Save 15% on Pro Membership Plan with discount code: NTX67 (limited time offer). Study specialized LV/MV/HV technical articles and papers.

# Transformer Fault Current Calculation

Home / Download Center / Electrical Software Reviews / Transformer Fault Current Calculation

## Transformer Impedance

Transformer Impedance is measured in Percent Impedance, this is the percentage of rated primary voltage applied to the Transformer’s primary winding in order for the rated secondary Full Load Current to flow in the secondary winding (this test is preformed with the primary winding connected to a Variac or variable supply and the secondary winding shorted-out).

Transformer Impedance values may vary but typically Blakley Electrics transformers will be between 4 to 5% of primary Voltage.

Impedance Voltage Vz = ( Primary Volts V x Percent Impedance Z% ) / 100

### Transformer Maximum Fault Current Allowing for Loog Impedance

To calculate the Maximum Fault Current that can be achieved in a circuit fed by a transformer we refer to the below formula.

This formula calculates the loop impedance at the end ofa circuit fed from the secondary winding of a transformer. When calculating Fault Loop Impedance Select the Correct Transformer Type Above. Three Phase Transformers Divide the Values for Vs secondary Voltage by √3 and the VA by 3.

For Centre Tapped to Earth (C TE) transformers halve the values for Vs and VA . For RLV / 110V C TE Disconnection Times & Zs figures refer to BS 7671:2008, 411.8 Table 41.6.

 Software: Transformer Fault Current Calculation – Blakley Electrics Version: 2.0 Developer: BLAKLEY Electrics Size: 110kB Price: Free Downloads: Right here | Video Courses | Membership | Download Updates

50% Discount 💥 - Save 50% on all 90+ video courses with Enterprise Membership plan.

1. Kalyan
May 22, 2021

very cool

Apr 15, 2020

Very Good platform for brushing the Fundamentals. Excellent approach.

3. Bui hong Diep
Apr 15, 2020

I like this site a lot its really good

4. Mario Meneses
Apr 14, 2020

I download the calculator but don’t’ work, I can’t change the values.
Please let me know what can I do.

• Rommel Dagayday
Apr 15, 2020

You have to click enable editing

5. jhun damot
May 27, 2019

I like this site, its ery helpful… Thank you and more power to all of you!

6. Tom
Apr 29, 2019

There might be some problem about the 3^(1/2)

7. TAYEB
Apr 01, 2019

10/10

8. Eric
May 13, 2018

9. B K SINGH
Jun 28, 2017

i like this site nice

10. success
Oct 20, 2014

Keep up the good work

11. Bassam alhaboob
Aug 18, 2013

thank you

12. nedal nemer
Jun 09, 2013

very cool

13. KALYAN
Mar 21, 2013

this site
helps lot.

14. carsona
Sep 23, 2012

I like this site a lot its really good.