Setup CT for Grid Tied Solar

Support
1

Hi, I have just recieved, installed and setup my IotaWatt here in the UK. It was a tight squeeze for the CT’s but they went in OK and all seems to be working.
I have a question (probably the first of many :wink:
I have a grid tied solar system installed so want to measure the power I am using from the grid and the power I am feeding back to the grid.
I have the CT on my grid feed set to allow negative values.
At the moment I am exporting to the grid but IotaWatt is reporting a positive value?
Have I got the CT the wrong way around or is that correct with negatives allowed?
If I want to differentiate between power in and power out should I turn allow negatives off?
Also what does the circular arrow to the left of the CT name mean?
I attach a pic of the IotaWatt status screen.

iotawattstatus
iotawattstatus742×688 38.9 KB

Just to update: I have set the CT on my grid input to reverse and it seems to be showing correctly now. My only concern is that I have the arrow on the CT (an AcuCT H06-100) pointing from the meter to my consumer unit, i.e. the flow of power when importing from the grid. All the others are pointing out from the consumer unit to the respective house circuit and are displaying correctly. Should I turn the grid CT around? It’s easily accessible.

2

The reverse checkbox is the same as physically reversing.

To measure the total power imported and exported you should look at setting up an integrator in the IoTaWatt.

1 Like
3

Thanks overeasy, I have set up an integrator. My concern was it appeared to be working in reverse. I have set it to reverse now and looks good.
I’ll let it gather a decent amount of data and take a look again.
Oh, and what is the meaning of the arrowed circles to left of the name?
Found it in a YouTube video. It seems all my CT’s are reversed. Doh!

4

You can simply check reverse in the VT setup. It’s all relative. If you do that, you will want to toggle reverse in the main CT where you have “allow negative values”.