how we have to calculate the short circuit current for
33/11kv 2mva, 7.5% Z, Transformer primary side breaker and
secondary side breaker short circuit current for both sides?.

Answer Posted / dipak

Short Circuit Current=mva/z=2/.075=2.67MA,rating of
transformer is always same for primary or secondary

Is This Answer Correct ?    2 Yes 6 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What is primary and backup protection?

756


What are the differences between single phase and three phase?

1539


1. A 380 / 220 V r.m.s. 3-phase 4-wire circuit carries loads of 8 + j8.1 ohm; 4 + j4.1 ohm; and 2 +j2.1 ohmin the three phases respectively. The length of the circuit is 100 m, and the resistivity of the phase conductors is 0.0005 Ω/m. The neutral conductor is of the same size as the phase conductors. a) Select a reference angle 0for the first phase. Then write down the three phase voltages in both polar format and complex number format. b) Make appropriate assumptions, and take temperature effects on resistance is insignificant. Calculate the currents in the three phases. (Note: Determine conductor resistance, and apply Kirchhoff’s Voltage Law) Based on the result, suggest a main switch rating for the circuit. c) Show your preferred direction of neutral current in a diagram, and then determine its value. (Note: Apply superposition principle, and Kirchhoff’s Current Law) Use its magnitude to show that in this circuit, the unbalanced load may increase the voltage drop in some of the phases. (Note: Also observe the common volt drip in neutral) State your assumptions, if there are any. d) Suddenly the neutral wire of the circuit is broken. Estimate the new currents in the first phase, i.e. Phase L1. State your assumptions, if there are any.

1490


Explain in details how you would react to an unexpected incident when your supervisor or manager is not around to give instructions?

7321


how to identify vector group of three phase transformer by voltage method?

1162






oil cooled transformer

1774


A TRANSFORMER 440/400V,DELTA/STAR CONNECTED.THE NEUTRAL CONNECTED WITH GROUND CABLE THAT IS DIRECTLY CONNECTED TO THE PANEL,FROM PANEL IT IS CONNECTED EARTH PIT.IS IT RIGHT? IF IT IS RIGHT LEAKAGE CURRENT AFFECTED.SECONDATY IS PROTECTED WITH EARTH LEAKAGE RELAY.

1717


How shall i select the value of capacitor or inductor in a system?

1452


what is the difference between earth leakage and earth fault?

1749


On Which Pressure PRV is operated.

1281


WHAT IS THE DIFFERENCE BETWEEN AN ACB & mccb 7 WHAT IS THE CRITERIA WHEN TO USE WHICH OF THE TWO

1846


What is the need for a controller?

664


1. What is differential relay? How it operates? 2.How to calculate the Short Circuit Impedance in Transformer? 3.What is the alternate solution for testing of polarity by using polarity tester while its milli ammeter does not works? 4. While testing the 33KV Busbar by using Hipot kit, what should be the test voltage we have to apply? 5. What is the procedure/activities to be taken to inject the current more than 2000A by using 2000A Loading Transformer? 6. Explain how you can give the overload setting to any Motor Protection Relay for a HT motors with formula and example? 7. Why restricted earth fault protection is needed? Why can’t differential Protection is sufficient? 8. What should be the minimum and maximum ohmic value for earthing? 9. Why DC Currents are not used in transformer? 10. What is the Frequency while we step up the voltage from 220V to 11KV? Is it possible? Explain it?

1772


why tertiary winding is used in transformer with diagram?

1792


what type of motor used to move a 1 ton gate? and relate ratings with load.

1358