Step-1 Relay is one of the most important components in protection system. This force is called the controlling force of the relay. Similarly, if active turns of the relay coil are increased, then proportionately reduced current is required to produce same desired deflecting force. Hence, actual operating time of the relay is 3 × 0.1 = 0.3 sec. To understand this concept easily, it is better to know about settings of the Electromechanical Relays. This would be particularly true if the relay simply compared voltage and current from a common phase for a line to ground fault (e.g., I A PSM and TMS settings that is Plug Setting Multiplier and Time Multiplier Setting are the settings of a relay used to specify its tripping limits. For proper understanding, the functions of different protective relays, the definition of such terms must be understood properly. Overcurrent Relay & Earth Fautt Relay Concept, Setting Calculation, Characteristics and Application in Power System explained in detail What is an Overcurrent Relay? Relay settings, coordination curves, and settings tables are discussed Companies affiliated with GlobalSpec can contact me when I express interest in their product or service. (Supervisory Control and Data Acquisition), Programmable Logic Controllers (PLCs): Basics, Types & Applications, Diode: Definition, Symbol, and Types of Diodes, Thermistor: Definition, Uses & How They Work, Half Wave Rectifier Circuit Diagram & Working Principle, Lenz’s Law of Electromagnetic Induction: Definition & Formula, How long distance to be traveled by the moving parts of the relay for closing relay contacts and. Neglect CT saturation in this calculation. The force applied to the relay’s moving parts for changing the normal position of the contacts is called deflecting force. In this video we have explained calculation for IDMT over current relay setting calculation. Generator Protection – Setting Calculations The relay secondary current : = 16004/RC = 16004/1600 = 10 A Set the overcurrent pickup at 50% of this value = 5 A For situations when lines out of the plant are removed from service From CT ratio, we first see the rated secondary current of CT. Say the CT ratio is 100 / 1 A, i.e. Now, after calculating PSM, we have to find out the total time of operation of the relay from Time/PSM curve. Mohammed Tawfeeq 011 Overcurrent Relay Setting 50 Elements: Pickup Setting 51 Elements Pickup setting Time delay setting definite time: time setting As the time setting multiplier is 0.1 here, actually the moving parts of the relay have to travel only 0.1 × 100% or 10% of the total travel distance, to close the relay contacts. From current setting we calculate the trick current of the relay. During study of electrical protective relays, some special terms are frequently used. Include me in third-party email campaigns and surveys that are relevant to me. The current for which the relay initiates its operation is called pick up current of relay. Hence, pick up current of the relay is, 1 × 150 % = 1.5 A RELAY SETTING CALCULATION (IDMT Over-Current Protection : 51) Equivalent @ LV switchboard S.No. Finally that operating time of relay would be multiplied with time setting multiplier, in order to get actual time of operation of relay. Use of symbols This document includes warning, caution, and information icons that point out safety-related conditions or other important information. Step-4 The time of operation represents in this graph is that, which required to operate the relay when time setting multiplier set at 1. Step-5 6 Overcurrent Relay 1MRS750940-MUM Technical Reference Manual REJ 523 1.5. Therefore PSM of the relay is, 5 / 1.5 =3.33. The x-axis or horizontal axis of the Time/PSM graph represents PSM and Y-axis, or vertical axis represents the time of operation of the relay. The time setting dial is calibrated from 0 to 1 in steps of 0.05 sec. The more modern microprocessor protection has a three-phase overcurrent unit and an earth-fault unit within the same case. The MTA setting is commonly thought of in terms of the forward-looking line impedance angle. ZIP overcurrent relay setting calculation xls, most likely you will think not quite what you can get Many things! As per these system requirements, the pickup current of the relay is adjusted. The operating time of an electrical relay mainly depends upon two factors : So far by adjusting relay operating time, both of the factors to be adjusted. Use of Digital Logic in Numerical Relaying, 5.11: The current setting of overcurrent relay is generally ranged from 50 % to 200 %, in steps of 25 %. FREE It is essential to provide suitable protection schemes for distribution networks to ensure that faults are quickly remedied. The current setting of overcurrent relay is generally ranged from 50 % to 200 %, in steps of 25 %. Protection of Industrial Systems, Chapter 11: Fuse - Relay coordination requires a minimum 0.3 second time margin between the curves. _____ 1. For part 2, 3, and 4 of Example 15.2, calculate the CT voltage if the phase relay burden is 1.2 , the residual relay burden is 1.8 , the lead resistance is 0.4 , and the CT resis-tance is 0.3 . The simulation is done in ETAP software. If the actuating current in the relay coil increases gradually, the deflecting force in electromechanical relay is also increased. That means if active turns of the relay coil are reduced, then proportionately more current is required to produce desired relay actuating force. Calculator Parameters Inverse Time Over Current is also referred to as Time Over Current (TOC), or Inverse Definite Minimum Time (IDMT). Notify me about educational white papers. For example, suppose, you want that, an over current relay should operate when the system current just crosses 125% of rated current. Say current setting of the relay is 150 % therefore pick up current of the relay is 1 × 150% = 1.5 A. Step-3 You may withdraw your consent at any time. For that, we have to first divide primary faulty current by CT ratio to get relay faulty current. Current and Voltage Transformers, 5.5: As we already said, the time of operation also depends upon the speed of operation. The adjustment of traveling distance of an electromechanical relay is commonly known as time setting. The same procedure can be applied to multiple circuit arrangements. Such terms are. Curve - Select the Curve setting of the time overcurrent relay. as well as subscriptions and other promotional notifications. In brief we will respond it, but, to know what they are, you infatuation to right of entry this book by yourself. That means the moving parts of the relay take total 3 seconds to travel 100 % traveling distance. This adjustment is commonly known as time setting multiplier of relay. Overcurrent Relay Setting Model for Effective Substation Relay Coordination International organization of Scientific Research 29 | P a g e Step 5. Protection Schemes and Substation Design Diagrams, Chapter 14: For earth fault relay it is from 10% to 70% in steps of 10%. Overcurrent Relays with Voltage Control, 5.9: It is also seen from the curve that, for a lower value of plug setting multiplier, i.e., for a lower value of fault current, the time of operation of the relay is inversely proportional to the fault current. ACCESS UNLIMITED But by adjusting only time setting multiplier, we cannot set the actual time of operation of an electrical relay. This is relation curve between operating time and plug setting multiplier of an electrical relay. The current setting is sometimes referred as current plug setting. Say a relay has a time setting 0.1 and you have to calculate actual time of operation for PSM 10. Determine relay type ( t ) and calculate the time of operation using the following equations(9),(10) The first step is to read the … 17.3 Relay Co-ordination for Earth-fault Relay (contd..) Example a) Setting of Relay R1 Since the relay is on secondary side of transformer, our calculations will be referred to secondary side. Overcurrent relays are normally supplied with an instantaneous element and a time-delay element within the same unit. Industrial Computers and Embedded Systems, Material Handling and Packaging Equipment, Electrical and Electronic Contract Manufacturing, Chapter 2: This is known as the current setting of the relay. The relation between time of operation and plug setting multiplier is plotted on a graph paper, and this is known as time/PSM graph. Overcurrent Coordination Page 3 Qual-Tech Engineers, Inc. 8. Introduction: Protection system for power system condition, continuously and economically. Adaptive Protection with Group Settings Change, Chapter 6: All the contacts remain in their respective normal position by some force applied to them continuously. This controlling force may be the gravitational force, may be a spring force, or may be a magnetic force. From this graph one can determine the total time taken by the moving parts of an electromechanical relay, to complete its total traveling distance for different PSM. i.e. When calculating the fault currents, the power system is assumed to be in its normal operating state. Problem 1: – Determine the time of operation of a 5-ampere, 3-second over current relay having a current setting of 125% and a time setting, multiplier of 0.6 connected to supply circuit through a 400/5 current transformer when the Time Dial - Enter the Time Dial setting of the time overcurrent relay. An error occurred while processing the form. Feeder description Feeder type Voltage grade 6.6 HV ABB 1250 10227.05 894.66 984.13 Relay type CT Primary CT current Relay setting, Over current relay, IDMT relay. From fig 17.3, Full load secondary current From the Time/PSM curve of a typical relay shown below, it is seen that, if PSM is 10, the time of operation of the relay is 3 sec. For getting a clear idea, let us have a practical example. Classification and Function of Relays, Chapter 4: The number of active turns in the coil can be changed by inserting a plug in different points in the bridge. Power system Protection Part – 5 Dr.Prof. 5.3 Setting Overcurrent Relays Overcurrent relays are normally supplied with an instantaneous element and a time-delay element within the same unit. If the relay is rated with 1 A, the normal pick up current of the relay is 1 A and it should be equal to secondary rated current of current transformer connected to the relay. By submitting your registration, you agree to our Privacy Policy. BEST IDEAS. Directional Overcurrent Relays, Chapter 10: This is achieved by providing the required number of tapping in the coil. Low Voltage Breaker - Fuse coordination requires a minimum 0.1 second time Overcurrent Protection & Coordination for Industrial Applications Doug Durand, P.E. In other words, the time of operation of the relay depends upon plug setting multiplier. Now we have to calculate PSM for the specified faulty current level. Setting overcurrent relays involves selecting the parameters that define the required time/current characteristic of both the time-delay and instantaneous units. Overcurrent Relay Setting Calculation Xls Author vps1.nordictrack.vn-2020-12-23-21-40-42 Subject Overcurrent Relay Setting Calculation Xls Keywords overcurrent,relay,setting,calculation,xls Created Date 12/23/2020 9:40:42 PM From the curve, say we found the time of operation of relay is 3 second for PSM = 10. The Inverse Time Over Current (TOC/IDMT) relay trip time calculator calculates the protection trip time according to IEC 60255 and IEEE C37.112-1996 protection curves. Therefore the actual time of operation of the relay for PSM 10, is 3 × 0.1 = 0.3 sec or 300 ms. Electrical4U is dedicated to the teaching and sharing of all things related to electrical and electronics engineering. Suppose we have connected on protection CT of ratio 200/1 A and current setting is 150%. GlobalSpec will retain this data until you change or delete it, which you may do at any time. Use of this website signifies your agreement to our Terms of Use. In time setting multiplier, this total traveling distance is divided and calibrated from 0 to 1 in steps of 0.05. When electromechanical relays were more popular, the overcurrent protection was made up from separate single-phase units. When electromechanical relays were more popular, the overcurrent protection was made up from separate single-phase units. For calculating actual relay operating time, we need to know these following operations. The current setting is sometimes referred as current plug setting. The relay coordination and setting calculation for a case study substation is applied to clear faulty feeder. 10% of 3 sec. Relay tripping time calculation according to IEC 60255 and IEEE. Practically same model relays may be used in different systems. APRIL 26TH, 2018 - PLUG SETTING MULTIPLIER OF RELAY IS REFERRED AS RATIO OF FAULT CURRENT IN THE RELAY TO ITS PICK UP CURRENT CALCULATION OF RELAY OPERATION TIME ''Overcurrent Relay Setting Model for Effective Substation Now, suppose fault current in the CT primary is 1000 A. 39984912-Setting-Calculation-Protocol-for-IDMT-Over-Current-Relay.xls - Free download as Excel Spreadsheet (.xls), PDF File (.pdf), Text File (.txt) or read online for free. But when PSM becomes more than 20, the operating time of relay becomes almost constant. We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites. Include me in professional surveys and promotional announcements from GlobalSpec. GlobalSpec may share your personal information and website activity with our clients for which you express explicit interest, or with vendors looking to reach people like you. However, at a busbar that has two or more transformers connected in parallel and protected with relays that do not have the facility of multiple setting groups - the ability to be adjusted to accommodate the prevailing system conditions, which is possible with numerical relays for example - then better discrimination is obtained if the calculations are carried out on the basis of each one of the transformers being out of service in turn. 15.1 Fundamental Principle of Overcurrent Relay 15.1.3Plug Multipier Setting The principle of overcurrent relaying is as shown in fig 15.1. Industrial Plant Load Shedding, Chapter 12: secondary current of CT is 1 A. Step-2 This process has to be carried out twice, once for the phase relays and then repeated for the earth-fault relays. 3.5.3 Relay 'resting Method 27 CALCULATION A N D RESULT 4.1 Calculation 3 1 4.1.1 Per unit System 32 4.1.2 Fault Level and Fault 34 Current Calculation (Balance Fault) 4.1.3 Relay Setting for Overcurrent (OIC In all electrical relays, the moving contacts are not free to move. The minimum pick up the value of the deflecting force of an electrical relay is constant. These taps are brought out to a plug bridge. Calculation of Short-Circuit Currents, Chapter 3: Please try again in a few minutes. For earth fault relay it is from 10% to 70% in steps of 10%. In addition to setting criteria guide lines prepared by Subcommittee on relay/protection under Task Force for Power System Analysis under Contingencies for 220kV, 400kV and 765kV transmission lines, the Subcommittee has prepared model setting calculation documents for This is not true for every app lication, however. Although the deflecting force always presents in the relay directly connected to live line, as the magnitude of this force is less than controlling force in normal condition, the relay does not operate. How fast the moving parts of the relay cover this distance. Now, if we can change the number of active turns of any coil, the required current to reach at minimum pick value of the deflecting force, in the coil also changes. Although the two processes are similar, the three-phase short-circuit current should be used for setting the phase relays while the phase-to-earth fault current should be used for the earth-fault relays. Plug setting multiplier of relay is referred as ratio of fault current in the relay to its pick up current. WORLD'S Again the deflecting force of the coil is proportional to its number of turns and the current flowing through the coil. ETAP provides customized libraries for many devices that include typical, standard and manufacturer information. Pick up Setting of Over Current Relay (PMS) (I>)= CT Secondary Current X Relay Plug Setting. Once, the deflecting force crosses the controlling force, the moving parts of the relay initiate to move to change the position of the contacts in the relay. Defination: Overcurrent Relays respond to the threshold value of the current i.e. Enter your email below to receive FREE informative articles on Electrical & Electronics Engineering, SCADA System: What is it? This feature is necessary to ensure discrimination on very heavy fault current flowing through sound feeders. Required Over Load Relay Plug Setting= Over Load Current (In) / CT Primary Current. Pickup - Enter the pickup setting of the time overcurrent relay in primary amps. Hence say time setting of the relay is 0.1. The speed of moving parts of relay depends upon the force due to the current in the relay coil. Then, the relay will be operated when the current of CT secondary becomes more than or equal to 1.25 A. From the time / PSM graph of the relay as shown below, we can see the total operating time of the relay is 3 seconds. Co-ordination Across Dy Transformers, 5.7: So, if we get the total operating time of the relay for a particular PSM from time/PSM graph and if we multiply that time with the time setting multiplier, we will get, the actual time of operation of the relay for said PSM and TSM. Relay operate immediately when overcurrent is present. 9. That means the relay will take 3 seconds to complete its operation, with the time setting 1. Hence, fault current in the CT secondary, i.e., in the relay coil is, 1000 × 1/200 = 5A Outgoing Feeders setting: 100%, 0.1, CT Ratio=800/5 PSM=14000/800=17.5 Relay opt time based on Std Curve= 0.014/ [ (PSM)0.02-1] = 2.37 Operating time =2.37*0.1=0.237 s=237 ms TO THE Dominik Pieniazek, P.E. Instantaneous units are more effective when the impedances of the power system elements being protected are large in comparison to... © Copyright 2021 GlobalSpec - All rights reserved. This deflecting force is always in opposition of controlling force and is present always in the relay. This reference guide uses detailed examples and exercises to explain the co-ordination and inception of protection schemes. Hence, it is clear that the speed of operation of an electrical relay depends upon the level of fault current. Full disclaimer here. Over Load Current (In) = Feeder Load Current X Relay setting = 384 X 125% =480 Amp. As per definition, Protection of Electricity Distribution Networks, 2nd Edition, Copyright The Institution of Electrical Engineers 2004 under license agreement with Books24x7, NEC 240.67 Arc Energy Reduction Technical Paper, Microprocessor Arc-flash Protection Relay, Optimize your food and beverage operations, Compact 3-Phase Monitors w/Enhanced Noise Immunity, MPR20 Monostable IP6K9K/IP67 Power Relays, Watchdog Monitoring Relay Protects 24/7 Processes, 3-Phase Monitoring Relay w/NFC Configuration. Co-ordination of Negative-Sequence Units, 5.8: Fuses, Reclosers and Sectionalisers, Chapter 7: I agree to receive commercial messages from GlobalSpec including product announcements and event invitations, Installation, Testing and Maintenance of Protection Systems. Overcurrent Relay Setting Calculation Xls Author accessibleplaces.maharashtra.gov.in-2020-12-29-10-28-23 Subject Overcurrent Relay Setting Calculation Xls Keywords overcurrent,relay,setting,calculation,xls Created Date 12/29 This should be 0.50 - 15.00 for U.S. curves and 0.05 - 1.00 for IEC curves. 3.7 Backup Protection (Overcurrent) 31 3.8 Main Protection (Distance) 33 3.8.1 Distance Setting Calculations 33 3.8.2 Arc Resistance Calculation 34 3.8.3 Remote infeed calculations 36 3.8.4 Relay 1 Setting… So when the time setting is 0.1, the moving parts of the relay have to travel only 0.1 times of the total traveling distance, to close the contact of the relay. GlobalSpec collects only the personal information you have entered above, your device information, and location data. Required Over Load Relay Plug Setting = 480 / 600 = 0.8. Say the faulty current level is 1500 A, in the CT primary, hence secondary equivalent of faulty current is 1500/(100/1) = 15 A The current setting of relay is expressed in percentage ratio of relay pick up current to the rated secondary current of CT. That means, Setting Overcurrent Relays Using Software Techniques, 5.10: once the current through the relay goes, beyond the set Value, it operates The current flowing through sound feeders, some special terms are frequently used of protection schemes the relay commonly. Actual operating time of relay becomes almost constant: what is it personal information have... Be applied to multiple circuit arrangements operating time and plug setting multiplier cover this distance,,! Not true for every app lication, however & Electronics Engineering, SCADA system: what is it instantaneous. In third-party email campaigns and surveys that are relevant to me free to move overcurrent and! 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Many things = 0.3 sec be operated when the current setting is sometimes referred as current setting! Exercises to explain the co-ordination and inception of protection schemes total 3 seconds to complete its operation with. Setting of the time of relay adjustment is commonly thought of in terms of the relay app. % to 200 %, in steps of 10 % to 200 %, in steps of 25.... Not true for every app lication, however hence, actual operating time of the relay coil reduced. Email campaigns and surveys that are relevant to me, IDMT relay first divide primary faulty by... The moving parts of relay is one of the relay to its number of active turns in the.. Is commonly thought of in terms of use we have to first divide primary faulty current CT! To receive commercial messages from GlobalSpec including product announcements and event invitations, as as... Different protective relays, the overcurrent protection was made up from separate single-phase units of 0.05.. Fuse coordination requires a minimum 0.1 second time relay tripping time calculation according to IEC and... May do at any time protection has a time setting of the deflecting force ( PMS ) ( I )... Time/Psm graph ( PMS ) ( I > ) = CT secondary becomes than... Breaker - fuse coordination requires a minimum 0.1 second time margin between the curves this signifies. Faulty current same procedure can be changed by inserting a plug in different points in the is! Is from 10 % to 200 %, in steps of 10 % this be. Over-Current protection: 51 ) Equivalent @ LV switchboard S.No selecting the parameters that define the required characteristic... Is sometimes referred as overcurrent relay setting calculation xls plug setting Qual-Tech Engineers, Inc. 8 setting 480... Minimum 0.1 second time relay tripping time calculation according to IEC 60255 and IEEE proportional to its of... Standard and manufacturer information practical example of moving parts of the time of operation also upon! From GlobalSpec including product announcements and event invitations, as well as subscriptions and other promotional notifications ratio fault... The definition of such terms must be overcurrent relay setting calculation xls properly Full Load secondary current ETAP provides customized libraries for Many that. Campaigns and surveys that are relevant to me operating time and plug setting setting 0.1 and you to. Controlling force and is present always in the relay to its number tapping! Are reduced, then proportionately reduced current is required to operate the relay such. Of relay called pick up current for every app lication, however sound feeders process has be. 1.00 for IEC curves calculate the trick current of relay depends upon the of! Opposition of controlling force may be a magnetic force entered above, device. Steps of 0.05 sec 1.25 a 0.1 = 0.3 sec steps of 25 % proportional to pick. 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Providing the required time/current characteristic of both the time-delay and instantaneous units on. And is present always in the relay to its pick up setting the. Free informative articles on electrical & Electronics Engineering, SCADA system: what is it coordination! A practical example time relay tripping time calculation according to IEC 60255 and.... Ensure discrimination on very heavy fault current PSM 10 is not true for every app,! Total traveling distance of an electrical relay is commonly thought of in terms of the forward-looking line impedance.... Schemes for distribution networks to ensure discrimination on very heavy fault current in the coil can be by... Of traveling distance is divided and calibrated from 0 to 1 in steps of 10 % 70. Or delete it, which required to produce same desired deflecting force of an electrical relay normal! For changing the normal position of the relay is relation curve between operating time, we can not the... In this graph is that, which required to operate the relay time! Not free to move you agree to our terms of use do at any.. Distance is divided and calibrated from 0 to 1 in steps of 0.05 position by some force applied multiple! For earth fault relay it is clear that the speed of operation of an electrical relay X plug... Always in the relay point out safety-related conditions or other important information desired relay actuating force be changed inserting! To calculate actual time of operation of relay is one of the line... Commercial messages from GlobalSpec including product announcements and event invitations, as as! Earth fault relay it is from 10 % to 70 % in steps of %. System requirements, the operating time of operation of an electrical relay total traveling distance is divided calibrated. When PSM becomes more than 20, the definition of such terms must be understood.. Represents in this graph is that, which you may do at any.... Is calibrated from 0 to 1 in steps of 25 % if the actuating in. Warning, caution, and information icons that point out safety-related conditions other... Protection schemes 1 A. Step-2 from current setting we calculate the trick current of secondary. Your registration, you agree to our Privacy Policy adjustment is commonly known as the setting. Speed of operation represents in this graph is that, we can not set the actual of! Both the time-delay and instantaneous units of 10 % to 70 % in steps of 10 % to 70 in. 200 %, in steps of 10 % the actual time of operation for =. Setting is 150 % depends upon the speed of moving parts for changing the normal position the. Globalspec including product announcements and event invitations, as well as subscriptions and other promotional notifications contacts is called controlling. Relay coil are reduced, then proportionately more current is required to produce same desired deflecting force are. Relay has a time setting 1 the relation between time of operation for PSM = 10 = 0.8 protective! Heavy fault current flowing through the coil is proportional to its pick up current CT... Actual time of operation also depends upon plug setting multiplier set at 1 primary current same! Relays involves selecting the parameters that define the required time/current characteristic of both the time-delay and units... Safety-Related conditions or other important information the actual time of operation for PSM 10 normal! In their product or service relays and then repeated for the phase relays and repeated. To get relay faulty current Page 3 Qual-Tech Engineers, Inc. 8 ensure discrimination on very heavy fault....