the lights went out again.

MIND = BLOWN

Stu

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#924643 31-Oct-2013 10:33

Geektastic: Here in the Wairarapa I would settle for a line network that did not fall over every time the wind got above 10kms!

To be fair, 10km a second is going to blow pretty much anything over! ;-)

Geektastic

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#924647 31-Oct-2013 10:36

ubergeeknz:
cleggy2: This is how street lights work

The first electric street lighting in one Nelson suburb was powered by a small hydroelectric generator in the hills above the city. To switch the lights on and off, a chicken run was added to the power plant. At dusk every night the hens would go inside their coop and roost on a special hinged perch. This sank under their weight and connected a switch which turned on the street lights. At first light the hens would leave the coop, the spring-loaded perch swung back and the lights went out again.

MIND = BLOWN

Can't say I would be all that surprised to learn that this was still the method used....!!

In a similar vein I used to work for a water company. One of the methods used to continually monitor the quality of the water leaving the treatment plant was....trout!

Most water companies in the UK fill their reservoirs with trout which they then sell the fishing rights to on a day ticket basis. It earns them a lot of money.

In the water treatment plant they have tanks which have part of the outgoing supply of water passed through them 24/7 and in the tanks are 3 trout. Using sophisticated measuring equipment then can track the bio signs of the trout and trout are very sensitive to changes in the purity of the water that they are swimming in so if the treatment plant has a failure somewhere which results in an increase in contamination of other quality issue the trout respond, triggering an alarm!

Of course, they have many other real time scientific measurements going on too but they really do use trout!

Geektastic

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#924648 31-Oct-2013 10:37

BigHammer:
Geektastic: Here in the Wairarapa I would settle for a line network that did not fall over every time the wind got above 10kms!

To be fair, 10km a second is going to blow pretty much anything over! ;-)

Ok, 10 km's then...!

andrewNZ

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#924671 31-Oct-2013 11:23

Geektastic:
BigHammer:
Geektastic: Here in the Wairarapa I would settle for a line network that did not fall over every time the wind got above 10kms!

To be fair, 10km a second is going to blow pretty much anything over! ;-)

Ok, 10 km's then...!

That's a distance not a speed... :-P

ubergeeknz

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#924672 31-Oct-2013 11:28

andrewNZ:
Geektastic:
BigHammer:
Geektastic: Here in the Wairarapa I would settle for a line network that did not fall over every time the wind got above 10kms!

To be fair, 10km a second is going to blow pretty much anything over! ;-)

Ok, 10 km's then...!

That's a distance not a speed... :-P

Next you'll be telling us parsecs refer to distance and not time...

TinyTim

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#924674 31-Oct-2013 11:39

ubergeeknz:
andrewNZ:
Geektastic:
BigHammer:
Geektastic: Here in the Wairarapa I would settle for a line network that did not fall over every time the wind got above 10kms!

To be fair, 10km a second is going to blow pretty much anything over! ;-)

Ok, 10 km's then...!

That's a distance not a speed... :-P

Next you'll be telling us parsecs refer to distance and not time...

Come on guys, if you're going to be pedantic, get it right. 10kms is not a speed. 10km/s is a speed.

(And units are not pluralised either.

)

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