what composit error,ratio error,phase error in CT and PT??
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Answer / siddharth
composit error- it is difference between instataneous
primary current and inst. secondry current multiplied by
turn ratio.
ratio error and phase error is occured due to some primary
current is utilised to magnetise the core.
Is This Answer Correct ? | 25 Yes | 13 No |
Answer / raghavendran.r
1) Composite error = [Ip - KIs]/Ip * 100
2) phase error = error or deviation in the phase
displacement of primary and secondary
current.
3) Ratio error = The secondary current is less than the
expected value. The secondary is less in magnitude. This
diffence is known as ratio error.
Is This Answer Correct ? | 16 Yes | 13 No |
Answer / karuppasamy
The total error vector (composite error) can be seen as the composition of:
an amplitude error (ratio error), expressed in % and
an angle error, expressed in radians or seconds.
Note that for protection CT's, the angle error is disregarded and only the total composite error is given in %. When examining the equivalent diagram, one would easily conclude that the error current can only be the magnetising current of the CT. Indeed, normally the magnetising current is very low but at the saturation point of the core, 50% increase in magnetising current produces only 10% extra secondary voltage so at saturation the error current rises quickly. Therefore, the property's accuracy and saturation of the core are closely linked. Hense the error vector is allways a reducion in secondary output current; negative error. Positive error is only possible by ratio-turn correction.
Is This Answer Correct ? | 4 Yes | 1 No |
Answer / gunasekaran
composite error is combine of the ratio and phase angle
error ratio error deviation from the rated sec current phase
angle error is phase displaceme from primary current it is
+-60sec
suppose 5p20 ct composite error is +-5%
ratio error is +-5% phase angle error +- 60sec
Is This Answer Correct ? | 9 Yes | 19 No |
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