5 Jaw Meter?

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NorthwestPV

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The Energy Trust Of Oregon requires any pv system that has batteries attached to have a 5 jaw meter. I can find the socket but not the meter. Has anyone seen any of these for sale?
 
NorthwestPV said:
The Energy Trust Of Oregon requires any pv system that has batteries attached to have a 5 jaw meter. I can find the socket but not the meter. Has anyone seen any of these for sale?
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The 5 jaw meter will be a 12S meter. Usually reserved for single phase services fed from a three phase bank. Why isn't the POCO supplying one?
 
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I'm assuming the meter is required for RECs or something similar, and is distinct from the service (net)meter.

What I don't understand is why batteries make any difference to the type of meter required. Just curious if anyone knows why.
 
jaggedben said:
I'm assuming the meter is required for RECs or something similar, and is distinct from the service (net)meter.

What I don't understand is why batteries make any difference to the type of meter required. Just curious if anyone knows why.
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This is actually an advantage to the PV generator owner.With a simple kWh meter, the currents are sensed with one sensor around the two legs going to load. The inverter will supply the backup loads during the day, along with exporting some energy, but with the currents going in two directions, the meter will slow or stand still and not read true production.

With a 12S meter, there are two current sensors around each 120 volt leg. This way the energy used by the backup that is produced by the generator is counted as production also.
I still don't understand why the POCO won't sell them one.
 
It appears that a 5 jaw meter, which is a 12S, is for a 3 Phase application. This will be installed in a single phase home. In Oregon the POCO replaces their meter with a net meter. Then we are required to install another customer owned watt hour meter in addition. I'm not sure what difference the batteries make.
 
NorthwestPV said:
It appears that a 5 jaw meter, which is a 12S, is for a 3 Phase application. This will be installed in a single phase home. In Oregon the POCO replaces their meter with a net meter. Then we are required to install another customer owned watt hour meter in addition. I'm not sure what difference the batteries make.
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The 12S can be used for single phase and three phase applications. As for the batteries, I hope I explained it in post 6
Your last post explained alot. (at least to me)
The net metering will not register all the energy produced because of the batteries explained in post 6. It will work for the POCO, but not to record and sell REC's. In order to claim credit for ALL the energy produced, you need a form 12S
 
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NorthwestPV said:
It appears that a 5 jaw meter, which is a 12S, is for a 3 Phase application. This will be installed in a single phase home. In Oregon the POCO replaces their meter with a net meter. Then we are required to install another customer owned watt hour meter in addition. I'm not sure what difference the batteries make.
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What is the purpose of the customer owned watt hour meter, and where is it installed?
 
A form 12S meter has 2 voltage windings. This allows the voltage to current "calculation" made by the meter to be made independently for each hot leg (Phase A and Phase B). It is often used when metering a 3-wire (two hots and a neutral) service from a 120/208V 3 Phase source. It can also be used when the POCO suspects that there may be a significant imbalance between Phase A to neutral and Phase B to neutral voltages. This could occur if a battery (or any other source) supplies only 1 Phase and not both.


The standard residential service typically uses a form 2S with a single voltage winding. The metering assumes that the voltage between the neutral and each of the two phase wires is balanced and in phase with the currents.
 
kwired said:
OK makes sense, why is it required? I can see it being highly desired but don't see why an outside party would require it. Also why would 5 jaw meter be needed? This would have to be on load side of an inverter that is not shown in your link, and I see no reason why typical 4 jaw meter would not work if it is typical 120/240 single phase.
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The picture is a simplification of the system. Did you read my post about the way the meters are configured? or the one regarding the RECS?
One meter can be used for net metering, but with a battery backup, a 2S meter will stop while the battery is supplying loads and the generator is exporting. The 12S is needed to measure all production with a battery backup.

The outside party is the one responsible for taking care of their REC's not the POCO. It is their meter that they have to record these REC's with. As with any tradeable commodity, you need a record.
 
Hv&Lv said:
The picture is a simplification of the system. Did you read my post about the way the meters are configured? or the one regarding the RECS?
One meter can be used for net metering, but with a battery backup, a 2S meter will stop while the battery is supplying loads and the generator is exporting. The 12S is needed to measure all production with a battery backup.

The outside party is the one responsible for taking care of their REC's not the POCO. It is their meter that they have to record these REC's with. As with any tradeable commodity, you need a record.
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Please tell me what REC stands for. When it comes to trading commodities and measuring devices the accuracy of the device is strictly regulated. Just look at scales used for sale of goods or meters at fuel pumping stations - who verifies this privately owned meter is accurate?

Why is energy sold going to be differerent from the results of net metering? Energy either goes in or out and the net metering records it, I see no reason why it should matter where energy is coming from but rather that it passes one direction or the other.
 
kwired said:
Please tell me what REC stands for. ...
Why is energy sold going to be differerent from the results of net metering?
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REC stands for Renewable Energy Credit. In some states (e.g. Oregon, where the OP is from), government incentives for installing solar include direct payments to the system owner for energy produced by the system. This total is different from the net-metering total so a separate meter is required, which answers your other question and comments.

BTW, this also applies to quite a few 'lease' arrangements where a financing company takes responsiblity for the system production and uses a meter either for billing purposes or as a performance monitor.

When it comes to trading commodities and measuring devices the accuracy of the device is strictly regulated. Just look at scales used for sale of goods or meters at fuel pumping stations - who verifies this privately owned meter is accurate?
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Well, ANSI makes standards, and whoever is paying the RECs typically requires a meter that meets ANSI's standard for a revenue grade meter. So if you don't install something that meets the standard, you don't get paid.

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As for the 5 jaw meter...

Hv&Lv I don't really get what you mean by current going in two different directions. Maybe a diagram would help. I do get that the 5 jaw meter has something to do with the fact that most hybrid systems use 120V inverters, so there is unbalanced current on the hot legs, and they require independent measuring. So if one installs a 240V system, would a 5 jaw meter still be required?

Of course it would surely help me if I really understood how solar inverters handle unbalanced current, but that was another whole thread.
 
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