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% Impedence


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i had read in one of the forums that"An increasing transformer impedance has the effect of reducing the fault current, and also reducing the voltage regulation.


From a voltage regulation perspective, you want to have a very low impedance. If you want a low fault current you want to have a high impedance.

Generally, in most applications, a low impedance is preferable"


so now i would like to know why a low impedence is preferable because both voltage regulation and fault currents are important factors when designing a transformer?

Thanks in advance



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  • 2 months later...

The transformer impedance voltage must be between a minimum impedance voltage and a maximum impedance voltage.


Measurement of impedance voltage is typically performed according to IEC 60076-1. The impedance voltage, which is expressed as a percentage of the rated voltage, represents the transformer’s impedance.


The IEC standard requires the impedance voltage to be calculated at the reference temperature of 75°C. The transformer impedance voltage is guaranteed by the manufacturer and is verified for the customer during the impedance voltage routine test. The minimum limitation of impedance voltage is related to transformer short circuit withstand. IEC 60076-5 specify the Power transformers ability to withstand short circuit.


According to Short-Circuit Withstand test, the transformer is subjected to successive short-circuits of 0.5 second duration and the transformer must withstand these short-circuits.






Creative thinking is breezy, Then think about your surrounding things and other thought products. http://electrical-riddles.com



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