Phase to Ground Fault Delta/Star Tx

[Twinsen]

Hi All,

At work recently we had a phase to ground fault on one of our 8MVA transformers.

I have two questions:

1. What effect does the phase to ground fault have on the voltages on the primary (delta) side of the transformer and will their be a significant voltage drop?

2. How will this effect the voltages on the secondary star side of the transformer?

Am pretty new to the industry so would be very appreciative of some answers.

Thanks.

 

[waross]

The magnitude of the ground fault current will depend first on the impedance of the fault path including intentional grounding impedance, second on the impedance of the transformer and third by the system impedance.
The secondary line to ground current will reflect to the primary as a phase to phase current. The secondary voltage will depend on the magnitude of the current and the transformer impedance.


Bill
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