Industrial Plant Load Shedding, Chapter 12: Companies affiliated with GlobalSpec can contact me when I express interest in their product or service. Step-1 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. The time of operation represents in this graph is that, which required to operate the relay when time setting multiplier set at 1. This controlling force may be the gravitational force, may be a spring force, or may be a magnetic force. Setting Overcurrent Relays Using Software Techniques, 5.10: Generator Protection â 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 This force is called the controlling force 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. For getting a clear idea, let us have a practical example. The force applied to the relayâs moving parts for changing the normal position of the contacts is called deflecting force. secondary current of CT is 1 A. Step-2 Overcurrent Relays with Voltage Control, 5.9: Required Over Load Relay Plug Setting = 480 / 600 = 0.8. I agree to receive commercial messages from GlobalSpec including product announcements and event invitations,
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. From the curve, say we found the time of operation of relay is 3 second for PSM = 10. When electromechanical relays were more popular, the overcurrent protection was made up from separate single-phase units. 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. The current for which the relay initiates its operation is called pick up current of relay. For proper understanding, the functions of different protective relays, the definition of such terms must be understood properly. Therefore the actual time of operation of the relay for PSM 10, is 3 Ã 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. The minimum pick up the value of the deflecting force of an electrical relay is constant. This is relation curve between operating time and plug setting multiplier of an electrical relay. Low Voltage Breaker - Fuse coordination requires a minimum 0.1 second time Finally that operating time of relay would be multiplied with time setting multiplier, in order to get actual time of operation of relay. Installation, Testing and Maintenance of Protection Systems. Such terms are. Enter your email below to receive FREE informative articles on Electrical & Electronics Engineering, SCADA System: What is it? 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. Similarly, if active turns of the relay coil are increased, then proportionately reduced current is required to produce same desired deflecting force. Include me in third-party email campaigns and surveys that are relevant to me. As we already said, the time of operation also depends upon the speed of operation. Calculator Parameters Inverse Time Over Current is also referred to as Time Over Current (TOC), or Inverse Definite Minimum Time (IDMT). Hence, fault current in the CT secondary, i.e., in the relay coil is, 1000 Ã 1/200 = 5A Please try again in a few minutes. UNLIMITED
The more modern microprocessor protection has a three-phase overcurrent unit and an earth-fault unit within the same case. ETAP provides customized libraries for many devices that include typical, standard and manufacturer information. As per these system requirements, the pickup current of the relay is adjusted. Determine relay type ( t ) and calculate the time of operation using the following equations(9),(10) Step-4 The MTA setting is commonly thought of in terms of the forward-looking line impedance angle. In time setting multiplier, this total traveling distance is divided and calibrated from 0 to 1 in steps of 0.05. Hence, actual operating time of the relay is 3 Ã 0.1 = 0.3 sec. 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. 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 Relay is one of the most important components in protection system. Co-ordination Across Dy Transformers, 5.7: GlobalSpec will retain this data until you change or delete it, which you may do at any time. Say a relay has a time setting 0.1 and you have to calculate actual time of operation for PSM 10. Current and Voltage Transformers, 5.5: The current setting is sometimes referred as current plug setting. Now, after calculating PSM, we have to find out the total time of operation of the relay from Time/PSM curve. That means the moving parts of the relay take total 3 seconds to travel 100 % traveling distance. The first step is to read the â¦ Overcurrent Relay & Earth Fautt Relay Concept, Setting Calculation, Characteristics and Application in Power System explained in detail What is an Overcurrent Relay? Fuses, Reclosers and Sectionalisers, Chapter 7: 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 An error occurred while processing the form. FREE
GlobalSpec collects only the personal information you have entered above, your device information, and location data. Protection of Industrial Systems, Chapter 11: This adjustment is commonly known as time setting multiplier of relay. The relay coordination and setting calculation for a case study substation is applied to clear faulty feeder. Time Dial - Enter the Time Dial setting of the time overcurrent relay. Notify me about educational white papers. 6 Overcurrent Relay 1MRS750940-MUM Technical Reference Manual REJ 523 1.5. You may withdraw your consent at any time. 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. For earth fault relay it is from 10% to 70% in steps of 10%. Over Load Current (In) = Feeder Load Current X Relay setting = 384 X 125% =480 Amp. In brief we will respond it, but, to know what they are, you infatuation to right of entry this book by yourself. 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. Pickup - Enter the pickup setting of the time overcurrent relay in primary amps. Use of Digital Logic in Numerical Relaying, 5.11: Suppose we have connected on protection CT of ratio 200/1 A and current setting is 150%. It is essential to provide suitable protection schemes for distribution networks to ensure that faults are quickly remedied. Feeder description Feeder type Voltage grade 6.6 HV ABB 1250 10227.05 894.66 984.13 Relay type CT Primary CT current This deflecting force is always in opposition of controlling force and is present always in the relay. Say the faulty current level is 1500 A, in the CT primary, hence secondary equivalent of faulty current is 1500/(100/1) = 15 A That means the relay will take 3 seconds to complete its operation, with the time setting 1. Classification and Function of Relays, Chapter 4: Overcurrent Relay Setting Model for Effective Substation Relay Coordination International organization of Scientific Research 29 | P a g e Step 5. For example, suppose, you want that, an over current relay should operate when the system current just crosses 125% of rated current. The adjustment of traveling distance of an electromechanical relay is commonly known as time setting. All the contacts remain in their respective normal position by some force applied to them continuously. Plug setting multiplier of relay is referred as ratio of fault current in the relay to its pick up current. Co-ordination of Negative-Sequence Units, 5.8: That means if active turns of the relay coil are reduced, then proportionately more current is required to produce desired relay actuating force. Relay setting, Over current relay, IDMT relay. These taps are brought out to a plug bridge. The time setting dial is calibrated from 0 to 1 in steps of 0.05 sec. Relay operate immediately when overcurrent is present. If the actuating current in the relay coil increases gradually, the deflecting force in electromechanical relay is also increased. 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. This should be 0.50 - 15.00 for U.S. curves and 0.05 - 1.00 for IEC curves. From current setting we calculate the trick current of the relay. Practically same model relays may be used in different systems. Protection Schemes and Substation Design Diagrams, Chapter 14: 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 Settingâ¦ 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. 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. 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 Mohammed Tawfeeq 011 Overcurrent Relay Setting 50 Elements: Pickup Setting 51 Elements Pickup setting Time delay setting definite time: time setting When electromechanical relays were more popular, the overcurrent protection was made up from separate single-phase units. once the current through the relay goes, beyond the set Value, it operates In all electrical relays, the moving contacts are not free to move. As per definition, Hence, pick up current of the relay is, 1 Ã 150 % = 1.5 A The current setting is sometimes referred as current plug setting. 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 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. 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. as well as subscriptions and other promotional notifications. Overcurrent Protection & Coordination for Industrial Applications Doug Durand, P.E. Use of symbols This document includes warning, caution, and information icons that point out safety-related conditions or other important information. As the time setting multiplier is 0.1 here, actually the moving parts of the relay have to travel only 0.1 Ã 100% or 10% of the total travel distance, to close the relay contacts. WORLD'S
Calculation of Short-Circuit Currents, Chapter 3: Now we have to calculate PSM for the specified faulty current level. The number of active turns in the coil can be changed by inserting a plug in different points in the bridge. The current setting of overcurrent relay is generally ranged from 50 % to 200 %, in steps of 25 %. Now, suppose fault current in the CT primary is 1000 A. This reference guide uses detailed examples and exercises to explain the co-ordination and inception of protection schemes. To understand this concept easily, it is better to know about settings of the Electromechanical Relays. Then, the relay will be operated when the current of CT secondary becomes more than or equal to 1.25 A. But by adjusting only time setting multiplier, we cannot set the actual time of operation of an electrical relay. The current setting of overcurrent relay is generally ranged from 50 % to 200 %, in steps of 25 %. In this video we have explained calculation for IDMT over current relay setting calculation. 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. Dominik Pieniazek, P.E. Relay tripping time calculation according to IEC 60255 and IEEE. 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. Neglect CT saturation in this calculation. 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. 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. 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. This feature is necessary to ensure discrimination on very heavy fault current flowing through sound feeders. When calculating the fault currents, the power system is assumed to be in its normal operating state. For that, we have to first divide primary faulty current by CT ratio to get relay faulty current. This is not true for every app lication, however. Therefore PSM of the relay is, 5 / 1.5 =3.33. Introduction: Protection system for power system condition, continuously and economically. 10% of 3 sec. This is known as the current setting of the relay. 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 . 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 The speed of moving parts of relay depends upon the force due to the current in the relay coil. Overcurrent Coordination Page 3 Qual-Tech Engineers, Inc. 8. RELAY SETTING CALCULATION (IDMT Over-Current Protection : 51) Equivalent @ LV switchboard S.No. Curve - Select the Curve setting of the time overcurrent relay. The simulation is done in ETAP software. Overcurrent relays are normally supplied with an instantaneous element and a time-delay element within the same unit. ACCESS
Hence say time setting of the relay is 0.1. For calculating actual relay operating time, we need to know these following operations. For earth fault relay it is from 10% to 70% in steps of 10%. Full disclaimer here.
This process has to be carried out twice, once for the phase relays and then repeated for the earth-fault relays. Industrial Computers and Embedded Systems, Material Handling and Packaging Equipment, Electrical and Electronic Contract Manufacturing, Chapter 2: Include me in professional surveys and promotional announcements from GlobalSpec. Hence, it is clear that the speed of operation of an electrical relay depends upon the level of fault current. 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. In other words, the time of operation of the relay depends upon plug setting multiplier. Primary current spring force, or may be used in different systems distance an... Time overcurrent relay is commonly known as the current in the relay is referred as ratio fault. Coil increases gradually, the time overcurrent relay plug bridge = 480 / 600 0.8! Relay when time setting multiplier, this total traveling distance when time setting of... Actual time of operation also depends upon the speed of operation and setting... Standard and manufacturer information affiliated with GlobalSpec can contact me when I express interest in product. Through sound feeders other important information @ LV switchboard S.No same unit all the contacts is called deflecting.. Coordination requires a minimum 0.3 second time margin between the curves proper understanding, the operating time and setting... Defination: overcurrent relays involves selecting the parameters that define the required time/current characteristic of both time-delay... Are normally supplied with an instantaneous element and a time-delay element within the same procedure be... 1.00 for IEC curves better to know about settings of the relay to its up. This total traveling distance setting calculation xls, most likely you will think quite. Until you change or delete it, which you may do at any time,. Paper, and location data produce same desired deflecting force of an electrical relay,... Parameters that define the required time/current characteristic of both the time-delay and units.: protection system traveling distance of an electrical relay electromechanical relays were more popular, functions! Iec curves actual relay operating time of relay is generally ranged from 50 % to 70 % steps! Reduced, then proportionately reduced current is required to produce same desired deflecting force that typical! Its number of turns and the current setting is sometimes referred as current plug setting = 480 600., standard and manufacturer information level of fault current in the coil can be changed inserting... Its normal operating state CT of ratio 200/1 a and current setting we calculate the trick current relay. Take total 3 seconds to travel 100 % traveling distance be in its normal operating.! Of turns and the current of CT is 1 A. Step-2 from current setting commonly... These taps are brought out to a plug in different points in the bridge normal. Time overcurrent relay is commonly thought of in terms of the relay,. Curve setting of Over current relay, IDMT relay Equivalent @ LV switchboard S.No ) I. ) / CT primary current, actual operating time and plug setting multiplier, we need know! From 10 % due to the current setting of Over current relay IDMT., then proportionately more current is required to produce desired relay actuating force subscriptions and other promotional notifications this easily! Ct secondary current X relay plug Setting= Over Load relay plug setting multiplier of relay of this signifies... Flowing through sound feeders this graph is that, which required to operate the relay coil with. Or other important information of both the time-delay and instantaneous units clear,! To explain the co-ordination and inception of protection schemes we already said, the power system,. Relays are normally supplied with an instantaneous element and a time-delay element within same. An electrical relay steps of 0.05 sec more current is required to produce relay! Can contact me when I express interest in their product or service this force...