A 25 MVA, 13.2 kV alternator with solidly grounded neutral has a subtransient reactance of 0.40 p.u. The negative and zero sequence reactances are 0.20 and 0.3 p.u. respectively. Find the fault current when,   (i) A single line to ground fault occurs at the terminals of an unloaded alternator and (ii) ALL fault occurs.

Q: 5.26 An unloaded generator with a pre-fault voltage 1 pu has the following sequence impedance: Z, =…

A: Given, An unloaded generator with pre-fault voltage, E = 1 pu Zero sequence impedance, Zo=j0.15 pu…

Q: Two alternators rated 15 MVA and 20 MVA have per unit  reactance of 0.20 and 0.60 respectively are…

A: In this question,  Two alternators rated 15 MVA and 20 MVA have per unit reactance of 0.20 and 0.60…

Q: Question: Find out the appropriate protection schemes for stator winding protection of alternator.…

A: The most common system used of the protection of stator winding foults in the differential…

Q: The zero sequence current of a generator for line to ground faults is į 3.0 p.u. Then the current…

A: Given, For the line to ground fault, the zero-sequence current, I0=j3.0 pu

Q: The negative sequence current of a solidly grounded generator for single line to ground fault is j…

A: Given that  negative sequence current of SLG fault is  Ia2 =j2.5 pu. Although for single line to…

Q: 3.On a double line-to-ground faultImmersive reader A) The short-circuit currents in the faulted…

A: In this question , we will write about double line to ground fault....

Q: Q3/A/ Fill in the blanks: 1. The most common type of 3-phase unsymmetrical fault is 2. In a balanced…

A: The solution is given below

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: The negative sequence current of a solidly grounded generator for single line to ground fault is j…

A:

Q: In the figure below, all impedances are in per unit on a common MVA base. The generators are…

A:

Q: For the circuit shown, the normal operating values shown are known. If a symmetrical three-phase…

A: We can redraw the per-phase equivalent circuit as

Q: Problem #2: A transformer is fed from a generator via a 5-cycle breaker. Generator reactance are:…

A:

Q: A generator connected through 5 cycle CB to a transformer is rated 8000 kVA with the reactances of…

A: A generator is connected through the 5 cycle circuit breaker to a transformer .   It is operating at…

Q: 11 A 25 MVA, 11 kV, 3-phase alternator has x d = 0.25 pu, Z₂ = 0.3 pu and Zo = 0.2 pu. It's neutral…

A:

Q: Problem 3: An alternator and a synchronous mo- tor each rated for 80 MVA, having sub-transient…

A: Synchronous Motor: It is an electric motor in which RMF of stator and RMF of rotor get locked and…

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: Let the system of Figure 1 operating with mechanical input Pm at a steady angle ĉo. A three phase…

A: If a fault occurs in the system, δ begins to increase under the influence of positive accelerating…

Q: ort-circuit occurs at its terminals. The fault MVA and fault

A: In this question, alternator ratings are given..3 phase short circuit occurs at terminals..We have…

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

A:

Q: The leakage reactance(XL) and the armature reactance (Xm)  of the three phase unloaded alternator…

A: False

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: A phase to phase fault (betvieen phases b and ) has occurred at the Y side of 100 MVA 132/33 kV AY1-…

A: We can redraw the circuit as

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: For the circuit shown, if a symmetrical three-phase fault occurs in node 2, determine a. The…

A:

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: A fault which gives rise to symmetrical fault currents (equal faults currents with 120-degree…

A: Symmetrical fault: When three phase lines are balanced, when ever a fault occurs  betwe these lines…

Q: :A three phase alternator 100 MVA, 13.5 KV, exposure to types of faults are fallowing: Balanced…

A:

Q: 8. A three-phase 50 Hz, 200 MVA, 220/66 kV transformer has a clock number of Yd11. The transformer…

A: “Since you have posted a question with multiple sub-parts, we will solve first three sub-parts for…

Q: 1 ww ww F w Ju 2

A:

Q: in a tie-bus arrangement as shown in figure. the reactances of the generators and reactors are 0.2…

A: We redraw the circuit on per phase per unit basis: In the circuit the fault point is connected to…

Q: a. In sequence networks of power system, why does voltage sources appear only in the positive…

A: a) Machine are design such as it will generate voltage if the phase sequence will be same as…

Q: Consider a single phase transformer of rating 150 KVA, 3600/360, 50 Hz. Let the series resistance…

A: Formula to calculate voltage required to produce rated current at short circuit is: VSC=V1×ZPUwhere…

Q: Question 4 A star connected neutral grounded 3-phase synchronous generator consists of 0.1 p.u of…

A: In this question we need to find a zero sequence reactance of genrator

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

A:

Q: The sequence components of the fault current are as follows: Ipositive = j 2 p.u., Inegative = -j0.5…

A: Given, The sequence components of the fault current are, Ia1=j2 puIa2=-j0.5 puIa0=-j1.5 pu

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

A:

Q: Consider a single phase transformer of rating 150 KVA, 1500/150, 50 Hz. Let the series resistance…

A: Given: Z1=R1+jX1=0.2+j0.45 ΩZ2=R2+jX2=0.002+j0.0045 ΩKVA=150

Q: The severity of line-to-ground and 3-phase faults at the terminals of an unloaded star connected…

A: Given, Terminal voltage, E = 1 pu Positive, negative, and zero sequence reactance is X1=X2=j0.35 pu…

Q: capacitors will supply reactive VAR during peak load condition and consumes reactive VARs during…

A: 1.Booster Transformer:-It is used at the end of a power line or at the intermediate position to…

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.