how calculate the current faut level

2 Answers   ABB,

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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.

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KVAR Kilovolt-Ampere-Reactance

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Electrical Engineering

0 Answers   Gamesa, Medha Servo,

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What is the difference of grounding and earthing?

6 Answers  

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which motors are used in electric traction?

1 Answers  

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what is the response time of relays when a FAULT OCCURS IN A POWER SYSTEM?

2 Answers  

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how to calculate the conductor size for certain KV transmission line and distribution line?

0 Answers   Hyundai,

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how the earhing is done on ship and airplane.

2 Answers  

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How many losses in generators? how we can reduce them? and also in motors,transformers?

1 Answers  

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what is meant by crawling??

10 Answers  

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When i went to a interview the interviewer ask me a question for that i cant able to answer him if anyone knows answer me How will you design a capacitor bank for a plant? if my p.f is 0.6 i have to improve it to 0.9 or 1 what kind of steps i have to do? and is there any formula for calculating this?

6 Answers   APNPDCL,

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