Bharatiya Vidya.Bhavart's

Sardar Patel College of Engineering Government Aided Autonomous Institute)

Munshi Nagar, Andheri (West), Mumbai — 400058

Reexamination

Program: Electrical Engineering Duration: 3 hrs. Maximum Marks: 100

• Date: June 2019 Course code: BTE302 Semester: V

Course Name: Control System I Instructions: Solve any 5 questions

Q. No.

Questions Max

Marks

1 a Using Routh Hurvyz criterion, determine whether the control system characterized by the characteristic equation

s4 + 5s3 + 6s2+2s+5=0 is stable or not

10

b Explain 'absolute stability and relative stability with the help of some suitable example of control system

10

2. a

I-1)

With an example explain open and klosed loop control systems

For the following closed loop control system find position, velocity and acceleration error constants.

---- , ..

10

Define transfer funetion. '

D-etermine the-tratisfer function for the fdllo J

r

mg system T (s) --:--Vc.. (S)

V CS)

10

\,)cL- c v CO --

P:

3. a> Find

shown

b> Draw

Masson's

the overall transfer

below using

signal flow graph

gain formula

block

for

find

function for the control system block

diagram reduction technique.

the block diagram shown below and ,i

diagram

using

20

'

the overn1114ansfer function

fti

—I—

, .,.-

, 1: fr

lr

(

4 a Transfer function of a closed loop control system is given by 10

C(s) 4

R(s) s + 5s + 25

Find rise time, settling time 2%band, damping frequency. Unit step input is

applied.

b Differentiate between type and order of the control system with an example. 10

Define overshoot, settling time and rise time for second order system

5 a Give the complete procedure of Root Locus construction 10

b Draw Root Locus for the cases

k

10

a> G (s) H (s)=-i b> G (s)H s •

(s)—s (s +7)

6 a Compare P, P1, PD and PID controller 10

c Why is the compensator required Compare series and feedback 10

compensators

7 a Derive and plot gain and phase variations with request to frequency for Lead 1 10

Lag compensators

b 1 k 10 A unity feedback system has its open loop transfer function given as

(s10)

What compensator you proposed for it? Why?

Bharatiya Vidya,ghavaO's

Sardar Pate! College ofi Engineering (X Government Aided A4Dnot-nus Institute)

Mnp.shi Nagar, Aadhcri (W4), lytt lInbai —400058

Re-Examination

Date: June 2019 Course code: PC-BTE502 Semester: V

Course Name: Control System

Note: Solve any five questions. I Points

No. QQuestions

':,,,i, • -1.! - 7, --,., i 08

la. Make a detailed comparative ."' A,.

control Systems

analysis of the v.apious stability methods of .1'. ,I,' .,1,

' ! 1

't 1._ , Tv.' 1

b. Explain the proCesii to draw,trodelocuS. .± i

For the fallowing G (s) H (s) prcidilitt,' construct Root Locus !

the range.ofpositive adjustable gain K for which overall system . ..

stable.

s .

sketch. Find is,

12

G(s)ff(s) =

2 a " Find step, ramp and parabolic error Coefficietiti foiiiTty1eedback

system which has the transfer function ., ,

5(s

08

( -i 1 ) 52 + 2s -I 2)1

12 b ! e me gain amcJ phase in ii=, in

trt, tie Rink Plots tor _

(s + '3)

. (s:+ 1)(s + 2)I .3!

DeterMine gain and phase diargin! -,---: - - ' 1

3 a Obtain state spate model asing paralleldcotnposition method for-the

following transfer (unction

Y(s) 1

10

Y U(s) -• (s-+ 2)(s + 4,)($ + 6)

10 b I- Given the system, hy the following equations .- Find the transfer function

T(s) =-- Y(s)/U(s) Where, U(s) is the input and Y(s) is the output

.---,,,,,,!------ !,!'--- '' •

PrOgram: Electrical Engineering Duration: 3 hrs. Maximum Marks: 100

i =

y =

[ —21

0 2 1 1-1

[1 017c +

y 4_ — ' 1011— 1

[O]u

1,,

4 a Define transfer function.Evnluate the transfer function for the following

system using a> Block Diagram Reduction method b> Mason's gain formula ;

12

-1-- - 1

g(-9

;

. ,

b Comment on controllability,

by

i =

and observability

0 { 0 0 1

—5 —10 —2

,y = [1 0 O]x

x +

of a

0 8

system represented

u

08

5 a What is Lead compensator'i ShoW the pole zernIplot of Lead , I,!

compensator. What are the effects of Lead compensator on step

response of the system k. . .

07

b What are the advantages of velocity algorithm compared to position algorithm for digital implementation of PID controller?

07

c Explain Linear Quadratic Regulator- . 06

6 a Describe how the stability model

A system is represented in

± =

y = [1 0 01x. Determine plane, in left half plane and

of the system

state space as

0 1 2 I 1 1 —2 { 1-23 '

how many on jw axis

x

Eigen

1 101

0

is dete±mined.using state space

u

values are in right half

10

b The characteristic equation of the system is given by

s6 + .0 + 5s4 + 2s3 + 7s2 + 4s — 5 =

Comment on the pole location and stability of the system using Routh's

10

array. 1 08

7 a Explain Compare P, PD, Pl and PID controllers on step response. any

tuning method used to tune PID controller

b. Show that state space representation of a system is not unique. Convert the following single input single output difference equation to discrete

time state space model.

y[lc] = —2y[k -- 1] — y[k - 2] — 2y[k — 3] + k - 1] + 2u[k - 2]

-F ii [k -- 3]

12

Bharatiya Vidya Bhavan's

Sardar Patel College of Engineering (A Government Aided Autonomous Institute)

Munshi Nagar, Andheri (West), Mumbai —400058. KT- Examination

Max. Marks: 100

Duration: 03 Hours Class: T.Y. B.Tech Semester: V

Program: B.Tech

Name of the Course: Electrical Machines-II

Course Code:

Instructions:

• Solve any five questions • Answers to all sub questions should be grouped together • Figures to the right indicates full mark • Assume suitable data if required and justify the same.

Ques. No.

Description Max. Marks

C.O. No.

Q.1 a) Compare the cylindrical pole and salient pole synchronous machines. 10 01

b) Discuss the armature reaction for synchronous generator. 10 01

Q.2 a) Compare EMF and MMF Method by drawing suitable phasor diagram. 10 02

bThe

) synchronous reactance calculated by EMF method varies. Justify the

statement. 10 I 02

Q.3 a)

What is synchronization? Discuss the method of connecting two generators in parallel. Discuss the parallel operation of synchronous generator supplying common load.

03+03 +06

02

b)

A three phase synchronous generator feeds into a 22 kV grid. It has a synchronous reactance of 8 ohm/phase and delivering 12 MW and 6 MVAR to the system. Determine:

(i) the phase angle of the current (ii) the power angle (iii) the generated emf

08 02

) QA astarting"?. What is the condition to make single phase induction motor "self-

Prove that (mathematically or graphically) the magnetic field produced by two winding of single phase induction motor excited by the same source is rotating.

10 03

b)

A synchronous generator is connected to infinite bus and supplies constant power. Discuss the effect of variation in excitation on the operation of synchronous generator.

10 03

Q.5 a) What are the starting methods of synchronous motor. 10 01

b) Unloaded synchronous motor can be made to act as a synchronous condenser. Explain.

10 01

Q.6 a) Discuss the slip test with suitable diagrams. 10 02

b) Derive the expression for the power developed by cylindrical pole synchronous generator. Do not neglect armature resistance.

10 02

Q.7a) What is hunting phenomenon in case of synchronous machines? 10 02

b) Draw and explain the V curves and inverted V curves for cylindrical pole synchronous motor.

10 01

•

Bharatiya Vidya Bhavan's f It

' tta r.L 14 Sardar Patel College of Engineering 1

• • ',1 viD 0 (Govt. Aided Autonomous Institute under University of Mumbai)

%leer

Academic Year 2018 — 19 Re-Examination [Academic Year 2017-18]

Program: B. Tech. Electrical Class: T Course: Digital Signal Processing Course Total Points: 100 Date: 7th

Y. Sem. V ode: BTE305 June 2019

Note: Solve any FIVE questions of the following. All questions carry equal points.

Que. No.

Question CO i

Mod. No.

PointsNo.

1 Design an analog lowpass filter using Butterworth, Chebyshev and Chebyshev approximation to meet following specifications: Al dB for Op < 4 rad/s and A> 20 dB for SI, > 8 rad/s.

inverse I 3/7 (20)

a Determine 8-point DFT of the sequence x(n)= {1,2,4,8,16,32,64,128} usin

DIT FFT algorithm.

radix-2

-

2/4 (10)

b Determine IDFT of the following sequence using radix-2 DIT-FFT argorithm: X(1c). {36, —4 + j9.656,— 4 + j4,-4 + j1.656,— 4,— 4 — j1.656,-4 — j4,-4 — j9.656}

2/4 (10)

3 a Design a 4th order FIR filter, using rectangular window function, to approximate ideal low-pass filter with passband gain of unity, cut-off frequency of 850 working at a sampling frequency of 5000 Hz.

an Hz and

3/6 (10) 1

Design a linear phase FIR highpass filter using Hanning window functio specifications given below: Stopband edge = 2 kHz, Stopband attenuation 40 dB, Passband edge = 9. Passband attenuation < I dB, Samplintz. frequency = 25 kHz.

, for the

kHz,

3/6 (10)

4 a 4 filter function, H(s)= into , a

3/7 I (10) Convert the analog with system

(s+1)(s 2 +4s+5)

digital HR filter using impulse invariance method, with T., = 0.5 sec.

b A simple LRC notch filter has following normalized, s-plane transfer function:

H(s)= S 2 +1

Assume a

3/7 (10)

2 S + s +1

Determine the transfer function of an equivalent digital filter using BLT. notch frequency of 60 Hz and sampling frequency of 960 Hz

-1-

5 a Discuss symmetry properties of DFT for a signal with following cases: i. real (even and odd) and ii. purely imaginary (even and odd).

,

2/3 (1.0)

b For the sequences xl (n) = 11,1,2,21 and x2 (n) = {1,2,3,4) , determine:

i. linear convolution

1,2 /

3, 1

(10)

ii. circular periodic convolution using DFT / IDFT.

6 a For a causal discrete-time LT1 system, which is described by a difference equation 1/ (10) 1,2

y(n)+ —1

An —1)= x( n) + —1

x(n —1), determine its, 4 ' 2

i. impulse response, ii. system transfer function iii. frequency response and iv. magnitude and phase response •

,. b 1 0 n 3 1,2 (10)

Determine 8-point DFT of the sequence x(n)= I , 0 4 _. n 7 .

Using DFT properties only determine, DFT of, 1, 2

11 n = 0 10 0 < n <1

x,(n)= 10 1 < n 4; x2 (n)= l 2 ._ n < 5;

1l 7---------< n

7 a I Determine linear convolution of the following signals using convolution property of 1/2 (20) DTFT.

x, (n) = nu (n) and x 2 (n) = (2)" u(n — 1) .

b For the system described by the difference equation, 1/ 1,2

\ 1 An) — —

1An —1) + — y(n — 2) = x(n),

2 4

Determine, i. transfer function and

\ On i ‘

[ — ii. response

- of the system to the input x(n ) = —

3--i_ u ki2). .

_i

- 2 -

Bharatiya Vidya Bhavan's

Sardar Patel College of Engineering (A Government Aided Autonomous institute)

Munshi Nagar, Andheri (West), Mumhai — 400058

KT EXAMINATION JUNE 2019

Program : T.Y. B.Tech. Electrical Engineering. Semester : V Course code: BTE 304

Duration :Q3 Hr Name of the Course :POWER SYSTEM ANALYSIS

Maximum Marks: 100

Instructions: 1. Attempt any 5 questions from 7 ( Qs.I to QsVII). 2. Assume suitable data if necessary. 3. Draw relevant neat circuit diagrams wherever required.

Qs No.

Max. Mark CO

Module No.

Qs I. a. Determine the symmetrical components of three voltages

given V. = 200L0°; Vb = 200z245°; V, = 200L.105°. 10 01 01

b. Draw the Zero Sequence network diagram for the following types of transformer connections. (i) Y-Y transformer with anyone neutral grounded; (ii) Y-Y transformer with both

neutral grounded; (iii) Y-6, transformer with grounded Y

neutral; (iv) )6,-A transformer with grounded Y neutral.

10 01 01

State the main assumption made in for the above.

Qs II. a. Mention the steps involved in short circuit studies. 10 03 02

b. For a line to ground (LG) fault derive the equivalent sequence network diagram and the respective currents.

10 03 02

Qs III, a. How Bus admittance matrix (Ybus) is related Primittive

admittance matrix (Y) and Bus incidence matrix (A). Justify your answer analytically.

10 02 03

b. Obtain the alogorithm for Vbus formation incorporating addition of new transmission lines in the system.

10 02 03

Qs IV a. For a radial network consisting three buses have the following data. Busl is a slack bus with V1=1.0z.0°, P2 + iQ2

10 03 03

= -5.96 + j11.46, IV3j= 1.02. Assume V1=1.02L0° and V2=1.0G0'. The impedances of line connecting buses 1-2 &

2-3 are (04 + j0.06) & (02 + j0.03) respectively. Obtain the complex bus bar voltage at bus 2 at the end of first iteration using Gauss-Seidel method.

b. Compre of Do-coupled and Fast De-coupled method of Load flow analysis. 10

02 04

Qs V. a. Derive the swing equation that governs the dynamics of rotor of a synchronous machine.

b. A 50Hz, 4pole, turbogenerator rated 100 MVA, 11 kv has an inertia constant of 8.0 MJ/MVA.

(i) Find the stored energy in the rotor at synhronous speed.

(ii) If the mechanical input is suddenly increased to 80 MW for an electrical load of 50 MW, find rotor acceleration, neglecting mechanical and electrical

losses. (iii) If the eLcceleration calculated in part (ii) is maintained

for 10 cycles, find the change in torqueangle and rotor speed in rpm at the end of this period.

10

10

03

03

05

05

1

Qs VI Explain any the following:

a. Condition for stability of a power system using Equal area criterion.

b. Determination of stability of a multimachine system using poin-by-point solution of swing equation.

10

10

03

03

06

06

Qs VII Explain any two from the following: a. Bewley Lattice diagram. b. Write the algorithm for load flow analysis using N-R

method. c. Factors affecting transient stability.

10 10 10

04 03 03

07 05 06

Bharanya Vidya Bhavan's

SARDAR PATEL COLLEGE OF ENGINEERING (Government Aided Autonomous Institute)

Munshi Nagar, Andheri (W) Mumbai —400058 ODD SEM REEXAMINATION JUNE 2019

(OLD SYLLABUS)

Program: ELECTRICAL ENGG. Duration: 3 HOURS

Course Code: BTE 306

Maximum Points: 100

Course Name: POWER ELECTRONICS

Semester: V

• Solve any 5 quest ions

Q) Question points

1. a.

b.

Draw source side phase 'a' current waveforms of three phase controlled converter with firing angle alpha (a) = 30°. Indicate conducting thyrister numbers on it.

Draw output voltage and output current waveforms of single-phase half bridge and full bridge VSI with pure inductive load. Indicate conducting switches on output current waveforms

10

to

2. a. Draw circuit diagram (4m), output voltage (4m), input voltage (4m), output current (4m) and input phase 'A' current waveform (4m) of three phase-controlled converter (rectifier) with continuous current (RLE) load. Assume a=30°

20

3. a. Write note on any one of fully controlled switch from following list

• MOSFET • GTO • TRIAC • IGBT

10

b. Write short note on SCR using following points

v-I characteristics, three modes of operation

10

4. a. Draw circuit diagram (4M), triggering pulses OM), output Phase (4M) and Line voltage (4M), input voltage (2M), output line

20

current waveform (3M) of three phase VSI with star connected 'IV load.

5. Draw output voltage, current waveforms and derive output voltage of the following circuits.

a) Single phase full wave bridge controlled rectifier with a=120° (load current is continuous and ripple free RLE load) and derive average output voltage

b) Single phase full wave bridge controlled rectifier with a=120° (pure L load)

20

6. a. What is pulse width modulated inverter? Explain sine triangular PWM inverter.

10

b. With the help of input voltage, output voltage, voltage across inductor, voltage across capacitor, capacitor current, inductor current and load current waveforms derive critical L and critical C of the DC-DC Boost regulator.

10

7. a. Compare VSI and CSI. 10

b. Deduce effect of source side inductance on single phase and three phase rectifiers.

10

Bharatiya Vidya Bhavan's

Sardar Patel College of Engineering (Govt. Aided Autonomous Institute Affiliated to University of Mumbai)

Re-examination [June 20191 Academic Year 2018 — 19

Program: B. Tech, Electrical Engineering Course: Digital Signal Processing Course Code: PE -BTE501

Semester: V Date: 8th June 2019 Total Points: 100

Note: Solve any FIVE questions of the following. Write answers of all sub-questions together.

CO: Course Outcomes

BL: Bloom's Taxonomy Level

PI Performance Indicator

Q. No.

Question Points CO BL PI 1

1 A Design an analog lowpass filter using Butterworth, Chebyshev and inverse Chebyshev approximation to meet following specifications: Ap <1 dB for 12p < 4 radis and As > 20 dB for Cls. > 8 rad/s.

20 4 6 1.6.1

2 A Design a lovvpass half band filter using Hamming Window to meet following specifications: Passband edge = 8 kHz, Stopband edge = 16 kHz

10 4 6 1.5.1

B Design a linear phase FIR highpass filter using Hanning window function, for the specifications given below: Stopband edge = 2 kHz, Stopband attenuation 40 dB, Passband edge = 9.5 kHz, Passband attenuation < 1 dB, Sampling frequency = 25 kHz.

10 4 6 1.5.1

3 A A second order discrete time system is characterized by the difference equation y(n)— 0 .1y(n —1)— OM An —2) = 2x(n)— x(n —1). Determine

An) for n ..>. 0 when x(n)= u(n) and the initial conditions are

y(— 1) = --10 and y(— 2) = 5 .

10 2 3 1.3.1

B Consider the interconnection

\ Figure. If hi (1 i ) =

h(n) and the response

x(n)= 8(n + 2)-F 38(n

, 1 1 1 —'

— —

—1)— 48(n

of

21then

LTI systems as shown following

h2 (n)= h3 (n)= (n + l(n) for

calculate the impulse response _ .._ _ T i

of this system to the inpf,

—3).

10

_

1 3 1.3.1

—4,,-. h

ht(27)

4 A For the sequences x 1 (n) = {1,1, 2, 2} and x2 (n) = {1,2,3,4},

determine:

i. linear convolution

ii. circular periodic convolution using DFT / IDFT.

02 . 08

3 31 1.5.1

' -

_

B Determine and sketch the magnitude and phase response of the sequence given below: y(n). x(n)+0.9x(n- 2)- 0.4An -2). [Note: Plot the magnitude and phase response on a graph paper only.] _

10 2 3 1.5.1

5 A Determine 8-point DFT of the sequence x(n)= {2,1,2,1,1,2,1,2} using radix-2 DIT FFT algorithm.

10 3 3 2.5.1

B Determine IDFT of

algorithm: X(1c)

the following sequence using radix-2 DIT-FFT 36,- 4 + j9.656,- 4 + j4,-4 + j1.656, - 4, 1

- 4 - j1.656,-4 - j4,-4 - j9.656 i

10 3 3 2.5.1

A -',Deriverthe bilinearzostransformatioirrnappingmf”lanevcileraridt

zeros into z-plane poles and zeros.

Discuss the advantages and drawbacks of this mapping.

Ili'6 mi..103=0 w&gg,

2

71-41m#

B Design an equivalent

1 H(s)= using

digital filter from an analog filter

impulse invariance method. Assume T

10 4 6

_

1.6.1

s2 +lis+1

- I sec.

7 A Using frequency sampling draw realization diagram which has a symmetric unit response that satisfies the

Hi 27t 15)

method calculate the coefficients and of a linear-phase FIR filter of length 15

sample response and a frequency condition,

fl, k = 0,1,2,3 '

k = 4

0, k =5,6,7

10 4 3 1.5.1

0

B A causal system is represented by the following difference equation.

y(n)+ -1

An -1)= x(n)+ 1 x(n-1) ' 4 2

Determine the system transfer function, impulse response and frequency response of the system. Show the magnitude and phase functions clearly.

10 2 3 1.5.1

2

Bharatiya Vidya Bhavan's

Sardar Patel College of Engineering (A Government Aided Autonomous Institute)

Munshi Nagar, Andheri (West), Mumbai —400058

EXAMINATION September 2018

Program: Electrical Engg. Duration: 1 hr. Maximum Marks: 20 Name of the Course: Electrical Machines-II

Date: September 2018 Course code: PC-BTE503 Semester: V

Instructions: • Solve any 4 questions • Assume suitable data if necessary give justifications for the same

Question Q1) Explain in detail the concept of Armature leakage

reactance.

02 1 3 1.6.1

What do you understand by armature reaction effect with power factor variation of the load? Also explain how it affects the terminal voltage of alternator

03 2 1

1.6.1

Q2) Explain in detail the effect of excitation on armature current and power factor in case of synchronous motor. Draw the associated characteristics diagram.

05 2 3 1.6.1

Q3) A 100 kVA, 3000 V, 50 Hz, 3-phase star connected alternator has effective armature resistance of 0.2 ohm per phase, the field current of 40 A produces short circuit current of 200 A and open circuit emf of 1040 V (Line), Calculate the full load voltage regulation at 0.8 pf lagging and 0.8 pf leading. Draw the phasor diagram.

05 2 3 2.8.4

Q4) Explain in detail the concept of Rohert's MMF method for calculating the voltage regulation of alternator. Also mention the advantages of the same method compared to synchronous impedance method.

05 I 2 3 2.8.4

I Q5) Explain the concept of synchronizing current in case of parallel operation of three phase alternator. Derive an expression for the synchronizing power.

05 2 3 1.6.1

Bharatiya Vidya Bhavan's

Sardar Patel College of Engineering (A Government Aided Autonomous Institute)

Munshi Nagar, Andheri (West), Mumbai —400058

EXAMINATION September 2018

Program: Electrical Engg. Duration: 1 hr. Maximum Marks: 20 Name of the Course: Electrical Machines-II

Date: September 2018 Course code: PC-BTE503 Semester: V

Instructions: • Solve any 4 questions • Assume suitable data if necessary give justifications for the same

Question Q ) Explain in detail the concept of Armature leakage

reactance.

02 1 3 1.6.1

What do you understand by armature reaction effect with power factor variation of the load? Also explain how it affects the terminal voiltage of alternator

03 2 1.6.1

Q2) Explain in detail the effect of excitation on armature current and power factor in case of synchronous motor. Draw the associated characteristics diagram.

05 2 3 1.6.1

Q3) A 100 kVA, 3000 V, 50 Hz, 3-phase star connected alternator has effective armature resistance of 0.2 ohm per phase, the field current of 40 A produces short circuit current of 200 A and open circuit emf of 1040 V (Line), Calculate the full load voltage regulation at 0.8 pf lagging and 0.8 pf leading. Draw the phasor diagram.

05 2 3 2.8.4

Q4) Explain in detail the concept of Rohert's MMF method for calculating the voltage regulation of alternator. Also mention the advantages of the same method compared to synchronous impedance method.

05 I 2 3 2.8.4

Q5) Explain the concept of synchronizing current in case of parallel operation of three phase alternator. Derive an expression for the synchronizing power.

05 2 3 1.6.1