Q: For the following OLD, take Sg = 50 MVA and VB = 22 kV at the %3D transmission line to find the short circuit current if a 3-ph fault occurs at the middle of transmission line. 15 MVA 20 MVA X = j0.6 pu (15:35) kV X = j0.3 pu (40:15) kV 25 MVA 15 MVA (6+j8) Q 23 kV (G X = j0.5 pu (м) 18KV x = j0.3 pu TL T1 T2

Q: The maximum size overcurrent device for primary only protection of a three-phase, 37.50 kVA,…

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Q: Consider the network given in figure below, where the numbers indicate admittances in per unit. Find…

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Q: The subtransient reactance of a generator is typically much larger than the steady-state reactance.…

A: 1 ) generally the subtrasient  response of a generator is larger than the steady state reactance. So…

Q: Write the equation, starting at A and going clockwise for the KVL loop

A: Consider the given circuit,

Q: The maximum size overcurrent device for primary only protection of a three-phase 75 kVA transformer…

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Fault Analysis

In an electrical engineering system, a fault is an abnormal electric current flowing through the system, and fault analysis is the study of these faults. For instance, a short-circuit is a fault where the live wire touches the ground or neutral wire. If a circuit is interrupted by a failure of a current-carrying wire then an open circuit fault occurs. The open-circuit faults are also called series faults. One or more phases or ground may be involved in a three-phase fault or may occur only between two phases. Current flows into the earth in case of a ground fault or earth fault. For most situations, the prospective short circuit current of a fault that is predictable can be calculated. To limit the loss of service because of a failure, the protective devices can detect fault conditions and operate circuit breakers and also other devices. All phases equally can be affected in a poly-phase system which is known as symmetric electrical fault. The asymmetric fault becomes more complicated to analyze if only some phases are affected. By using methods such as symmetrical components, the power system analysis of these types of faults is often simplified. The main objective of power system protection is to design, detect, and interrupt power system faults.