Strange Monitoring via a Henley Block !!??

[danesol]

Right, I've been struggling with proper monitoring now for sometime, but seemed to have partly solved this now ...... however, it isnt exactly right on a conditional basis - can you experts point me in the right direction why this is happening;

OK, the tails are split straight after the DNO meter into a Henley Block, where the 6mm AC SWC cable from the PV also connect to, naturally the CU connects to this using the existing but previous cut tails. Currently nothing else runs off the SWC cable/ 2nd CU of the PV system.

Now here is the interesting bit - when I use a CT claw around the "+tail" to the CU so that I can monitor all useage of electric in the property ( not really interested in the net reading as the DNO reading provides this ) its not fully correct, which is odd as both the DNO and the PV are technically behind this in the wiring scheme and therefore in my mind should provide the net value of electric flowing into the property .........

I have now acquired an additional CT claw, which I have placed around the DNO "+tail" to the Henley block - the two addup to exactly what I am using within the property as long as the PV is working, if the PV is not on, naturally the figure is nearly dble what it should be - lol

Just to elaborate on the two figures equalling - I am assuming partially this, as the old DNO meter wheel has stopped, the PV reads xx and the Envir monitor also reads xx - therefore I am assuming from that that im using exactly what the PV is generating and importing no electric whatsover.......

I just cant workout why I have this situation unless within the property there is an underlining wiring issue ????

Doesnt make sense in someways - any comments ?

 

[SolarCity]

When you say "is not fully correct", what makes you think that the figure isn't correct?

 

[danesol]

When you say "is not fully correct", what makes you think that the figure isn't correct?

For example the PV states its generating 2000watts - the DNO meter is stationary (wheel stopped ) and the Envir states 585watts say ?

When you measure the other tail its the balance ( ~1415watts ) .... lol

 

[Worcester]

OK, the tails are split straight after the DNO meter into a Henley Block, where the 6mm AC SWC cable from the PV also connect to, naturally the CU connects to this using the existing but previous cut tails. Currently nothing else runs off the SWC cable/ 2nd CU of the PV system.

I hope not. The PV CU should be connected to the Henley block with the same size tails as the incoming DNO - probably 25mm2

A diagram of where you are putting the CT's and what readings you get would help.

 

[danesol]

I hope not. The PV CU should be connected to the Henley block with the same size tails as the incoming DNO - probably 25mm2
.

Sorry they are via a 100amp breaker - sorry excluded that info, didnt think it was relevant and assumed you would know a fellow expert would do that anyway

 

[danesol]

Here you Worcester......

Blue Sensor is for the Solar Immersion device ONLY

The two RED Eon CT clamps connected to one EOn transmitter to one Envir Monitor

Henley Block
Left is incoming main
Middle is PV
Right is tails to CU

 

[Worcester]

Have you tried swapping the different sensors around?
Are they all connected to the one transmitter?
Have you tried with just one sensor at a time connected to the transmitter?
drom my conversations with current cost the transmitter does weird things with multiple CT connections.....

 

[danesol]

Have you tried swapping the different sensors around?
Are they all connected to the one transmitter?
Have you tried with just one sensor at a time connected to the transmitter?
drom my conversations with current cost the transmitter does weird things with multiple CT connections.....

Yep one transmitter and this is the best and most accurate reading on all electric consumed on the premises as long as the PV is working.....

ie. two different readings which add up correctly to generation figure as long as demand isnt greater than PV generation, otherwise reading is higher and then the DNO meter wheel starts to turn

 

[Worcester]

Current cost doesn't detect the DIRECTION of the flow.
It may be adding up some of the readings..
Knowing that, do the figures make sense?

 

[danesol]

Current cost doesn't detect the DIRECTION of the flow.
It may be adding up some of the readings..
Knowing that, do the figures make sense?

But what I find very strange indeed is that all demand for electric in the premises is made through the CU and you would logically suggest/think that a CT on the wires leading to the CU ( on the right with cable ties ) would give you the correct demand reading within the premises - would it not ??

whether I turn the clamps round makes no difference either nor the fact if I use the neg tails..... or a mixture of + & - tails - lol

 

[danesol]

But NO - in my case the Envir Monitor meter only shows the correct useage in the premises when I have the 2nd CT clamp fitted ( left ) - which completely makes no sense whatsoever in my mind .....

 

[Gavin A]

there appear to be 2 clamps on the same tail to the suppliers meter, is this deliberate?

 

[danesol]

there appear to be 2 clamps on the same tail to the suppliers meter, is this deliberate?

Yes the BLUE one is for the Solar Immersion device and is directional - and naturally is NOT connected to the Envir monitoring system

 

[Worcester]

from memory there are three sockets on the bottom of the transmitter and it does matter what is plugged in to what.

The only way to work out what is really going on is to plug only one CT into each of the sockets at a time and place it at the various monitoring points (CU. PV. Incoming) and then to increase the load to case import / export conditions abd then to record all 18 values (3 x 3 x 2) abd ten you have a cghance of working out what is going on.

Then add in the second CT to socket 2 and do the same, move it to socket 3 repeat. put the primary CT in socket2 and the secondary in 1 then 3, repeat, put the primary in socket 3 and teh seconday in socket1 then socket 2...

You have quite a few permutations to work through, hence I recomend either http://openergymonitor.org for thr geeks, Eco-Eye | Real Time Electricity Monitors | Eco-Eye with Microgeneration/Photovoltaic Installations for the average consumer and Elios4You - Sibert - automated equipment manufacturer and supplier of process consumables for those that want flashy displays

I gave up trying to get the Current Cost monitors to work properly after long (6 months) worth of development work with them... and still no working solution. the big problem was the lack of the ability to measure the DIRECTION of the current and hence import/export power (i.e it doesn't matter which way round you put the CT clamp)

 

[danesol]

AFAIK Worcester - there is no differential between the three sockets, wasnt this merely to cater for 3phase. The monitor merely adds the readings from all three sockets ( if used ) and displays it on screen as a total reading

All I know is that when the PV system is working - the reading on the Envir monitor ie. CT1 & CT2 = approx' PV generation figure or more should demand be greater than generation.

 

[danesol]

However, when the PV isn't ON - the monitor displays the wrong reading altogether as IMO is doubling the same reading on the same tail ???

Which makes sense, but what doesnt make sense is why the resultant figure is correct once the PV is generating

 

[danesol]

If I was to place a 3rd sensor on the PV input it would simply add the generation fig' to the existing combined fig' of CT1 & CT2 i think.....

 

[Worcester]

In that case here is what you SHOULD see:
No Generation using 0.5kW exporting 0kW Double makes sense CT1 (on the main leg) +CT2 (on the CU) (no PV) = 2 x CT2 CT1 = 0.5kW CT2 = 0.5kW Gener = 0 === Reading shuld be 0.5+0.5 = 1kW
Generating 1.5 kw using 0.5kw exporting 1 kw CT1=1 CT2 = 0.5 ==== Reading should be 1.0+0.5 = 1.5 kw
Generating 0.3kw using 0.5kw importing 0.2kw === Reading should be 0.5+0.2 = 0.7Kw

I would get well confused seeing those figures

 

[Worcester]

If you are generating more than you are consuming the two add up to what you are generating
If you are not generating they are twice what you are consuming
If you are generating less than what you are consuming they add up to consumption PLUS import

 

[danesol]

lol

Right i now have a theory about what going on - i will test this mid morning tomorrow !!!