ELECTIlCAL ENGINEERlNG PAPER-11

Answer any three of the folloWing 3x20=60
A second order closed loop system is stable, If the open loop system has all its poLes in RHS of s-plane. Use NyqUist criterion to Justify your answer
Thermistors have a Temperature-Coefficient. If this is correct discuss explain their working, construction and applications. Compare reSiStance-temperature characteristic of a typical thermister and platinum
For over head tranSmiSSl0 lines, shunt admittance is mainly capacitive susceptance (jwlc)'Comment
Huffman coding is done to increase the rate 0 information bits to make them approach the rate 0f binary digits while in panty-check coding rate 0f binary digits iS increased to make the information transmiSSion more reliable' Comment
What do you mean by a state transition Matrix? State and explain properties of state transition Matrix A process control system iS described by the state model <img src='./qimages/1138-2a.jpg'> Use Laplace Transform method to 0btam state transition matrix for the system
An ll-kV, 25-MV.A, 3-phase, star-connected alternator was subj ected to three different types of fault at its terminals. The fault currents were . 5610 A for 3-phase fault 6760 A for line-to-line fault and 8630 A for single line-to-ground fault If the alternator neutral1S solidly grounded, find the p.u. values of the three sequence reactances 0f the alternator Assume that the reS! stances of windings are negligible

State and explain principle of Magnetio Hydro Dynnamics generation, Draw a block diagram of close cycle MHD system and explain operation of the system State the advantages of MHD generation over other metho ds 0f electric generation
An ideal MHD generator usmg gas as working flUid has the following data
Electrode Area: 0.2
Distance between electrodes :24 cm
Magnetic F1ux denSity: l1Nb/m2
Conductivity of gas: 50 Slemenslm
Gasve10city :1800 WS
Find
(i)Output voltage,power and efficlenc ata loading factor of 0.7
Open Circuit voltage and short Circuit current
Maximum power output
How are diodes realized in integrated Circuits using tranSiStor structures? Describe and compare the three most popular diode structures with diagrams
A power system is supplied by only two plants, both of which are operating on economic dispatch. At the bus 0 f plant the incremental co stl s Rs. 275/-per MWh and at plant 2 lS Rs 300/-per MWh. Which plant has the higher penality factor? WhatlS the penalty factor of plant l1f the co st per hour 0f lncreasmg the 10 ad on the system 0f 1 MW is Rs.
Show how three distance relays should be cOlUlected to current and potential transformers of a 3-phase transnusslOn line in order that the protective system has the same sensitivity for all types of multiphase faults. What will be the response of this protective system to Single-phase earth faults?
What is the effect of fault lmpedance on the performance of distance protection?
Suggest a method for overcoming this effect

Differentiate between Instruction Cycle and Machine Cycle Explain all the basiC Machine Cycles of 8085 mlcroprocessor Explain difference between a FETCH cycle and an lNTA Signal
What is meant by eccentricity, semi-major axiS, apogee and pengee? The cosmos 1675 satellite has an apogee height of 39,342 kms and a perigee height of 613 kms. Determine the semi-maJor axis and the eccentricity of its orbit Assume the mean earth radius of 6371 kms
(c) Summarize the attractive attributes and limitations of phased away radar.
SECTION B
Answer any three of the folloWlng 3x20=60
Measurement of Hall-Coefficient reveals the Sign of charge carriers, thus giving type of conductivity and the concentration of charge carriers", Explain the 'Hall-Effect in D-type semiconductors. Hence define Hall-Coefficient

Bridges can be used for the determination of frequency in terms of values of various bridge elements" If this iS correct draw the bridge and device condition for balance. Why and how are two resiStances and capaatances made equal? Can this bridge be used for measurement of capacitance?

HVDC transmission is economically superior to HVAC transmission in respect of transmission power and line losses. Comment Assume equal conductor reSiStance for the two transnussion systems

In a single mode fibre the wavegUlde dispersion can cancel the matenal disperslOn making intra modal dispersion zero over a small range of wavelength. Comment. The wavelength range iS around' 1.3mewm
Discuss the phenomenon of superconductivity. What iS 'critical-field' m a superconductor? How it iS affected by temperature? Write the functional relationship Write application of superconductor as an electrical switching element

In a TOM digital communiucation system 774 vOice samples (using S bits/sample) and 36 control bytes are multiplexed in one frame. If the sampling rate for vOice Signals lS 8000 sample/sec. calculate frame duration m sec, bit rate of the system, If the upstream SignallS higher in frequency than this bit rate (calculated in part ii) by 1 ppm, calculate the number of frames after which one negative stuffing byte will be provided

discuss how a CW radar extracts the Doppler frequency shift from a moving target with the stationary clutter echoes rejected
Discuss the processes mvolved in realizing the expitaxial growth, masking and etching for the fabrication of integrated circuits

What are the conSiderations for chOice of the differentiating and the integrating circuit used for separating the H and V sync pulses? Discuss with schematic and waveforms; how iS nipple reduced at the integrating circuit
consider a Fabry Perot Laser diode made of InGaAsP with refractive index 35
If the gain profile iS g(y)=goe-(lamda-lamda0)1/sigma2 With go 1500 m-l sigma 10 mm and distributive caVity loss, a 1000 m-1 find the lower limit 0f cavity length for lasing
If the cavity length, L 2000 mewm, alpha= 500 m-1 and lamda0=1.5 mewm,find the number of longitudinal modes in the output of the laser.
Draw a schematic block diagram of a microprocessor based system for over-current protection. Describe the operation of the system With the help of a flow chart or otherwise explain associated system software
What iS load frequency control and why it iS used?
100 MVA synchronous generator lS operating on full load at a frequency of 50 Hz The load iS suddenly reduced to 65 MW. Due to time Jag in governor system, the steam valve begins to close after 0.5 second. Determine the change In frequency that occurs in this period 0f time. Assume H 5 MJ/MVA of generator capacity
In a 132-kV, 3-phase earthed-neutral transmiSSion circuit, a 3-phase solid fault occurred at some distance from the arcuit breaker In substation. The power factor of the faulted section of the Circuit (between the breaker and the fault) was 0 the recovery voltage was 0 95 of the full rated value, the breaking current was symmetrical and the restriking voltage transient had a natural frequency of 16kHz Compute the average value of the rate-of-riSe of restriking voltage (RRRV)