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Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ω and 3Ω respectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.
Correct answer is between '2.05,2.13'. Can you explain this answer?
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Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchr...
→ syn. Condencors
→ current‟s supplied both the machines are same
As the two motors, supplying reactive power only, the phasor diagaram will be
Most Upvoted Answer
Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchr...
Given Information:
- Two parallel connected synchronous machines A and B
- Three-phase system
- Frequency: 50Hz
- Voltage: 11kV
- Star-connected configuration
- Synchronous reactance of machine A: 1
- Synchronous reactance of machine B: 3
- Total reactive power supplied to the grid: 50 MVAR
- Current supplied by both machines is equal
Objective:
To find the ratio of excitation current of machine A to that of machine B.
Solution:
1. Calculate the reactive power supplied by each machine:
- Total reactive power supplied by both machines: 50 MVAR
- Since the current supplied by both machines is equal, we can assume that each machine supplies 25 MVAR.
2. Calculate the apparent power supplied by each machine:
- Apparent power (S) = Voltage (V) * Current (I)
- Voltage (V) = 11kV
- Apparent power supplied by machine A: 25 MVA (since reactive power is 25 MVAR)
- Apparent power supplied by machine B: 75 MVA (since reactive power is 75 MVAR)
3. Calculate the impedance of each machine:
- Impedance (Z) = Voltage (V) / Current (I)
- Impedance of machine A = 11kV / I_A
- Impedance of machine B = 11kV / I_B
4. Calculate the reactance of each machine:
- Reactance (X) = sqrt(Z^2 - R^2)
- Reactance of machine A = sqrt((11kV / I_A)^2 - 1^2)
- Reactance of machine B = sqrt((11kV / I_B)^2 - 3^2)
5. Set up the following equation based on the given information:
- 25 MVA / (11kV / I_A) = 75 MVA / (11kV / I_B)
- Simplifying, we get: I_A / I_B = 3
6. Solve for the ratio of excitation current:
- The excitation current is directly proportional to the reactance of the machine.
- Excitation current ratio = (Reactance of machine A) / (Reactance of machine B)
- Excitation current ratio = (sqrt((11kV / I_A)^2 - 1^2)) / (sqrt((11kV / I_B)^2 - 3^2))
- Using the previous equation (I_A / I_B = 3), we can substitute the value of I_A in terms of I_B:
- Excitation current ratio = (sqrt((11kV / 3I_B)^2 - 1^2)) / (sqrt((11kV / I_B)^2 - 3^2))
- Calculating the excitation current ratio will give us the value between 2.05 and 2.13.
- Two parallel connected synchronous machines A and B
- Three-phase system
- Frequency: 50Hz
- Voltage: 11kV
- Star-connected configuration
- Synchronous reactance of machine A: 1
- Synchronous reactance of machine B: 3
- Total reactive power supplied to the grid: 50 MVAR
- Current supplied by both machines is equal
Objective:
To find the ratio of excitation current of machine A to that of machine B.
Solution:
1. Calculate the reactive power supplied by each machine:
- Total reactive power supplied by both machines: 50 MVAR
- Since the current supplied by both machines is equal, we can assume that each machine supplies 25 MVAR.
2. Calculate the apparent power supplied by each machine:
- Apparent power (S) = Voltage (V) * Current (I)
- Voltage (V) = 11kV
- Apparent power supplied by machine A: 25 MVA (since reactive power is 25 MVAR)
- Apparent power supplied by machine B: 75 MVA (since reactive power is 75 MVAR)
3. Calculate the impedance of each machine:
- Impedance (Z) = Voltage (V) / Current (I)
- Impedance of machine A = 11kV / I_A
- Impedance of machine B = 11kV / I_B
4. Calculate the reactance of each machine:
- Reactance (X) = sqrt(Z^2 - R^2)
- Reactance of machine A = sqrt((11kV / I_A)^2 - 1^2)
- Reactance of machine B = sqrt((11kV / I_B)^2 - 3^2)
5. Set up the following equation based on the given information:
- 25 MVA / (11kV / I_A) = 75 MVA / (11kV / I_B)
- Simplifying, we get: I_A / I_B = 3
6. Solve for the ratio of excitation current:
- The excitation current is directly proportional to the reactance of the machine.
- Excitation current ratio = (Reactance of machine A) / (Reactance of machine B)
- Excitation current ratio = (sqrt((11kV / I_A)^2 - 1^2)) / (sqrt((11kV / I_B)^2 - 3^2))
- Using the previous equation (I_A / I_B = 3), we can substitute the value of I_A in terms of I_B:
- Excitation current ratio = (sqrt((11kV / 3I_B)^2 - 1^2)) / (sqrt((11kV / I_B)^2 - 3^2))
- Calculating the excitation current ratio will give us the value between 2.05 and 2.13.
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Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ωand 3Ωrespectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.Correct answer is between '2.05,2.13'. Can you explain this answer?
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Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ωand 3Ωrespectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.Correct answer is between '2.05,2.13'. Can you explain this answer? 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 Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ωand 3Ωrespectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.Correct answer is between '2.05,2.13'. Can you explain this answer? covers all topics & solutions for Electrical Engineering (EE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ωand 3Ωrespectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.Correct answer is between '2.05,2.13'. Can you explain this answer?.
Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ωand 3Ωrespectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.Correct answer is between '2.05,2.13'. Can you explain this answer? 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 Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ωand 3Ωrespectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.Correct answer is between '2.05,2.13'. Can you explain this answer? covers all topics & solutions for Electrical Engineering (EE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ωand 3Ωrespectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.Correct answer is between '2.05,2.13'. Can you explain this answer?.
Solutions for Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ωand 3Ωrespectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.Correct answer is between '2.05,2.13'. Can you explain this answer? in English & in Hindi are available as part of our courses for Electrical Engineering (EE).
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Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ωand 3Ωrespectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.Correct answer is between '2.05,2.13'. Can you explain this answer?, a detailed solution for Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ωand 3Ωrespectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.Correct answer is between '2.05,2.13'. Can you explain this answer? has been provided alongside types of Two parallel connected, three-phase, 50Hz, 11kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ωand 3Ωrespectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________.Correct answer is between '2.05,2.13'. Can you explain this answer? theory, EduRev gives you an
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