Protection on a Corner Grounded Delta System

Issue:

Can I use a phase monitor for protection on a corner grounded delta system?

Answer:

Yes, Macromatic phase monitor relays provide the same reliable protection on corner grounded delta systems.

A corner grounded delta system is a common way to establish a reference to safety ground when dealing with an otherwise floating output from a delta secondary transformer. It is implemented by grounding any one of the three phases of the transformer secondary (corners of the delta).

In order to apply a phase monitor relay in this type of installation, it is important to realize that despite the connection to ground the three phase delta output remains unchanged.  A phase monitor relay should be connected to phases A, B, & C (one of which will be grounded) as you would in any standard application.  

Please contact Macromatic for more details.