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In a 3-bus system, if a symmetrical three phase fault occurs at bus 1, 2 or 3 fault currents are 20 pu, 25 pu and 40 pu respectively. Also if fault is at bus 1, voltage at bus 2 will be 0.8 pu , if fault is at bus 2, voltage at bus 3 will be 0.5 pu and if the fault is at bus 3, voltage at bus 1 will be 0.6 pu. Consider no load pre-fault conditions. What will be the sum of all the elements of ZBUS of the system in per unit?
  • a)
    0.125
  • b)
    0.215
Correct answer is between '0.125,0.215'. Can you explain this answer?
Verified Answer
In a 3-bus system, if a symmetrical three phase fault occurs at bus 1...
Fault at bus
Similarity at Bus
At bus
Now, we know that, voltage at bus 'j' due to fault at bus 'k'
Voltage at 2 due to fault at 1 :
Voltage at 3 due to fault at 2 .
Voltage at 1 due to fault at 3 :
Sum of all elements of Zbus = 0.195
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Most Upvoted Answer
In a 3-bus system, if a symmetrical three phase fault occurs at bus 1...
Fault at bus
Similarity at Bus
At bus
Now, we know that, voltage at bus 'j' due to fault at bus 'k'
Voltage at 2 due to fault at 1 :
Voltage at 3 due to fault at 2 .
Voltage at 1 due to fault at 3 :
Sum of all elements of Zbus = 0.195
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Community Answer
In a 3-bus system, if a symmetrical three phase fault occurs at bus 1...
Calculation of ZBUS Elements:

Fault at Bus 1:
- Current at Bus 1 = 20 pu
- Voltage at Bus 2 = 0.8 pu
- Impedance from Bus 1 to Bus 2 = V2/I1 = 0.8/20 = 0.04 pu

Fault at Bus 2:
- Current at Bus 2 = 25 pu
- Voltage at Bus 3 = 0.5 pu
- Impedance from Bus 2 to Bus 3 = V3/I2 = 0.5/25 = 0.02 pu

Fault at Bus 3:
- Current at Bus 3 = 40 pu
- Voltage at Bus 1 = 0.6 pu
- Impedance from Bus 3 to Bus 1 = V1/I3 = 0.6/40 = 0.015 pu

Sum of ZBUS Elements:
- ZBUS = Z12 + Z23 + Z31
- ZBUS = 0.04 + 0.02 + 0.015
- ZBUS = 0.075 pu
Therefore, the sum of all the elements of ZBUS of the system in per unit is 0.075 pu, which is not within the given range of 0.125 to 0.215.
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In a 3-bus system, if a symmetrical three phase fault occurs at bus 1, 2 or 3 fault currents are 20 pu, 25 pu and 40 pu respectively. Also if fault is at bus 1, voltage at bus 2 will be 0.8 pu , if fault is at bus 2, voltage at bus 3 will be 0.5 pu and if the fault is at bus 3, voltage at bus 1 will be 0.6 pu. Consider no load pre-fault conditions. What will be the sum of all the elements of ZBUS of the system in per unit?a)0.125b)0.215Correct answer is between '0.125,0.215'. Can you explain this answer?
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In a 3-bus system, if a symmetrical three phase fault occurs at bus 1, 2 or 3 fault currents are 20 pu, 25 pu and 40 pu respectively. Also if fault is at bus 1, voltage at bus 2 will be 0.8 pu , if fault is at bus 2, voltage at bus 3 will be 0.5 pu and if the fault is at bus 3, voltage at bus 1 will be 0.6 pu. Consider no load pre-fault conditions. What will be the sum of all the elements of ZBUS of the system in per unit?a)0.125b)0.215Correct answer is between '0.125,0.215'. 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 In a 3-bus system, if a symmetrical three phase fault occurs at bus 1, 2 or 3 fault currents are 20 pu, 25 pu and 40 pu respectively. Also if fault is at bus 1, voltage at bus 2 will be 0.8 pu , if fault is at bus 2, voltage at bus 3 will be 0.5 pu and if the fault is at bus 3, voltage at bus 1 will be 0.6 pu. Consider no load pre-fault conditions. What will be the sum of all the elements of ZBUS of the system in per unit?a)0.125b)0.215Correct answer is between '0.125,0.215'. Can you explain this answer? covers all topics & solutions for GATE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for In a 3-bus system, if a symmetrical three phase fault occurs at bus 1, 2 or 3 fault currents are 20 pu, 25 pu and 40 pu respectively. Also if fault is at bus 1, voltage at bus 2 will be 0.8 pu , if fault is at bus 2, voltage at bus 3 will be 0.5 pu and if the fault is at bus 3, voltage at bus 1 will be 0.6 pu. Consider no load pre-fault conditions. What will be the sum of all the elements of ZBUS of the system in per unit?a)0.125b)0.215Correct answer is between '0.125,0.215'. Can you explain this answer?.
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