A 3 phase, 50 Hz, 50 MVA, 11 kV, alternator has a solidly grounded neutral with zero, positive, negative sequence reactance's of j0.05 p.u , jo.2 p.u and j0.12 p.u respectively. It is desired to limit the double line to ground fault current to 75% of three phase fault current. Calculate the ohmic value of reactance that must be placed between the alternator neutral and ground.

Q: A fault occurs at bus 4 of the network shown in Figure Q3. Pre-fault nodal voltages throughout the…

A: x=1y=7Note: reactance of element right to bus 4 is not given. Hence we will not consider that in…

Q: A short circuit occurs in the series R-L circuit with V = 20 kV, X = 8 ohm, and R = 0.8 ohm. The…

A: Given V- 20 kV R= 0.8 ohm X= 8 ohm

Q: A 25 MVA, II kV generator has X"d=0.2 p.u. X2 = 0.3p.u. and X0=0.1 p.u. Tht neutral of generator is…

A:

Q: b) A fault occurs at bus 2 of the network shown in Figure Q3. Pre-fault nodal voltages throughout…

A:

Q: A 3 phase fault occurs at bus 1. Fault impedance Z, =j0.2 p.u. Z,, = 0.07286 p.u. Then the fault…

A: In this answer we will try to find out the fault current at bus-1 as shown below. Fault current is…

Q: ence components of the fault current are as Ipositive 12 p.u., Inegative and Izero The type of fault…

A: SOLVE ABOVE QUES

Q: A line to ground fault occurs on the terminals of an alternator, sequence voltages and sequence…

A: The given data is shown below:

Q: Problem #2: A transformer is fed from a 100 MVA, 18 kV generator via a 5-cycle breaker. Generator…

A: Given S =100 MVA V =18 KV Xd'' =18%Xd' =25%Xd =120%

Q: 1. The subscript d in the generator subtransient reactance refers to: 1. Generator 2. Generator 3.…

A: Subtransient:  It occurs extremely fast- faster than even transient. The subtransient time period…

Q: An unloaded star connected solidly grounded 10 MVA, 11 KV generator has positive, negative and zero…

A:

Q: The plant capacity of a three phase generating station consists of two 15,000 kVA generators of…

A:

Q: Q.3 When a line-to-ground fault occurs, the current in faulted phase 'a' is 100A. The zero-sequence…

A:

Q: What is the significance of fault analysis in power systems, and how is fault location determined?

A: Fault analysis is an essential tool for the determination of short-circuit currents that result from…

Q: A 50 MVA, 11 KV three-phase alternator was subjected to a different types of faults. The fault…

A:

Q: A 3-phase system has a phase to phase fault (i.e. phase B is short circuit to phase C while phase A…

A: In this question we will find per unit positive sequence current of line to line fault......

Q: Q.3 When a line-to-ground fault occurs, the current in faulted phase 'a' is 100A. The zero-sequence…

A:

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.