Electrical Engineering (EE) Exam  >  Electrical Engineering (EE) Questions  >  For the system, the ratings of the various co... Start Learning for Free
For the system, the ratings of the various components are: Generator: 25 MVA, 12.4 kV, 10% subtransient reactance Motor: 20 MVA, 3.8 kV, 15% subtransient reactance Transformer T₁: 25 MVA, 11/33 kV, 8% reactance Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance Line: 20 ohms reactance The system is loaded so that the motor is drawing 15 MW at 0.9 leading power factor, the motor terminal voltage being 3.1 kV. Prove that subtransient current in generator for a fault at generator bus is 8.87kA.?
Most Upvoted Answer
For the system, the ratings of the various components are: Generator:...
System Information:
- Generator: 25 MVA, 12.4 kV, 10% subtransient reactance
- Motor: 20 MVA, 3.8 kV, 15% subtransient reactance
- Transformer T₁: 25 MVA, 11/33 kV, 8% reactance
- Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance
- Line: 20 ohms reactance

Given:
- Motor power: 15 MW
- Motor power factor: 0.9 leading
- Motor terminal voltage: 3.1 kV

Calculating Subtransient Current in Generator:
To calculate the subtransient current in the generator for a fault at the generator bus, we need to consider the motor's power factor and terminal voltage.

Step 1: Calculate the motor current:
Using the formula:
Motor current (I) = Motor power (P) / (sqrt(3) * Motor power factor * Motor terminal voltage)
Plugging in the given values:
I = 15000 kW / (sqrt(3) * 0.9 * 3100 V)
I ≈ 271.75 A

Step 2: Calculate the motor apparent power:
Using the formula:
Motor apparent power (S) = Motor power (P) / Motor power factor
Plugging in the given values:
S = 15000 kW / 0.9
S ≈ 16666.67 kVA

Step 3: Calculate the motor reactive power:
Using the formula:
Motor reactive power (Q) = sqrt(Motor apparent power (S)^2 - Motor power (P)^2)
Plugging in the given values:
Q = sqrt((16666.67 kVA)^2 - (15000 kW)^2)
Q ≈ 6524.80 kVAR

Step 4: Calculate the total reactive power absorbed by the system:
The total reactive power absorbed by the system is the sum of the reactive power consumed by the motor and the reactive power absorbed by the generator.
Total reactive power = Motor reactive power + Generator reactive power

Since the motor is operating at a leading power factor, the generator will absorb reactive power. Therefore, the generator reactive power will be negative.

Step 5: Calculate the generator reactive power:
Generator reactive power (Qg) = Total reactive power - Motor reactive power
Qg = -6524.80 kVAR - 6524.80 kVAR
Qg = -13049.60 kVAR

Step 6: Calculate the generator subtransient current:
Using the formula:
Generator subtransient current (Ig) = Generator reactive power (Qg) / (sqrt(3) * Generator voltage * Generator subtransient reactance)
Plugging in the given values:
Ig = -13049.60 kVAR / (sqrt(3) * 12400 V * 0.1)
Ig ≈ -8.87 kA

Therefore, the subtransient current in the generator for a fault at the generator bus is approximately 8.87 kA.
Explore Courses for Electrical Engineering (EE) exam

Similar Electrical Engineering (EE) Doubts

Top Courses for Electrical Engineering (EE)

For the system, the ratings of the various components are: Generator: 25 MVA, 12.4 kV, 10% subtransient reactance Motor: 20 MVA, 3.8 kV, 15% subtransient reactance Transformer T₁: 25 MVA, 11/33 kV, 8% reactance Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance Line: 20 ohms reactance The system is loaded so that the motor is drawing 15 MW at 0.9 leading power factor, the motor terminal voltage being 3.1 kV. Prove that subtransient current in generator for a fault at generator bus is 8.87kA.?
Question Description
For the system, the ratings of the various components are: Generator: 25 MVA, 12.4 kV, 10% subtransient reactance Motor: 20 MVA, 3.8 kV, 15% subtransient reactance Transformer T₁: 25 MVA, 11/33 kV, 8% reactance Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance Line: 20 ohms reactance The system is loaded so that the motor is drawing 15 MW at 0.9 leading power factor, the motor terminal voltage being 3.1 kV. Prove that subtransient current in generator for a fault at generator bus is 8.87kA.? for Electrical Engineering (EE) 2024 is part of Electrical Engineering (EE) preparation. The Question and answers have been prepared according to the Electrical Engineering (EE) exam syllabus. Information about For the system, the ratings of the various components are: Generator: 25 MVA, 12.4 kV, 10% subtransient reactance Motor: 20 MVA, 3.8 kV, 15% subtransient reactance Transformer T₁: 25 MVA, 11/33 kV, 8% reactance Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance Line: 20 ohms reactance The system is loaded so that the motor is drawing 15 MW at 0.9 leading power factor, the motor terminal voltage being 3.1 kV. Prove that subtransient current in generator for a fault at generator bus is 8.87kA.? covers all topics & solutions for Electrical Engineering (EE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for For the system, the ratings of the various components are: Generator: 25 MVA, 12.4 kV, 10% subtransient reactance Motor: 20 MVA, 3.8 kV, 15% subtransient reactance Transformer T₁: 25 MVA, 11/33 kV, 8% reactance Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance Line: 20 ohms reactance The system is loaded so that the motor is drawing 15 MW at 0.9 leading power factor, the motor terminal voltage being 3.1 kV. Prove that subtransient current in generator for a fault at generator bus is 8.87kA.?.
Solutions for For the system, the ratings of the various components are: Generator: 25 MVA, 12.4 kV, 10% subtransient reactance Motor: 20 MVA, 3.8 kV, 15% subtransient reactance Transformer T₁: 25 MVA, 11/33 kV, 8% reactance Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance Line: 20 ohms reactance The system is loaded so that the motor is drawing 15 MW at 0.9 leading power factor, the motor terminal voltage being 3.1 kV. Prove that subtransient current in generator for a fault at generator bus is 8.87kA.? in English & in Hindi are available as part of our courses for Electrical Engineering (EE). Download more important topics, notes, lectures and mock test series for Electrical Engineering (EE) Exam by signing up for free.
Here you can find the meaning of For the system, the ratings of the various components are: Generator: 25 MVA, 12.4 kV, 10% subtransient reactance Motor: 20 MVA, 3.8 kV, 15% subtransient reactance Transformer T₁: 25 MVA, 11/33 kV, 8% reactance Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance Line: 20 ohms reactance The system is loaded so that the motor is drawing 15 MW at 0.9 leading power factor, the motor terminal voltage being 3.1 kV. Prove that subtransient current in generator for a fault at generator bus is 8.87kA.? defined & explained in the simplest way possible. Besides giving the explanation of For the system, the ratings of the various components are: Generator: 25 MVA, 12.4 kV, 10% subtransient reactance Motor: 20 MVA, 3.8 kV, 15% subtransient reactance Transformer T₁: 25 MVA, 11/33 kV, 8% reactance Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance Line: 20 ohms reactance The system is loaded so that the motor is drawing 15 MW at 0.9 leading power factor, the motor terminal voltage being 3.1 kV. Prove that subtransient current in generator for a fault at generator bus is 8.87kA.?, a detailed solution for For the system, the ratings of the various components are: Generator: 25 MVA, 12.4 kV, 10% subtransient reactance Motor: 20 MVA, 3.8 kV, 15% subtransient reactance Transformer T₁: 25 MVA, 11/33 kV, 8% reactance Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance Line: 20 ohms reactance The system is loaded so that the motor is drawing 15 MW at 0.9 leading power factor, the motor terminal voltage being 3.1 kV. Prove that subtransient current in generator for a fault at generator bus is 8.87kA.? has been provided alongside types of For the system, the ratings of the various components are: Generator: 25 MVA, 12.4 kV, 10% subtransient reactance Motor: 20 MVA, 3.8 kV, 15% subtransient reactance Transformer T₁: 25 MVA, 11/33 kV, 8% reactance Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance Line: 20 ohms reactance The system is loaded so that the motor is drawing 15 MW at 0.9 leading power factor, the motor terminal voltage being 3.1 kV. Prove that subtransient current in generator for a fault at generator bus is 8.87kA.? theory, EduRev gives you an ample number of questions to practice For the system, the ratings of the various components are: Generator: 25 MVA, 12.4 kV, 10% subtransient reactance Motor: 20 MVA, 3.8 kV, 15% subtransient reactance Transformer T₁: 25 MVA, 11/33 kV, 8% reactance Transformer T2: 20 MVA, 33/3.3 kV, 10% reactance Line: 20 ohms reactance The system is loaded so that the motor is drawing 15 MW at 0.9 leading power factor, the motor terminal voltage being 3.1 kV. Prove that subtransient current in generator for a fault at generator bus is 8.87kA.? tests, examples and also practice Electrical Engineering (EE) tests.
Explore Courses for Electrical Engineering (EE) exam

Top Courses for Electrical Engineering (EE)

Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev