positive sequence element for balanced fault.

[johndaniel]

Hello Folks,

I want to know how positive directional element(F32P) is used to determine the direction of the fault current in SEL351S relay.
I have a system where I have to develop a PSCAD model to determine the direction of all possible kind of fault in loop. I have successfully implemented the system for all possible unsymmetrical fault due to prevalence of negative sequence components. But I have trouble in finding direction for balanced faults(symmetrical fault).
can anybody give me an idea how to do this?

Thanks

 

[waross]

Do some searching on reverse power protection or reverse power relays. An explanation of the working of a reverse power relay will include techniques to discriminate reverse power flow (negative sequence) from forward power flow (positive sequence).

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

 

[davidbeach]

3-phase fault is actually the easiest case. I'm pretty sure it is covered in the manual, but consider the phase angle difference between the (+) sequence voltage and the (+) sequence current for forward and reverse faults.

 

[piterpol]

Review the setting of the pickup of the positive-sequence overcurrent element 50P32P that fixes the threshold of the phase-phase overcurrent elements. See Fig. 4.21, p. 4-34, in the Instruction Manual.