In a generator, why zero sequence impedance is less than positive or negative sequence impedance? But, in transformer positive & negative sequence are same. Why? Please clarify.
dear student zero sequence is the condition at which all the three phases of the machine get shorted .it is the symmetrical fault in which due to short value of thereactance involved in machine by field winding, armature winding, and danmper winding are very minimal and due to 3-phase short there is return path for the current so current flows through the ground which resist up to .5 ohm as the value of res. and reactance is negoshiated during fault so impedance is also very low so zero sequence impedance is small and 0- sequence current is larger
in transformar change in phase can'nt heartthe magnetic force applied only it reverses giving - iv voltage but in case of rotating machine change in maget poles disturbs the mmf so -iv sequence is smaller than +iv sequence in rotating M/c
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Zero Sequence Impedance
Re: Zero Sequence Impedance
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