Knee Point Voltage for Generator Diffnl. ct's

Why should it matter? The CT Knee Point Voltage claculation takes into account only the maximum anticipated fault current at the CT location, the CT secondary winding resistance, the two way CT Secondary Lead Resistance & a factor of safety. Where & how does it matter if it is for a Trafo. or for a generator?

thts fine sir, but only my doubt is for maximum fault primary current is Ift = kVA/ (0.415x1.732x Z) in tranformer, is this the same formulae for generator also for max. primary fault current.

Yes! But instead of %Z, you must substitute the sub-transient reactance (%x"d) of the generator. And.... please remember that this formula is true only if the fault is at the terminals of the generator or transformer. If the fault is away from the transformer or generator, then the line/cable impedances shall be used to calculate the fault current.

ok, thanks a lot sir

hello sir, i posted a question but still nobody given a proper answer i hope you can help me , it was my question,

hai all,

There is a coding system for switchgears and control panels, like for 11kv panels- +k01, +k02.. and for 132kv panels E01, E02..., 33kv - H01, 02...,11kv control panels it will be WR01, WR02... for lv panels using NN01, 02... etc, some times instead of + symbol = also using. can any one tell what is the base of this coding system, is it related IEC or something, please let me where i can find the meaning of this coding and procedure for each system. let me know what will be the coding for 3.3kv panels.

with thanks