This Presentation gives information on How Generator in Power Plants are protected with State of art technologies. Also provide information how latest Power System Protection technologies are more reliable operation.
Unit I: Introduction to Protection System:
Introduction to protection system and its elements, functions of protective relaying, protective zones, primary and backup protection, desirable qualities of protective relaying, basic terminology.
Relays:
Electromagnetic, attracted and induction type relays, thermal relay, gas actuated relay, design considerations of electromagnetic relay.
Unit-II: Relay Application and Characteristics:
Amplitude and phase comparators, over current relays, directional relays, distance relays, differential relay.
Static Relays: Comparison with electromagnetic relay, classification and their description, over current relays, directional relay, distance relays, differential relay.
Unit-III Protection of Transmission Line:
Over current protection, distance protection, pilot wire protection, carrier current protection, protection of bus, auto re-closing,
Unit-IV: Circuit Breaking:
Properties of arc, arc extinction theories, re-striking voltage transient, current chopping, resistance switching, capacitive current interruption, short line interruption, circuit breaker ratings.
Testing Of Circuit Breaker: Classification, testing station and equipments, testing procedure, direct and indirect testing.
Unit-V Apparatus Protection:
Protection of Transformer, generator and motor.
Circuit Breaker: Operating modes, selection of circuit breakers, constructional features and operation of Bulk Oil, Minimum Oil, Air Blast, SF6, Vacuum and d. c. circuit breakers.
How is power transformer protected??? This provides a basic understanding of power transformer. Furthermore, the protective relay application on power transformer is included.
The following topics are covered: components of power distribution systems, fuses, padmounted transformers, pole mounted transformers, vault installed transformers, transformer stations protection, transformer connections, thermometers, pressure relief devices, restricted ground faults, differential protection current transformers connections, overexcitation, inrush current, percentage differential relays, gas relays, characteristics of CTs.
Unit I: Introduction to Protection System:
Introduction to protection system and its elements, functions of protective relaying, protective zones, primary and backup protection, desirable qualities of protective relaying, basic terminology.
Relays:
Electromagnetic, attracted and induction type relays, thermal relay, gas actuated relay, design considerations of electromagnetic relay.
Unit-II: Relay Application and Characteristics:
Amplitude and phase comparators, over current relays, directional relays, distance relays, differential relay.
Static Relays: Comparison with electromagnetic relay, classification and their description, over current relays, directional relay, distance relays, differential relay.
Unit-III Protection of Transmission Line:
Over current protection, distance protection, pilot wire protection, carrier current protection, protection of bus, auto re-closing,
Unit-IV: Circuit Breaking:
Properties of arc, arc extinction theories, re-striking voltage transient, current chopping, resistance switching, capacitive current interruption, short line interruption, circuit breaker ratings.
Testing Of Circuit Breaker: Classification, testing station and equipments, testing procedure, direct and indirect testing.
Unit-V Apparatus Protection:
Protection of Transformer, generator and motor.
Circuit Breaker: Operating modes, selection of circuit breakers, constructional features and operation of Bulk Oil, Minimum Oil, Air Blast, SF6, Vacuum and d. c. circuit breakers.
How is power transformer protected??? This provides a basic understanding of power transformer. Furthermore, the protective relay application on power transformer is included.
The following topics are covered: components of power distribution systems, fuses, padmounted transformers, pole mounted transformers, vault installed transformers, transformer stations protection, transformer connections, thermometers, pressure relief devices, restricted ground faults, differential protection current transformers connections, overexcitation, inrush current, percentage differential relays, gas relays, characteristics of CTs.
Practical handbook-for-relay-protection-engineersSARAVANAN A
The ‘Hand Book’ covers the Code of Practice in Protection Circuitry including standard lead and device numbers, mode of connections at terminal strips, colour codes in multicore cables, Dos and Donts in execution. Also, principles of various protective relays and schemes including special protection schemes like differential,
restricted, directional and distance relays are explained with sketches. The norms of protection of generators, transformers, lines & Capacitor Banks are also given.
Electrical substation (one and half breaker scheme)Sourabh sharma
Double Bus One and Half Breaker Scheme is mostly adopted in high voltage electrical substations (220 KV or 400KV, 700 KV). Due to many advantages of this arrangement like high selectivity, reliability and less cost as compare to other bus arrangements for power stations or switch yards
On Load Tap Changer (OLTC) is used in "High Power Transformers" to control output voltage, when electric load on transformers get increase the output voltage get decrease due to internal voltage drop inside winding, change in tap is required to maintain output voltage. OLTC is a device which perform tap changing in High Power Transformers during On Load conditions and is powered by a motor.
Rotor earth fault protection of electric generatorCS V
As the field is operated ungrounded, a single fault does not cause any flow of current or affect the operation of the electric generator. However, a single rotor earth fault increases the stress to the ground in the field
This ppt describes the function of Power Transformer in a Power Generation plant. Here DPL(Durgapur Projects Limited) was our VT venue, so chose it as the Base.
Practical handbook-for-relay-protection-engineersSARAVANAN A
The ‘Hand Book’ covers the Code of Practice in Protection Circuitry including standard lead and device numbers, mode of connections at terminal strips, colour codes in multicore cables, Dos and Donts in execution. Also, principles of various protective relays and schemes including special protection schemes like differential,
restricted, directional and distance relays are explained with sketches. The norms of protection of generators, transformers, lines & Capacitor Banks are also given.
Electrical substation (one and half breaker scheme)Sourabh sharma
Double Bus One and Half Breaker Scheme is mostly adopted in high voltage electrical substations (220 KV or 400KV, 700 KV). Due to many advantages of this arrangement like high selectivity, reliability and less cost as compare to other bus arrangements for power stations or switch yards
On Load Tap Changer (OLTC) is used in "High Power Transformers" to control output voltage, when electric load on transformers get increase the output voltage get decrease due to internal voltage drop inside winding, change in tap is required to maintain output voltage. OLTC is a device which perform tap changing in High Power Transformers during On Load conditions and is powered by a motor.
Rotor earth fault protection of electric generatorCS V
As the field is operated ungrounded, a single fault does not cause any flow of current or affect the operation of the electric generator. However, a single rotor earth fault increases the stress to the ground in the field
This ppt describes the function of Power Transformer in a Power Generation plant. Here DPL(Durgapur Projects Limited) was our VT venue, so chose it as the Base.
Main equipment in the power plant is Generator. It's cost is much higher than any other equipment so we will have to protect the generator from all the possible faults and errors.
Need for protection
Nature and causes of faults
Types of faults
Fault current calculation using symmetrical components
Zones of protection
Primary and back up protection
Essential qualities of protection
Typical protection schemes.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
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Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
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.
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.
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.
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.