CIVILS MAINS 2013 ELECTRICAL ENGINEERING Paper-II

Time Allowed: Three Hours

Maximum Marks: 250

QUESTION PAPER SPECIFIC INSTRUCTIONS

Please read each of the following instructions carefully before attempting questions.

There are EIGHT questions divided in Two Sections and printed both in HINDI and, in ENGLISH.

Candidate has to attempt FIVE questions in all.

Question no. 1 and 5 are compulsory and out of the remaining, THREE are to be attempted choosing at least ONE from each section.

The number of marks carried by a question/part is indicated against it.
Answers must be written in the medium authorized in the Admission certificate which must be stated clearly on the cover of this Question-cum-Answer booklet in the space provided. No marks will be given for answers written in medium other than the authorized one.
Assume suitable data, if considered necessary, and indicate the same clearly.
Unless other-wise mentioned, symbols and notations have their usual standard meanings.


SECTION-A

Q. Giving classification of errors in measurement, explain these errors giving suitable examples. Explain how systematic errors can be minimised. 5

circuit consists of two branches in parallel. The current in one branch is II 10 ± 0.2/ and in other is 12 20 ± 0.5 A. Determine the value of the total current I =II 12 considering the errors in II and 12 as limiting errors, considering the errors as standard deviations. Comment on the result. 5

Q.l(b) A 3-phase I38-kV, transmission line is connected to a 49-MW load at a 0.85 lagging power factor. The line constants of the 80 km Iong rme are 95 L78° n and Y 0.001 L90° S. Using nominal-T circuit representation, compute:
The C and D constants of the line
Sending-end voltage;
Sending-end current;
Sending-end power factor; and
Efficiency of transmission. 10

Q.l(c) (i)Draw the block diagram indicating the typical architecture of a microcomputer. Briefly discuss the salient features. 5

How can square wave generation with a variable bit rate, be done using the microprocessor? Output should be available on a chosen port, using bit 5

Q.l(d) Define the terms given below":
Pick up value
Reset time .
Operating time and
Reset value
for protective relays. 10

Q. State and explain various test inputs in control systems. 10

Q. Using the Block diagram simplification method reduce the block diagram of the following control system
<img src='./qimages/175-2a.jpg'>
to a block diagram of the following type 20

Q. Time currence characteristic of an indqction-type overcurrent relay is
<img src='./qimages/175-2b.jpg'>
It is desired to determine the time of operation of 5-ampere relay having a current setting of 125% and TMS of 0.6 connected to a supply circuit through a C.T. ratio 400/5 ampere when the circuit carries a fault current of 4,000 amperes. 20

Q Classify different types of buses for load flow study in power systems. 3

Discuss formulation of Newton-Raphson method with mathematical details in polar co-ordinates. 7
Q. The asymptotic approximation of the variation of gain with frequency of a control system <img src='./qimages/175-3a.jpg'>


Q. What are the main causes of low power factor and discuss measures by which low power factor can be avoided 10

A consumer is taking a load of 20 kW at power factor 0.8 lagging. Find the rating of capacitor to raise the power factor to 0.95 lagging. 10

Q. An ll-kV, 50-Hz generator was supplying power to a load when a three-phase fault occurred on the system. The inductive reactance and capacitance of the faulted section were 4.0 ohms and 0.01 respectively, and the resistance was negligible. Compute the active recovery voltage, peak value of the restriking voltage, the frequency of transient oscillatory voltagealid the average rate-of-rise ofrestriking voltage (RRRV) up to the first peak of oscillations. 20

Draw a functional block diagram and explain the working of a digital frequency meter. 10

Describe the circuit 'and working of a wave analyser for audio frequency and Megahertz 10

Q. Draw the timing diagram for memory read cycle and memory write cycle and explain the significance of the time periods therein. 10

A systematic linear code has the parity matrix P given as

<img src='./qimages/175-4c.jpg'>

Find the code vectors for message vectors 1000, 0001, 0010 and 0111. 8

Draw the corresponding encoding diagram. 8

If the received vector [0111110] has a single error, detect the error and correct it.

SECTION-B

Q. Determine the break-in point in the root locus of a control system with: K s 10) 5

For the control system <img src='./qimages/175-5a2.jpg'> the steady state error for unit ramp input is 0.01. Determine the value of K. 5

Q. What is the need for a multi input comparator? Show with diagrams how to obtain the quadrilateral characteristic in the R-X plane using 4-input phase comparator. 4+6=10

Q. What is the need for sending digital data over analog carriers? In this regard how is FSK better than PSK 5 .

With reference to the 7 layer architecture of data networks, distinguish between Protocol Data Unit and Service Data Unit (SDU). 5

Q.5(d) State various insulating materials used for cables and comparatively discuss any two widely used materials. 10

Q. What do you mean by Thermistor? Explain briefly resistance-temperature characteristic curve of Thermistor and compare the same with thermocouple. 10

Q. What is a digital voltmeter? 3

What are its advantages as compared to analogue voltmeters

Listing different types ofDVMs explain anyone type for the measurement of current.4

Q. Show how DAC 1200 can be interfaced to the 8255. Write the schematic diagram. Use 'double buffering' to prevent glitches. 14

Write 8085 subroutine to transfer 12 bits of data stored in two sequential memory locations to the DAC interface carried out in part Assume that the address of the first byte is stored in the HL pair. 6

Q. How is DPCM better than PCM With the help of illustrations, show how DPCM signals are generated and decoded. 10

Consider the convolutional encoder shown in the figure below. The code is systematic Draw the state diagram using the State Transition Table Draw the Code Tree.
<img src='./qimages/175-6c2.jpg'>

Q. Describe the functioning of a charge amplifier using an OPAMP with piezoelectric transducer used at the input for measurement of displacement. 10

Derive the expression for the transfer function and draw its curve showing frequency response. 10

Q. List the features of 8086's segmented memory. 5

What are the different addressing modes available in 8086 Indicate their features. Write the mnemonics for each of them taking as an example. Indicate the symbolic notation also for each of them. 15

Q. What are the advantages of digital carrier systems over Baseband digital transmission? Develop the mathematical formulation for a BPSK signal. 10

Q. control system is represented by the state space equations

Xl X2
X2 X 3 UI
X3 -2x2 3x3 u2
and the output equations are
y1 Xl 3x2 2u1
Y2 x2
Draw the state transition signal flow graph and find the characteristic roots of the system. 20
Q. With the help of single line diagrams, discuss the classification ofHVDe transmission links.14
State their comparative advantages and disadvantages. 6
Q. Draw the block diagram of a Digital Relay and name all the blocks of this relay. 10