diy solar

diy solar

Backup down under

The USA split phase is totally different from anything else in the world, don't be getting yourselves all confused about how everyone else does it.
The UK and Austrailia are similar in that everything is either earthed or double insulated. However I did not know that 3 phase is common in Austrailia. Makes sense because the distances are further ???
That's it in a nutshell.
The utility where I grew up was a coop and in the early days distributed 3-phase power to some of the neighborhoods and any homes originally provided with 3-phase power that have survived, still use it.
I think where we are now is our ability to communicate has outpaced our understanding. Most of us including myself, base our own best practice on the developed best practice in our own neighborhood since the early days.
If your provider doesn't care that their wire is carrying the imbalance in your system then they have probably calculated the risk to their wire as being worth exercising Grandpa's Right and leaving it as is.
I think this is the first forum I've been on where I can discuss the differences in how rules are made and implemented around the world. It used to be we only had to argue between the 50 states in the U.S. and even then some differences are stark.
 
In unrelated news on my home's system, we experience highly variable grid voltages, with most issues at the high end, particularly on one of my phases during the daytime. As an example here's what the peak voltages each hour per phase have looked like over the past fortnight:

Screen Shot 2022-02-03 at 7.40.34 am.png

It's a long story with many parts I won't go into here but the end result is my grid tied inverter is frequently having to enter Grid Voltage Dependent Power Reduction (GVDPR) mode (volt-watt settings) which reduces the output of the inverter above a certain line voltage threshold (253V) in an attempt to reduce the voltage increase. Can see above that phase L2 (WHITE) is particularly problematic on the high side.

Once it persists above 258V for a certain time then the inverter will shut down (as it should) and restart once line voltage fall back below the lower threshold. These inverter shut down events are beginning to occur more often. I have a log of my inverter's error states being captured by my Home Assistant system so, in theory at least, I should be able to work out how often it has been occurring. Still working out how best to extract all that error state data!

There are a number of causes/remedies and they fall into broadly two types
- the ones I have control over, and
- the ones I don't.

Of the latter, my only recourse is to request the power transmission company to make adjustments to the supply, such as tapping down the transformer, but I have been through that exercise with them. Unsuccessfully. That is a whole long story in itself.

So I am focussed on the stuff I can control.

One of those is to correct an unintended phase load imbalance to place more daytime load on L2 (WHITE).

Our (single phase) ducted aircon system, which is used a lot, had its assigned phase accidentally swapped over with our other large aircon circuit which I rarely used. Happened June last year and would have been an honest mistake by the electrician doing work on my board related to the backup system transfer switch (I requested both circuits be excluded from backup supply). It took a bit of sleuthing on my part to work out what happened and when. Benefit of collecting so much data on system performance is I can spot when something changes, or new trends emerge.

From a load balance POV this would ordinarily be fine as, on paper at least, both aircon units have a fairly similar power draw, except the commonly used load is no longer able to help bring down the voltage on the problem child phase. It used to be on that phase (L1 WHITE) but is now on L1 (RED). Note also the corresponding drop in voltage on L1 (RED) at the same time as L1 (WHITE) is high.

So my sparky will be back, in a few weeks, to correct that (along with installing a smart power diverter for our hot water system which will monitor available excess solar PV and send that power to the water heater's resistive element). Hoping this will go a fair way to reducing inverter over voltage shut downs.

I have a couple of other options up my sleeve.

One is is move the hot water system from L1 (RED) to L2 (WHITE) and the smart diverter will then use it to soak up excess solar PV on that phase. I'd rather my hot water stayed on L1 (RED) for now as it also has access to a dedicated off-peak tariff circuit on that phase and it will help us self-consume more solar PV if connected to that phase.

Another option is to talk with my solar installer about invoking the Volt-VAR management settings on my inverter. Currently it does no reactive power adjustments (default setting) in response to line voltages. There is probably a fair bit of impedance on our power lines and it may be I need my inverter to sacrifice some real generation and apply a bit of phase shifting as required. This is permitted by the power transmission company and there are specific volt-var management settings we may apply.
 
In unrelated news on my home's system, we experience highly variable grid voltages, with most issues at the high end, particularly on one of my phases during the daytime. As an example here's what the peak voltages each hour per phase have looked like over the past fortnight:

View attachment 82263
These are some amazing statistics you have been recording! What system are you using to capture this?
 
These are some amazing statistics you have been recording! What system are you using to capture this?
My grid tied inverter system is a Fronius Symo 10.3 and I have the data from that (via Home Assistant Fronius integration) populating an InfluxDB and that provides the data for creating charts with Grafana. My Home Assistant operates on Raspberry Pi 4.

I also have my Fronius system integrated with PVOutput.org, Fronius Solarweb and also the Energy panel within Home Assistant.

The HA Fronius integration is interesting as it regularly polls all the data channels the inverter and the associated meter supplies. All sorts of stuff, per phase voltages, real and apparent power, along with a multitude of system performance data. Production, consumption, export and import. Net and per phase. Error log data, status data.

Having the data has helped me to understand the issues, identify trends and work out some possible solutions.

A couple of days ago I implemented one of my options for helping with grid over voltage, that being invoking the use of Volt-VAr management settings in the inverter. I have been monitoring and it looks to be having a positive impact. I'll report more on that a bit later after I have collected some more data.
 
These inverter shut down events are beginning to occur more often. I have a log of my inverter's error states being captured by my Home Assistant system so, in theory at least, I should be able to work out how often it has been occurring. Still working out how best to extract all that error state data!
I developed a chart in Grafana on my Home Assistant to visually display my Fronius inverter error/status codes:

Screen Shot 2022-02-14 at 4.13.17 pm.png

Each dot represents when an error/status code is updated on my system. The value of the dot is the numerical code for the error/status. e.g. Code 0 = all normal, Code 567 = grid voltage dependent power reduction (GVDPR) mode is active.

Most codes are inconsequential / indicate normal operation.

The two codes of most interest are those highlighted by the horizontal coloured bands across the chart, being state 567 (GVDPR mode active) and state 102 (Inverter shutdown due to grid over voltage). We can see the frequency of those modes being enacted. GVDPR is pretty much any day there is sun as our grid voltage rises quite a lot.

The worst ones are the state 102 errors as that means the inverter has shut down as grid voltage has exceeded the upper threshold. In that 90-day window the inverter shut down 24 times. In a normal season it probably would have occurred more frequently but it has been a particularly wet/cloudy Summer and so grid voltages have experienced less pressure.

A couple of days ago I implemented one of my options for helping with grid over voltage, that being invoking the use of Volt-VAr management settings in the inverter. I have been monitoring and it looks to be having a positive impact. I'll report more on that a bit later after I have collected some more data.
In the above chart the vertical dotted line over to the right is when I implemented the changes to the inverter's volt-var settings. No shut downs since.

Below is an updated chart showing the grid voltages before and after making this change. This is the last 21 days and the change was made where the dotted vertical line is showing:

Screen Shot 2022-02-15 at 9.47.12 am.png

Just to refresh - the dots are grid voltage samples for each phase (white, red, blue) while the thin yellow bars indicate net real power flow (negative = export to grid).

Easy to see the daily peaks in voltage. The purple horizontal line = 258V, which is a level above which the inverter will shut down if that voltage is sustained for too long (~10-min). GVDPR mode is active once voltage reaches 253V.

Can see that in the past 8 days or so since I made the change to volt-var settings the grid voltages have been contained within that threshold.

Just to get a sense of how much reactive power the inverter has been supplying before/after the change, I started recording that only recently in Home Assistant so went back to my Solarweb archive. Here is the plot of reactive power (VAr) since the start of the year. Pretty easy to spot when I made the volt-var setting change.

Screen Shot 2022-02-15 at 10.21.35 am.png

Next up I will be do a phase reassignment for a couple of loads, to remove some regularly used load (a ducted aircon system) from the red phase and assign it to the white phase. That should also help with the voltage imbalance.

I will report on that project and another - a smart variable solar PV power diverter for my hot water system once they are done some time in the coming weeks.
 
Quick update.

I did the aircon phase reassignment, and it was successful in helping with the grid voltage issues which I'll expand on later.

I also had my smart power diverter for hot water installed. That's turning out to be a bit of an ongoing saga, and also a tale for later as there is much to unpack with that.
 
Oooh, and I forgot - I also had a GPO installed in the office supplied by the off-grid system, so now the office equipment (my wife does a lot of work from our home office) is powered by the off-grid system. Computers/monitors mostly + mesh router. These were the only computing devices I didn't have covered by a UPS, so they all now have an uninterrupted power supply too.

Standard double GPO on the left, with a USB charger and the ubiquitous 4 outlet power board for plugging in all the computer stuff. In the middle is a separate battery monitor - while I have all the stuff viewable on computer/phone, it's handy sometimes to just have that instant viewable display too.

Not a lot of power draw despite the number of plugs, perhaps 45W when in use and less when idle. Could use a bit of a cable tidy up.

IMG_3495.jpeg
 
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General Purpose Outlet = GPO ??
General Power Outlet. Not sure if the term is used outside of Australia.

In lay language most people here refer to them as "power points" but of course that term got hijacked by a software company enabling people to do all sorts of awful slide presentations.

What is the make & model of the meter? It looks like you are getting a lot of information through a USB plug.
The data is transmitted wirelessly from a monitoring unit which uses a CT clamp around the battery main negative cable. The USB plug is simply to provide power to the display. The actual data is processed by the monitor, which draws its power directly from the battery. IOW you can unplug the display, and plug it back in later on and the data will be current as per the meter.

IMG_3248.jpeg

Close up view of the display:
IMG_3183.jpeg

The user guide says it's a "Multi Function Panel Meter Elite Model - VAC8010

It was loaned to me by a helpful soul on an Australian forum I frequent to help me along with this project. He is free to have it back any time he wants/needs it.

The have a few neat features, such as being able to control a relay based on various parameters. But no archive logging of data.
 
The data is transmitted wirelessly from a monitoring unit which uses a CT clamp around the battery main negative cable.

I hope that is actually a "Hall Effect Sensor", not a "Current Transformer".
 
I hope that is actually a "Hall Effect Sensor", not a "Current Transformer".
Good pick up. Yeah, my bad.

I only just recently had a CT put into my main circuit board as part of my smart solar PV diversion to the water heater project, and so that was the term in my head, when yes indeed it's a Hall Effect Current Sensor.
 
There was a scheduled grid power outage today 9AM - 4PM, so I was all set to run the home from the backup system. I had the battery nicely topped up in preparation. Even checked the generator was all ready just in case. But the power company cancelled the planned outage last night.

But I thought, bugger it, I'll run a test of the backup system anyway. So I didn't tell the others the grid wasn't actually going off and so I have the property running on backup power today.

Regular household loads, wife working from home office today and the pool pump running as normal. We have 3 buildings = 3 fridges and multitude of regular electronic stuff running. Oven/stove and large aircon systems don't operate on backup.

All going well so far. I kicked over to backup at 8:23AM. I got a bit of a shock with a load that kicked in almost straight away. "WTF was that?" I wondered. It dropped away after a couple of minutes.

Turns out my 89yo mum in her home decided to boil a kettle to fill a thermos flask with boiling water before the power switched over so she could make some tea later on without needing to boil the kettle again. She didn't know I decided to switch over early!

Anyway - system managed that just fine.

Screen Shot 2022-05-17 at 11.17.31 am.png

At lunchtime, when the wife has a break, I'm going to test putting the mancave aircon on just to see how it goes with power draw. I don't want to risk that while she is working!
 
Ha Ha, Mum got ya because you said this and did that. :ROFLMAO:
But lord what a treasure - I never said anything about needing to fill a thermos, just to live the day as normal, the only rule for her is to not use the oven, stovetop or the laundry appliances (although it would be able to power the laundry if absolutely necessary). Eventually I will have the oven/stove in her home isolated from backup in the same manner ours is (it took me a while to work out how but I have a plan).

At lunchtime, when the wife has a break, I'm going to test putting the mancave aircon on just to see how it goes with power draw. I don't want to risk that while she is working!

Test was fine, the mancave aircon on dehumidify mode does not draw all that much power, maybe 500W. So that was on, along with the pool pump and the regular household loads. Before doing that I tell the wife I'm just doing a load experiment and without a care she goes and puts on the electric kettle (2 kW). :oops:

No issue, system was supplying 3 kW for a bit. I think that's the highest load I've run through it. It's rated for 4 kW (5 kVA) so it should be OK. Being a cheap PIP clone I haven't had high expectations but I have to say it's been a pretty impressive little unit. Not sure how long it will last though.

I have some more plans for this system. I mean why stop now? :)

More storage, more power, more use. Less grid.
 
Me, when I want to load test the system I just turn on a 10kW furnace (actually electric duct heater).
I also have to turn off some PV inverters if I want to draw down the battery. (Don't think it'll work that well in winter.)

I was putting the system through its paces, grid fails, grid returns, checking to see SMA did the switching and controlling properly.
It didn't completely, not all as documented. I changed some parameters so it performs more acceptably.
Seems their verification of firmware didn't check all operating modes.

My future plans including automatically switching from electric heat to gas when grid goes down. It is relay controlled now, just not automated.
Variable loads to consume excess production would be ideal. Just not many PF corrected options for that.
 
Here's the data on the day's outage test:

Screen Shot 2022-05-17 at 4.44.58 pm.png

Code:
Duration:         7h:32:30    Avg
Consumption:       6.30 kWh   836 W
Parasitic Load*:   0.45 kWh    60 W
TOTAL Load:        6.75 kWh   895 W
PV Output:         5.47 kWh
Battery Discharge: 2.00 kWh
Battery Charge:    0.72 kWh
.
* Parasitic load includes inverter self-consumption (~45 W)
  and battery charge efficiency losses which are
  not counted by the inverter's monitoring

Aside from regular household loads (3 buildings and fridges and general electronics), wife was working from home office, pool pump was on 9am-2pm and I tested using the mancave aircon on dry mode for an hour at lunchtime. Morning was clear and sunny, clouds stayed appearing at lunchtime and the afternoon was overcast.

A successful trial of the system to manage a pretty typical day should we need to operate on backup.

I'm looking at expanding the capability of the system to take these "essential" loads off-grid on a more regular basis.
 
Today I added a Victron (500A/50mV) Smart shunt to the system.

IMG_3609.jpeg

A little bit of cable tidying up to do for the battery voltage and USB wires hanging down from under the shunt.

The physical job was a lot of work lugging all my tools out of their respective hiding places but it's in and the set up with the Victron bluetooth app was simple as was the connection with Solar Assistant. Indeed the connection/software side was trivially easy which is always nice.

Had to make a short connector cable to go between the shunt and the battery bus bar so out with the lugs and hydraulic crimper and heat shrink etc.

All talking with Solar Assistant:

Screen Shot 2022-06-05 at 4.23.22 pm.png

The nice thing I can see is the much better resolution in current and power readings than my inverter was supplying.

Screen Shot 2022-06-05 at 4.58.18 pm.png

This I hope will help give me a far better picture of how the battery is really performing.

Problem with the inverter's own monitoring is the battery current only reports in increments of 1 A and so it means low loads would register as zero current and zero power draw. It also did not report power consumption of the inverter itself, so having the shunt should also better account for inverter's self consumption.

I'm not sure what, if any, calibration I may need to do with the smart shunt but it's in and it's working. I set the battery capacity with the app.

I also have more battery storage coming, 2 x 100 Ah 51.2 V (16S) LiFePO4 server rack batteries, so that will add ~10 kWh to the system and I'll have some fun seeing how that works along with the 380 Ah of lead acid I have.

Plan then is to test using the system to run the home overnight instead of the grid. If that proves to be viable then I am looking at upgrading the inverter to a more powerful option, as well as a main panel upgrade.
 
Today I added a Victron (500A/50mV) Smart shunt to the system.

View attachment 97292

A little bit of cable tidying up to do for the battery voltage and USB wires hanging down from under the shunt.

The physical job was a lot of work lugging all my tools out of their respective hiding places but it's in and the set up with the Victron bluetooth app was simple as was the connection with Solar Assistant. Indeed the connection/software side was trivially easy which is always nice.

Had to make a short connector cable to go between the shunt and the battery bus bar so out with the lugs and hydraulic crimper and heat shrink etc.

All talking with Solar Assistant:

View attachment 97290

The nice thing I can see is the much better resolution in current and power readings than my inverter was supplying.

View attachment 97294

This I hope will help give me a far better picture of how the battery is really performing.

Problem with the inverter's own monitoring is the battery current only reports in increments of 1 A and so it means low loads would register as zero current and zero power draw. It also did not report power consumption of the inverter itself, so having the shunt should also better account for inverter's self consumption.

I'm not sure what, if any, calibration I may need to do with the smart shunt but it's in and it's working. I set the battery capacity with the app.

I also have more battery storage coming, 2 x 100 Ah 51.2 V (16S) LiFePO4 server rack batteries, so that will add ~10 kWh to the system and I'll have some fun seeing how that works along with the 380 Ah of lead acid I have.

Plan then is to test using the system to run the home overnight instead of the grid. If that proves to be viable then I am looking at upgrading the inverter to a more powerful option, as well as a main panel upgrade.
I've been looking over your posts in this thread over the last few days whilst hiding from the current wave of poor weather. I'm in East Gippsland in Victoria and am mid way through upgrading the solar system that was on our house when we bought a few months ago. Having left a rural farming area to move here, I was motivated by constant interruptions to supply, both planned and unplanned as well as two separate week long outages a year ago, to get off the grid altogether. ( Its nice to see I'm not the only one who has suffered appalling quality of grid power supply and we were trying to run a dairy farm at the same time)
It seems to me that you're halfway there already. I can't see any reason to be exporting power into the grid and getting paid a pittance for doing so whilst paying 6 times the amount for power from the grid. As a result we are getting a battery system added, inverter upgrades and additional panels to double the array size. I plan for now, to leave the grid connect in place and see how we go. I'm waiting to see if the Government does in fact start charging people to feed into the grid and/or take control of when home arrays can and cant be turned on. When that day comes, the switch will get flicked to off! I'd be monitoring this closely as it seems to be happening by stealth.
We have woodfired heating (although there are 2 split systems in house) and have a woodfired cooker coming shortly to supplement the modern appliances in the kitchen - our wood is free, LPG and electricity is not. The BIGGEST single reduction in power consumption I noticed from one property to our new one, is that we now have a heat pump hot water service. Its great even in the cold weather we have down here and I imagine would be much better in your warmer climbs so its probably easier for me consumption wise.
My upgrade will result in the loss of mains power to my workshop as they will use the current supply line underground to the shed to feed power from the array on that building back to the house and main system instead. I was fortunate to have been giving a large battery bank of second hand 1000ah ex Telstra batteries a few years ago. Unfortunately the people doing the upgrade cant, or won't do anything to include these into the new supply so I'm learning how to and building a separate off grid system to run the shed.
Your monitoring system is impressive, did you source it yourself? I believe we have some monitoring included when installed, but don't know what yet.
 
I've been looking over your posts in this thread over the last few days whilst hiding from the current wave of poor weather. I'm in East Gippsland
Brrr.

Its nice to see I'm not the only one who has suffered appalling quality of grid power supply and we were trying to run a dairy farm at the same time
I think we are pretty lucky relative to many of our American cousins on this forum when it comes to grid energy reliability. Gisspland does cop it a bit though, probably worse that us.

I recently got notice that we will have a 9AM-4PM planned outage on 21 June, so another good test of the system. On the Winter Solstice no less!

It seems to me that you're halfway there already.
Yes, and the plan at the moment is to take most of our regular load off-grid, however removing grid connection is never going to be a realistic option for us. The power and energy demands for our heating and cooling would make that far too expensive. 100 kWh days can happen.

So I plan to leave our ducted aircon (heating/cooling), ovens and stoves grid connected only (hot water I'll get to separately below). During the day these will still be mostly powered by the grid-tied solar PV, so it's at night we will be importing energy for those.

But the rest of household loads can largely be taken off-grid, save for some pretty crummy solar days (which with all the rain this year has been pretty often although June has been much sunnier for us). I'm looking at 10-15 kWh/day in general consumption. Anything more usually means we have guests or we are doing some unusual activity. Just about all consumption above that level will be heating or cooling.

I can't see any reason to be exporting power into the grid and getting paid a pittance for doing so whilst paying 6 times the amount for power from the grid. As a result we are getting a battery system added, inverter upgrades and additional panels to double the array size. I plan for now, to leave the grid connect in place and see how we go.
A big project. all the best with it.

I'm perhaps a bit less down on energy suppliers than you are, I get why our feed in tariff is what it is and have no real big issue with it. Most of the cost of energy supply is in the network and transmission. The energy generation part (which is what our solar PV is) is a significant but minor component of the cost (save for recent world events which hopefully will not go on forever).

But yes there is appeal in reducing reliance on the grid in rural areas where we have the space and deal with reliability issues.

I'm waiting to see if the Government does in fact start charging people to feed into the grid and/or take control of when home arrays can and cant be turned on.
I think there is a bit of general misunderstanding on what each of these proposed system changes are about and what they mean at household level (in reality it will mean bugger all difference to costs and in many cases it will mean much better outcomes for households) but even so it will be quite a long time before such things take effect, if ever.

You will never be required pay to export. The changes include a provision that residential customers must be given an option which is free of any export tariffs (which BTW would be levied by distributors to retailers, not to end users directly). There are other elements to this which are actually pretty positive for solar PV system owners but I'll leave that for now - more a topic for a different thread perhaps.

I am completely unconcerned about them as they will ultimately enable more people to have more solar PV connected to the grid.

We have woodfired heating (although there are 2 split systems in house) and have a woodfired cooker coming shortly to supplement the modern appliances in the kitchen - our wood is free, LPG and electricity is not.
We do have a fireplace but really only use it for visitors/ambiance reasons. Being a large open fireplace it is terribly inefficient and burns through wood like there's no tomorrow! I don't have a decent renewable supply of our own wood so it is also pretty expensive as a regular heating option. Last time I had a wood store pile all it did was encourage termites! If we can ever get to do renovations we plan to swap the fireplace out for a more efficient burning unit, and then I would consider using it more. Winter is not much more than 8 weeks long here.

The BIGGEST single reduction in power consumption I noticed from one property to our new one, is that we now have a heat pump hot water service. Its great even in the cold weather we have down here and I imagine would be much better in your warmer climbs so its probably easier for me consumption wise.
They are fantastic options for reducing energy consumption.

I did look into one when I replaced our 30 year old HW tank a couple of years back but the layout of the house was not conducive to fitting the compressor and it was going to be terribly expensive, at least $3k more and closer to $4k more when all the extra plumbing and electrical were sorted.

Plus we just don't use enough hot water to justify it. With the regular electric resistance HW unit we average 4.9 kWh/day over the full year. So a heat pump is only going to save us about 3.5 kWh/day ~=20-25c/day. For something that would cost us ~$3.5k more to install it just wasn't worth it.

If we were a large family with a lot of hot water consumption, then absolutely I would be having a heat pump system installed. We are going to see increasing government support for them as well. They already qualify for federal STC credits (same credits as for solar PV) and the VIC govt has a program for helping to pay for swapping out gas HW system for heat pumps.

I did however have a smart solar PV diverter installed recently so the HW is mostly heated using the spare capacity from our grid-tied solar PV system. It's only early days with that, I'll know better over a full year what our grid consumption for hot water has been reduced by but I expect our hot water will become ~85-90% self powered, with the balance from the grid.

It's kind of fun to find ways to reduce consumption and shift loads so that you self consume more PV and import less from the grid. Our imports have been on a consistent downward trend over the past six years, and I'm looking to keep that trend line moving down.

akHn7QZ.png


The change to hot water should reduce grid imports by another 4 kWh/day, and if I do get to scale up my off-grid system in the way I plan to then I think I can drop it by another 5-7 kWh/day.

The last ~10 kWh/day, on average, is unlikely though as that's the heating and cooling demand. That will only be lowered through improvements to the thermal properties of the house. I have done some but there is much more work to do on that front.

My upgrade will result in the loss of mains power to my workshop as they will use the current supply line underground to the shed to feed power from the array on that building back to the house and main system instead. I was fortunate to have been giving a large battery bank of second hand 1000ah ex Telstra batteries a few years ago. Unfortunately the people doing the upgrade cant, or won't do anything to include these into the new supply so I'm learning how to and building a separate off grid system to run the shed.
That should be fun!

Your monitoring system is impressive, did you source it yourself?
The off-grid system monitoring is via Solar Assistant. There are a couple of threads here on it. It works with specific types of inverters and some battery monitoring systems.

The grid-tied system is Fronius and I have a Fronius smart meter as well, so I get full visibility on grid-tied production, consumption, imports and exports.

I have both integrated into Home Assistant and the Energy monitoring for them both are combined.
 
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