196. A 2-bus system and corresponding zero sequence network are shown in the figure.
     
     The transformers T₁ and T₂ are connected as

1. 1. 

   
   
   

   2. 

   
   
   

   3. 

   
   
   

   4. 

   
   
   

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1. View Hint View Answer Discuss in Forum

   
   

   Correct Option: B

   
   

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197. Three-phase to ground fault takes place at locations F₁ and F₂ in the system shown in the figure
     
     If the fault takes place at location F₁, then the voltage and the current at bus A are V_F1 and I_F1 respectively. If the fault takes place at location F₂, then the voltage and the current at bus A are V_F2 and I_F2 respectively. The correct statements about voltages and currents during faults at F₁ and F₂ is

1. 1. V_F1 leads I_F1 and V_F2 leads I_F2

   
   
   

   2. V_F1 leads I_F1 and V_F2 lags I_F2

   
   
   

   3. V_F1 lags I_F1 and V_F2 leads I_F2

   
   
   

   4. V_F1 lags I_F1 and V_F2 lags I_F2

   
   
   

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1. View Hint View Answer Discuss in Forum

   When fault takes place at F₁
   
   Current is feeding into the BUS A. It is like a generator delivering power to BUS (A) When fault takes place at F₂, F₂ point is like load, taking power from generator.

   Correct Option: C

   When fault takes place at F₁
   
   Current is feeding into the BUS A. It is like a generator delivering power to BUS (A) When fault takes place at F₂, F₂ point is like load, taking power from generator.

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198. A 3-bus power system network consists of 3 transmission lines. The bus admittance matrix of the uncompensated system is
     

     	-j6		j3		j4		pu.
     	j3		-j7		j5
     	-j4		j		-j8

     
     If the shunt capacitance of all transmission line is 50% compensated, the imaginary part of the 3^rd row 3^rd column element (in pu) of the bus admittance matrix after compensation is

1. 1. – j 7.0

   
   
   

   2. – j 8.5

   
   
   

   3. – j 7.5

   
   
   

   4. – j 9.0

   
   
   

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1. View Hint View Answer Discuss in Forum

   yBus =		y10 + y12 + y13		-y12		-y13
   		-y12		y20 + y21 + y23		-y23
   		-y13		- y23		y30 + y31 + y32

   
   Now comparing with the given matrix, we get and
   y₃₁ = y₁₃ = – j₄
   y₃₂ = y₂₃ = – j₅
   thus, y₃₀ + y₃₁ + y₃₂
   ∴ y₃₀ + (-j4) + (-j5) = -j8
   ∴ y₃₀ = j1
   Now, after compensating, y₃₀ = j1/2
   ∴ y₃₀ + y₃₁ + y₃₂ = j0.5 – j4 – j5 = – j8.5
   ∴ Option (b) is correct.

   Correct Option: B

   yBus =		y10 + y12 + y13		-y12		-y13
   		-y12		y20 + y21 + y23		-y23
   		-y13		- y23		y30 + y31 + y32

   
   Now comparing with the given matrix, we get and
   y₃₁ = y₁₃ = – j₄
   y₃₂ = y₂₃ = – j₅
   thus, y₃₀ + y₃₁ + y₃₂
   ∴ y₃₀ + (-j4) + (-j5) = -j8
   ∴ y₃₀ = j1
   Now, after compensating, y₃₀ = j1/2
   ∴ y₃₀ + y₃₁ + y₃₂ = j0.5 – j4 – j5 = – j8.5
   ∴ Option (b) is correct.

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199. A sustained t hr ee-phase fault occurs in the power system shown in the figure. The current and voltage phasors during the fault (on a common reference), after the natural transients have died down, are also shown. Where is the fault located?
     

1. 1. Location P

   
   
   

   2. Location Q

   
   
   

   3. Location R

   
   
   

   4. Location S

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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200. Determine the correctness or otherwise of the following Assertion [a] and the Reason [r]. Assertion: Fast decoupled load flow method gives approximate load flow solution because it uses several assumptions.
     Reason: Accuracy depends on the power mismatch vector tolerance.

1. 1. Both [a] and [r] are true and [r] is the correct reason for [a].

   
   
   

   2. Both [a] and [r] are true and [r] is not the correct reason for [a].

   
   
   

   3. Both [a] and [r] are false.

   
   
   

   4. [a] is false and [r] is true.

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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