Download POWER SYSTEM LAB

Code No.: ETEE 304
L
T
C
Paper: Power System - II
3
1
4
INSTRUCTIONS TO PAPER SETTERS:
Max. Marks-75
1. Question No. 1 should be compulsory and cover the entire syllabus. This question should have objective or short answer type
questions. It should be of 25 marks.
2. Apart from Q. No.1 rest of the paper shall consist of four units as per the syllabus, every unit should have two questions. However,
student may be asked to attempt only 1 question from each unit. Each question should be 12.5 marks.
Unit – I:
Fault Calculations: Per unit system, calculation of symmetrical and unsymmetrical fault currents in power
system networks using the symmetrical components, use of current limiting reactors.
[No. of Hrs.: 09]
Unit – II:
Protective Relays and circuit Breakers; Basic operating principle, types of relays, distance and inverse definite
minimum time relays, phase and amplitude comparators, development of static relays basic elements of a static
relay.
Fuse: Introduction, Types & Applications.
Circuit Breakers: Principle, Types, Ratings & Applications.
[No. of Hrs.: 12]
Unit – III:
Protective Scheme & Over Voltage Protection
Protection of feeders, merz-price and translays systems, protection of generators and transformers, carrier current
protection, protection against surges, surge diverters, surge absorbers, use of ground wires on transmission lines,
methods of grounding method, insulation coordination.
[No. of Hrs.: 12]
Unit – IV:
Compensation in Power System
Introduction of compensation in power systems, characteristics of uncompensated and compensated lines, series
and shunt compensations elementary concept of FACTS.
[No. of Hrs.: 11]
Text Books:
1. C L Wadhva, “Electrical Power System” Wiley Eastern Ltd., 3rd edition 2000
2. M. L. Soni, P. V. Gupta and U.S. Bhatnagar, “A course in electrical power” Dhanpat Rai & Sons.
Reference Books:
1. Narain G. Hingonani “Understanding FACTS” IEEE Press, year of publication 1999
2. Paul M. Anderson “Power System Protection” IEEE Press.
POWER SYSTEM LAB
ITEM NO. 1
TO MEASURE NEGATIVE SEQUENCE AND ZERO SEQUENCE REACTANCE OF SYNCBRONOUS
MACHINE
MACHINES REQUIRED
M G Set: D C SHUNT MOTOR/3 PHASE ALTERNATOR:
M G Set: DC SHUNT MOTOR/3 PHASE ALTERNATOR SALIENT POLE TYPE (ROTATING FIELD)
DC Motor
Type.
Alternator:
Type
Capacity
RPM
Volts
Insulation
Cooling
Connections
Capacity RPM
Volts Insulation Frequency Power factor Connections
Excitor
Shunt, all the terminals of Armature and field winding shall be brought over to a bakelite
sheet fixed to C I terminal fix fitted on top of Motor.
INSTRUMENTS REQUIRED PORTABLE TYPE
S.No Items
1.
2.
3.
4.
5.
6.
7.
8.
9.
Qty.
M.I. AMMETER PORTABLE 0-2.5/5 A
M.I. VOLTMETER PORT 300/600V
M.I. VOLTMETER PORT 75/1 5 0/3 OOV
RHEOSTAT 1.4 AMP 230 OHMS
RHEOSTAT 1.1 A 1800 OHMS
M.C. VOLTMETER PORT 150/300 V
M.C. AMMETER PORT 1/2 AMP
UPF WATTMETER 2.5/5 AMP, 125/250/500 V
SINGLE PHASE VARIAC 4 A
1
1
1
1
1
1
1
1
1
D.C Shunt Motor 3 HP/AC. Generator 2 KVA (Separately Excited) Salient Pole type
ALTERNATIVELY
TO MEASURE NEGATIVE SEQUENCE AND ZERO SEOUENCE REACTANCE OF SYNCHRONOUS
MACHINE
M G Set: DC SHUNT MOTOR/3 PHASE ALTERNATOR SALIENT POLE TYPE (ROTATING FIELD)
DC Motor
Type.
Capacity
RPM
Volts Insulation
Cooling
Connections
Alternator:
Type
Capacity.
RPM
Volts Insulation
Frequency Power
factor
Connections
Excitor
Type Make
DC Shunt wound, screen protected. Horizontal foot mounted, with interpoles and 3 points
DC Starter, having No volt and overload release coils.
3HP
1500 (controlled variation) 230
Class 'B'
Fan cooled
Shunt, all the terminals of Armature and x field winding shall be brought over to a bakelite
sheet fixed to C I terminal fix fitted on top of Motor.
Salient pole type (Rotating Field type), 3 ph 4 wire screen protected, horizontal foot
mounted, fan cooled, separately excited
2KVA
1500 for max output and frequency of 50 Hz 415V
Class 'B'
50Hz
0.8 p.flagging 3
phase 4 wire
D.C Shunt Generator or Rectifier, 220V, DC through sliprings.
Standard
2
CONTROL PANEL FOR ABOVE EXPERIMENT
Fitted on bakelite sheet 48" x 24" enclosed in almirah type ms box with lock & handle arrangement suitable for table
mounting.
For DC Motor
(i)
MC Voltmeter Flush mounted 96 x 96 mm, 0-300 V
(ii)
MC Ammeter Flush mounted 96 x 96 mm, 0-10 A or 20 Amp
(iii)
Starting Compensator, DC Starter faceplate type.
(iv)
Double Pole Iron clad cutout 32 A, 'HA YELL'S make.
(v)
Field Rheostat 1.4 A, 230 Ohms
For AC Generator
(i)
MI Voltmeter, Flush mounted, 96 x 96 mm, 0-500V
(ii)
MI Ammeter, Flush mounted, 96 x 96 mm, 0-10 A or 5 Amp
(iii)
(iv)
(v)
For Excitor
(i)
(ii)
MCB
Indicating Light.
Shunt field Rheostat
MC Volt meter Flush mounted 96 x 96 mm, 0-300V MC
Ammeter Flush mounted 96 x 96 mm, 0-5 A
D. C Shunt Motor 3 HP/ A. C. Generator 2 KV A (Separately Excited) Salient Pole
type
ADDITIONAL ACCESSORIES
UPF Wattmeter 2.5/5 A, 125/250/500 V
ITEM NO. 2
TOMEASURE:
(a)
DIRECT AXIS AND QUADRATURE AXIS REACTANCE OF SYNCHRONOUS
(b)
MACHINE
DIRECT AXIS AND QUADRATURE AXIS SUBTRANSIENT REACTANCE OF
SYNCHRONOUS MACHINE
MACHINES REOUIRED
M G Set: DC SHUNT MOTOR/3 PHASE ALTERNATOR SALIENT POLE TYPE (ROTATING FIELD)
DC Motor
Type.
DC Shunt wound, screen protected. Horizontal foot mounted, with interpoles and 3 points DC
Starter, having No volt and overload release coils.
Capacity.
RPM Volts
Insulation
Cooling
3HP
1500 (controlled variation) 230
Class 'B'
Fan cooled
Connections
Shunt, all the terminals of Armature and x field winding shall be brought over to a bakelite sheet
fixed to C I terminal fix fitted on top of Motor.
Altemator:
Type
Salient pole type (Rotating Field type), 3 ph 4 wire screen protected, horizontal foot mounted,
fan cooled, separately excited
2KVA
1500 for max output and frequency of 50 Hz 415V
Class 'B'
50Hz
0.8 p.flagging 3
phase 4 wire
Capacity.
RPM
Volts
Insulation
Frequency
Power factor
Connections
Excitor Type
Make
D.C Shunt Generator or Rectifier, 220V, DC through sliprings.
Standard
INSTRUMENTS REOUIRED PORTABLE TYPE
S.No.
Item
1.
2.
3.
4.
5.
6.
7.
M.l. AMMETER POTABLE 0-2.5/5 A
M.I. VOLTMETER PORT 300/600V
M.I. VOLTMETER PORT 75/150/300V
RHEOSTAT 5 AMP 45 OHMS
RHEOSTAT 1.1 A 1800 OHMS
THREE PHASE VARIAC 8 A,
M.C. AMMETER PORTABLE 1/2 A,
Qty.
1
1
1
1
1
1
1
D.C Shunt Motor 3 HP/A.C. Generator 2 KVA (Separately Excited) Salient Pole
type
ALTERNATIVELY
TOMEASURE:
(a)
(b)
DIRECT AXIS AND QUADRATURE AXIS REACTANCE OF SYNCHRONOUS
MACHINE
DIRECT AXIS AND QUADRATURE AXIS SUBTRANSIENT REACTANCE OF
SYNCHRONOUS MACHINE
MACHINES REOUIRED
M G Set: DC SHUNT MOTOR/3 PHASE ALTERNATOR SALIENT POLE TYPE (ROTATING FIELD)
D
Capacity.
C
RPM
Volts
Insulation
Cooling
Connections
M
o
t
o
r
Alternator
Type
Capacity
RPM
Volts
Insulation
Frequency
Power factor
Connections
Excitor
T
y
p
e
.
D
C
S
h
u
n
t
rpoles and 3 points DC Starter, having No volt and overload release coils.
3 HP
1500
230
Class ‘B’
Fan Cooled
Shunt, all the terminals of Armature nad x field winding shall be brought
over to a bakelite sheet fixed to C I terminal fix fitted on top of Motor.
Salient pole type (Rotating Field type), 3 ph 4 wire screen protected,
horizontal foot mounted, fan cooled, separately excited
2 KVA
1500 for max output and frequency of 50 Hz
415 V
Class ‘B’
50 Hz
0.8 p.f lagging
3 phase 4 wire
Type
D.C. Shunt Generator or Rectifier, 220 V, DC through sliprings
w
o
u
CONTROL PANEL
FOR ABOVE EXPERIMENT
n
d sheet 48" x 24" enclosed in almirah type ms box with lock & handle arrangement
Fitted on bakelite
,
suitable for table mounting.
s
For DC Motorc
1. r
MC Voltmeter Flush mounted 96 x 96 rom, 0-300 V
2. e MC Ammeter Flush mounted 96 x 96 mm, 0-10 A or 20
e Amp
3. n Starting Compensator, DC Starter face plate type.
4.
Double Pole Iron clad cutout 32 A, 'HA VELL'S make.
5. p Field Rheostat 1.4 A, 230 Ohms
r
o
For AC Generator
t
1.e
MI Voltmeter, Flush mounted, 96 x 96 mm, 0-500V
2.c
MI Ammeter, Flush mounted, 96 x 96 mm,O-1 0 A or 5
Amp
t
3.e
Knife Switch. TPST.
4.d
Fuses 15 A (Rewireable).
5..
Indicating Light.
6.
Shunt field Rheostat
For Excitor H
o
r Volt meter Flush mounted 96 x 96 mm, 0-300V
1.
MC
i Ammeter Flush mounted 96 x 96 mm, 0-5 A
2.
MC
z
o
n
Additional Accessories
t
a
l
3 Ph Variac 8 Amp
f
o
o
t
m
o
u
n
t
e
d
,
w
i
t
h
i
n
t
e
ITEM NO. 3
TO STUDY THE SINGLE LINE TO GROUND FAULT
This comes under shunt type of fault. These are the fault, which are characterized by increase in current and fall in
voltage. So for lab purpose, we will create the fault condition for our lab study purpose.
Powder Coated m. s. box having locking arrangement with following accessories :1.
Instantaneous Earth Fault (Electro Mechanical Type)
2.
Digital MI Voltmeter
3.
Neon Lamp
4.
DP Switch
5.
Insulating Terminals
6.
Transformers Single Phase
7.
Line Impedances
8.
Variable current Source
9.
Loading CT
10.
Digital Clamp on Meter
All the accessories will be fitted on Bakelite sheet fixed to M.S. box cabinet almirah type suitable for table mounting
with provision for lock and key arrangement.
ITEM NO. 4
TO STUDY LINE TO LINE FAULT
This comes under Shunt type of fault. These are the faults which are characterized by increase in current and
fall in voltage. So, for lab purpose, we will create the fault conditions in our lab.
Powder Coated m.s. box having locking arrangement with following accessories :1.
Three Phase Earth Fault Relay, Static Type
2.
Digital MI Voltmeter
3.
Neon Lamp
4.
TP Switch
5.
Insulating Terminals
6.
Transformers Three Phase
7.
Line Impedances
8.
Variable Current Source
9.
Loading CT
10.
Digital Clamp on Meter
All the accessories will be fitted on Bakelite sheet fixed to M.S. box cabinet almirah type suitable for table mounting
with provision for lock and key arrangement.
The study will be conducted by giving & creating the Impedance by using the Inductor in our schematic diagram.
5.
4.
ITEM NO. 5
I.D.M. T. OVER CURRENT RELAY (ELECTRO MECHANICAL TYPE)
(a)
(b)
To study the construction of the Relay.
To find the operating characteristics of the Relay for two time and current settings.
To determine Reset ration.
(c)
APPARATUS REOUIRED
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Digital AC Voltmeter 0-300 V,
Digital AC Ammeter 0-10 A Digital
Time Totaliser
IDMT Relay' ALSTOM (AREV A)' make
Type CDG-ll Electro Mechanical Type (INVERSE)
1 Ph Variac
Loading CT
Diode Type Rectifier Supply
Multipoint Relay
PushButton
Indicating Light
DP Isolator
Rotary Switch
1 No.
1 No.
1 No.
1 No.
1 No.
1 No.
1 No.
1 No.
2 No.
All the accessories and Relays will be fitted on sheet fixed to M.8. box cabinet almirah type suitable for table mounting
with provision for lock and key arrangement.
ALTERNATIVELY
OVER CURRENT RELAY tELECTRONIC-STA TIC TYPE)
Experimental setup consisting of Digital AC Voltmeter, Digital AC Ammeter, Digital Time Totaliser, Over Current
Relay (Electronic-Static type), 1 Ph Variac, Loading CT, Push Button, Indicating Light, DP Isolator, Rotary Switch.
All the accessories and Relays will be fitted on sheet fixed to M.S. box cabinet almirah type suitable for table mounting
with provision for lock and key arrangement.
ITEM NO. 6
PERCENTAGE DIFFERENTIAL RELAY
(a)
(b)
(c)
To study the construction of relay.
To find the operating characteristics of the Relay.
To calculate % bias and determine minimum operating current.
Apparatus Required
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Percentage Differential Relays ‘Alstom (AREVA) make Type DDT
Digital Time Totaliser
Digital AC Ammeter 0-10 A
DP Isolator
Push Button
Loading CT
Multipoint Relay with Transformer & Rectifier Supply
Rotary Switch
Isolation Transformer
Tubular Rheostat for Differential Current & Through Current
:
:
1 No.
:
:
1 No.
2 No.
:
:
1 No.
2 No.
1 No.
:
1 No.
All the accessories and Relays will be fitted on sheet fixed to M.S. box cabinet almirah type suitable for table mounting with
provision of lock and key arrangement.
6.
ITEMNQ.7
TO STUDY THE INSTANTANEOUS RELAY AND DETERMINE THE PICK UP AND RESET VALUES.
APPARATUS REQUIRED
1.
2.
3.
4.
5.
6.
7.
8.
Instantaneous Relay single phase Type CAG ALSTOM (AREVA) MAKE.
Electromechanical type
Digital MI Ammeter, 0-10 A.
Digital MI Voltmeter 0-300 V
Loading C.T.
Timer
Auto transformer Variac, 0-270V
Indicating Light
DP Isolator
All the accessories and Relays will be fitted on sheet fixed to M.S. box cabinet almirah type suitable for table mounting
with provision for lock and key arrangement.
ITEM NO. 8
THERMAL RELAY & FUSE CHARACTERISTICS
(a)
(i)
(ii)
(b)
To study the time-current characteristics of the given fuse.
To study the construction of the Relay.
To find the operating characteristics of the Relay.
APPARATUS REQUIRED
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Thermal Relay
Digital AC Voltmeter 0-300 V,
:
Digital AC Ammeter 0-10 A
Push Button
Rotary Switch
DP Isolator
Multipoint Relay with transformer & rectifier supply
1 Ph Variac
Loading CT
Digital Time Totaliser
Indicating Light
Fuse Holder
:
1 No.
:
:
1 No.
:
:
:
:
:
:
1 No
1 No
1 No.
2 No.
one each
2 No.
1 No.
2 No.
All the accessories and Relays will be fitted on sheet fixed to M.S. box cabinet almirah type suitable for table
mounting with provision for lock and key arrangement.
ITEM NO. 9
TO STUDY THE EARTH FAULT RELAY OR OVER CURRENT RELAY DETERMINE THE
CHARACTERISTICS.
APPARA TUS REQUIRED
1. Earth Fault or Over Current Relay single phase Type COO (ALSTOM AREV A).
2.
3.
4.
5.
6.
7.
Electromechanical type
Digital MI Ammeter, 0-10 A.
Digital MI Voltmeter 0-300 V
Loading C.T.
Timer
Variable Current Source
Neon lamp, 230 V.
All the accessories and Relays will be fitted on sheet fixed to M.S. box cabinet a1mirah type suitable for table mounting
with provision for lock and key arrangement.
ITEM NO. 10
(A)
STUDY OF OVER VOLTAGE RELAY
Electro Mechanical, inverse time over voltage protection of AC circuits, capacitors and machines such as generator and
synchronous motors.
APPARATUS REQUIRED
(i)
Model VDG-II Over voltage relay' ALSTOM AREV A'
(ii)
(iii)
(iv)
(v)
Digital MI Voltmeter
Variable Current Source
Neon Lamp
Digital Timer
All the accessories and Relays will be fitted on sheet fixed to M.S. Box cabinet almirah type suitable for table mounting
with provision for lock and key arrangement.
(B) STUDY OF UNDER VOLTAGE RELAY
Electro Mechanical, inverse time under voltage protection of AC circuits, capacitors, rectifiers and machines such as
Induction motors.
APPARATUS REQUIRED
1.
2.
3.
4.
5.
Model VDG-13 Under voltage relay' ALSTOM AREV A'
Digital MI Voltmeter
Variable Current Source
Neon Lamp
Digital Timer
All the accessories and Relays will be fitted on sheet fixed to M.S. Box cabinet almirah type suitable for table mounting
with provision for lock and key arrangement.
ITEM NO. 11
(a)
STUDY OF UNDER VOLTAGE RELAY (ELECTRONICS-STATIC TYPE)
Experimental setup consisting of under voltage relay with internal schematic diagram engraved on front panel
board with necessary set points, Digital MI voltmeter, single phase variac, Neon Lamp, Loading CT.
All the accessories and Relays will be fitted on sheet fixed to M.S. Box cabinet almirah type suitable for table mounting
with provision for lock and key arrangement.
(b)
STUDY OF OVER VOLTAGE RELAY (ELECTRONICS – STATIC TYPE)
Experimental setup consisting of Over voltage relay with internal schematic diagram engraved on front panel
board with necessary set points, Digital MI voltmeter, single phase variac, Neon Lamp, Loading CT.
All the accessories and Relays will be fitted on sheet fixed to M.S. Box cabinet almirah type suitable for table mounting
with provision for lock and key arrangement.
ITEM No. 12
EXPERIMENT KIT TO FIND OUT A, B, C, D, PARAMETER, HYBRID PARAMETER AND IMAGE
PARAMETER OF GIVEN TRANSMISSION MODEL.
Transmission line model consisting of four action of transmission on line operatable at 220 V with current rating at 2-A
connected in  network, A continues variable power supply with two digital voltmeter & two digital ammeter, mounted
on front panel fitted in m.s. sheet box complete with patch cords for inter connection & Manual. Detailed calculation
supplied alongwith the setup.
ITEM No. 13
EXPERIMENT SETUP TO STUDY THE PERFORMANCE OF A LONG TRANSMISSION LINE UNDER NO
LOAD AND UNDER LIGHT LOAD CONDITION
Transmission line model consisting of four action of transmission on line operatable at 220 V with current rating at 2 A
connected in  network, A continues variable power supply with two digital voltmeter & two digital ammeter, mounted
on front panel with resistive, inductive, capacitive load fitted in m.s. sheet box complete with patch cords for inter
connection & Manual.
ITEM No. 14
EXPERIMENT KIT TO STUDY THE PERFORMANCE OF A LONG TRANSMISSION LINE UNDER LOAD
AT DIFFERENT POWER FACTORS
Transmission line model consisting of four action of transmission on line operatable at 220 V with current rating at 2 A
connected in  network, A continues variable power supply with two digital voltmeter & two digital ammeter, mounted
on front panel with resistive, inductive, capacitive load fitted in m.s. sheet box complete with patch cords for inter
connection & Manual.
ITEM No. 15
EXPERIMENT KIT TO STUDY THE PERFORMANCE CHARACTERISTICS OF A TYPICAL DC
DISTRIBUTION SYSTEM (RADIAL CONFIGURATION)
DC Distribution network is operatable at 110 V with current rating at 2 A and is consisting of 5 radial distribution with 5
digital ammeter and one voltmeter with variable power supply (0-100V, 2A)
POWER SYSTEM LAB
List of Experiments
1.
2.
To measure negative sequence and zero sequence reactance of syncbronous machine
Tomeasure:
(a)
DIRECT AXIS AND QUADRATURE AXIS REACTANCE OF SYNCHRONOUS
(b)
MACHINE
DIRECT AXIS AND QUADRATURE AXIS SUBTRANSIENT REACTANCE OF
3.
SYNCHRONOUS MACHINE
To Study The Single Line To Ground Fault
4.
To Study Line To Line Fault
5.
To study I.D.M. T. Over current relay (electro mechanical type)
6.
To study Percentage Differential Relay
7.
To study the instantaneous relay and determine the pick up and reset values.
8.
To study Thermal Relay & Fuse Characteristics
9.
To study the earth fault relay or over current relay determine the characteristics.
10.
11.
(A)
Study Of Over Voltage Relay
(B)
Study Of Under Voltage Relay
(a)
Study Of Under Voltage Relay (Electronics-Static Type)
(b)
Study Of Over Voltage Relay (Electronics – Static Type)
12.
Experiment kit to find out a, b, c, d, parameter, hybrid parameter and image parameter of given
transmission model.
13.
Experiment Setup To Study The Performance Of A Long Transmission Line Under No Load And Under
Light Load Condition
14.
Experiment Kit To Study The Performance Of A Long Transmission Line Under Load At Different Power
Factors
15.
Experiment Kit To Study The Performance Characteristics Of A Typical Dc Distribution System (Radial
Configuration)
Transmission And Distribution
1. Witch is usually not the generating voltage ?
(a) 11 KV (b) 6.6 KV (c) 7.7 KV (d) 13.2 KV
2. Highest transmission voltage in India is
(a) 400 Kv (b) 550 KV (c) 700 KV (d) 753 KV
3. Extra high voltage range is
(a) 11KV and above
(b) 100 KV and above
(c) 132 Kv and above
(d) 220 KV and above
4. As overhead conductor, hard drawn copper has the advantage of
(a) high conductivity
(b) high conductivity and high tensile strength
(c) high resistivity
(d) (a) and (b) both
5. Shunt conductance in transmission lines is caused by the
(a) lecage currant (b) capacitance
(c) shunt inductance (d) series resistance loss
6. with increase of line conductor cross-section and system frequency, the skin effect
a) decreases (b) remains independent
(c) increases (d) changes exponentially
7. The of bundle conductor increases
(a) GMR (b) GMD
(c) potential gradient (d) radius of the conductor
8. The inductance of a bundle conductor line is_____than that of the line with one conductor per
Phase
(a) less (b) greter (c) same
9. Transmission voltage can be regulated by
(a) use of tap changing transformers
(b) use of series capacitors to neutralise the effect of series reactence
(c) switching in shunt capacitor at the reaceiving and during heavy loads
(d) any of the above methods
10. The most economic voltage for transmitting power over a distance by transmission lines is
approximately
(a) 0.6 KV/KM (b) 1.6 KV/KM (c) 2.6 KV/KM
(d) 3.6 KV/KM
11. Which type of copperright will have higest tensile strengh
(a) soft drawn (b) medium drawn (c) hard drawn
(d) non of the above
12. Witch of the following is not normally used at 11KV distribution system
(a) single phese-3 wire (b) single phase 4- wire
(c) three phase 4- wire (d) three phase 3- wire
13. High voltage transmission line conductor are suspended from towers
(a) to reduce wind and snow loda
(b) to reduce clearence from ground
(c) to increase clearence from ground
(d) to take care extention in length during summer
14. power loss in transmission line is mainly due to its
(a) impedence (b) cpacitance (c) remain same
(d) inductance
15. if the lentgh of the transmitting tower is reduced the inductance of the line will
(a) increase (b) decrase (c) remain same
(d) non of these
16. the total induntance of two wire overhead line is
where, D= spacing between conductor
r= radious of any of the conductor
17. The capacitance of a two wire line is given by
where, D= spacing between conductor
r= radious of any of the conductor
18. Capacitance between two conductors of a there-phase line being 2 the capacitance of each
condoctor to becomes
(a) 3 μF (b) 6μF (c) 9μF (d) 12 μF
19. If the length of the transmission line is is increased its capacitance will
(a) increase (b) decrease
(c) remain same
(d) none of these
20. The overall dia meter (D) of stranded conductor is given by
(a) D = (2n – 1. d (b) D =(n – 1. d
(c) D = 2 (n – 1. d (d) D = (2n – 1 /d
21. ‘Hessian’ is placed between various layers of strands in stranded conductor used in EHV
transmission in order to
(a) increase the overall conductor diameter
(b) reduce the electrical stress at conductor surface
(c) (a) and (b) both
(d) none of the above
22. A.C. resistance of a line conductor is more then its d.c. resistance beacuse of
(a) skin effect (b) proximity effect
(c) (a) and (b) (d) none of these
23. skin effect of the line conductor increase the effective velue of
(a) reactance of the conductor (b) capacitance of conductor
(c) resistance of the conductor (d) none of these
24. The minimun vertical clearence from the roof of the building to the live wire in 66 Kv system
Must be
(a) 8 feet (b) 12 feet (c) 13 feet (d) 16 feet
25. for the samr resistance of line the ratio
weight of copper conductor___
is
weight of eluminium conductors
(a) 0.50 (b) 0.75 (c) 1.50 (d) 2.0
26. The minimum clearence of low and midium voltage lines from ground accross streets is
(a) 8 fee
t (b) 12 feet
(c) 19 feet
(d) 30 feet
27. When the system frequencey increase, the skin effect is
(a) increased (b) decrease (c) remain same
(d) none of these
28. When the spacing between the conductors is decreased, the inductance of the line
(a) increase (b) decrease (c) remain same (d) none of thease
29. The skin effect of conductor does not depend on
(a) size of wire (b) supply frequency (c) ambient temreture
(d) nature of material
30. With reduction in effective diameter of line conductor, the inductance of the line
(a) increase (b) decrease (c) remain same
(d) none of thease
31. Under no load conditionas the current in atransmission line is due to
(a) spining reserve (b) corona effects
(c) back flow from earth (d) cpacitance of the line
32. ACSR conductor having 7 steel strands surrounded by 25 eluminium conductor will be specified
as
(a) 5/25 (b) 7/32 (c) 25/7 (d)25/32
33. Which of the following not a standerd transmission voltage
(a) 132KV (b) 222KV (c) 400KV (d) 750KV
34. If the hight of transmission tower is increase
(a) the line capacitance and inductance will not change
(b) the line capacitance will increase but the line inductance will decrease
(c) the line capacitance will decrease and line inductance will increase
(d) the line capacitance will decrase but line inductance will remain unchanged
35. In a7/6 A.C.S.R. conductor these are
(a) 35 aluminium conductor and 3 steel conductors
(b) 70 aluminium conductor and 6 steel conductors
(c) 70 steel conductor and 6 aluminium conductors
(d) none of above
36. A gay wire
(a) supports of pole
(b) protects conductor against short-circuiting
(c) provide emergency earth route
(d) provides protection against surges
37. The steel used in ACSR conductors is usually
(a) stainless steel (b) mild steel
(c) alloy steel (d) none of above
38. Line supports for transmission linesshould be of
(a) low cost (b) longer life
(c) high mechenical strangth (d) all of the above
39. Skin effect in a conductor of diameter d can is proportional to
(a)
40. In A.C.S.R. conductprs, the insulation and steel conductors is
(a) bitumen (b) increase thr tensile strangth
(c) insulin (d) no insulation is required
41. In ACSR conductor, steel code provided to
(a) reduce line inductance
(b) increase the tensile strangth
(c) compensate for skin effect
(d) neutralise proximity effect
42. Skin effect depend on
(a) size of the conductor (b) frequency of current
(c) resistivity of the conductor metrial (d) all of the above
43. Line conductor carries more corrent of the surface as compared to core due to
(a) corona (b) skin effect (c) unsymmetrical fault
(d) permeability variation
44. skin effect depends on
(a) frequency of the current
(b) resitivity of the conductor metirial
(c) size of the conductor
(d) all of the above
45 The skin effect of a conductor reduces if
(a) frequency increases
(b) diameter increases
(c) resistivity of conductor metirial increases
(d) permeability of conductor metirial increases
46. Transmission efficiency increases as
(a) voltage increase but power factor decrease
(b) voltage decrease but power factor increase
(c) voltage and power factor both increase
(d) voltage and power factor both decrease
47. The fact that a conductor carries more current on the surface as compeard to core, is known as
(a) corona (b) permeability
(c) unsymmetricalfault (d) skin effect
48. The disadvantage of transmission line as compared to cable is
(a) exposure of lighting
(b) inductive interference between power and communication circuits
(c) exposure of atmospheric hazards like smoke,ice,etc.
(d) all of the above
49. ACSR conductors name
(a) anode current sinsusoidally run
(b) anodised core smooth run
(c) all conductors surfacetreted and realigned
(d) aluminium conductor steel reinforced
50. When the power is to be transmitted overa distance of three hundred KM, the transmission
voltage
Should be in the range
(a)
33KV (b) 66KV (c) 132KV (d) 220/400KV
Switchgear and Protection (DPG-301)
Assignment No. I (2009-10)
Note: Attempt All Questions MM.=25
1. (a) What are the materials used for making the fuse wires? 5
(b) What is the difference between Circuit breaker and the isolator?
(c) Define the terms "fuse rating" and "prospective current" of a fuse.
(d) How does an HRC fuse work?
2. (a) Explain the arc phenomenon in circuit breakers. 10
(b) Classify the circuit breakers on the basis of arc-quenching medium.
(c) Explain low resistance method of arc quenching in circuit breakers.
3. (a) Describe the SF6 circuit breaker with the help of a neat diagram. 10
(b) Explain the construction and working of Earth Leakage Circuit Breaker.
(c) How is a circuit breaker specified
Assignment No. II (2009-10)
Note: Attempt All Questions M.M.=25
1. Define the following terms: 5
i) Switchgear
ii) Protective Relay
iii) Pick-up value of relay
iv) Relay Reach
v) Reset value
vi) Plug Setting Multiplier
vii) Time Setting Multiplier
viii) Reinforcing Relay
ix) Secondary Relay
x) Reset Time
2. (a) What are the fundamental requirements of protective systems? 10
(b) Describe Directional over-current relay with the help of a neat diagram.
(c) What do you understand by symmetrical and asymmetrical faults?
(d) What is the difference between earth fault relay and the over-current relay?
3. (a) Classify the protective relays on the basis of function they perform in the 10
protection of power system.
(b) What do you mean by a short circuit fault?
(c) What is the purpose of current limiting reactors in the power system?
Assignment No. I (2009-10)
4
Note: Attempt All Questions M.M.=25
1. (a) Draw the typical single line diagram for the power system. 5
(b) List the various advantages of using high voltage for transmission line and give
its limitations.
2. (a) Mention the commonly used voltages in India for generation, transmission & 10
Distribution.
(b) State the factors affecting capacitance of time.
3. (a) A 10 km., 3-ph transmission line delivers 8 MW at a p.f. of 0.8 lagging at a line 10
voltage of 11 KV. The impedance of single conductor is (0.1 + j 0.2) ohm/Km.
Find sending end voltage, transmission efficiency & regulation of line.
(b) Explain how the effect of corona can be minimized.
Assignment No. II (2009-10)
Note: Attempt All Questions M.M.=25
1. (a) State the advantages and disadvantages of out door sub stations over indoor sub 10
stations.
(b) Describe briefly the equipments with their specifications needed for an 11 KV
pole mounted sub station.
(c) Explain any one method in detail for locating fault in the underground cable.
(d) In a test for a fault on a 500 m length of cable having a resistance of 1.0 ohm/km.
faulty cable is looped with a sound cable of the same length but having a
resistance of 2.25 ohms/km. The resistances of the other two arms of the testing
network, at balance, are in the ratio of 2.75:1. Calculate the distance of the fault
from the testing end of the cable.
2. (a) What are the advantages of 3 wire d.c. distribution over two wire distribution? 5
(b) Mention advantages of ring main system over the radial system of distribution.
(c) State the properties that the insulation used in under ground cable should have.
3. (a) Three loads, A, B and C are connected to 250 volts supply points through 10
separate cables having resistance of 0.08, 0.1 and 0.12 Ω respectively. A is
joined with B through 0.06 ohm connector and B is joined with C through a
connector of resistance 0.04 Q. If the loads of 40, 60 and 30A are connected at
points A & B and C respectively, determine the voltage at these load points.
(b) A d.c. two wire distributor AB 600 m long is fed with 440 V at point A and 230
V at point B, the distributor is loaded as: lOOAatC, 150m from A;
Electrical Machines II (DPG-302
Assignment No. I (2009-10)
Note: Attempt All Questions M.M.-25
1. (a) Obtain the speed-frequency relationship of synchronous generator. 9
(b) Derive the expression of coil spanfactor and distribution factor
(c) How is armature reaction compensated in synchronous generators?
2. (a) What are the conditions for parallel operation of 3-phase synchronous generators. 9
(b) A 1000 KVA, 6.6 KV, 3-phase, 50 Hz star connected synchronous generator
has a synchronous reactance of 25Ω per phase. It supplies full load
current at 0.8 lagging p.f. and rated terminal voltage. Compute the terminal
voltage for the same excitation when the generator supplies full load current at 0.8
leading p.f.
(c) Explain the dark lamp method of synchronization of synchronous generators.
3. (a) What are the effects of change of prime mover input on the synchronous 7
generator?
(b) Draw and explain the curves between power developed and the power angle for
salient-pole and non-salient pole synchronous generators.
(c) A 2500 V, 3-phase star connected motor has a synchronous reactance of 5Ω per
phase. The motor input is 1000 KW at rated voltage and an excitation emf of
3600 V (line). Calculate the line current and power factor.
POWER SYSTEM –II
Sub. Code: E-401
UNIT I
Faults in power systems, single line diagram, equivalent impedance diagram, per unit
reactances. Analysis (using matrices) of power systems by symmetrical components
under:
(a) Three phase short circuit (b) Line to line fault (c) Line to ground fault (d) Double line
to ground fault.
Sequence networks and their inter connections for different types of faults, effects of fault
impedance.Current Limiting Reactors: Applications, types, construction and location of
current limiting reactors, short circuit calculation using reactors.
UNIT II
Introduction, Bus Admittance Matrix, Formation of Ybus & Zbus, Load flow equation &
solution, iterative methods, Gauss-Seidel and Newton-Raphson methods, Jacobian
Matrix, Fast Decoupled load flow.
UNIT III
Philosophy of protective relaying system, construction and realization of characteristics
of different protective relays. Components of Protection System
Conventional and Static relays – advantages and limitations, static amplitude and phase
comparators, level detectors, logic and training circuits, static over current, directional,
distance relays. Numerical over current and distance protection.
UNIT IV
Types & detection of faults and their effects, alternator protection scheme (stator, rotor,
reverse power protection etc.). Power transformer protection (external and internal faults
protection), bus bar protection. Transmission line protection (current/time grading,
distance, carrier aided protection).
UNIT V
Theory of current interruption- energy balance and recovery rate theory, arc quenching,
recovery and restriking voltages. Types of circuit breakers. bulk oil and minimum oil, air
break and air blast, sulphur hexa floride (SF6) and vacuum circuit breakers. Rating
selection and testing of circuit breakers/operating mechanisms. LT switchgear, HRC
fuses, types construction and applications.
Reference Books :
- Electrical Power Systems - C.L.Wadhwa
- Modern Power System Analysis - Nagrath & Kothari
- Fundamentals of power system protection - Y.G.Paithankar & S.R.Bhinde
- Power System Protection - Badriram & Vishwakarma
- Power System Protection & Switchgear - Ravindranath & Chander
CONTROL SYSTEM –II
Sub. Code: