(dee 311) - anucde · (dee 311) b.tech. degree ... field power generation and the limitation of...

(DEE 311)

B.Tech. DEGREE EXAMINATION, DECEMBER 2011.

(Examination at the end of Third Year)

Electricals and Electronics Engineering

Paper I – LINEAR CONTROL SYSTEMS

Time : Three hours Maximum : 75 marks

Answer Question No. 1 compulsorily. (15 1 = 15)

Answer ONE question from each Unit. (4 15 = 60) 1. (a) Give an example of closed loop system. (b) Define sensitivity. (c) Define non linear system. (d) Name the two types of electrical analysis for

the mechanical systems. (e) State the rule for shifting the summing point

ahead of a block. (f) What is the effect of positive feedback of

stability? (g) Explain what you understand by a signal

flow graph. (h) Compare the step responses of first order

and second order systems. (i) Explain the relationship between damping

radio and percentage overshoot.

(DEE 311) 2

(j) What are the time domain specifications? (k) Define "Bounded input bounded output

stability". (l) What is "Gain margin"? (m) What is meant by the term "magnitude

criteria in root locus technique"? (n) What is meant by relative stability? (o) What are frequency domains specifications?

UNIT I 2. (a) Derive the transfer function of the system

shown in fig using block diagram reduction techniques.

(b) Write and explain the Masou's Gain formula.

Or 3. (a) In the closed loop system shown in fig. Find

the sensitivities TG

TG SandS 21

.

(DEE 311) 3

(b) Evaluate the transfer functions of the following networks shown below in fig.

UNIT II

4. Explain the following terms :

(a) Delay time

(b) Rise time

(c) Peak time

(d) Maximum overshoot

(e) Settling time

(f) Steady state error

(g) Kp, Ku, Ka.

Or

5. (a) A unity feedback system has

2114

12

sss

sKsG . Determine the value of

K if the steady state value of error to be less than 0.1, when an input r(t) = 1 + 5t is applied.

(DEE 311) 4

(b) Use Routh’s criterion to check the stability of a system given by the characteristic equation.

.065322 3456 ssssss v

UNIT III

6. Sketch the root locus for 11

32.

ssssK

sHsG .

Or

7. Sketch the Bode plot for a unity feedback system characterized by the loop transfer function

sss

ssKsG

005.01001.01025.012.01

3

.

UNIT IV

8. (a) Explain the necessity of a compensator.

(b) Write the differences between lead and lag compensator.

Or

9. (a) Write short notes on 'controllability and observability.

(b) Compute the STM for the system given the system matrix

1101

A .

—————————

(DEE 312)




Paper II — ELECTRONIC CIRCUITS – II


Answer questions No 1 compulsory.

(15 1 = 15)

Answer ONE question from each Unit. (4 15 = 60)

1. (a) What is crossover distortion?

(b) Define conversion efficiency?

(c) Classify the amplifier based on operating point selection.

(d) What is a class - c amplifier?

(e) Define feed back factor .

(f) Classify various feedback amplifiers.

(g) What is the effect of feed back on amplifier bandwidth?

(h) Classify the oscillators based on circuit components.

(DEE 312) 2

(i) Classify tuned amplifiers.

(j) What are the high-frequency limitations of a tuned amplifier?

(k) What are the applications of astable multivibrators?

(l) What is duel power supply?

(m) How the over voltage protection is provided?

(n) Why voltage regulator need short circuit protection?

(o) What are the applications of voltage sweep circuits?

UNIT I

2. (a) Explain the working of series fed, directly coupled class A amplifier with the help of neat circuit diagram.

(b) Prove that the maximum efficiency of class B amplifier is 78.5%.

Or

3. (a) What is harmonic distortion? How the output signal gets distorted due to the harmonic distortion?

(b) How is cross over distortion eliminated is class AB amplifier? Discuss in detail.

(DEE 312) 3

UNIT II

4. (a) Draw the circuit diagram of voltage series feed back and derive expression for voltage gain.

(b) What is the effect of feed back on band width? Explain in details

Or

5. (a) Derive an expression for frequency of oscillation of Hartley oscillator using BJT.

(b) Explain the working of RC phase shift oscillator with circuit diagram.

UNIT III

6. (a) Explain the operation of schmitted trigger with help of diagram. Draw its characteristics.

(b) Draw and explain the single tuned transformer coupled amplifier.

Or

7. (a) Explain the operation of Bistable multivibrator with neat sketch?

(b) What is narrow bend neutralization? Explain.

(DEE 312) 4

UNIT IV

8. (a) Derive the expression for output voltage and explain how it can be varied for the feed back type series regulator.

(b) Explain the operation of current sweep circuits.

Or

9. (a) Explain the current limit protection circuit in details.

(b) What is the need for a trapezoidal waveform for linearity correction?

———————

(DEE 313) B.Tech. DEGREE EXAMINATION, DECEMBER 2011.



Paper III — GENERATION OF ELECTRICAL POWER


Answer Question No. 1 is compulsorily. (15 1 = 15)


1. Write brief note on :

(a) Define load duration curve.

(b) Define Demand factor.

(c) Define plant capacity factor.

(d) What is wind power?

(e) Define load factor.

(f) What is an ash handling system?

(g) What is critical mass of reactor?

(h) What is a super heater?

(DEE 313) 2

(i) Explain the term modulator.

(j) What is a tariff?

(k) What is two-part tariff?

(l) Define power factor.

(m) What is the need for depreciation reserve?

(n) What is meant by fuel cell?

(o) What are control rods in the nuclear power plant?

UNIT I

2. Draw and explain of typical layout of thermal power plant. Describe the function of a coal and ash handling plant.

Or

3. Explain the following :

(a) Choice of generation

(b) Size of generator units

(c) Economizers.

(DEE 313) 3

UNIT II

4. Write short notes on the following :

(a) Hydrology

(b) Hydrographs

(c) Mass curve

(d) Characteristics of turbines.

Or

5. (a) Explain the principles of nuclear power station.

(b) Explain the boiling water reactor and CANDU reactor.

UNIT III

6. Explain with neat sketches, various methods of field power generation and the limitation of each method.

Or

7. (a) Explain the principle operation of Gas Turbine plants.

(b) What is solar power? Discuss briefly various possible large scale applications of solar power.

(DEE 313) 4

UNIT IV

8. (a) Derive an expression for the most economic power factor.

(b) Discuss various costs go into the generation of electric energy.

Or

9. What are the basic requirements of a scheme for raising depreciation fund? Explain various schemes of determining depreciation and compare them in reference to the burden imposed on the electric utilities.

——————————

(DEE 314)




Paper IV — ELECTRICAL MEASUREMENTS




1. (a) What are the main parts of a moving coil instrument?

(b) What is the material generally used for control spring?

(c) What type of damping is used in M.C. type instruments?

(d) What are the uses of M.C. type instruments?

(e) What are the types of M.I. type instruments?

(f) Which magnetic property is used in repulsion types instrument?

(DEE 314) 2

(g) Which value of current r.m.s. (or) maximum is measured by M.I. instruments.

(h) What is frictional error?

(i) What is the working principle of this type of instrument?

(j) What type of coils are there in a dynamometer type instrument.

(k) Name the different energy meters generally used.

(l) Name the instrument used for finding out the frequency.

(m) How many coils are there is a single phase power factor meter?

(n) How the supply is given to the moving coil?

(o) What are the different types of syndroscope?

UNIT I

2. Describe the construction and working of PMMC instrument. Derive the equation for deflection if the instrument is spring controlled. Describe the method of damping in these instruments.

Or

(DEE 314) 3

3. Derive a general equation for deflection for a spring controlled repulsion type moving iron instrument. Comment upon the shape of the scale. Explain the methods adopted to linearize the scale.

UNIT II

4. Describe how high currents and voltages are measured with the help of instrument transformers. Draw diagrams to illustrate your answer. Describe the advantages of instrument transformers as regards extension of range of current and voltage on high voltage a.c. systems.

Or

5. Derive the equations of balance for an Anderson's bridge. Draw the phasor diagram for conditions under balance. Discuss the advantages and disadvantages of the bridge.

UNIT III

6. (a) Explain the method of measuring core hives by using Epstein's square method.

(b) How do you measure leakage factor using flunmeter?

Or

(DEE 314) 4

7. Write short notes on the following :

(a) Ballistic galvanometer

(b) Measurement of permeability.

UNIT IV

8. (a) Describe an overview of applications of a CRO.

(b) Describe in details the vertical amplifier used in a CRO.

Or

9. Describe the construction and working of

(a) LVDT

(b) Therno Carple.

———————

(DEE 315)




Paper V — TRANSMISSION AND DISTRIBUTION


All questions carry equal marks.



1. (a) How are the line parameters calculated for a single phase and three phase systems?

(b) Explain bundled conductors.

(c) Draw the diagram of a double circuit, three phase, transmission line.

(d) What is the main use of GMO method of inductance calculations?

(e) What is corona?

(f) Define disruptive critical voltage.

(g) What is sending end and receiving end?

(h) What is transmission capacity of a line?

(DEE 315) 2

(i) What are stringing charts?

(j) What are dampers?

(k) Define Kelvin's law.

(l) State any two types of insulators used on overhead lives.

(m) What is the use of an insulator?

(n) What is grading of cables?

(o) What are the methods of laying of underground cables.

UNIT I

2. (a) Derive an expression for the capacitance between conductors of a single phase over head line.

(b) Calculate the inductance of a double circuit 34 line wit flat regular spacing.

Or

3. Find the inductance per conductor of a three phase line :

(a) when the conductors are in the same plane.

(b) when the conductors are at the corners of a right angled triangle.

(DEE 315) 3

UNIT II

4. A 3-phase, 50 Hz transmission line 100 km long has 110 kv between lines at the receiving end has the following constants.

,153.0 phkmR ,21.1 mHphkmL

.00958.0 fphkmC

The line supplies a load q 20,000 kw at 0.9 pf lag. Calculate using nominal representation, the sending end voltage, current, power factor, regulation and efficiency of the line, Neglect leakage.

Or

5. (a) Explain the receiving end power circle diagram.

(b) A transmission line conductors at a river crossing is supported by two towers at heights of 40m and 90m above water level. The horizontal distance between towers is 275 m. If the tension in the conductors is 1362 kg, find the clearance between the conductors and water at a point midway between the towers. Weight of conductor per metre run is 0.8 kg.

UNIT III

6. (a) Briefly explain about various types of cables used in underground system.

(DEE 315) 4

(b) Describe with the neat sketches, the construction of a 3 core belted type cable.

Or 7. (a) Explain the indoor and outdoor substations.

(b) In a 250500 Volt, 3-wire DC system there is an out-of-balance load of 200 kw on the positive side. The loss in each balancer is 10 kw and the current in the negative main is 2800A calculate the current each armature of the balancer set and the total load on the generators.

UNIT IV

8. A 3-4 OH line is being supported by four disc insulators. The self capacitance is equal to 10 times the mutual capacitance.

Find : (a) The voltage distribution across various units

expressed as a percentage a total voltage across the string and

(b) String efficiency.

Or

9. Explain the following : (a) Capacitance grading (b) Thermal characteristics of cases (c) Currents in bonded sheaths.

———————–––

(DEE 316)




Paper VI — ELECTRO MECHANICS – III




1. Write brief notes on the following :

(a) What is armature reaction?

(b) Define synchronous impedance.

(c) Define regulation of a synchronous generator.

(d) Define efficiency of a synchronous generator.

(e) What are losses of a synchronous generator?

(f) What are the applications of salient pole alternator?

(g) Define synchronizing power.

(h) Explain the term load sharing.

(DEE 316) 2

(i) What are the factors that effect parallel operators of two alternators?

(j) Define V curve.

(k) Explain the term hunting.

(l) What are the applications of Repulsion motors?

(m) What are the applications of linear induction motor?

(n) Draw the load characteristics of universal motor.

(o) What is synchronous condenser?

UNIT I

2. (a) Write the expression, showing the relationship between speed, frequency and number of poles of a synchronous machine.

(b) The speed of notation of the turbine driving an alternator is 166.7 rpm. What should be the number of poles of the alternator if it is to generate voltage at 50 Hz?

Or

3. (a) Explain the effect of distribution of winding and use of short-pitch coil on the magnitude and wave shape of the induced emf of an alternator.

(DEE 316) 3

(b) A 500 KVA, 3 , star-connected alternator has a rated line-to-line terminal voltage of 3300 V. The resistance and synchronous reactance per phase are 0.3 and 4 respectively. Calculate the voltage regulation at full load., 0.8 pt lassing.

UNIT II

4. (a) State the need for parallel operation of alternators.

(b) Explain the effect of change of excitation of a synchronous generator connected to an infinite bus-bar.

Or

5. (a) Explain three-lamp method of synchronising an alternator with the bus-bar. What should be done to cause an alternator to share load after synchronisation.

(b) Explain synchronous impedance method of determining regulation of an alternator.

UNIT III

6. (a) Explain why synchronous machines are designed to have a high ratio of armature reactance to resistance.

(b) Write short notes on Hunting of Synchronous motor.

Or

(DEE 316) 4

7. (a) State two important applications of synchronous motor giving reasons.

(b) An over excited synchronous motor is called as synchronous condenser, explain.

UNIT IV

8. (a) Explain the working of principle of AC series motors.

(b) Write short notes on repulsion motors and its applications.

Or

9. (a) Explain the main constructional features and principle of reluctance motor.

(b) Explain the principal operation of linear induction motor.

–––––––––––

(DEE 321)




Paper I — LINEAR IC's AND APPLICATIONS




1. (a) What are the different linear IC packages?

(b) List the characteristics of an ideal op-amp.

(c) Define Thermal drift.

(d) How is the slew rate measured?

(e) What is a precision diode?

(f) List the different types of comparators.

(g) What is an instrumentation Amplifier?

(h) What is the other name of one shot?

(i) What is the function of a voltage regulator?

(DEE 321) 2

(j) What are the limitations of three terminal regulator?

(k) How is current boosting achieved in a 723 IC?

(l) Define state variable filter.

(m) What is the roll-off rate of a first older filter?

(n) List the applications of PLL.

(o) What is the range of modulating input voltage applied to a VCO?

UNIT I

2. (a) Explain briefly why negative feedback is desirable in amplifier applications.

(b) Draw the circuit diagram of op-amp differentiator, integrator and derive an expression for output in terms of Input.

Or

3. Draw the circuit diagram of different amplifier with two-op-amps and derive an expression for voltage gain. Input resistance.

UNIT II

4. (a) Draw the schematic diagram of wein bridge oscillator and explain its operation.

(b) How a comparator can be used as a zero crossing detector? Explain.

Or

(DEE 321) 3

5. (a) Explain the working principle of Schmitt Trigger with neat sketch.

(b) Draw the circuit diagram of Triangles order generator and explain its working.

UNIT III

6. (a) What is the need for sample and hold circuit? And explain its operation with neat circuit diagram.

(b) Explain the operation of nuel scope ADC.

Or

7. (a) Draw the circuit for positive clipper by using op-amp. Explain input and output were from with +Vref = IV.

(b) Explain the R-2R ladder type DAC.

UNIT IV

8. (a) Draw the block diagram of Astable Multivibrator using 555 timer and derive an expression for its frequency of oscillations.

(b) Design a second-order low-pass filter at a cut off frequency of 1.2 kHz.

Or

(DEE 321) 4

9. (a) Design a narrow tunal-pass filter, so that fe = 2 KHz, Q = 20 and Af = 10.

(b) List one application of the PLL and then describe the role of the PLL in that application.

–––––––––––

(DEE 322)




Paper II — MICROPROCESSORS AND INTERFACING


Answer Question No. 1 compulsorily. (15 × 1 = 15)

Answer ONE question from each Unit. (4 × 15 = 60)

1. (a) What is the purpose of index resisted?

(b) What is an interrupt?

(c) What is the difference between NEAR and

FAR Calls?

(d) Why CX register is called the count register?

(e) What is lock prefix?

(f) What is the use of REP prefix?

(g) What is an assembler?

(h) What do you mean by nested macro?

(DEE 322) 2

(i) What are the resisters available in 8257?

(j) What do you mean by cycle stealing?

(k) What is light pen?

(l) What is interrupt response?

(m) What is the difference between static and dynamic RAM?

(n) How do you generate Cheakyss in software?

(o) What is the role of stock in calling sub routines?

UNIT I

2. (a) What are the different addressing modes of 8086? Explain them.

(b) Draw the Architecture of 8086 and explain Bus interface unit and execution unit.

Or

3. (a) Explain about general purpose resistens and special purpose registers in 8086.

(b) Draw and discuss flag resistance of 8086 in brief.

UNIT II

4. (a) Write an ALP and find out decimal addition of sixteen.

(b) Explain the minimum made of the 8086 system with help of a neat diagram.

Or

(DEE 322) 3

5. (a) Write an ALP to find out the number of even

and odd numbers from a given series of 16-

bit hexadecimal numbers.

(b) Explain in detail the significance of the

assembly language program development

tool.

UNIT III

6. (a) What is an interrupt pointer table? Explain.

(b) Explain the term nested interrupt.

Or

7. (a) Explain the stack structure of 8086 in

details.

(b) Explain the working of successive

approximation A/D converter circuit.

UNIT IV

8. (a) Draw and discuss the internal architecture of

8253.

(b) What is the difference between 8259 and

8259A?

Or

(DEE 322) 4

9. (a) Explain the mode instruction control world

format of 8251.

(b) Explain the working of DMA controller with

the help of block diagram.

——————

(DEE 323)



Electricals and Electronics

Paper III — DIGITAL SIGNAL PROCESSING


Answer Question No. 1 compulsorily.

(15 1 = 15)

Answer ONE question from each Unit.

(4 15 = 60)

1. Write brief note about the following :

(a) Define causal system.

(b) What is the condition of system stability?

(c) State sampling theorem.

(d) Find the z-transform of a digital step.

(e) State the initial value theorem.

(f) What is the time shifting property of z-transform?

(g) Define circular convolution.

(h) What is zero padding?

(DEE 323) 2

(i) What are the applications of FFT algorithms?

(j) Give the bilinear transform equation between s-plane and f-plane.

(k) What are the properties of chebyshev filter?

(l) What is the reason that FIR filters always stable?

(m) Draw the frequency response the N-point rectangular window.

(n) What do you mean by pre warping?

(o) What is the disadvantages of direct form realization?

UNIT I

2. (a) Find the natural response of the system described by difference equation

)1()()2()1(2)( nxnxnynyny with initial condition 1)2()1( yy .

(b) Test the following systems are stable or not

(i) )1)(()()( nxnnxny

(ii) bnaxny )()(

(iii) )cos()()( wonnxny .

Or

(DEE 323) 3

3. (a) Find the inverse z-transform of

21 2311

)(

zzzx using convolution

method.

(b) Explain about any method of evoluting z-transform.

UNIT II

4. (a) Compute the DFT of sequence n)1( for 4N .

(b) List out the properties of DFT.

Or

5. (a) Compute the DFT of the sequence whose values for one period is given by

}2,2,1,1{)( nx .

(b) Find the DFT of a sequence

otherwise020for1)(

nnx

for 8N plot )(kx .

UNIT III

6. (a) Given the specifications dBp 3 , dBs 16 ,

KHzfp 1 and KHzfs 2 . Determine the

odes of filters using chebyshev approximation. Find H(s).

(DEE 323) 4

(b) Give the comparison between Butterworth filters and chebyshev filter.

Or

7. (a) Write about frequency transformation.

(b) Design a butterworth high pass filter satisfying Hzfp 32.0 ; dBp 5.0

Hzfs 16.0 ; dBs 30 Hzf 1 .

UNIT IV

8. (a) Determine the cascade relation of the system 11

11

11)

)(

bzaz

bzazzH with only 3 dealy

elements.

(b) For the system function

11

21

61

121

1

1)(

zz

zzzH obtain parallel

structure.

Or

9. (a) Compare different windows.

(b) Use the windows method with a hamming window to design a 13. tap differentiators.

——————————

(DEE 324)




Paper IV – POWER ELECTRONICS




1. (a) What is a thyristor?

(b) What is the meaning of gate triggering?

(c) Define a valve.

(d) What is snubber circuit?

(e) Define fiving angle.

(f) What is meant by pulse number of a converter?

(g) What are different types of chopper circuit?

(h) What is a dual converter?

(i) What is meant by gain of an inverter?

(DEE 324) 2

(j) What are different types of inverters?

(k) What is meant by modulation index?

(l) What is meant by distortion factor in spwm?

(m) What is a full bridge inverter?

(n) What is a LASER?

(o) Define cycloconverter.

2. (a) Explain the static V-I characteristics of a thyristors and different modes of operation.

(b) Two thyristors having a difference of 4MA is latching current are connected in series with the circuit. Voltage across the devices are 420V and 300V. Calculate the required equalizing resistance and also design a suitable RC circuit for thyristor if the permissible difference in blocking voltage is 8V and difference is recovery charge is 2MC.

Or

3. Explain briefly the triggering circuit for SCR. Explain the circuits necessary to protect an SCR from false triggering. Explain various protection schemes.

(DEE 324) 3

4. (a) Explain 1 half wave rectifier for RL load with suitable voltage and current waveforms.

(b) Derive the expressions for average output voltage, current, RMS load current.

Or

5. (a) Explain the principle operation of pulse width modulation control for PF improvement.

(b) A 3 half wave rectifier is operating in the inverting mode connected to a 440 V (line) supply. If the angle of firing advance is 18 and the overlap is 4.2, find the mean voltage at the load.

6. Explain the operations of McMurray full bridge inverter in detail with reference to different modes of operation. What are its applications?

Or

7. (a) Explain the principle operation of PWM inverters.

(b) Calculate the output frequency of a series inverter with the following parameters. Inductance (L) = 6 mH, capacitance (c) = 1.2 Mf, load Resistance (R) 100 n, Tgt = 0.2 msec. If the load resistance is varied from 40-140n find the range of output frequency.

(DEE 324) 4

8. Explain the operating principle of both stepup and stepdown choppers involving different modes with the neat circuit diagrams.

Or

9. Briefly explain the principle operation of single phase cyclo converters and their applications.

————————

(DEE 325)


(Exanimation at the end of Third Year)


Paper V — UTILIZATION OF ELECTRICAL POWER


Answer Question No. 1 Compulsorily. (15 1 = 15)


1. (a) Define load equalization.

(b) What are the advantages of Electric braking?

(c) Define plugging.

(d) Mention the requirements of an ideal traction system.

(e) What is braking?

(f) Write a note on train lighting system.

(g) Define Stefan's law.

(h) Bring out the advantages of electrical heating.

(DEE 325) 2

(i) Give the reasons for the failure of heating element.

(j) What are different types of arc welding?

(k) What are the requirements of ac welding equipments?

(l) Define luminous flux.

(m) Define luninous intensity.

(n) Define mean horizontal candle power.

(o) What do you mean by tractive effect?

UNIT I

2. (a) Explain the general considerations in selecting motor power ratings.

(b) Discuss briefly about heating and cooling of motors.

Or

3. (a) Explain the flywheel and its applications in load equalization.

(b) Write short notes on selection of capacity for short time and intermittent periodic duty.

UNIT II

4. What is speed time curve and deduce expressions to get the relationship between various quantities using (a) trapezoidal (b) quadrilateral speed time curves?

Or

(DEE 325) 3

5. (a) Explain the effect of adhesion and co-efficient of adhesion.

(b) An electric train weighing 180 tonnes runs at a speed of 75 kmph. The train resistance at this speed in 48NW per tonne. Determine the current drawn from 1500 voltage dc mains at total efficiency of 82%. How long will it continue to run if the supply is switched off. Assume accelerating weight as 1.05 times the dead weight of the train.

UNIT III

6. (a) How efficiency of resistance furnance is estimated? Explain.

(b) Explain the design procedure for a circular heating element.

Or

7. (a) Explain the characteristics of carbon and metallic arc welding.

(b) Find the current in the line in a 3 arc

furnance to melt 5 metric tonne of steel in one hour at an overall efficiency of 50%, if the arc voltage is 115v, initial temperature 18C, melting point of steel 1370C, specific heat of steel 0.12 and latent heat of steel is 8.89 kcal/kg.

(DEE 325) 4

UNIT IV

8. (a) State and explain inverse square law.

(b) Determine the distance for a 25 cp lamp from a normally placed screen in order that the illumination shall be (i) 5 lux (ii) 15lux (iii) 8 fc.

Or

9. Explain the following :

(a) Factory lighting

(b) Flood lighting

(c) Street lighting.

———————

(DEE 326) B.Tech. DEGREE EXAMINATION, DECEMBER 2011.



Paper VI — SWITCH GEAR AND PROTECTION


Answer Question No. 1 compulsory. (15 1 = 15)

Answer ONE question from each Unit.

(4 15 = 60)

1. Write short notes on :

(a) What is a protective relay?

(b) What are the basic requirement of protective relay?

(c) What is Buchholz's relay?

(d) Define Restraining force.

(e) Define operating time.

(f) What are the requirement of time protection?

(g) Define time setting multiplier.

(h) Explain arc quenching.

(i) Define recovery voltage.

(j) Define restriking voltage.

(DEE 326) 2

(k) What is the meaning of Neutral grounding?

(l) What is the resistance grounding?

(m) What is static relays?

(n) What is a circuit breaker?

(o) What are the factors, which influence the arc voltage?

UNIT I

2. Discuss with necessary circuit diagram, the principle of operation of an induction disc relay. What are the advantages of induction up relays over induction disc relays?

Or

3. (a) What are the various types of overcurrent relays? Discuss their area of application.

(b) It is given that fault current level at 33 kV side is 2700 amps. CT ratio at 33 kV side is 200 : 1 and 132 kV side is 100 : 1. If both the relays 1R and 2R are set for 100% plus setting. Determining the operating time for both the relays when time grading margin of 0.6 sec is given and TMS for relay R1 is 0.15.

UNIT II

4. (a) Explain the techniques adopted in circuit breakers to extinguish the arc rapidly.

(DEE 326) 3

(b) Derive an expression for restricting voltage in terms of system capacitance and inductance.

Or

5. (a) Explain the construction principle and working of an oil circuit breaker with a neat sketch.

(b) Explain the principle of resistance switching. Why is it necessary in air blast circuit.

UNIT III

6. (a) Make a list of faults, which may occur on an alternator. State the protection to be used for each of faults.

(b) Explain biased differential protection for faults.

Or

7. (a) Explain the soil resistivity and earth resistance.

(b) A 3 transformer rated for 33/6.6 kV is connected star/delta and the protecting current transformer on the low voltage side has a ratio of 400/5. Determine the ratio of transformer on the HV side.

(DEE 326) 4

UNIT IV

8. (a) What are the merits and demerits of static relay over electromagnetic relay?

(b) Explain the basic principle working and characteristics of static relay.

Or

9. Show that the amplitude and phase comparator are due to each others. Explain operation of circulating current type rectifier bridge amplitude comparator. What do you understand by them directional? Explain 90, 60 and 30 connections.

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(dee 311) - anucde · (dee 311) b.tech. degree ... field power generation and the limitation of...

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