Transformer Impedance:
Enter the values of short-circuit voltage, SCV(V) and rated voltage, RV(V) to determine the value of transformer impedance, I(%).
Transformer Impedance Calculator:
Transformer impedance represents the total opposition a transformer provides to alternating current (AC) flow, resulting from both its resistance and reactance. It represents the combined effect of the internal winding resistance and magnetic leakage reactance. Transformer impedance is crucial because it affects voltage regulation, fault levels, and the overall performance of the electrical system. A higher impedance leads to greater voltage drop under load and limits short-circuit currents, while a lower impedance improves voltage regulation but increases fault current levels.
Transformer impedance is generally expressed as a percentage, comparing the voltage drop across the transformer under full-load conditions to the rated voltage. Impedance affects how transformers share load in parallel operation and determines the mechanical strength needed to withstand fault conditions.
Manufacturers specify transformer impedance values to ensure safe operation and compliance with system requirements. Accurate knowledge of transformer impedance helps in system design, protective device coordination, and fault current calculation.
The impedance value depends on the design of the core, the windings, the geometry, and the materials used. Regular testing ensures that the transformer impedance remains within acceptable limits over time.
Transformer impedance is determined by applying a reduced voltage to the primary side and measuring the resulting short-circuit current on the secondary side.
Transformer Impedance, I(%) in percentage, equals short-circuit voltage, SCV(V) in volts, divided by rated voltage, RV(V) in volts and the result multiplied by 100.
Transformer Impedance, I(%)= SCV(V)/ RV(V)* 100
I(%)= transformer impedance in percentage.
SCV(V)= short-circuit voltage in volts, V.
RV(V)= rated voltage in volts, V.
Transformer Impedance Calculation:
- A transformer has a short-circuit voltage (SCV) of 6 volts and a rated voltage (RV) of 240 volts. Calculate the transformer impedance.
Given:SCV(V)= 6V, RV(V)= 240V.
Transformer Impedance, I(%)= SCV(V)/ RV(V)* 100
I(%)= 6 / 240 * 100
I(%)= 0.025 * 100
I(%)= 2.5%.
- A transformer has an impedance (I) of 5%, and a rated voltage (RV) of 400 V. Find the short-circuit voltage (SCV).
Given:I(%)= 5%, RV(V)= 400V.
Transformer Impedance, I(%)= SCV(V)/ RV(V)* 100
SCV(V)= I(%)* RV(V)/ 100
SCV(V)= 5 * 400 / 100
SCV(V)= 2000 / 100
SCV(V)= 20V.