PowerLogic T300 - SC150 compatibility with Holmgren CT wiring for Earth Fault detection

[jean-luc_batard]

Hello All
Here relaying some question from DSPS


Does PowerLogic T300 support following CT cabling, known as Holmgreen connection ?

If yes, does it work with current firmware and what should be the settings?

What is the difference with a classical 3 phase CT mounting and calculating I0 by summing the 3 currents by software ?

[Gregory_Meunier]

Hi Jean-Luc,

I don't know the T300 specificaly, but if the device can perform earth fault detection from a dedicated input, I don't see anything that prevents Holmgreen connection.

Holmgreen connection or summing the 3 currents by software are kind of redundant.
They both face the same limitations regarding sensitivity and stablity against inrush current compared to dedicated Core balance CT.

[Rajasekar_Chandrasekar]

Hello Jean-Luc,

I think this connection is not tested and we don't have this connection can be set in the T300 setting of SC150 Page. we need to ask R&D team. if posisble we have add the setting option in the SC150 setting page.

BR

Rajasekar

[JYPOC]

Hello Raj,

Mathieu has successfully tested the solution but as Gregory wrote, the result is not better than with the calculation based on the 3 CTs...