This document discusses relay coordination and overcurrent protection. It begins with an introduction to relay coordination, covering the basic philosophy of selectivity, sensitivity and speed. It then discusses the need for protection coordination to ensure equipment safety, proper discrimination of faulty vs healthy portions of the power system, and reduced outage times. The document outlines various protection schemes including unit and non-unit schemes. It also covers overcurrent protection characteristics such as time-overcurrent, definite time, and instantaneous and provides examples of how relay trip times are calculated based on standards.
�The sample calculations shown here illustrate steps involved in calculating the relay settings for generator protection.
�Other methodologies and techniques may be applied to calculate relay settings based on specific applications.
Tutorial on Distance and Over Current ProtectionSARAVANAN A
Contents
• Protection Philosophy of ERPC
• Computation of Distance Relay Setting
• System Study to Understand Distance Relay
Behaviour
• DOC and DEF for EHV system
�The sample calculations shown here illustrate steps involved in calculating the relay settings for generator protection.
�Other methodologies and techniques may be applied to calculate relay settings based on specific applications.
The protections of generator are the most complex and elaborate due to the following reasons: Generator is a large machine, connected to bus-bars. It is accompanied by unit transformers, auxiliary transformers and a bus system. ... The protection of generator should be co-ordinate with associated equipment's.
�The sample calculations shown here illustrate steps involved in calculating the relay settings for generator protection.
�Other methodologies and techniques may be applied to calculate relay settings based on specific applications.
Tutorial on Distance and Over Current ProtectionSARAVANAN A
Contents
• Protection Philosophy of ERPC
• Computation of Distance Relay Setting
• System Study to Understand Distance Relay
Behaviour
• DOC and DEF for EHV system
�The sample calculations shown here illustrate steps involved in calculating the relay settings for generator protection.
�Other methodologies and techniques may be applied to calculate relay settings based on specific applications.
The protections of generator are the most complex and elaborate due to the following reasons: Generator is a large machine, connected to bus-bars. It is accompanied by unit transformers, auxiliary transformers and a bus system. ... The protection of generator should be co-ordinate with associated equipment's.
Why do Transformers Fail?
�The electrical windings and the magnetic core in a transformer are subject to a number of different forces during operation, for example:
�Expansion and contraction due to thermal cycling
�Vibration
�Local heating due to magnetic flux
�Impact forces due to through-fault current
�Excessive heating due to overloading or inadequate cooling
Protection of transmission lines (distance)Rohini Haridas
This gives idea about necessity of protection of transmission line and protection based on time grading as well as on current grading. Also includes three step distance protection of transmission line
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.
Modelling and Implementation of Microprocessor Based Numerical Relay for Prot...Kashif Mehmood
This paper includes the design and implementation of Numerical Relay that can protect the equipment against over-voltage, over-current and under voltage. Although, every power system is subjected to faults and these faults can severe damage to the power system. Therefore, it is necessary
to observe and resolve in time to avoid a large damage such as blackouts. For this purpose, there
should be some sensing devices, which give signals to the circuit breakers for preventing of power
system damages. The multipurpose relays have much importance role in power system for sensing
and measuring the amplitude of faults. Numerical relay provides settings of over-current, overvoltage and under voltage values. Simulations have been carried out using Proteus software along
with tested on hardware with Arduino Uno Microcontroller that proves the working and operation of
numerical relay.
Why do Transformers Fail?
�The electrical windings and the magnetic core in a transformer are subject to a number of different forces during operation, for example:
�Expansion and contraction due to thermal cycling
�Vibration
�Local heating due to magnetic flux
�Impact forces due to through-fault current
�Excessive heating due to overloading or inadequate cooling
Protection of transmission lines (distance)Rohini Haridas
This gives idea about necessity of protection of transmission line and protection based on time grading as well as on current grading. Also includes three step distance protection of transmission line
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.
Modelling and Implementation of Microprocessor Based Numerical Relay for Prot...Kashif Mehmood
This paper includes the design and implementation of Numerical Relay that can protect the equipment against over-voltage, over-current and under voltage. Although, every power system is subjected to faults and these faults can severe damage to the power system. Therefore, it is necessary
to observe and resolve in time to avoid a large damage such as blackouts. For this purpose, there
should be some sensing devices, which give signals to the circuit breakers for preventing of power
system damages. The multipurpose relays have much importance role in power system for sensing
and measuring the amplitude of faults. Numerical relay provides settings of over-current, overvoltage and under voltage values. Simulations have been carried out using Proteus software along
with tested on hardware with Arduino Uno Microcontroller that proves the working and operation of
numerical relay.
Fault analysis in power system using power systems computer aided designIJAAS Team
This work presents a fault analysis simulation model of an IEEE 30 bus system in a distribution network. This work annalysed the effect of fault current and fault voltage in a distribution system. A circuit breaker was introduced into the system to neutralize the effect of the fault. The system was run on a PSCAD software and results were obtained. The system was monitored based on the start time and the end time of the fault and how well the circuit breaker reacts with those times. Fault occurred from 0.100 to 0.300 seconds before it was removed. At the time fault was not applied (i.e. from 0.00 to 0.100 and from 0.300 to 0.72), the circuit breaker was close and became open when fault was applied so as to cut off current flow through the line.The result obtained gave the disruption caused by the fault and the quick response of the circuit breaker in neutralizing it. Results gotten are based on when the circuit breaker is close and no fault is applied and when the circuit breaker is open due to fault. From this work, it was obtained that circuit breakers are very essential in system protection and reliability.
An adaptive protection scheme to prevent recloser-fuse miscoordination in dis...iosrjce
IOSR Journal of Electrical and Electronics Engineering(IOSR-JEEE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electrical and electronics engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electrical and electronics engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Smart Local Backup Protection for Smart SubstationIJECEIAES
This paper presents a novel smart local backup protection SLBP used for the support and backup of the protective relays in a smart substation. The proposed SLBP is based on the IEC61850 standards and the concept consists of the acquisition of Generic Object Oriented Substation Event GOOSE used for tripping and interlocks exchange between Intelligent Equipment Devices IEDs and the reading of the Sampled Value SV existing in the process bus coming from Mergin Units MU or Non-Conventional Instrument Transformers NCIT. Several logical schemes to protect different zones of the substation are presented and how can be integrated using data in the substation automation system. The SLBP was developed using an open source library and free operating system. Moreover, a low cost prototype is presented in order to evaluate the efficiency and the operation of the SLBP under diverse scenarios of the proposed logical protective schemes such us breaker failure and overcurrent protection.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
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/
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.
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This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
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.
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
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The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
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Ipsa mv relay co-ordiantion shaik adam
1. RELAY CO-ORDINATION
BY
SHAIK ABDULLAH ADAM
PRINCIPAL ENGINEER – POWERPROJECTSINDIA – CHENNAI
28 August 2020 info@powerprojectsindia.com +91-996-218-8337
1
IPSA
MV – TRANSFORMER /BASICS
2. AGENDA - 1
INTRODUCTION MV RELAY CO-ORDINATION.
NEED FOR PROTECTION COORDINATION.
PROTECTION SYSTEM DESING.
SIGNIFICANCE OF RELAY AND RELEASE .
OVER CURRENT PROTECTION AND ITS CHARACTERISTICS.
2
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3. INTRODUCTION
BASIC PHILOSOPHY - S S S ( Selectivity - Sensitivity – Speed)
The selected protection principle affects the operating speed of the protection,
which has a significant impact on the harm caused by short circuits. The faster
the protection operates, the smaller the resulting hazards, damage and the
thermal stress will be.
Further, the duration of the voltage dip caused by the short circuit fault will be
shorter, the faster the protection operates. Thus, the disadvantage to other parts
of the network due to undervoltage will be reduced to a minimum.
3
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4. INTRODUCTION
BASIC PHILOSOPHY
The fast operation of the protection also reduces post-fault load peaks which, in
combination with the voltage dip, increase the risk of the disturbance spreading
into healthy parts of the network.
In transmission networks, any increase of the operation speed of the protection
will allow the loading of the lines to be increased without increasing the risk of
losing the network stability.4
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5. INTRODUCTION
BASIC PHILOSOPHY
Good and reliable selectivity of the protection is essential in order to limit the
supply interruption to the smallest area possible and to give a clear indication of
the faulted part of the network.
This makes it possible to direct the corrective action to the faulty part of the
network and the supply to be restored as rapidly as possible.
5
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6. INTRODUCTION
BASIC PHILOSOPHY
AS PER IEEE242.2001
Quick isolation of the affected portion of the system while maintaining normal
operation elsewhere.
Reduction of the short-circuit current to minimize damage to the system, its
components, and the utilization equipment it supplies.
Provision of alternate circuits, automatic throw overs, and automatic reclosing
devices
6
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7. NEED FOR RELAY COORDINATION
NEEDS OF RC
Ensure the Equipment and Personnel Safety.
To make proper discrimination of faulty portions and healthy portions of the
power system network.
Reduce the outage time that will ensure the economic aspects.
7
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8. PROTECTION SYSTEM DESIGN
PROTECTION SCHEME:
Protection schemes can be divided into two major groups:
a) Unit schemes b) Non-unit schemes :
UNIT PROTECTION:
Unit type schemes protect a specific area of the system i.e. a transformer,
transmission line, motor, generator or busbar. The unit protection schemes are
based on Kirchhoff’s Current Law – the sum of the currents entering an area
of the system must be zero.
Any deviation from this must indicate an abnormal current path. In these
schemes, the effects of any disturbance or operating condition outside the
area of interest are totally ignored and the protection must be designed to
be stable above the maximum possible fault current that could flow through
the protected area.
8
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9. PROTECTION SYSTEM DESIGN
PROTECTION SCHEME:
NON-UNIT PROTECTION:
The non-unit schemes, while also intended to protect specific areas, have no
fixed boundaries. As well as protecting their own designated areas, the
protective zones can overlap into other areas. While this can be very
beneficial for backup purposes, there can be a tendency for too great an
area to be isolated if a fault is detected by different non unit schemes.
The most simple of these schemes measures current and incorporates an
inverse time characteristic into the protection operation to allow protection
nearer to the fault to operate first.
9
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10. PROTECTION SYSTEM DESIGN
PROTECTION SCHEME:
NON-UNIT PROTECTION:
The non unit type protection system includes following schemes:
Time graded over-current protection.
Current graded over-current protection.
Distance or Impedance protection.
Interlocking protection.
Differential protection.
10
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11. PROTECTION SYSTEM DESIGN
PROTECTION SYSTEM DESIGN :
Protection system design is based on the knowledge that the faults or abnormal
operating conditions can lead to:
overloads;
phase-to-ground faults;
phase to phase and three phase faults.
11
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12. PROTECTION SYSTEM DESIGN :
The detection of the above conditions is undertaken by the protective relays,
whose tasks are:
To quickly isolate the faulted part of the electrical distribution system while
maintaining normal service for the rest of the system and minimizing damage
to the affected portion;
To ensure that only the protective device nearest the faults opens to remove
the short-circuit, while the other upstream protective devices remain closed.
The settings of the relays shall be selected to allow a reliable operation of
the system, keeping as long and as much as possible the feeders or the
system in service without risk of damage.
12
PROTECTION SYSTEM DESIGN
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13. TYPE OF PROTECTION
PROTECTION COORDINATION:
To achieve the above goals the protective devices shall be properly selected,
adjusted and coordinated to ensure a reliable operation of the electrical system,
keeping as long and as much as possible the feeders or the system in service without
risk of damage.
Two different kinds of protective devices are used to protect the electrical system, as
per the reference protection and metering diagrams:
Electromagnetic relays, thermal overload relays and electronic/SST built-in
overcurrent and ground fault releases for low voltage distribution;
Indirect relays fed from CTs and VTs for overcurrent and short-circuit protection,
motor protection and ground fault protection, for low and high voltage distribution.
13
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14. PROTECTION COORDINATION:
For the indirect relays, the microprocessor technology has been selected; the
protection functions which have been considered active in the multifunction
relays are indicated in the setting tables and in the one line diagrams.
14
Relay function ANSI code
Impedance (Distance) 21
Synchro check 25
Undervoltage 27
Reverse Power 32
Phase Current Balance 46
Thermal 49
Overvoltage 59
Frequency 81
Differential 87
AC Time and
Instantaneous Phase
Overcurrent
50/51
Breaker Failure 50BF
AC Time and Instantaneous
Ground Overcurrent
50G/51G
Trip Circuit Supervision 74TC
Time delay blocking relay 62
Auxiliary time delay blocking
relay
62A
Time delay blocking relay for
breaker failure scheme
62BE
Directional ground
overcurrent relay
67N
Directional overcurrent relay 67
TYPE OF PROTECTION
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15. RC TYPES:
15
SIGNIFICANCE OF RELAY AND RELEASE
RELAY CO-ORDINATION
>1kV <1kV
MV LV
RELAY
RELEASE
OVER CURRENT OVER CURRENTEARTH FAULT EARTH FAULT
TIME OVER CURRENT(TOC)
OR IDMT [51]
DEFINITE MINI’M TIME(DMT)
OR DEFINITE TIME( DT) ,[50]
INSTANTANEOUS [50 I]
LONG [51]
SHORT [50 ]
INSTANTANEOUS [50 I]
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16. OVER CURRENT PROTECTION:
It finds its application from the fact that in the event of fault the current will increase to a value several
times greater than maximum load current.
A relay that operates or picks up when its current exceeds a predetermined value (setting value) is
called Over-current Relay.
Over-current protection protects electrical power systems against excessive currents which are
caused by short circuits, ground faults, etc.
Over-current relays can be used to protect practically any power system elements, i.e. transmission
lines, transformers, generators, or motors.
For feeder protection, there would be more than one over-current relay to protect different sections
of the feeder. These over-current relays need to coordinate with each other such that the relay
nearest fault operates first.
16
OVER CURRENT PROTECTION AND ITS CHARACTERISTICS
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17. DESIGN PHILOSOPHY OF OVER CURRENT PROTECTION:
Use time, current and a combination of both time and current are three ways
to discriminate adjacent over-current relays.
Over-current Relay gives protection against:
Phase faults.
Earth faults.
Winding faults.
17
OVER CURRENT PROTECTION AND ITS CHARACTERISTICS
Discrimination:
Current setting
Time setting
Current and time
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18. DESIGN PHILOSOPHY OF OVER CURRENT PROTECTION:
Short-circuit currents are generally several times (5 to 20) full load current.
Hence fast fault clearance is always desirable on short circuits.
Primary requirement of Over-current protection is that the protection
should not operate for starting currents, permissible over-current, and
current surges. To achieve this, the time delay is provided.
18
OVER CURRENT PROTECTION AND ITS CHARACTERISTICS
28 August 2020 info@powerprojectsindia.com +91-996-218-8337
19. DESIGN PHILOSOPHY OF OVER CURRENT PROTECTION:
As per IEEE242 , there is NO discrimination co-ordination needed for LV
system but overlapping shall be avoided .
But MV/HV 200ms minimum of time discrimination /grading is required
while do co-ordination.
19
OVER CURRENT PROTECTION AND ITS CHARACTERISTICS
28 August 2020 info@powerprojectsindia.com +91-996-218-8337
20. CHARACTERISTICS :
Depending on the time of operation of relays, they are categorized as follows:
TOC – TIME OVER CURRENT (OR) INVERSE DEFINITE MINIMUM TIME ( IDMT) [51]
Standard / Normal / Moderate Inverse [ IEC/IEEE /ANSI ]
Long Inverse [ IEC/IEEE /ANSI ]
Very Inverse [ IEC/IEEE /ANSI ]
Extreme Inverse [ IEC/IEEE /ANSI ]
DEFINITE MINIMUM TIME OR DEFINITE TIME [50]
INSTANTANEOUS [50I]
20
OVER CURRENT PROTECTION AND ITS CHARACTERISTICS
28 August 2020 info@powerprojectsindia.com +91-996-218-8337
21. CHARACTERISTICS :
TOC – TIME OVER CURRENT (OR) INVERSE DEFINITE MINIMUM TIME ( IDMT) [51]
Inverse definite minimum time (IDMT) over-current Relay is one in which the
operating time is approximately inversely proportional to the fault current near
pick-up value and then becomes constant above the pick-up value of the
relay.
The relay will go to a definite time after 20 times of pickup current.
21
OVER CURRENT PROTECTION AND ITS CHARACTERISTICS
28 August 2020 info@powerprojectsindia.com +91-996-218-8337
22. TOC – TIME OVER CURRENT (OR) INVERSE DEFINITE MINIMUM TIME ( IDMT) [51]
From the picture, it is clear that there is some definite time after which the Relay
will operate. It is also clear that the time of operation at Pick-up value is nearly
very high and as the fault current increases the time of operation decreases
maintaining some definite time.
22
OVER CURRENT PROTECTION AND ITS CHARACTERISTICS
28 August 2020 info@powerprojectsindia.com +91-996-218-8337
23. CHARECTERISTICS :
DEFINITE MINIMUM TIME OR DEFINITE TIME [50]
This relay is created by applying intentional time delay after crossing pick up
the value of the current. A definite minimum time overcurrent relay can be
adjusted to issue a trip output at an exact amount of time after it picks up.
Thus, it has a time setting adjustment and pickup adjustment.
23
OVER CURRENT PROTECTION AND ITS CHARACTERISTICS
28 August 2020 info@powerprojectsindia.com +91-996-218-8337
24. CHARECTERISTICS :
INSTANTANEOUS [50I]
This relay is referred as instantaneous over current relay, as ideally, the relay
operates as soon as the current gets higher than pick upsetting current. There
is no intentional time delay applied. But there is always an inherent time delay
which we cannot avoid practically. In practice, the operating time of an
instantaneous relay is of the order of a few milliseconds..
24
OVER CURRENT PROTECTION AND ITS CHARACTERISTICS
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25. RELAY SUITABILITY:
As we discussed earlier , to provide desired settings at relays, ensure that the
minimum and maximum current and time settings available at selected relay. It
can ensured from vendor catalogue of that relay and Also have responsibility
to cross verification of ETAP library relay models are well verse modelled as per
the vendor catalogue.
All relays, including instantaneous ( 50I ) have some minimum delay to operate
such as relay sensing needs 20ms and breaker operating time is 40ms as an
example.25
RELAY SUITABILITY
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26. RELAY TRIP TIME CALCULATIONS
STANDARD FOR RELAY CO-ORDINATION
EQUIPMENT DETAILS
BASICS OF CURRENT TRANSFORMER AND ITS CONNECTIONS
CO-ORDINATION TIME INTERVAL (CTI)
STATIC AND NUMERICAL RELAYS
26
AGENDA - 1
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27. RELAY TRIP TIME CALCULATIONS - IEC
The formula for Trip time of a relay is based its standards and relay manufacturer.
WHERE, as per IEC 60255 -151 -2009CURVES
IActual - Fault Current or Fault current (A)
Iset - Setting Current or Relay pickup current (A)
T - TMS
k, , β or c - Constants – It will be subjected to vary based on the curves.
27
RELAY TRIP TIME CALCULATION
-1
k
I Actual
I Set
T βX +Trip time ( Top) t(G) =
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28. RELAY TRIP TIME CALCULATIONS - IEC
WHERE, as per IEC 60255 -151 -2009CURVES
- PLUG SETTING MULTIPLIER [ PSM ]28
RELAY TRIP TIME CALCULATION
I Actual
I Set
-1
k
I Actual
I Set
T βX +Trip time ( Top) t(G) =
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29. RELAY TRIP TIME CALCULATIONS - IEEE
as per IEEE C37.112-1996
WHERE,
IActual - Fault Current or Fault current (A)
Iset - Setting Current or Relay pickup current (A)
T - Time Dial
p , B ,A- Constants – It will be subjected to vary based on the curves.
29
RELAY TRIP TIME CALCULATION
-1
A
I Actual
I Set
p
T BX +Trip time ( Top) t(I) =
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30. RELAY TRIP TIME CALCULATIONS - IEEE
WHERE, as per IEEE C37.112-1996
- PLUG SETTING MULTIPLIER [ PSM ]30
RELAY TRIP TIME CALCULATION
I Actual
I Set
-1
A
I Actual
I Set
p
T BX +Trip time ( Top) t(I) =
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31. CONSTANTS VALUES AS PER IEC & ANSI/IEEE
31
RELAY TRIP TIME CALCULATION
TOC CURVES - IEC K β OR c
STANDARD INVERSE 0.14 0.02 0
LONG INVERSE 120 1 0
VERY INVERSE 13.5 1 0
EXTREME INVERSE 80 2 0
TOC CURVES - IEEE K p B
MODERATE INVERSE 0.0515 0.02 0.01140
VERY INVERSE 19.61 2 0.419
EXTREME INVERSE 28.2 2 0.1217
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32. TMS SHORT NOTES:
TIME DIAL OR TIME MULTIPLIER SETTINGS will be adjusted at graph based on
the curve positioning on plotted graph.
The Desired Cases Are Two , 1)GRAPHS SHALL NOT BE OVER LAPPED AND
2) NEED TO MAINTAIN SOME TIME GRADINGS .
IEC time multiplier setting (TMS).
IEEE time dial (TD). In some relays and literature, a TDM (Time Dial Multiplier) is
used, instead of a TD (Time Dial).
TDM =
32
RELAY TRIP TIME CALCULATION
TD
7
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33. MODEL CALCULATION: IEC
Given Data: I Actual -132 A , I Set -33.7 A , TMS – 0.6 , CURVE: STANDARD INV
Solution:
Formula Used as per IEC:
33
RELAY TRIP TIME CALCULATION
- 1
k
I Actual
I Set
T βX +Trip time ( Top) t(G) =
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34. MODEL CALCULATION:
Trip time ( Top) = 3.034 Sec
34
RELAY TRIP TIME CALCULATION
- 1
k
I Actual
I Set
T βX +Trip time ( Top) t(G) =
- 1
0.14
132
33.7
0.02
0.6 0X +Trip time ( Top) t(G) =
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35. MODEL CALCULATION:
Trip time ( Top) = 3.034 Sec Ω 3.04 Sec for fault current 132A and Setting current is
33.7 A
35
RELAY TRIP TIME CALCULATION
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36. TOC CURVES - PRIOIRITY SELECTION: [51] ( TRIPPING TIME MODERATE)
SOURCE / INCOMER SIDE - STANDARD INVERSE.
EQUIPMENT LOAD SIDE- LONG INVERSE/ EXTREME INVERSE / VERY INVERSE.
IOC - PRIOIRITY SELECTION: [50] ( TRIPPING TIME IMMEDIATE)
SOURCE / INCOMER /EUIPMENT SIDE - DMT - TIME DELAY / TIME GRADE IS
DESIRED.
LOAD SIDE – NO INTENTIONAL TIME DELAY ( INHERENT TIME DELAY)
36
RELAY TRIP TIME CALCULATION
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38. IOC (DMT) : [50] ( TRIPPING TIME IMMEDIATE) as per ALSTOM P141
Phase IOC [50I]
Neutral IOC [50N]
Ground IOC [50G]
Sensitive Ground IOC [50SG]
Negative Sequence IOC [50NS]
38
RELAY TRIP TIME CALCULATION
PROTECTION PHASE NEUTRAL GROUND SEN .GROUND NEG SEQ
INSTANTANEOUS 50I 50N 50G 50SG 50NS
DEFINITE/SHORT TIME
(DMT)
50D 50D 50D 50D 50D
LOCATION (INSTANT)
PREFERRED
LOAD SIDE/END
EQUIPMENT
TRANFORMER/
INCOMER
FEEDER -- --
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39. STANDARDS:
IEEE Std 242-2001, the IEEE Buff Book™ - IEEE Recommended Practice
for Protection and Coordination of Industrial and Commercial
Power Systems.
IEEE Std 141-1993 , IEEE Recommended Practice for Electric Power
Distribution for Industrial Plants
The IEEE color books are organized into new form, termed as “The IEEE 3000
standard collection”
IEEE 3004 Standards: Protection & Coordination
39
STANDARDS FOR RELAY CO-ORDINATION
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40. STANDARDS:
IEEE 3004 Standards: Protection & Coordination
3004.1-2013 - IEEE Recommended Practice for the Application of
Instrument Transformers in Industrial and Commercial Power Systems
3004.11-2019 - IEEE Recommended Practice for Bus and Switchgear
Protection in Industrial and Commercial Power Systems
3004.5-2014 - IEEE Recommended Practice for the Application of
Low-Voltage Circuit Breakers in Industrial and Commercial Power
Systems
3004.8-2016 - IEEE Recommended Practice for Motor Protection in
Industrial and Commercial Power Systems
40
STANDARDS FOR RELAY CO-ORDINATION
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41. PROTECTION CO-ORDINATION : OVERCURRENT [51] AND EARTH FAULT [51G/N]
EQUIPMENTS TO BE COVERED :
TRANSFORMER
MOTOR
41
EQUIPMENTS DETAILS
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42. INSTRUMENT TRANFORMERS: CURRENT TRANSFORMER
STANDARDS FOR INSTRUMENT TRANSFORMERS:
IEC 61869 1-5(CONVENTIONAL) 6-12 ( NON –CONVENTIONAL).
IS 2705 1-4
IEEE C57.31
42
BASICS OF CURRENT TRANSFORMER AND ITS CONNECTIONS
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43. INTRUMENT TRANFORMERS: CURRENT TRANSFORMER
A current transformer is a device that is used for the transformation of current
from a higher value into a proportionate current to a lower value.
Current transformers will be used for measuring and protection purposes.
STANDARD CT RATIOS: 5A / 1A
For the secondary current, choose 1 A or 5 A depending on the instrument
or relay, and on the distance between the transformer and the instrument
it is feeding:
- 5A secondary is used when instruments or relays are close to the
transformer, i.e less than 10m (30ft).
- 1A secondary is preferably selected when the distance between the
current transformer and the instrument transformer or the relay is above
10m (30ft). Joule losses(I2r) by wire resistance are 25 times higher with 5A
than with 1A. Its widely choose for protection.
43
BASICS OF CURRENT TRANSFORMER AND ITS CONNECTIONS
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44. INSTRUMENT TRANFORMERS: CURRENT TRANSFORMER
PHASE CT / GROUND CT ( CBCT – CORE BALANCED CT)
CBCT – Preferred on Resistance Grounded System , in order to sense the fault
current which is comparatively low value.
CBCT ratio is widely used as 50:1A which is independent of the continuous
current flowing through the circuit.
CBCT ratio is 50:1A for 100A resistance earthed system and CBCT value is LOWER
than the limited current value of the earthed system.
44
BASICS OF CURRENT TRANSFORMER AND ITS CONNECTIONS
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45. INTRUMENT TRANFORMERS: CURRENT TRANSFORMER
CONFIGURATION CT FOR GROUND
PHASE CT CBCT
45
BASICS OF CURRENT TRANSFORMER AND ITS CONNECTIONS
• In built function on Relay to
sense the Ground Fault
Current.
• Not – Suitable for
Resistance Grounded
System.
• A dedicated and high sensitive CT
(CBCT) connected with relay for Ground
fault current.
• Resistance Grounded system has limited
ground fault current to certain value
(100A- 800A) where CBCT is employed to
sense the lowest ground fault current.
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46. INTRUMENT TRANFORMERS: CURRENT TRANSFORMER
CONNECTION CONFIGURATION
TYPE1: NEUTRAL CURRENT MEASURED –WITHOUT CBCT
46
BASICS OF CURRENT TRANSFORMER AND ITS CONNECTIONS
RELAY
R
Y
B
N
V
S1
S2 S1
S2 S1
S2 V
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47. INTRUMENT TRANFORMERS: CURRENT TRANSFORMER
CONNECTION CONFIGURATION
TYPE1: NEUTRAL CURRENT NOT MEASURED –WITHOUT CBCT
47
BASICS OF CURRENT TRANSFORMER AND ITS CONNECTIONS
RELAY
R
Y
B
S1
S2 S1
S2 S1
S2
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48. INTRUMENT TRANFORMERS: CURRENT TRANSFORMER
CONNECTION CONFIGURATION
TYPE1: NEUTRAL CURRENT MEASURED –WITH CBCT
48
BASICS OF CURRENT TRANSFORMER AND ITS CONNECTIONS
RELAY
R
Y
B
G
S1
S2 S1
S2 S1
S2
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49. CTI: IEEE242 – 15.5
When plotting coordination curves, certain time intervals should be maintained
between the curves of various protective devices to ensure correct selective
operation and to reduce nuisance tripping. Without adequate CTIs, these
protective devices could trip incorrectly.
49
CO-ORDINATION TIME INTERVAL [ CTI ]
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50. CTI:
When coordinating inverse time overcurrent relays, the time interval
according to ANSI/ IEEE Std-242 is usually 0.3 to 0.4 seconds. This interval is
measured between relays in series at the instantaneous setting of the
load side feeder circuit breaker relay and upcoming incomer relays.
The recommended time has the following components:
• circuit breaker opening time (5 cycles): 0.10 seconds
• relay overtravel: 0.10 seconds ( Electromechanical relay)
• safety factor for CT saturation, setting errors, etc.: 0.22 seconds.
NOTE: CYCLE( T) = 1/ f , Where f- supply frequency [50Hz], then 1 cycle
=1/50 , =20ms (0.02 seconds).
50
CO-ORDINATION TIME INTERVAL [ CTI ]
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51. CTI:
The recommended time has the following components:
Traditional Time ( 200ms)
Relay Sensing time : 20ms
Breaker opening time : 40ms
CT saturation, setting error : 20ms
Safety factor / Margin : 100ms
So total 180ms ≈ 200ms or 250ms is provided between series relay’s time
discrimination.
51
CO-ORDINATION TIME INTERVAL [ CTI ]
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52. CTI:
The CTI time interval is changing with respect to the country where the
project is executed and plant’s complex network.
52
CO-ORDINATION TIME INTERVAL [ CTI ]
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53. CTI CALCULATION:
CTI =
WHERE,
tR – Relay Timing Error IN %
tCT – CT Error IN %
tOP – Breaker Operation Time Max.1000ms( Changeable With Country / Client)
When Fault Occurred The Immediate Breaker Operate To Isolate.
tOV – Over Travel Time of Electro-Mechanical Relay ( Not Applicable for
Numerical relay)
53
CO-ORDINATION TIME INTERVAL [ CTI ]
2tR + tCT
100
X tOP + tOv + tCB + tAT + tS
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54. CTI CALCULATION:
CTI =
WHERE,
tCB – Breaker Opening Time ( Vendor catalogue) - 40-45ms.
tAT – Additional Time required by the relay.
tS – Safety factor
When the overcurrent relays have independent definite time delay
characteristics, it is not necessary to include the allowance for CT error. Hence:
54
CO-ORDINATION TIME INTERVAL [ CTI ]
2tR + tCT
100
X tOP + tOv + tCB + tAT + tS
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55. CONCLUSION ON CTI :
CTI =
BETWEEN DOWNSTREAM AND UPSTREAM RELAYS CTI
55
CO-ORDINATION TIME INTERVAL [ CTI ]
2tR + tCT
100
X tOP + tOv + tCB + tAT + tS
RELAY TYPE CTI ( ms)
STATIC RELAY / SST MAX 350 NO MIN
ELECTRO MECHANICAL RELAY MIN 400
NUMERICAL RELAY 200 TO 300
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56. EXAMPLE SCENARIOS:
SCENARIO 1: Load To Source All Feeders are
Cables And Source Incomer [CB7]
Is Located At Plant Premises.
CTI : 200ms each stage .
56
CO-ORDINATION TIME INTERVAL [ CTI ]
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57. EXAMPLE SCENARIOS:
SCENARIO 2: Load To Source All Feeders are
Cables And Source Incomer [CB4]
Is Located At Plant Premises.
CTI : Even a single cable always maintain
an additional time interval to avoid nuisance
relations with utility.
So CTI is 600ms at Relay-5 [ utility ]when its
Down stream incomer relay Relay-4 has CTI 400ms.
57
CO-ORDINATION TIME INTERVAL [ CTI ]
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58. EXAMPLE SCENARIOS:
SCENARIO 3: Load To Source All Feeders are
Cables and has Transformer [CB5]
Is Located At Plant Premises.
CTI : In order to avoid tripping Transformer HV frequently
respect to LV faults 50- 100ms additional CTI is
added at Transformer HV Relay-5. Avoid frequent
In-rush currents on transformer.
So CTI is 500ms at Relay-5 [ Transformer HV ]when its
Down stream Transformer LV Relay-4 has CTI 400ms.
58
CO-ORDINATION TIME INTERVAL [ CTI ]
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59. 59
RELAYS
RELAY
STATIC ( SST) ELECTRO MECHANICAL
ANALOG
( DIODE)
DIGITAL
(THYRISTER)
NUMERICAL
(MICROPROCESSOR)
NOT WIDELY USED
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60. 60
STATIC AND NUMERICAL RELAYS
STATIC NUMERICAL
Less Accuracy High Accuracy
Not compatible to IEC61850 Compatible to IEC61850
Functions are controlled by
microcontroller
Convert all signal into digital and
processed by microprocessors
Disturbance Recorder is not
available
Disturbance Recorder’s report
useful for analysis.
Non –Programmable Programmable
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