SlideShare a Scribd company logo
GENERATOR PROTECTION
By – Parimal Bhagat
B.E Electrical, PG Diploma In Sub
T&D(NPTI,Bengaluru)
SYSTEM OVERVIEW
There are two Generator protection panel installed.
GRP Cubicle A & GRP Cubicle B
Both protection cubicles are having following IED’s
1) Micom P344 Generator Protection
2) Micom P342 Generator Protection
3) Micom P141 Excitation Transformer Protection
MICOM P344 RELAY INCORPORATED WITH
FOLLOWING PROTECTIONS
1) Generator Differential Protection (87G)
2) Inter turn fault Protection (50G1)
3) Negative sequence Over Current Protection (46G)
4) Stator Over Load(Current) Protection (50GS)
5) Voltage Restrained Over Current Protection (51V)
6) Dead Machine (61B)
7) Back Up Impedance (21G)
8) Over Fluxing (99G)
9) 95% Stator Earth Fault Protection (64G1)
10) 100% Stator Earth Fault (64G2)
11) Breaker failure (50LBB)
12) Loss Of excitation with under voltage (27/40G)
13) Generator Rotor Earth fault (64F)
14) Generator Pole Slipping(Out of step) Protection (78G)
PROTECTION SCHEME TESTING
Generator Differential Protection (87G)
It operates on principle that current entering & leaving protection zone should be equal. Any
difference between that indicates fault current present in protected zone.
HEALTHY CIRCUIT :
By lenz law secondary current in healthy circuit will be just opposite to primary
current.
Since primary current is equal then circulating current also will be the same.
Id = i1-i2 =0Amp
where i1=i2
Heavy through current arising from external faults can cause one
CT to saturate more than other, resulting in difference between
secondary current produced by each CT’s, its essential to stabilize
the protection for these condition. A biasing technique where the
relay setting increased as the through current increased. The
through current is calculated as the average of the scalar sum of
current entering & leaving the zone of protection, this calculated
through current is then used to apply a percentage bias to increase
the differential setting.
RELAY SETTINGS :
INTER TURN FAULT PROTECTION (50G1)
In healthy 3 phase power system the addition of each phase to earth is normally
zero, as it is vector addition of three balanced vectors at 120° to another.
However when inter turn fault or earth fault occurs on primary system this balance
upset and residual voltage produced.
The neutral displacement voltage can be measured directly via the open delta PT .
RELAY SETTINGS:
STATOR OVER LOAD(50GS)
Protection reacts on current flowing on stator winding coil to protect winding from
overheat.
Overload can result in stator temp. rise which exceeds the thermal limits of windings.
Due to relatively large heat storage capacity of electric machine, infrequent
overload of short duration may not damage the machine, however sustained
overload of few percentage may result in premature aging and failure of insulation.
RELAY SETTINGS :
Over-load (50GS)
PHASE O/C
Menu text
Setting range
Setting
Min Max
I>1 Function
Disabled, DT, IEC S Inverse, IEC V Inverse, IEC E Inverse, UK LT Inverse, UK
Rectifier, RI, IEEE M Inverse, IEEE V Inverse, IEEE E Inverse, US Inverse, US ST
Inverse
DT
I>1 Direction Non-directional, Directional Fwd, Directional Rev Non-directional
I>1 Current Set 0.08 In 4.0 In 4.50A
I>1 Time Delay 0 100 5s (reduce load)
I>2 Function
Disabled, DT, IEC S Inverse, IEC V Inverse, IEC E Inverse, UK LT Inverse, UK
Rectifier, RI, IEEE M Inverse, IEEE V Inverse, IEEE E Inverse, US Inverse, US ST
Inverse
IEC E inverse
I>2 Direction Non-directional, Directional Fwd, Directional Rev Non-directional
I>2 Current Set 0.08 In 4.0 In 4.75A
I>2 Time Delay 0 100
I>2 TMS 0.025 1.2 0.45
VOLTAGE RESTRAINED OVER CURRENT (51V)
This protection reacts on voltage, negative sequence voltage and current as a back up
protection to detect grounding and phase to phase short circuits.
The voltage restrained over current adjust the pickup setting and characteristic curve of the
overcurrent function based on the system voltage. The relay is set pickup current greater
than overload, and sensitivity increase as the voltage drops.
The voltage controlled overcurrent relays uses and under voltage element to the supervise
the operation of overcurrent element.
When voltage drops below the set value the under voltage element permits the operation
of the time over current units.
Voltage Restrained Overcurrent (51V)
I>3 Status Disabled or Enabled Enabled
I>3 Direction Non-directional, Directional Fwd, Directional Rev Non-directional
I>3 Current Set 0.08 In 32 In 5.15A
I>3 Time Delay 0 s 100 s 0.0s
I>Function Link
Bit 0=VTS Blocks I>1, Bit 1=VTS Blocks I>2, Bit 2=VTS Blocks I
>3, Bit 3=VTS Block I>4, Bits 4~7 are not used.
Bit 3=VTS Block I>4
NEGATIVE SEQUENCE OVER CURRENT (46G)
NPS protection is provided to protect generator against the unbalanced load and as a back
up for uncleared unsymmetrical faults.
The Negative sequence current create magnetic flux in the air gap which rotates in
opposition to the rotor. This flux induce eddy current as twice the fundamental frequency in
the rotor which cause overheating of rotor body, wedged and retaining rings. The rotor body
gets heated instantaneously.
RELAY SETTINGS :
95% STATOR EARTH FAULT PROTECTION (64G1)
There is a limit on the percentage of winding that can be protected by stator earth fault
element. For the earth fault close to generator neutral side, the driving voltage will very low
and hence fault current will be severely reduced. In practice approximately 95% of stator
winding will can be protected for the fault in last 5% of winding the fault current is very low
which can not be detected by this type of earth fault.
Single phase earth fault with in 85%-95% range from terminal of stator winding can be
protected by fundamental zero-sequence overvoltage protection.
SCHEME ARRANGEMENT FOR 95% & 100% STATOR
EARTH FAULT PROTECTION :
RELAY SETTING :
100% STATOR EARTH FAULT PROTECTION (64G2)
In this protection 100% stator winding is covered in protection zone. Low probability
fault occurring in 5% of the stator winding near to star point is due to mechanical
damage such as creepage of conductors, loosening of boult etc.
Most of the generator produce third harmonic voltage due to non linearities in
magnetic circuit of generator design, under normal operating condition distribution of
third harmonic voltage along the stator winding. The value increases with the load.
To detect the fault in last 5% of winding the relay is provided with under & over
voltage element.
The third harmonic under voltage element is applicable when the neutral voltage measured
is available at the neutral end of the generator.
To prevent false tripping operation when the machine is dead or under no load condition
power interlock is used to detect load.
SCHEME ARRANGEMENT FOR 95% & 100% STATOR
EARTH FAULT PROTECTION :
RELAY SETTING :
V<Inhibit Set 80V
P<Inhibit set Disabled, Enabled Enabled
P<Inhibit set 20.00W
Q<Inhibit set Disabled, Enabled Disabled
S<Inhibit set Disabled, Enabled Disabled
POLE SLIPPING PROTECTION (78G)
Sudden changes or shock in electrical system such as line switching operation, transient
system fault, generator governor failure, excitation system failure, reconnection of islanding
system without synchronization, large jumps in load or fault may lead to power system
oscillations which appears as regular variations of current and angular separation between
systems.
At times, this power swing becomes so sever that it can lead lost of synchronism between
generator and system, this condition recognized as out of step or pole slipping.
OVER FLUXING PROTECTION (99G)
Over fluxing or over excitation of generator can increase if the ratio of voltage to
frequency (V/HZ) increased certain limits. High voltage or low frequency can rise V/Hz
ratio, it will produce high flux densities in magnetic core of machines, this can cause core of
generator to be saturated & stary flux to be induced in un laminated components that have
not been designed to carry this flux, the resulting eddy current in solid components (e.g. core,
bolts & supporting structure) can cause rapid overheating & damage.
Over fluxing likely to occur during machine start up & shutdown while the generator is not
connected to the system.
Failure in automatic control of excitation system or errors in manual control of machine field
current, could allow excessive voltage to be generated.
Sudden loss of load could cause an overvoltage condition, if generator excitation system
does not respond properly.
BREAKER FAILURE PROTECTION (50LBB)
The LBB protection is used as back up protection of main protection, during this
protection, relay sense the breaker position, flow of current & trip command
generated by itself.
RELAY SETTINGS
BACK UP IMPEDANCE PROTECTION (27G)
Generator is source of power & it will supply fault current until they are cleared by
the protection system.
Back up protection applied at the generator so that faults are cleared in the event of
downstream protection/breaker fails to operate.
Under impedance element is set to monitor the system impedance at machine
terminal, if the measured impedance falls below set value then relay will operate.
DEAD MACHINE (61B)
Accidental energization of breaker when machine is not running can cause severe
damage to machine.
If the breaker is closed when machine is not running then generator will began act as
induction motor with the surface of rotor core & rotor winding slot wedges acting as
rotor conductor ,this abnormal current will result in overheating and damaged.
The relay element is enabled when the machine is not running ,there for element can
have very low current setting, the undervoltage threshold typically set to 85% of
nominal voltage to ensure that machine is not running.
RELAY SETTINGS :
LOSS OF EXCITATION WITH UNDER
VOLTAGE(27/40)
Complete loss of excitation may arise as a result of accidental tripping of excitation
system, failure of field breaker , an open circuit or short circuit happened in DC
circuit, flashover of any slip ring or failure of excitation source.
When excitation of synchronous generator fails its internal emf will decay and output
of active power will reduce and it will draw large reactive power grid, hence
machine will act as a induction generator, after filed failure circulating current will
induce in rotor core and rotor heat, also stator winding may get damaged severely.
RELAY SETTING
ROTOR GROUND FAULT PROTECTION (64R)
The Generator rotor earth fault protection is provided to protect the generator rotor
and exciter rotor winding against earth fault. The rotor earth fault relay sense the
resistance between rotor winding and ground through carbon brushes mounted on slip
rings.
MICOM P342 RELAY INCORPORATED WITH FOLLOWING
PROTECTIONS :
1. Low Forward Power Protection (37G)
2. Reverse Power Protection (32G)
3. Under frequency Protection (81U)
4. Over frequency Protection (81O)
5. Over Voltage Protection (59G)
6. Under Voltage Protection (27G)
7. Generator Stator Water flow minimum
8. Excitation system failure
9. Excitation transformer temp. high
LOW FORWARD POWER PROTECTION (37G)
When machine is generating and CB connecting the generator to the system is
tripped, the electrical load on the generator is cut, this could lead to generator over
speed if the machine input power is not reduced quickly.
Trapped system in the turbine, risk of over speed damage to such sets, interlock is
used for non urgent tripping of the generator breaker and excitation system with a
low forward power check.
Relay Settings
REVERSE POWER PROTECTION (32G)
It is back up protection to low forward protection. If the generator prime mover falls,
generator is connected in parallel with another source of electrical supply will begin as
“Motor” . The generator will operator as a synchronous motor and drive the turbine. Here in
this condition draw the real power (MW) from the bus & and export reactive power (MVAR)
to grid.
If the filed breaker closed but field current is zero, the generator will act as an induction
motor. Here in this condition generator will draw real power as well as reactive power from
the grid
In this condition generator will not be harmed by synchronous motoring but steam
turbine can be harmed due to winding loss of causing overheating of turbine blade if
continued long enough.
The sensitivity and setting of the relay is depending on the type of prime movers.
Causes of Reverse Power Protection :
Two or more machines are running in parallel and prime mover of machine fails.
RELAY SETTINGS
OVER VOLTAGE (59G)
The over voltage protection will act as a back up protection of the over fluxing
protection. The over voltage protection is required to protect the stator conductor
insulation of the generator. This is directly connected to Gen. phase side PT secondary
terminals.
Causes of over voltage :
Prime mover over speed due to sudden loss of load.
Voltage regulator (AVR) is defective.
RELAY SETTING
OVER FREQUENCY PROTECTION (81O)
The over frequency protection is provided to protect the generator against over
speed. Sever high speed operation of generator set could result in damaged.
Causes of over frequency :
Demand of active power suddenly decreased in power grid
Full or partial load rejection (Load thrown off)
Over shedding of load during major disturbance. Generator CB oprn during load.
RELAY SETTING :
UNDER FREQUENCY PROTECTION (81U)
The under frequency protection is used to protect the generator against operation at
low frequency.
If the frequency goes down, the speed of turbine get reduced, hence the steam may
get condensed on turbine blades and damage them.
Causes of under frequency :
Demand of active power suddenly increased in grid.
Islanded system two or more system running in parallel on more than 70% load &
outage of nay machine due to fault increased the load to another machine will result
in under frequency operation.
RELAY SETTING :
UNDER VOLTAGE (27G)
Generator are usually designed to operate continuously at a minimum voltage of 95% of its
rated voltage, while generate power at rated frequency.
Generator terminal voltage goes lower than 85% of its rated voltage may result in
undesirable effects such as reduction in stability limits, import of excessive reactive power
from grid, malfunctioning of voltage sensing devices and equipment.
The under voltage relay works in secondary value if PT which is connected with generator
output terminals.
RELAY SETTING:
NON DIRECT PROTECTION
❑Generator stator water flow minimum
Generator CW flow minimum link to be closed, protection simulated from C&I cabinet ( if
stator water pump not running then signal will come high)
❑Excitation system fault
Protection simulated from AVR end at micom P342 relay assigned o/p becomes high & EXT
trip LED becomes high.
❑Excitation transformer temp. high
Protection simulated from excitation transformer end for low setting at P342 relay o/p
assigned becomes high.
For high setting at P342 assigned relay becomes high.
Thank You

More Related Content

What's hot

Practical handbook-for-relay-protection-engineers
Practical handbook-for-relay-protection-engineersPractical handbook-for-relay-protection-engineers
Practical handbook-for-relay-protection-engineers
SARAVANAN A
 
Switch yard & Protection
Switch yard & ProtectionSwitch yard & Protection
Switch yard & Protection
MANOJ KUMAR MAHARANA
 
Electrical substation (one and half breaker scheme)
Electrical substation (one and half breaker scheme)Electrical substation (one and half breaker scheme)
Electrical substation (one and half breaker scheme)
Sourabh sharma
 
On load tap changer
On load tap changerOn load tap changer
On load tap changer
Sourabh sharma
 
Protection of three phase synchronous generator
Protection of three phase synchronous generatorProtection of three phase synchronous generator
Protection of three phase synchronous generator
Mohammad Abdullah
 
Generator protection by a. kato
Generator protection by a. katoGenerator protection by a. kato
Generator protection by a. kato
Agrey Kato
 
Loss of excitation
Loss of excitationLoss of excitation
Loss of excitation
NTPC
 
Unit 04 Protection of generators and transformers
Unit  04 Protection of generators and transformers Unit  04 Protection of generators and transformers
Unit 04 Protection of generators and transformers
PremanandDesai
 
Motor Protection
Motor ProtectionMotor Protection
Motor Protection
michaeljmack
 
Ppt on protection of power transformers
Ppt on protection of power transformersPpt on protection of power transformers
Ppt on protection of power transformers
siddharam kantoli
 
Rotor earth fault protection of electric generator
Rotor earth fault protection of electric generatorRotor earth fault protection of electric generator
Rotor earth fault protection of electric generator
CS V
 
Generator protection
Generator protectionGenerator protection
Generator protectionKeshar Rawal
 
Generator capability curve
Generator capability curve Generator capability curve
Generator capability curve
Ashish Kumar Jain
 
Esp rectifier transformer
Esp rectifier transformerEsp rectifier transformer
Esp rectifier transformer
Molla Morshad
 
SWITCHYARD EQUIPMENTS & PROTECTION SYSTEMS
SWITCHYARD EQUIPMENTS & PROTECTION SYSTEMSSWITCHYARD EQUIPMENTS & PROTECTION SYSTEMS
SWITCHYARD EQUIPMENTS & PROTECTION SYSTEMSPartha Parida
 
Power Transformer in DPL
Power Transformer in DPLPower Transformer in DPL
Power Transformer in DPL
Abhishek Roy
 
Circuit interruption
Circuit interruptionCircuit interruption
Circuit interruption
jawaharramaya
 
Power transformer protection
Power transformer protectionPower transformer protection
Power transformer protection
michaeljmack
 

What's hot (20)

Practical handbook-for-relay-protection-engineers
Practical handbook-for-relay-protection-engineersPractical handbook-for-relay-protection-engineers
Practical handbook-for-relay-protection-engineers
 
Switch yard & Protection
Switch yard & ProtectionSwitch yard & Protection
Switch yard & Protection
 
Electrical substation (one and half breaker scheme)
Electrical substation (one and half breaker scheme)Electrical substation (one and half breaker scheme)
Electrical substation (one and half breaker scheme)
 
Transformers
TransformersTransformers
Transformers
 
On load tap changer
On load tap changerOn load tap changer
On load tap changer
 
Protection of three phase synchronous generator
Protection of three phase synchronous generatorProtection of three phase synchronous generator
Protection of three phase synchronous generator
 
Generator protection by a. kato
Generator protection by a. katoGenerator protection by a. kato
Generator protection by a. kato
 
Loss of excitation
Loss of excitationLoss of excitation
Loss of excitation
 
Unit 04 Protection of generators and transformers
Unit  04 Protection of generators and transformers Unit  04 Protection of generators and transformers
Unit 04 Protection of generators and transformers
 
Motor Protection
Motor ProtectionMotor Protection
Motor Protection
 
Ppt on protection of power transformers
Ppt on protection of power transformersPpt on protection of power transformers
Ppt on protection of power transformers
 
Rotor earth fault protection of electric generator
Rotor earth fault protection of electric generatorRotor earth fault protection of electric generator
Rotor earth fault protection of electric generator
 
Generator protection
Generator protectionGenerator protection
Generator protection
 
Generator capability curve
Generator capability curve Generator capability curve
Generator capability curve
 
Esp rectifier transformer
Esp rectifier transformerEsp rectifier transformer
Esp rectifier transformer
 
Out of step
Out of stepOut of step
Out of step
 
SWITCHYARD EQUIPMENTS & PROTECTION SYSTEMS
SWITCHYARD EQUIPMENTS & PROTECTION SYSTEMSSWITCHYARD EQUIPMENTS & PROTECTION SYSTEMS
SWITCHYARD EQUIPMENTS & PROTECTION SYSTEMS
 
Power Transformer in DPL
Power Transformer in DPLPower Transformer in DPL
Power Transformer in DPL
 
Circuit interruption
Circuit interruptionCircuit interruption
Circuit interruption
 
Power transformer protection
Power transformer protectionPower transformer protection
Power transformer protection
 

Similar to Generator protection

Protection & switchgear
Protection & switchgear  Protection & switchgear
Protection & switchgear
johny renoald
 
Generator protection
Generator protectionGenerator protection
Generator protection
SSVASAVA
 
MTA GENERATOR PROTECTION .PPT.pptx
MTA GENERATOR PROTECTION .PPT.pptxMTA GENERATOR PROTECTION .PPT.pptx
MTA GENERATOR PROTECTION .PPT.pptx
rajkumarmaurya31
 
An-Overview-of-Protection-System-Analysis-3.pdf
An-Overview-of-Protection-System-Analysis-3.pdfAn-Overview-of-Protection-System-Analysis-3.pdf
An-Overview-of-Protection-System-Analysis-3.pdf
RamprasadSarkar1
 
442639191-Generator-Protection-ppt.ppt
442639191-Generator-Protection-ppt.ppt442639191-Generator-Protection-ppt.ppt
442639191-Generator-Protection-ppt.ppt
sanipriadi1
 
class on Protection.pptx
class on Protection.pptxclass on Protection.pptx
class on Protection.pptx
SubhroSen9
 
Generator Protection By - Er Rahul Sharma
Generator Protection By - Er Rahul Sharma Generator Protection By - Er Rahul Sharma
Generator Protection By - Er Rahul Sharma
Rahul Ruddra
 
Generator protection by bhushan kumbhalkar
Generator protection by bhushan kumbhalkarGenerator protection by bhushan kumbhalkar
Generator protection by bhushan kumbhalkar
Bhushan Kumbhalkar
 
Generator protection LEC 2
Generator protection  LEC 2Generator protection  LEC 2
Generator protection LEC 2
Rahaf Waheep
 
protection Training.pptx
protection Training.pptxprotection Training.pptx
protection Training.pptx
MAHMOUDMOHAMED431205
 
Generator Transformer Protections.
Generator Transformer  Protections.Generator Transformer  Protections.
Generator Transformer Protections.
Nischal Popat
 
Major faults in an alternator and their protection.
Major faults in an alternator and their protection.Major faults in an alternator and their protection.
Major faults in an alternator and their protection.
javid iqbal sodagar
 
Backup fault protection for generators in case of a failure at the generation...
Backup fault protection for generators in case of a failure at the generation...Backup fault protection for generators in case of a failure at the generation...
Backup fault protection for generators in case of a failure at the generation...
Mohammad Raza
 
Protection Systems for Power generators
Protection Systems for Power generators Protection Systems for Power generators
Protection Systems for Power generators
Nicholas Naing
 
Report BQPS II- Saad Janjua
Report BQPS II- Saad JanjuaReport BQPS II- Saad Janjua
Report BQPS II- Saad JanjuaSaad Janjua
 
5010566.ppt
5010566.ppt5010566.ppt
5010566.ppt
Nafir Anas
 
Switch gear and protection
Switch gear and protectionSwitch gear and protection
Switch gear and protection
Dinesh Sharma
 
An Overview Of Agbami Fpso Electrical Power System
An Overview Of Agbami Fpso Electrical Power SystemAn Overview Of Agbami Fpso Electrical Power System
An Overview Of Agbami Fpso Electrical Power System
vkmalik
 
presentation_generator_protection.pptx
presentation_generator_protection.pptxpresentation_generator_protection.pptx
presentation_generator_protection.pptx
vasan35
 

Similar to Generator protection (20)

Protection & switchgear
Protection & switchgear  Protection & switchgear
Protection & switchgear
 
Generator protection
Generator protectionGenerator protection
Generator protection
 
MTA GENERATOR PROTECTION .PPT.pptx
MTA GENERATOR PROTECTION .PPT.pptxMTA GENERATOR PROTECTION .PPT.pptx
MTA GENERATOR PROTECTION .PPT.pptx
 
An-Overview-of-Protection-System-Analysis-3.pdf
An-Overview-of-Protection-System-Analysis-3.pdfAn-Overview-of-Protection-System-Analysis-3.pdf
An-Overview-of-Protection-System-Analysis-3.pdf
 
442639191-Generator-Protection-ppt.ppt
442639191-Generator-Protection-ppt.ppt442639191-Generator-Protection-ppt.ppt
442639191-Generator-Protection-ppt.ppt
 
class on Protection.pptx
class on Protection.pptxclass on Protection.pptx
class on Protection.pptx
 
Generator Protection By - Er Rahul Sharma
Generator Protection By - Er Rahul Sharma Generator Protection By - Er Rahul Sharma
Generator Protection By - Er Rahul Sharma
 
Generator protection by bhushan kumbhalkar
Generator protection by bhushan kumbhalkarGenerator protection by bhushan kumbhalkar
Generator protection by bhushan kumbhalkar
 
Generator protection LEC 2
Generator protection  LEC 2Generator protection  LEC 2
Generator protection LEC 2
 
protection Training.pptx
protection Training.pptxprotection Training.pptx
protection Training.pptx
 
Generator Transformer Protections.
Generator Transformer  Protections.Generator Transformer  Protections.
Generator Transformer Protections.
 
Major faults in an alternator and their protection.
Major faults in an alternator and their protection.Major faults in an alternator and their protection.
Major faults in an alternator and their protection.
 
Backup fault protection for generators in case of a failure at the generation...
Backup fault protection for generators in case of a failure at the generation...Backup fault protection for generators in case of a failure at the generation...
Backup fault protection for generators in case of a failure at the generation...
 
Protection of alternator
Protection of alternatorProtection of alternator
Protection of alternator
 
Protection Systems for Power generators
Protection Systems for Power generators Protection Systems for Power generators
Protection Systems for Power generators
 
Report BQPS II- Saad Janjua
Report BQPS II- Saad JanjuaReport BQPS II- Saad Janjua
Report BQPS II- Saad Janjua
 
5010566.ppt
5010566.ppt5010566.ppt
5010566.ppt
 
Switch gear and protection
Switch gear and protectionSwitch gear and protection
Switch gear and protection
 
An Overview Of Agbami Fpso Electrical Power System
An Overview Of Agbami Fpso Electrical Power SystemAn Overview Of Agbami Fpso Electrical Power System
An Overview Of Agbami Fpso Electrical Power System
 
presentation_generator_protection.pptx
presentation_generator_protection.pptxpresentation_generator_protection.pptx
presentation_generator_protection.pptx
 

Recently uploaded

CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptx
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxCFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptx
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptx
R&R Consult
 
Planning Of Procurement o different goods and services
Planning Of Procurement o different goods and servicesPlanning Of Procurement o different goods and services
Planning Of Procurement o different goods and services
JoytuBarua2
 
Design and Analysis of Algorithms-DP,Backtracking,Graphs,B&B
Design and Analysis of Algorithms-DP,Backtracking,Graphs,B&BDesign and Analysis of Algorithms-DP,Backtracking,Graphs,B&B
Design and Analysis of Algorithms-DP,Backtracking,Graphs,B&B
Sreedhar Chowdam
 
LIGA(E)11111111111111111111111111111111111111111.ppt
LIGA(E)11111111111111111111111111111111111111111.pptLIGA(E)11111111111111111111111111111111111111111.ppt
LIGA(E)11111111111111111111111111111111111111111.ppt
ssuser9bd3ba
 
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdf
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdfHybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdf
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdf
fxintegritypublishin
 
Top 10 Oil and Gas Projects in Saudi Arabia 2024.pdf
Top 10 Oil and Gas Projects in Saudi Arabia 2024.pdfTop 10 Oil and Gas Projects in Saudi Arabia 2024.pdf
Top 10 Oil and Gas Projects in Saudi Arabia 2024.pdf
Teleport Manpower Consultant
 
MCQ Soil mechanics questions (Soil shear strength).pdf
MCQ Soil mechanics questions (Soil shear strength).pdfMCQ Soil mechanics questions (Soil shear strength).pdf
MCQ Soil mechanics questions (Soil shear strength).pdf
Osamah Alsalih
 
ASME IX(9) 2007 Full Version .pdf
ASME IX(9)  2007 Full Version       .pdfASME IX(9)  2007 Full Version       .pdf
ASME IX(9) 2007 Full Version .pdf
AhmedHussein950959
 
WATER CRISIS and its solutions-pptx 1234
WATER CRISIS and its solutions-pptx 1234WATER CRISIS and its solutions-pptx 1234
WATER CRISIS and its solutions-pptx 1234
AafreenAbuthahir2
 
Standard Reomte Control Interface - Neometrix
Standard Reomte Control Interface - NeometrixStandard Reomte Control Interface - Neometrix
Standard Reomte Control Interface - Neometrix
Neometrix_Engineering_Pvt_Ltd
 
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)
MdTanvirMahtab2
 
Student information management system project report ii.pdf
Student information management system project report ii.pdfStudent information management system project report ii.pdf
Student information management system project report ii.pdf
Kamal Acharya
 
Immunizing Image Classifiers Against Localized Adversary Attacks
Immunizing Image Classifiers Against Localized Adversary AttacksImmunizing Image Classifiers Against Localized Adversary Attacks
Immunizing Image Classifiers Against Localized Adversary Attacks
gerogepatton
 
Final project report on grocery store management system..pdf
Final project report on grocery store management system..pdfFinal project report on grocery store management system..pdf
Final project report on grocery store management system..pdf
Kamal Acharya
 
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...
Amil Baba Dawood bangali
 
weather web application report.pdf
weather web application report.pdfweather web application report.pdf
weather web application report.pdf
Pratik Pawar
 
The role of big data in decision making.
The role of big data in decision making.The role of big data in decision making.
The role of big data in decision making.
ankuprajapati0525
 
Water Industry Process Automation and Control Monthly - May 2024.pdf
Water Industry Process Automation and Control Monthly - May 2024.pdfWater Industry Process Automation and Control Monthly - May 2024.pdf
Water Industry Process Automation and Control Monthly - May 2024.pdf
Water Industry Process Automation & Control
 
Cosmetic shop management system project report.pdf
Cosmetic shop management system project report.pdfCosmetic shop management system project report.pdf
Cosmetic shop management system project report.pdf
Kamal Acharya
 
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSE
TECHNICAL TRAINING MANUAL   GENERAL FAMILIARIZATION COURSETECHNICAL TRAINING MANUAL   GENERAL FAMILIARIZATION COURSE
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSE
DuvanRamosGarzon1
 

Recently uploaded (20)

CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptx
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxCFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptx
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptx
 
Planning Of Procurement o different goods and services
Planning Of Procurement o different goods and servicesPlanning Of Procurement o different goods and services
Planning Of Procurement o different goods and services
 
Design and Analysis of Algorithms-DP,Backtracking,Graphs,B&B
Design and Analysis of Algorithms-DP,Backtracking,Graphs,B&BDesign and Analysis of Algorithms-DP,Backtracking,Graphs,B&B
Design and Analysis of Algorithms-DP,Backtracking,Graphs,B&B
 
LIGA(E)11111111111111111111111111111111111111111.ppt
LIGA(E)11111111111111111111111111111111111111111.pptLIGA(E)11111111111111111111111111111111111111111.ppt
LIGA(E)11111111111111111111111111111111111111111.ppt
 
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdf
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdfHybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdf
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdf
 
Top 10 Oil and Gas Projects in Saudi Arabia 2024.pdf
Top 10 Oil and Gas Projects in Saudi Arabia 2024.pdfTop 10 Oil and Gas Projects in Saudi Arabia 2024.pdf
Top 10 Oil and Gas Projects in Saudi Arabia 2024.pdf
 
MCQ Soil mechanics questions (Soil shear strength).pdf
MCQ Soil mechanics questions (Soil shear strength).pdfMCQ Soil mechanics questions (Soil shear strength).pdf
MCQ Soil mechanics questions (Soil shear strength).pdf
 
ASME IX(9) 2007 Full Version .pdf
ASME IX(9)  2007 Full Version       .pdfASME IX(9)  2007 Full Version       .pdf
ASME IX(9) 2007 Full Version .pdf
 
WATER CRISIS and its solutions-pptx 1234
WATER CRISIS and its solutions-pptx 1234WATER CRISIS and its solutions-pptx 1234
WATER CRISIS and its solutions-pptx 1234
 
Standard Reomte Control Interface - Neometrix
Standard Reomte Control Interface - NeometrixStandard Reomte Control Interface - Neometrix
Standard Reomte Control Interface - Neometrix
 
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)
 
Student information management system project report ii.pdf
Student information management system project report ii.pdfStudent information management system project report ii.pdf
Student information management system project report ii.pdf
 
Immunizing Image Classifiers Against Localized Adversary Attacks
Immunizing Image Classifiers Against Localized Adversary AttacksImmunizing Image Classifiers Against Localized Adversary Attacks
Immunizing Image Classifiers Against Localized Adversary Attacks
 
Final project report on grocery store management system..pdf
Final project report on grocery store management system..pdfFinal project report on grocery store management system..pdf
Final project report on grocery store management system..pdf
 
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...
 
weather web application report.pdf
weather web application report.pdfweather web application report.pdf
weather web application report.pdf
 
The role of big data in decision making.
The role of big data in decision making.The role of big data in decision making.
The role of big data in decision making.
 
Water Industry Process Automation and Control Monthly - May 2024.pdf
Water Industry Process Automation and Control Monthly - May 2024.pdfWater Industry Process Automation and Control Monthly - May 2024.pdf
Water Industry Process Automation and Control Monthly - May 2024.pdf
 
Cosmetic shop management system project report.pdf
Cosmetic shop management system project report.pdfCosmetic shop management system project report.pdf
Cosmetic shop management system project report.pdf
 
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSE
TECHNICAL TRAINING MANUAL   GENERAL FAMILIARIZATION COURSETECHNICAL TRAINING MANUAL   GENERAL FAMILIARIZATION COURSE
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSE
 

Generator protection

  • 1. GENERATOR PROTECTION By – Parimal Bhagat B.E Electrical, PG Diploma In Sub T&D(NPTI,Bengaluru)
  • 2. SYSTEM OVERVIEW There are two Generator protection panel installed. GRP Cubicle A & GRP Cubicle B Both protection cubicles are having following IED’s 1) Micom P344 Generator Protection 2) Micom P342 Generator Protection 3) Micom P141 Excitation Transformer Protection
  • 3. MICOM P344 RELAY INCORPORATED WITH FOLLOWING PROTECTIONS 1) Generator Differential Protection (87G) 2) Inter turn fault Protection (50G1) 3) Negative sequence Over Current Protection (46G) 4) Stator Over Load(Current) Protection (50GS) 5) Voltage Restrained Over Current Protection (51V) 6) Dead Machine (61B) 7) Back Up Impedance (21G) 8) Over Fluxing (99G)
  • 4. 9) 95% Stator Earth Fault Protection (64G1) 10) 100% Stator Earth Fault (64G2) 11) Breaker failure (50LBB) 12) Loss Of excitation with under voltage (27/40G) 13) Generator Rotor Earth fault (64F) 14) Generator Pole Slipping(Out of step) Protection (78G)
  • 5. PROTECTION SCHEME TESTING Generator Differential Protection (87G) It operates on principle that current entering & leaving protection zone should be equal. Any difference between that indicates fault current present in protected zone.
  • 7. By lenz law secondary current in healthy circuit will be just opposite to primary current. Since primary current is equal then circulating current also will be the same. Id = i1-i2 =0Amp where i1=i2
  • 8. Heavy through current arising from external faults can cause one CT to saturate more than other, resulting in difference between secondary current produced by each CT’s, its essential to stabilize the protection for these condition. A biasing technique where the relay setting increased as the through current increased. The through current is calculated as the average of the scalar sum of current entering & leaving the zone of protection, this calculated through current is then used to apply a percentage bias to increase the differential setting.
  • 9.
  • 11. INTER TURN FAULT PROTECTION (50G1) In healthy 3 phase power system the addition of each phase to earth is normally zero, as it is vector addition of three balanced vectors at 120° to another. However when inter turn fault or earth fault occurs on primary system this balance upset and residual voltage produced. The neutral displacement voltage can be measured directly via the open delta PT .
  • 13. STATOR OVER LOAD(50GS) Protection reacts on current flowing on stator winding coil to protect winding from overheat. Overload can result in stator temp. rise which exceeds the thermal limits of windings. Due to relatively large heat storage capacity of electric machine, infrequent overload of short duration may not damage the machine, however sustained overload of few percentage may result in premature aging and failure of insulation.
  • 14. RELAY SETTINGS : Over-load (50GS) PHASE O/C Menu text Setting range Setting Min Max I>1 Function Disabled, DT, IEC S Inverse, IEC V Inverse, IEC E Inverse, UK LT Inverse, UK Rectifier, RI, IEEE M Inverse, IEEE V Inverse, IEEE E Inverse, US Inverse, US ST Inverse DT I>1 Direction Non-directional, Directional Fwd, Directional Rev Non-directional I>1 Current Set 0.08 In 4.0 In 4.50A I>1 Time Delay 0 100 5s (reduce load) I>2 Function Disabled, DT, IEC S Inverse, IEC V Inverse, IEC E Inverse, UK LT Inverse, UK Rectifier, RI, IEEE M Inverse, IEEE V Inverse, IEEE E Inverse, US Inverse, US ST Inverse IEC E inverse I>2 Direction Non-directional, Directional Fwd, Directional Rev Non-directional I>2 Current Set 0.08 In 4.0 In 4.75A I>2 Time Delay 0 100 I>2 TMS 0.025 1.2 0.45
  • 15. VOLTAGE RESTRAINED OVER CURRENT (51V) This protection reacts on voltage, negative sequence voltage and current as a back up protection to detect grounding and phase to phase short circuits. The voltage restrained over current adjust the pickup setting and characteristic curve of the overcurrent function based on the system voltage. The relay is set pickup current greater than overload, and sensitivity increase as the voltage drops. The voltage controlled overcurrent relays uses and under voltage element to the supervise the operation of overcurrent element. When voltage drops below the set value the under voltage element permits the operation of the time over current units.
  • 16. Voltage Restrained Overcurrent (51V) I>3 Status Disabled or Enabled Enabled I>3 Direction Non-directional, Directional Fwd, Directional Rev Non-directional I>3 Current Set 0.08 In 32 In 5.15A I>3 Time Delay 0 s 100 s 0.0s I>Function Link Bit 0=VTS Blocks I>1, Bit 1=VTS Blocks I>2, Bit 2=VTS Blocks I >3, Bit 3=VTS Block I>4, Bits 4~7 are not used. Bit 3=VTS Block I>4
  • 17. NEGATIVE SEQUENCE OVER CURRENT (46G) NPS protection is provided to protect generator against the unbalanced load and as a back up for uncleared unsymmetrical faults. The Negative sequence current create magnetic flux in the air gap which rotates in opposition to the rotor. This flux induce eddy current as twice the fundamental frequency in the rotor which cause overheating of rotor body, wedged and retaining rings. The rotor body gets heated instantaneously.
  • 19. 95% STATOR EARTH FAULT PROTECTION (64G1) There is a limit on the percentage of winding that can be protected by stator earth fault element. For the earth fault close to generator neutral side, the driving voltage will very low and hence fault current will be severely reduced. In practice approximately 95% of stator winding will can be protected for the fault in last 5% of winding the fault current is very low which can not be detected by this type of earth fault. Single phase earth fault with in 85%-95% range from terminal of stator winding can be protected by fundamental zero-sequence overvoltage protection.
  • 20. SCHEME ARRANGEMENT FOR 95% & 100% STATOR EARTH FAULT PROTECTION :
  • 22. 100% STATOR EARTH FAULT PROTECTION (64G2) In this protection 100% stator winding is covered in protection zone. Low probability fault occurring in 5% of the stator winding near to star point is due to mechanical damage such as creepage of conductors, loosening of boult etc. Most of the generator produce third harmonic voltage due to non linearities in magnetic circuit of generator design, under normal operating condition distribution of third harmonic voltage along the stator winding. The value increases with the load. To detect the fault in last 5% of winding the relay is provided with under & over voltage element.
  • 23. The third harmonic under voltage element is applicable when the neutral voltage measured is available at the neutral end of the generator. To prevent false tripping operation when the machine is dead or under no load condition power interlock is used to detect load.
  • 24. SCHEME ARRANGEMENT FOR 95% & 100% STATOR EARTH FAULT PROTECTION :
  • 25. RELAY SETTING : V<Inhibit Set 80V P<Inhibit set Disabled, Enabled Enabled P<Inhibit set 20.00W Q<Inhibit set Disabled, Enabled Disabled S<Inhibit set Disabled, Enabled Disabled
  • 26. POLE SLIPPING PROTECTION (78G) Sudden changes or shock in electrical system such as line switching operation, transient system fault, generator governor failure, excitation system failure, reconnection of islanding system without synchronization, large jumps in load or fault may lead to power system oscillations which appears as regular variations of current and angular separation between systems. At times, this power swing becomes so sever that it can lead lost of synchronism between generator and system, this condition recognized as out of step or pole slipping.
  • 27. OVER FLUXING PROTECTION (99G) Over fluxing or over excitation of generator can increase if the ratio of voltage to frequency (V/HZ) increased certain limits. High voltage or low frequency can rise V/Hz ratio, it will produce high flux densities in magnetic core of machines, this can cause core of generator to be saturated & stary flux to be induced in un laminated components that have not been designed to carry this flux, the resulting eddy current in solid components (e.g. core, bolts & supporting structure) can cause rapid overheating & damage. Over fluxing likely to occur during machine start up & shutdown while the generator is not connected to the system. Failure in automatic control of excitation system or errors in manual control of machine field current, could allow excessive voltage to be generated. Sudden loss of load could cause an overvoltage condition, if generator excitation system does not respond properly.
  • 28. BREAKER FAILURE PROTECTION (50LBB) The LBB protection is used as back up protection of main protection, during this protection, relay sense the breaker position, flow of current & trip command generated by itself.
  • 30. BACK UP IMPEDANCE PROTECTION (27G) Generator is source of power & it will supply fault current until they are cleared by the protection system. Back up protection applied at the generator so that faults are cleared in the event of downstream protection/breaker fails to operate. Under impedance element is set to monitor the system impedance at machine terminal, if the measured impedance falls below set value then relay will operate.
  • 31. DEAD MACHINE (61B) Accidental energization of breaker when machine is not running can cause severe damage to machine. If the breaker is closed when machine is not running then generator will began act as induction motor with the surface of rotor core & rotor winding slot wedges acting as rotor conductor ,this abnormal current will result in overheating and damaged. The relay element is enabled when the machine is not running ,there for element can have very low current setting, the undervoltage threshold typically set to 85% of nominal voltage to ensure that machine is not running.
  • 33. LOSS OF EXCITATION WITH UNDER VOLTAGE(27/40) Complete loss of excitation may arise as a result of accidental tripping of excitation system, failure of field breaker , an open circuit or short circuit happened in DC circuit, flashover of any slip ring or failure of excitation source. When excitation of synchronous generator fails its internal emf will decay and output of active power will reduce and it will draw large reactive power grid, hence machine will act as a induction generator, after filed failure circulating current will induce in rotor core and rotor heat, also stator winding may get damaged severely.
  • 35. ROTOR GROUND FAULT PROTECTION (64R) The Generator rotor earth fault protection is provided to protect the generator rotor and exciter rotor winding against earth fault. The rotor earth fault relay sense the resistance between rotor winding and ground through carbon brushes mounted on slip rings.
  • 36. MICOM P342 RELAY INCORPORATED WITH FOLLOWING PROTECTIONS : 1. Low Forward Power Protection (37G) 2. Reverse Power Protection (32G) 3. Under frequency Protection (81U) 4. Over frequency Protection (81O) 5. Over Voltage Protection (59G) 6. Under Voltage Protection (27G) 7. Generator Stator Water flow minimum 8. Excitation system failure 9. Excitation transformer temp. high
  • 37. LOW FORWARD POWER PROTECTION (37G) When machine is generating and CB connecting the generator to the system is tripped, the electrical load on the generator is cut, this could lead to generator over speed if the machine input power is not reduced quickly. Trapped system in the turbine, risk of over speed damage to such sets, interlock is used for non urgent tripping of the generator breaker and excitation system with a low forward power check.
  • 39. REVERSE POWER PROTECTION (32G) It is back up protection to low forward protection. If the generator prime mover falls, generator is connected in parallel with another source of electrical supply will begin as “Motor” . The generator will operator as a synchronous motor and drive the turbine. Here in this condition draw the real power (MW) from the bus & and export reactive power (MVAR) to grid. If the filed breaker closed but field current is zero, the generator will act as an induction motor. Here in this condition generator will draw real power as well as reactive power from the grid
  • 40. In this condition generator will not be harmed by synchronous motoring but steam turbine can be harmed due to winding loss of causing overheating of turbine blade if continued long enough. The sensitivity and setting of the relay is depending on the type of prime movers. Causes of Reverse Power Protection : Two or more machines are running in parallel and prime mover of machine fails.
  • 42. OVER VOLTAGE (59G) The over voltage protection will act as a back up protection of the over fluxing protection. The over voltage protection is required to protect the stator conductor insulation of the generator. This is directly connected to Gen. phase side PT secondary terminals. Causes of over voltage : Prime mover over speed due to sudden loss of load. Voltage regulator (AVR) is defective.
  • 44. OVER FREQUENCY PROTECTION (81O) The over frequency protection is provided to protect the generator against over speed. Sever high speed operation of generator set could result in damaged. Causes of over frequency : Demand of active power suddenly decreased in power grid Full or partial load rejection (Load thrown off) Over shedding of load during major disturbance. Generator CB oprn during load.
  • 46. UNDER FREQUENCY PROTECTION (81U) The under frequency protection is used to protect the generator against operation at low frequency. If the frequency goes down, the speed of turbine get reduced, hence the steam may get condensed on turbine blades and damage them. Causes of under frequency : Demand of active power suddenly increased in grid. Islanded system two or more system running in parallel on more than 70% load & outage of nay machine due to fault increased the load to another machine will result in under frequency operation.
  • 48. UNDER VOLTAGE (27G) Generator are usually designed to operate continuously at a minimum voltage of 95% of its rated voltage, while generate power at rated frequency. Generator terminal voltage goes lower than 85% of its rated voltage may result in undesirable effects such as reduction in stability limits, import of excessive reactive power from grid, malfunctioning of voltage sensing devices and equipment. The under voltage relay works in secondary value if PT which is connected with generator output terminals.
  • 50. NON DIRECT PROTECTION ❑Generator stator water flow minimum Generator CW flow minimum link to be closed, protection simulated from C&I cabinet ( if stator water pump not running then signal will come high) ❑Excitation system fault Protection simulated from AVR end at micom P342 relay assigned o/p becomes high & EXT trip LED becomes high. ❑Excitation transformer temp. high Protection simulated from excitation transformer end for low setting at P342 relay o/p assigned becomes high. For high setting at P342 assigned relay becomes high.