211. A 50 Hz, four-pole turboalternator rated at 20 MVA, 13·2 kV has an inertia constant H = 4 kW sec/kVA. The kinetic energy stored in the rotor at __________ MJ

1. 1. 0.80

   
   
   

   2. 8.0

   
   
   

   3. 80

   
   
   

   4. 0.08

   
   
   

---

1. View Hint View Answer Discuss in Forum

   Kinetic energy stored = GH,
   where G = rating in MVA and
   H = inertia constant
   ∴ Kinetic energy stored = 20 × 4 = 80 MJ

   Correct Option: C

   Kinetic energy stored = GH,
   where G = rating in MVA and
   H = inertia constant
   ∴ Kinetic energy stored = 20 × 4 = 80 MJ

---

212. A power station consists of two sychronous generators A and B or ratings 250 MVA and 500 MVA with inertia 1.6 p.u. and 1 p.u.respectively on their own base MVA ratings. The equivalent p.u. inertia constant for the system on 100 MVA common base is ____________

1. 1. 615

   
   
   

   2. 6.15

   
   
   

   3. 61.5

   
   
   

   4. 0.615

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

---

---

213. A power system has two synchronous generators. The governor-turbine characteristics orresponding to the generators are
     P₁ = 50(50 – ƒ), P₂ = 100(51 – ƒ). where f denotes the system frequency in Hz and P₁ and P₂ are respectively, the power outputs (in MW) of turbines 1 and 2. Assuming the generat or s and transmission network to be lossless, the system frequency for a total load of 400 MW is __________ Hz

1. 1. 0.48 Hz.

   
   
   

   2. 48 Hz.

   
   
   

   3. 4.08 Hz.

   
   
   

   4. 4.8 Hz.

   
   
   

---

1. View Hint View Answer Discuss in Forum

   P₁ + P₂ = 400
   or 50 (50 – ƒ) + 100 (51 – ƒ) = 400
   or 50 + 102 – 8 = 3ƒ
   or ƒ = 48 Hz.

   Correct Option: B

   P₁ + P₂ = 400
   or 50 (50 – ƒ) + 100 (51 – ƒ) = 400
   or 50 + 102 – 8 = 3ƒ
   or ƒ = 48 Hz.

---

214. A 100 M VA, 11 k V 3-phase, 50 H z, 8-pol e synchronous generator has an inetria constant H equal to 4 seconds. The stored energy in the rotor of the generator at synchronous speed will be
     

     	H =	E		_______ MJ
     		G

1. 1. 8.00

   
   
   

   2. 80.0

   
   
   

   3. 800

   
   
   

   4. .08

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

---

---

215. If time of operation of a relay for unity TMS is 10 secs, then time of operation for 0.5 TMS will be _______ secs

1. 1. 1

   
   
   

   2. 3

   
   
   

   3. 5

   
   
   

   4. 7

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

---