Hi All,

I have a question on the subject of power engineering regarding Tertiary Delta.


I know that the Tertiary Delta is used for the following

1) To limit the fault level on the LV system by subdividing the infeed that is, double secondary transformers.
2) The interconnection of several power systems operating at different supply voltages.
3) The regulation of system voltage and of reactive power by means of a synchronous capacitor connected to the terminals of one winding.


So if there was a system which consisted of

Y(grounded) Generator 1 connected to bus 4
Bus 4 connected to a D-Y(grounded) transformer to Bus 1.
Bus 1 connected to bus 2 via a transmission line
Bus 2 connected to bus 5 via a D-Y(grounded) transformer
Bus 5 connected to a Y(grounded) Generator 2.
Bus 1 & 2 are connected though transmission lines to bus 3
Bus 3 connected to bus 6 via a Y(grounded)-D-D transformer.
The Tertiary Delta winding is not connected to anything.


So if the question was asked that the tertiary Delta winding was open, what effects would this have on the fault level of the system. Would I be right in saying that, becuase its not connected and it is open not short to earth that there would be no effect to the fault level in the system.

Hopefully I have explained myself enough.

Thanks for your time and help in advance

 

Did the original question imply the fault level at any point in the entire system or at a particular point?

 

T_N_K,

Yes it did,

It said to assume that a single line ground fault occured on the transmission line at an equal distance between Bus 1 and Bus 3.

 

So if the question was asked that the tertiary Delta winding was open, what effects would this have on the fault level of the system. Would I be right in saying that, becuase its not connected and it is open not short to earth that there would be no effect to the fault level in the system.

I would agree with you since the open delta tertiary contributes nothing to the fault analysis.