Hi waross,
Thank you much for your response.
It was not a breaker condition issue as we had a trip on the other MCB too which was supplying to another similar panel.
As we had no tripping when we had disconnected the sync isolation PT (PTB), I hope circulating currents might not be an issue...
The nominal rating of the MCB is to be decided based on the rated thermal burden (Rated output) of the VT.
In your case, it is 1000 VA.
The Secondary Fuse or MCB Rating should be 1000VA / 115/sqrt 3
1000 / 66.4 = 15A
Additionally, you may also need to consider how the thermal burden (Rated...
thread238-200371
Hi,
Referring to the old thread, please note that this is the situation we are also having in one of the old Generator Protection/Synchronization Panel. The Bus VT secondary 4A Z curve MCB supplying to the Generator panel trips instantaneously 2 or 3 out of five times and is...
Appreciate your response Scottf.
Consider the VT rated 150kV/√3:100V/√3 and has a thermal burden rating of 1500VA (per phase as per IEC). What would be the secondary MCB or fuse rating in this case?
I believe your interpretation would be valid for a V-connection (Ratios would be 150kV:100V...
thread238-209138
The thread is old but the problems are still the same. One such problem I had encountered and found useful information related to the old thread.
One thing that mikeangel was looking for was a calculation and justification to the selected MCB rating in the secondary of the...
