100% reactive load on transformer.

[micapp]

I have a problem with a supply. One side of the supply is a connection of two users on a private grid and a generator on one (secondary) side of a transformer (1000V). The primary side of the transformer is connected to official grid (230V). On certain loads the active power transformer is close to zero, but the reactive power is high (i.e. ratio 2:40). The reactive component is for magnetizing the generator and the active power is net supply to official grid.
The MMCB on the primary side is set to 200A, and keep on tripping after just a few minutes. Instability in transformer? I hav installed a capacitor battery at the generator. When logging currents (capacitor, generator and line current from generator) at 2 seconds interval, all currents are stable. Anyone seem this before?

 

[magoo2]

Is this a new installation or an existing one?

Is this a single-phase or three-phase installation?

What transformer winding arrangement do you have?

What size generator and transformer are you dealing with?

 

[waross]

Induction generator?
There is so, so much that you didn't tell us.
Is this a new breaker or one that was sitting around?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[oldfieldguy]

Amps are amps, reactive or not. a standard CT or a clamp-on ammeter will tell you what the current is. If it exceeds the trip setting of the breaker or an overcurrent relay, it's going to trip.

That's the way things are supposed to work. Heat buildup in cables and other apparatus is based on current.

old field guy

 

[jghrist]

You may be having a harmonic resonance problem among the capacitor, generator, and transformer. If you have a source of harmonic current at a resonant frequency, there may be high harmonic currents. If you logging meter does not measure true rms current, it may not show the full current.