Friday 20 April 2012

POWER SYSTEM ANALYSIS QB


DEPARTMENT OF ELECTRICAL AND  ELECTRONICS  ENGINEERING
6TH SEMESTER - EE 1352  -  POWER SYSTEM ANALYSIS

QUESTION  BANK
UNIT – 01                                                                        2 Marks

01.   What is one line diagram? How the power system components are represented?
02.   What are the components of power system?
03.   What is tap changing transformer? State its types.
04.   What is Off-nominal transformation ratio?
05.   Define Per unit value.
06.  What is the need for base values?
07.  State the Advantages of per unit computations.
08.  The base kV and base MVA of a three phase transmission line 33 kV and 10 MVA respectively.
       Calculate the base current and base impedance.
09.   State the any two demerits of per unit computations.
10.  What is impedance and reactance diagram?
11.  What are the approximations made in the reactance diagram?
12.  Give the equations for transforming base kV on LV side to HV side of transformer and vice-versa.
13.  Write the equation for converting the p.u. impedance expressed in one base to another.
14.  A generator rated at 30 MVA, 11 kV has a reactance of 20%. Calculate its p.u. reactance for a base
       of 50 MVA and 10 kV.
15.  What are the step by step procedure to be followed to find the per unit impedance diagram?
16.  What is the need for system analysis in planning and operation of power systems?
17.  How the generator transient analysis is represented?
18.  What is the purpose of providing third winding (tertiary) in a Transformer?

Note : Apart from the above theory questions small types of Problems may be asked (if necessary).
           (i)  Existing p.u. will be given and you are asked to find out the new p.u.
          (ii)  Values in ohm will be given you are asked to find out new values in p.u

 Long Answered Questions                                           16 Marks.

1.(i)   Derive the equations to find out the Π equivalent circuit transformer with off nominal tap ratio.  (8)
  (ii)   Discuss about the per phase analysis of symmetrical three phase system.                                       (8)
2.      Explain the Modern Power system in detail.                                                                                     (16)
3.      Explain the per phase analysis of Equivalent network of Uniform long lines ( T model )               (16)

Note : Apart from the above theory questions Full Problems will be asked (compulsorily).
           (i)  One sample power system network with values in either ohm (or) in p.u. will be given and you
                are asked to draw the reactance diagram also you have to mark the new values which has to be
                find out using simple formulas.
         
UNIT – 02                                                                        2 Marks
01.   What is Load flow study?
02.   What is the need for load flow study?
03.   Why power flow analysis is made?
04.   What are the informations that are obtained from a load flow study?
05.   How a load flow study is performed?
06.   What are the different types of buses in a power system?
07.   What is swing bus?
08.   Define Voltage controlled bus.
09.   What is Load bus?
10.   List the quantities specified and quantities to be determined from the load flow study for the various
        types of buses.
11.   What is the need for slack bus?
12.   Write the load flow equations for Gauss-Seidel and Newton-Raphson method.
13.   Discuss the effect of acceleration factor in the load flow solution algorithm and how will you account
        for voltage controlled bus in the algorithm.
14.   When the Generator bus is treated as load bus? What will be the reactive power and bus voltage?
15.   What are the advantages of Gauss-Seidel method?
16.   What are the disadvantages of Gauss-Seidel method?
17.   What is Jacobian matrix? How the elements of Jacobian matrix  are computed?
18.   What are the advantages of Newton-Raphson method?
19.   What are the disadvantages of Newton-Raphson method?
20.   Compare G-S method and N-R method of power flow solutions.
21.   How the disadvantages of N-R method are overcome?
22.   How the convergence of N-R method is speedup?
23.   What is an acceleration factor?
24.   What are the advantages and disadvantages of FDPF over N-R method?
25.   How the reactive power of a Generator is controlled?

Long Answered Questions                                           16 Marks.

1.  With the help of the neat flow chart, explain the  (a) or  (b) or  (c)  of load flow solution when the
      system contains voltage controlled buses in addition to the swing bus and load bus.                     Each
(a)  Newton – Raphson method        (b)  Gauss – Seidel method      (c)  Fast decoupled power flow    (16)

2.(i)  Derive the static load  flow equations of n bus systems.                                                                (11)
  (ii)  Explain the p-v adjustment in N-R method.                                                                                   (5)
3.(i)  Explain why power flow  studies are essential and vital parts of power system studies                (6)
   (ii) Discuss about the fast decoupled power flow method.                                                                   (10)

Note : Apart from the above theory questions Full Problems will be asked (compulsorily).
           Problem may be asked in the above mentioned three types of load flow solution technique.
           (i)  Gauss – Seidel method          -  Max. four bus problem shall be asked
          (ii)  Newton – Raphson method   -  Max. three bus bus problem shall be asked.
          (iii)  Fast decoupled power flow  -  Max. four bus problem shall be asked.  


UNIT – 03                                                                        2 Marks

01.  What is meant by a fault in power system?
02.  How faults are classified? List the various types of shunt and series faults.
03.  What is symmetrical and unsymmetrical faults.
04.  For a fault at a given location, rank the various faults in the order of severity.
05.  Write the relative frequency of occurrence of various types of fault.
06.  How symmetrical and unsymmetrical faults are analysed?
07.  What is the need for short circuit study (or) fault analysis?
08.  What is meant by doubling effect?
09.  What is synchronous reactance?
10.  Define sub transient reactance?
11.  Define transient reactance?
12.  What is bus admittance matrix? Write its equation.
13.  What are the advantages of  bus admittance matrix?
14.  What is bus impedance matrix?
15.  What are the methods available for forming bus impedance matrix?
16.  Write the four ways of adding impedance to an existing system so as to modify bus impedance matrix.
17.  What are the methods used for reducing short circuit current.
18.  What are the assumptions made in short circuit studies of large power system network.
19.   Define short circuit interrupting MVA of a circuit breaker.
20.  How circuit breakers can be selected?
21.  Define infinite bus in a power system.
22.  A three phase 20 MVA, 11 kV generator has 5% sub-transient reactance . A three phase short circuit
       occurs at its terminals find fault current in MVA.

Long Answered Questions                                           16 Marks.

1.  Explain the procedure for making short circuit studies of a large power system networks using digital
     computers.                                                                                                                                       (16)
2.  Explain the step by step procedure for Z bus building algorithm and explain its different types in detail 

Note : Apart from the above theory questions Full Problems will be asked (compulsorily).
           Problem may be asked in the following method.
           (i)  Sample power system will be given with fault in the network. Students are required to solve the
                 problem using (i) Kirchoff’s law  (ii) Thevenin’s method.
          (ii)  Using sample network  form the matrix ( Z bus building algorithm )         
            

UNIT – 04                                                                        2 Marks

1.   Define negative sequence impedance.
2.   Define Positive sequence impedance.
3.   What are symmetrical components? Write the symmetrical components.
4.   What are positive sequence components?
5.   What are negative sequence components?
6.   What are zero sequence components?
7.   Prove that 1+a+a square = 0

UNIT – 05                                                                        2 Marks

1.    Define Stability. What is stability study?
2.    Define steady state stability.
3.    Define dynamic stability. State its purpose.
3.    Define transient stability.
4.    What is transient stability limit?
5.    What is transient instability?
6.    When the transient stability studies are conducted and what is the need of transient stability study?
7.    Define Power angle.
8.    What is swing equation.
9.    What are the assumptions made by solving swing equation?
10.  Define swing curve. What is the use of swing curve?
11.  What is first swing and multi swing?
12.  What is damper winding?
13.   Define :  Critical clearing angle and time.
14.   Give the expression for critical clearing angle and time.
15.   List the methods of  improving the transient stability limit of a power system.
16.   State Equal area Criterion.
17.   State the application of Equal area criterion.
18.   What is voltage Instability?
19.   What is meant by Infinite bus?

 
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Basic Electrical and Electronics Engg - FT students


Department of Electrical and Electronics Engineering

QUESTION BANK
Subject: - 185203-Basic Electrical and Electronics Engg

Class: 1 FT                                                                                       

UNIT-I
PART – A (10 x 2 = 20)

  1. State ohm’s law.
  2. Mention the advantages of ohm’s law.
  3. State kirchoff’s laws
  4. What is meant by electric energy?
  5. Distinguish between power and energy.
  6. What are lumped circuits?
  7. Write the equivalent resistance when two resistors are connected in parallel?
  8. Write the expression to find the average value of a sinusoidal wave?
  9. Define RMS value.
  10. Define Peak factor.
  11. Draw power triangle.
  12. Define the term Instantaneous value.
  13. Define the term Average value.
  14. Define form factor.
  15. What is creeping of a meter?
  16. What is the basic operation principle of PMMC Instrument?
  17. What are the advantages and disadvantages of PMMC Instrument?
  18. Mention the two types of MI instrument.

PART – B

  1. State and explain kirchoff’s laws.                                                                    (16)
  2. Give the algorithm for solving a circuit problem using mesh analysis.      (8)
  3. What are the points to be considered for mesh analysis? Calculate the current    through 6 Ω resistance using mesh analysis in fig.                                                 (16)
                  

  1. A coil of resistance 10 ohms and inductance 0.1 H is connected in series with a 150 µF capacitor across 200 V, 50 Hz supply. Calculate i) Inductive reactance, Capacitive reactance, impedance, current and power factor and ii) the voltage across the coil and  capacitor respectively.                                                                                         (16)
  2. With the neat diagram, explain in detail on the three phase balanced circuits.   (16)            
  3. A series circuit has R = 10 ohm, L = 50 mH and C = 100 µF and is supplied with 200 V ,50 Hz. Find i) the impedance, ii) the current, iii) the power iv) the power factor and v) the voltage drops across each element.(16)
  4. With the neat diagram, explain in detail on the single phase balanced circuits.   (8)
  5. A circuit is composed of a resistance 6 Ω and a series capacitive reactance of 8 Ω. A voltage e(t) = 141 sin 314 t is supplied to the circuit. Find i) Complex  impedance,   ii) Effective value of current, iii) Power delivered to the circuit, iv) Capacitance of the capacitor.                                                                                                                        (16)
  6. Discuss the classes of systematic error giving suitable example for each type.   (8)
  7. Write short note on Constructional features of Energy meter.                              (8)
  8. With suitable diagram, describe the working principle of moving coil Ammeter and Voltmeter.                                                                                                                  (16)
  9. Explain the working principle, construction of PMMC type ammeter Permanent Magnet Moving Coil (PMMC) Instruments.                                                            (16)
  10. Explain briefly about Dynamo meter type wattmeter? Derive the torque equation and give its error.                                                                                                                        (16)
                                                                                                                                       
UNIT-II
PART – A (10 x 2 = 20)


  1. What is basic principle of dc generator?
  2. What are the basic parts of dc generator?
  3. What is the purpose of yoke in dc machine?
  4. Mention the two different types of armature winding in dc machines.
  5. What is the function of commutator in dc generator?
  6. Write down the e.m.f equation of a d.c generator.
  7. What are the different types of dc motor?
  8. What is basic principle of dc motor?
  9. Why series motor cannot be started without any load?
  10. Define the term speed regulation of a dc motor? 
  11. Write down the torque equation of a d.c motor.
  12. What is meant by transformer? Write down the e.m.f equation.
  13. Define transformation ratio.
  14. What is all-day efficiency of a transformer? 
  15. Why the transformer rating is in KVA?
  16. Define slip of an induction motor?
  17. What are the different types of single phase induction motor?
  18. Define slip of an induction motor?


     




 PART – B


  1. Draw and explain the principles of operation and constructional details of a DC generator.(16)
  2. A 200V, shunt motor develops an output of 17.158 kW when taking 20.2 kW.The field resistance is 50Ω and armature resistance 0.06 Ω. Calculate the efficiency and power input when the output is 7.46 kW.(16)
  3. Derive the emf equation of a DC generator.(8)
  4. Explain the working principle of d.c motor and also describe the production of back emf in it.(16)
  5. Describe the construction details of transformer and also explain the principle of operation.(16)
  6. Derive the EMF equation of a transformer.(8)
  7. Draw and explain the core type and shell type transformers.(16)
  8. State and Explain double revolving field theory of 1φ induction motor.(16)
  9. Explain the principle of operation of capacitor start and capacitor run induction motor.(16) 
  10. Explain the principle of operation of Split phase induction motor.(8)


UNIT-III
PART – A (10 x 2 = 20)

  1. Define forbidden energy gap.
  2. Define a semiconductor.
  3. What is intrinsic semiconductor?
  4. What is extrinsic semiconductor?
  5. What is Fermi level?
  6. What is meant by doping in a semi conductor?
  7. What is P- type and N-type semiconductor?
  8. Distinguish between intrinsic and extrinsic semiconductor.
  9. Compare N type and P type semiconductor.
  10. What are minority and majority carriers in a semiconductor?
  11. What is meant by energy band?
  12. Define filter circuit.
  13. What are the advantages and disadvantages of full wave rectifier?
  14. Define peak inverse voltage.
  15. Differentiate Avalanche breakdown and Zener breakdown.
  16. What is cut-in voltage?


PART – B

  1. Describe the working of a PN junction diode with neat diagrams. Also explain its V-I characteristics.(16)
  2. Write down the operation of PNP & NPN transistor.(16)     
  3. Describe the operation of full wave rectifier and also derive its rectifier efficiency, voltage regulations and ripple factor.(16)
  4. Describe the operation of half wave rectifier. And also derive its rectifier efficiency, voltage regulations and ripple factor.(16)
  5. Compare HWR and FWR.(8)
  6. Explain how will obtain the static characteristics of bipolar junction transistor in CE configuration.(8)
  7. Explain the input and output characteristics of a transistor in CB configuration.(8)
  8. Compare CE,CB and CC transistor configuration
i. in terms of input impedance, output impedance, current gain and voltage gain.
ii. Draw the output characteristics of CE configuration and mark its regions of operation.(16)
  1. Compare the performance of a bipolar junction transistor in different configurations.(8)
  2.  Explain in detail about small signal CE amplifier.(8)
                               

UNIT-IV
PART – A (10 x 2 = 20)

  1. Add the numbers (101101101)2 and (1110011)2.
  2. Convert 21.6 into its binary equivalent.
  3. Add 1A816 and 67B16.
  4. Apply Demorgan’s theorem to implement A.B = A+B with any gate.
  5. Give the truth table of NAND gate.
  6. Draw the symbolic representation of two input NAND gate and its truth table.
  7. Convert the given expression in standard sum of product form.                   
  8. Give the truth table of XNOR Gate.
  9. State the advantages and limitations of ripple counter.
  10. Give the various drawbacks suffered by variable resistive divider type of D/A converters.
  11. State and prove Demorgan’s theorem.
  12. Draw the circuit of a half adder.
  13. Draw the logic circuit for half adder.
  14. What is a flip-flop?
  15. What is counter?
  16. What are shift register?


PART – B

  1. Design a logic circuit to simulate the function f(A,B,C) = A(B+C) by using only NAND gates.(16)
  2. What are universal gates? Explain their principle of working with necessary truth table.(16)
  3. Design a full adder circuit using only NOR gates and write its truth table.(16)
  4. Explain half adder and full adder. (16)
  5. Briefly explain the working of JK flip flop and RS flip flop.(16)
  6. Briefly explain the working of D flip flop and T flip flop.(16)
  7. What are the types of shift register? Explain any one type.(16)
  8. Explain the working of a 4-bit asynchronous counter and state its primary disadvantages. (8)
  9. Write in detailed about Analog to Digital converter.(8)


UNIT-V
PART – A (10 x 2 = 20)
  1. Define Communication system.
  2. Draw the block Diagram of Communication system.
  3. What are the types of Communication?
  4. What is the difference between analog and digital signals?
  5. What is a transducer?
  6. Define Amplitude Modulation.
  7. What is the bandwidth of amplitude modulation?
  8. Define Frequency modulation.
  9. Compare AM and FM.
  10. Define PAM.
  11. Define PPM.
  12. Define PWM.
  13. What is meant by sampling?
  14. Draw the block diagram of satellite communication system.
  15. Draw the frequency spectrum of TV signal.
  16. Draw the general block diagram of FAX.



PART – B
  1. Draw the block diagram of communication system and explain its operation.(16)
  2. Discuss in detail on the frequency modulation techniques.(8)
  3. Draw the block diagram arrangement of an AM broadcast transmitter and explain its operation.(16)
  4. With a neat block diagram, Explain the working principle of TV transmission and receiving system.(16)
  5. Explain in detail about FAX.(8)
  6. With a neat block diagram, Explain the working principle of Microwave communication system.(16)
  7. Explain the functions of Communication satellites.(8)
  8. With neat block diagram explain the operation of optical fiber communication technique and mentions its applications.(16)

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