GATE Exam > GATE Questions > A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connect...
Start Learning for Free
A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.
Correct answer is '1.1'. Can you explain this answer?
| FREE This question is part of | Download PDF Attempt this Test |
Verified Answer
A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator ...
Most Upvoted Answer
A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator ...
A and C. The fault impedance is 0.2 + j0.6 ohms.
To determine the fault current, we can use the method of symmetrical components.
The positive sequence current (I1) is given by:
I1 = V1 / (Z1 + Xn)
where V1 is the positive sequence voltage = V / √3 = 13.8 kV / √3 = 7.98 kV
Z1 is the positive sequence impedance = 0.15 + j0.15 ohms
Substituting the values:
I1 = 7.98 kV / (0.15 + j0.15 + Xn)
The negative sequence current (I2) is given by:
I2 = V2 / (Z2 + Xn)
where V2 is the negative sequence voltage = V / √3 = 13.8 kV / √3 = 7.98 kV
Z2 is the negative sequence impedance = 0.15 + j0.15 ohms
Substituting the values:
I2 = 7.98 kV / (0.15 + j0.15 + Xn)
The zero sequence current (I0) is given by:
I0 = V0 / (Z0 + Xn)
where V0 is the zero sequence voltage = V / √3 = 13.8 kV / √3 = 7.98 kV
Z0 is the zero sequence impedance = 0.05 + j0 ohms
Substituting the values:
I0 = 7.98 kV / (0.05 + Xn)
Since the fault is a double line to ground fault, the fault current is the sum of the positive and zero sequence currents:
Ifault = I1 + I0
To solve for Xn, we need to equate the positive sequence current with the fault current:
7.98 kV / (0.15 + j0.15 + Xn) = Ifault
Similarly, we can equate the zero sequence current with the fault current:
7.98 kV / (0.05 + Xn) = Ifault
Solving these two equations simultaneously will give us the value of Xn.
To determine the fault current, we can use the method of symmetrical components.
The positive sequence current (I1) is given by:
I1 = V1 / (Z1 + Xn)
where V1 is the positive sequence voltage = V / √3 = 13.8 kV / √3 = 7.98 kV
Z1 is the positive sequence impedance = 0.15 + j0.15 ohms
Substituting the values:
I1 = 7.98 kV / (0.15 + j0.15 + Xn)
The negative sequence current (I2) is given by:
I2 = V2 / (Z2 + Xn)
where V2 is the negative sequence voltage = V / √3 = 13.8 kV / √3 = 7.98 kV
Z2 is the negative sequence impedance = 0.15 + j0.15 ohms
Substituting the values:
I2 = 7.98 kV / (0.15 + j0.15 + Xn)
The zero sequence current (I0) is given by:
I0 = V0 / (Z0 + Xn)
where V0 is the zero sequence voltage = V / √3 = 13.8 kV / √3 = 7.98 kV
Z0 is the zero sequence impedance = 0.05 + j0 ohms
Substituting the values:
I0 = 7.98 kV / (0.05 + Xn)
Since the fault is a double line to ground fault, the fault current is the sum of the positive and zero sequence currents:
Ifault = I1 + I0
To solve for Xn, we need to equate the positive sequence current with the fault current:
7.98 kV / (0.15 + j0.15 + Xn) = Ifault
Similarly, we can equate the zero sequence current with the fault current:
7.98 kV / (0.05 + Xn) = Ifault
Solving these two equations simultaneously will give us the value of Xn.
|
Explore Courses for GATE exam
|
|
Similar GATE Doubts
A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer?
Question Description
A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer? for GATE 2024 is part of GATE preparation. The Question and answers have been prepared according to the GATE exam syllabus. Information about A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer? covers all topics & solutions for GATE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer?.
A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer? for GATE 2024 is part of GATE preparation. The Question and answers have been prepared according to the GATE exam syllabus. Information about A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer? covers all topics & solutions for GATE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer?.
Solutions for A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer? in English & in Hindi are available as part of our courses for GATE.
Download more important topics, notes, lectures and mock test series for GATE Exam by signing up for free.
Here you can find the meaning of A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of
A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer?, a detailed solution for A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer? has been provided alongside types of A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice A 30 MVA 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u) that will limit the positive sequence current to 4270 A is _____________.Correct answer is '1.1'. Can you explain this answer? tests, examples and also practice GATE tests.
|
|
Explore Courses for GATE exam
|
|
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
|
© EduRev
|
Education Revolution
|
Follow Us
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup