Easergy T300 - Smart RM6 - sharing LPVT connection for Revenue meter

[sesa122761_brid]

Dear All ,

One of our Smart RM6 customers would like to share the existing LPVT voltage sensors (going to Easergy SC150 module) with a Revenue Meter. Is that possible and if yes, how?

Thanks in advance 

[Juha]

Hi @sesa122761_brid , 

LPIT's (Low Power Instrumentation Transformers) can not be paralleled like 
traditional instrumentation transformer. It requires an amplifier to distribute the

LPIT signal for several devices.

BR

-juha-

[JYPOC]

Hi,

We investigated a few years ago and it was deemed possible to connect up to 3 or 4 Easergy SC150-VT/LPVT modules to a single LPVT output. However, this has not been tested with other products: hence the solution provided (i.e. to use a LPVT sharing hub) will probably be needed to add this revenue meter.

Note: the RM6 is fitted with 3 LPVTs (Class 0.5) and 3 RM6 bushing CTs (Class 0.5). This is why the Easergy T300 provides a Power Measurement at Class 1.

If the revenue meter is connected to the same current/voltage sources, it cannot provide a Power Measurement better than Class1: so what is the idea here???

[sesa122761_brid]

Thank you very much.

Do we know the type of 'LPVT sharing hub' in the market  that could be used in this case ?

It looks to me any case with the existing LPVT type we use in RM6 , it is not possible to use external additional revenue meter beside SC150 since the accuracy for the meter will not be achieved except customer accepts with some tolerance on the accuracy for the meter  ? 

[JYPOC]

1. What LPVT hub can we use?
   • Since this has never been tested, I cannot recommend any.
   • I have found this reference on internet so I suggest you purchase one to test it (https://in.rsdelivers.com/product/rs-pro/21993050-50/rs-pro-cat5e-rj45-t-adapter-2-port-shielded-170...).
   • We ourselves plan to acquire some units to also do the test in Technopole/ Grenoble (FR)
2. Sharing Smart RM6 bushing current transformers?
   • To perform revenue metering on the MV side, your revenue meter will need to connect to CTs.
   • What do you intend to do: add another set of 3 CTs on the MV feeder, or share the existing ones?
     • The Smart RM6 is not designed to share the output from the 3 bushing CTs (1 A, 500/1).
     • In addition, opening the secondary side of 1 A CTs cannot be performed on a live line (meaning: you will need to switch off the MV on the RM6 bushing)

And as I said before, a Revenue Meter can provide a high accuracy on the complete chain when it is directly connected to the voltage (which is the case for LV measurement) and CTs with a Class better than 0.5. . But it won't be the case here as LPVT is Class 0.5 and RM6 bushing CT is Class 0.5.