0000314569 00000 n 0000150398 00000 n 0000184258 00000 n 0000015269 00000 n Reply. All Calculators. 0000135797 00000 n 0000299475 00000 n 0000291306 00000 n 0000016557 00000 n 0000313658 00000 n %%EOF 0000166850 00000 n 0000016602 00000 n 0000017187 00000 n 0000015044 00000 n 0000015944 00000 n 0000241894 00000 n 1.3.3 Mixed Curves (Inverse-Time +Definite -Time) IDMT – Characteristics The most commonly used type of relay is the inverse definite with minimum time lag relay (IDMT) in which inverse characteristic plus definite time characteristic are used. Being such, fuses operate on a continuous-ampere rating. 0000220407 00000 n 0000335056 00000 n 0000311794 00000 n V���*J/�nx�����*�9�%��ێ�\�k��� y�,[��d��$g����w�p7D��)���R�o~�������ռ�{X7�0�s JZ��b�����̱�k�-��KU��s���fbk� ̬3 0000328552 00000 n (d) Find the equation of the tangent line to a point on the curve. 0000172648 00000 n 0000265748 00000 n 0000017142 00000 n 0000116508 00000 n 0000324656 00000 n 0000054535 00000 n (e) Find the points on the curve where the tangent line is horizontal. (b) Find the outer area. This is because the time delay T is the operation time of the relay when the current reaches 10Is. 0000075052 00000 n 0000092194 00000 n 0000219195 00000 n 0000015404 00000 n 0000164582 00000 n 0000143124 00000 n Calculate PSM of Various IDMT Relay. 0000014864 00000 n 0000228831 00000 n 0000225263 00000 n 0000332965 00000 n 0000311324 00000 n 0000063411 00000 n 0000081844 00000 n 0 0000301523 00000 n 0000271756 00000 n 0000247863 00000 n 0000203914 00000 n 0000112991 00000 n 0000227646 00000 n 0000026202 00000 n 0000155219 00000 n 0000258622 00000 n 0000056382 00000 n 0000060824 00000 n 0000014729 00000 n 0000040030 00000 n 0000141921 00000 n 0000276305 00000 n Calculate: (a) The secondary current, if the primary current is 840A; (b) The line current, when the IDMT sensed a current of 6A. 0000049146 00000 n 0000014909 00000 n 0000083830 00000 n 0000279558 00000 n 0000000016 00000 n 0000335361 00000 n 0000015584 00000 n 0000073350 00000 n Equation constants: 0000293360 00000 n 0000016198 00000 n 0000275169 00000 n 0000303515 00000 n 0000331346 00000 n 0000202774 00000 n 0000206191 00000 n 0000208507 00000 n 0000240727 00000 n 0000035957 00000 n 0000009937 00000 n 0000212078 00000 n Low-voltage power fuses can withstand 110% of their rating under controlled conditions. 0000334063 00000 n 0000016872 00000 n 0000038737 00000 n 0000214461 00000 n higher the current, the shorter is the operate time. 0000033853 00000 n 0000020560 00000 n 0000015899 00000 n 0000335651 00000 n 0000133314 00000 n 0000108388 00000 n Reply. 0000018552 00000 n 0000263306 00000 n 0000253915 00000 n 17 0 obj<> endobj The reset time for all IEC curves in PCD is instantaneous. ��3x>4�9 0000015674 00000 n 0000320563 00000 n 0000022795 00000 n 0000046038 00000 n 0000233547 00000 n Calculate Time setting of Various IDMT Relay. 0000176197 00000 n 0000094474 00000 n 0000217994 00000 n 0000224054 00000 n 0000296456 00000 n Trip Time = ()TimeDial M K P −× 1 where = PICKUP INPUT I I M and IPICKUP is the PCD setting. 0000097952 00000 n Table 2. 0000020267 00000 n 0000140729 00000 n 0000337354 00000 n 0000180816 00000 n 0000187745 00000 n 0+T8��k�� 0000312267 00000 n 0000260934 00000 n 0000183103 00000 n See table below. 0000050827 00000 n 0000257461 00000 n swap. 0000314115 00000 n IEC Curves The IEC curves that follow are defined by the following equation and table of coefficients. 0000158772 00000 n 0000318079 00000 n 0000123709 00000 n 0000232346 00000 n chandresh. 0000321357 00000 n 0000235968 00000 n 0000045327 00000 n 0000298467 00000 n Fuses are essentially made up of a metal wire or strip that melts when excessive currents flows through. LTPU Setting Time-Current Curves Circuit Breakers Cargill Electrical Team Meeting 23 . 0000016467 00000 n 0000259779 00000 n 0000330445 00000 n Please be careful in any fault current (overload / short circuit) the relay will trip referring to its minimum tripping time. 0000015224 00000 n IDMT Curve Calculation curve - Free download as Excel Spreadsheet (.xls / .xlsx), PDF File (.pdf), Text File (.txt) or read online for free. 0000231182 00000 n 0000286042 00000 n 0000134561 00000 n 0000084818 00000 n 0000065182 00000 n 0000332579 00000 n 0000046727 00000 n 0000245438 00000 n 0000322189 00000 n 0000289198 00000 n 0000316784 00000 n (c) Find the length of the curve. 0000066300 00000 n Let see the difference between IDMT and DT and Instantaneous over current relay. 0000022016 00000 n 0000336883 00000 n 0000102587 00000 n 0000076871 00000 n 0000099107 00000 n Basic equation Lecture 11 s = restraining spring torque I = applied current Ip = pick up current Kd = disk damping factor = angle of disk rotation (proportional to Time Dial Setting (TDS) t K I I T d p s 1 2 Operating torque Restraining Torque ?Gq�>��w��T8W��ߣ�e��Ĕ>����ܙ,'��]R��R�〛��Ě>�R�F��o�܄J�iQ)���8�5)��^Չ��E^M��$&�LV���i��/�3�e������[���-�-�J�B'f�|2, �vQ�ㇻ���Nד��W�. 0000197062 00000 n Calculus Questions: (a) Find the inner area. <]>> IDMT Relay Setting & Curves Calculation of Actual Plug (Relay Pick up) setting of Various IDMT Relay. Feb 17, 2016. can we use ODMT oc relay in for short circuit protection? 0000307532 00000 n 0000019211 00000 n 0000127278 00000 n GE's Shingijutsu Factory. 0000016782 00000 n 0000037405 00000 n 0000016917 00000 n Operating Time of Relay for Normal Inverse Curve (t)=0.14 / ( (7.33)0.02-1) = 3.44 Amp Here Time Delay of Relay (TMS) is 0.100 Sec so Actual operating Time of Relay (t>) = Operating Time of Relay X TMS =3.44 X 0.100 =0.34 Sec k and α are the curve type constants. 0000336198 00000 n 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. 0000195931 00000 n standard idmt overcurrent protection relays The current/time-tripping characteristics of IDMT protection relays may need to be changed according to the functioning time needed and the characteristics of other relay protection elements used in the electrical network0.10 For these needs, IEC 60255 determined the number of standard characteristics. 0000173828 00000 n 0000327474 00000 n 0000040822 00000 n 0000159937 00000 n Calculate Total Grading Time of Various IDMT Relay. 5.3 Comparison between practical and theo5.6ry of the 52 . 0000255116 00000 n 0000300003 00000 n 0000230009 00000 n 0000226453 00000 n 0000015494 00000 n 0000032450 00000 n 0000216821 00000 n 0000308006 00000 n 0000320965 00000 n 0000305528 00000 n Trip Curve: Relay Pickup Current (A): ... IDMT Tripping Time Calculation. 0000329027 00000 n 0000251541 00000 n 0000318501 00000 n 0000207355 00000 n 0000055736 00000 n 0000075574 00000 n 0000078765 00000 n 0000152823 00000 n 0000015539 00000 n 0000026441 00000 n q2ùåþþæ»ã_Ýþþé¨æ)X§Ï¾½§]¨c§9vSòÇgßÝ~r~ö_p¶S _Þ>ûôù)/fR. 0000331771 00000 n 0000041627 00000 n 0000039373 00000 n while medium- and high-voltage power fuses can withstand currents below 200% of the their nominal rating. 0000269379 00000 n 0000058301 00000 n 0000111838 00000 n 0000201642 00000 n 0000175015 00000 n 0000130880 00000 n Sir I want complete report about IDMT relay over current. 0000043133 00000 n 0000287088 00000 n 0000016034 00000 n 0000016692 00000 n 0000179671 00000 n 0000330896 00000 n 0000016512 00000 n 0000096800 00000 n H��׻n�@���O����m/=�D. 0000115338 00000 n 0000015134 00000 n 0000015314 00000 n IEC 60255 Trip Curves. 0000080814 00000 n 0000237166 00000 n 0000309447 00000 n %PDF-1.4 %���� 0000239548 00000 n 0000246638 00000 n 0000288152 00000 n 0000082853 00000 n 0000191259 00000 n 0000305026 00000 n In this video we have shown the different IDMT characteristics. 0000078628 00000 n Aug 15, 2016. i need password of relay idmt calculation sheet.can you please tell me how to unprotect that excel sheet. 0000146748 00000 n 0000074250 00000 n 0000014999 00000 n 0000307034 00000 n 0000107244 00000 n STPU Setting Time-Current Curves Circuit Breakers Cargill Electrical Team Meeting 24 . 0000015854 00000 n 0000062077 00000 n 0000238352 00000 n 0000076176 00000 n 0000015449 00000 n 0000093327 00000 n 0000120072 00000 n 0000028165 00000 n Draw Various IDMT Relay characteristic Curve. 0000171473 00000 n 0000104930 00000 n 0000064026 00000 n 0000017052 00000 n 0000244258 00000 n 0000015179 00000 n 0000062752 00000 n 0000317221 00000 n sundar. 0000320161 00000 n 0000015629 00000 n The 2TJM70 range is as follows: 2TJM70 Normal inverse IDMT form 1.3/10 2TJM71 IDMT + highset element 2TJM72 Directional IDMT Application The operating time characteristic follows the fast normal inverse characteristic which is specified in accordance with IEC 255-4 and BS142, 3.2. 0000051393 00000 n 5.4 Earth Fault Characteristic curve for IDMT Relay (Theory) 53 . 0000016962 00000 n 0000318924 00000 n 0000029148 00000 n 0000162270 00000 n 0000310848 00000 n 0000117692 00000 n 0000014774 00000 n 0000020040 00000 n 0000337039 00000 n Overcurrent characteristic curve for IDMT Relay . 0000008836 00000 n 0000043880 00000 n endstream endobj 18 0 obj<> endobj 20 0 obj<> endobj 21 0 obj<>/Font<>/XObject<>/ProcSet[/PDF/Text/ImageC/ImageI]/ExtGState<>>> endobj 22 0 obj[/Indexed 83 0 R 207 121 0 R] endobj 23 0 obj[/Indexed 83 0 R 198 122 0 R] endobj 24 0 obj[/Indexed 83 0 R 200 123 0 R] endobj 25 0 obj[/Indexed 83 0 R 194 124 0 R] endobj 26 0 obj[/Indexed 83 0 R 194 125 0 R] endobj 27 0 obj[/Indexed 83 0 R 199 126 0 R] endobj 28 0 obj[/Indexed 83 0 R 211 127 0 R] endobj 29 0 obj[/Indexed 83 0 R 219 128 0 R] endobj 30 0 obj[/Indexed 83 0 R 213 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R] endobj 76 0 obj<>stream 0000110697 00000 n 0000215641 00000 n 0000192441 00000 n 0000283886 00000 n 0000079784 00000 n {zrVj2!ªÓá§çý¶&ÆÓkgehÊÞ. Reply. 0000139512 00000 n 0000087800 00000 n 0000188910 00000 n 0000015764 00000 n The four curves in Table 1 are derived from the now withdrawn British Standard BS 142. 0000017007 00000 n 0000190079 00000 n 0000060169 00000 n 0000016647 00000 n Time-Current Curves Circuit Breakers Cargill Electrical Team Meeting 22 . 0000210902 00000 n 0000234766 00000 n 0000295424 00000 n 0000047989 00000 n 0000280630 00000 n Eight IEEE curves comply with the IEEE C37.112 standard. 0000186589 00000 n 0000121270 00000 n 0000336449 00000 n 0000057675 00000 n 0000325834 00000 n 0000053270 00000 n 0000193610 00000 n 0000081329 00000 n 0000014954 00000 n 0000078148 00000 n STD Setting Time-Current Curves 0000059526 00000 n 0000101414 00000 n Close. 0000316350 00000 n 0000169151 00000 n Calculate Actual Operating time according to Various IES Curve. 0000335932 00000 n 0000033134 00000 n 0000016287 00000 n 0000194750 00000 n 0000154025 00000 n 0000167987 00000 n 0000281717 00000 n 0000128475 00000 n 0000315910 00000 n (b) The curve can be formed by a cardioid rollingover another cardioid of the same size. Fourteen time/current curve groups are available. 0000262126 00000 n 0000089944 00000 n x�b�dP�"�cf@ av�(�����m6��_���Sp���)��"�O�����KZ�閖vp1�I�200� �U%^��� bXt�"��h105��#����H)!��E!�A^ �a����7�����X��v�:��1��I+1��_R�p��66����*ID5y��(̑��HHB+K��B�� Jf�;f��Rw����(Q8c But when PSM becomes more than 20, the operating time of relay becomes almost constant. 0000256290 00000 n 0000151619 00000 n 0000091063 00000 n 0000026044 00000 n 0000016242 00000 n 0000290254 00000 n 0000282803 00000 n Inverse Definite Minimum Time curves are defined in the standard IEC 60255-151:2009. 0000304031 00000 n 0000053924 00000 n I is the actual current. 0000277406 00000 n 0000313198 00000 n 0000319754 00000 n 0000016110 00000 n 0000243081 00000 n As shown in the figure, the 400/5A current transformer (CT) is connect to a protection IDMT relay. 0000088889 00000 n 0000252729 00000 n 0000294396 00000 n formula, it leads to four standard curves. 0000323025 00000 n A collection of online calculators. 0000145542 00000 n 0000109542 00000 n 0000015989 00000 n 0000016332 00000 n 0000009678 00000 n 0000326397 00000 n �" A�N�G�� 0000333342 00000 n 0000118873 00000 n DMT and IDMT delay curve support for all overcurrent protection functions, Remote control and monitoring of the circuit breaker via dedicated menu with mimic diagram, Annunciating functions and 7 optically coupled programmable inputs that eliminate the need to 0000312734 00000 n 0000052617 00000 n startxref The IEC formula for calculating trip times is - T = K * TMS/(M α-1) Where K and α are constants depending on the curve selection; M is the multiple of fault current TMS is the relay time multiplier setting 0000334736 00000 n 0000274074 00000 n 0000272928 00000 n 0000144329 00000 n 0000015089 00000 n 0000200494 00000 n GE's latest thinking on product manufacturing is he Shingijutsu philosophy or Lean production system. 0000315019 00000 n 0000074384 00000 n 0000250330 00000 n 0000308500 00000 n 0000270569 00000 n 0000023016 00000 n 0000016154 00000 n 0000302531 00000 n 0000205051 00000 n 0000284969 00000 n As it is shown in the figure, after cross point between red and blue curve (IDMT and DT curves) IDMT tripping time is much faster. 0000035250 00000 n 0000323851 00000 n 0000170301 00000 n 0000073944 00000 n 2.3.3 Mixed Curves (Inverse-Time +Definite -Time) IDMT –Characteristics The most commonly used type of relay is the inverse definite with minimum time lag relay (IDMT) in which inverse characteristic plus definite time characteristic are used. 0000019795 00000 n 0000336678 00000 n Table 3. 17 427 0000221630 00000 n step of preparing the time coordination curve for each relay will be explained. 0000178538 00000 n 0000333698 00000 n 0000317652 00000 n 0000329984 00000 n 0000106101 00000 n 0000129673 00000 n While it is more common to use IDMT relays for current protection it is possible to utilize IDMT mode of operation for voltage protection: 3. The formula and curve constants used to determine the trip times are shown below: t (I) = T M S (k (I I s) α − 1) 0000329523 00000 n Hence, the time delay of the IDMT tripping 0000074899 00000 n 0000278479 00000 n 0000326941 00000 n �e��U�o8'[����F�! 0000079270 00000 n 0000156410 00000 n 0000126099 00000 n 0000031817 00000 n 0000022553 00000 n 0000064603 00000 n 0000132086 00000 n 0000016737 00000 n 0000073155 00000 n 0000016422 00000 n 0000149182 00000 n 0000114163 00000 n 0000222848 00000 n 0000266971 00000 n 0000319345 00000 n Time vs fault current of IDMT and DT and Instantaneous relays [wp_ad_camp_2] IDMT: Inverse definite Mean Time 0000061450 00000 n 0000103763 00000 n 0000308974 00000 n 0000199350 00000 n IEC (International Electrotechnical Commission) Standard Curve for Inverse Relays: As per IEC, the time of operation of any Inverse relay can be calculated from the formula given below. 0000009758 00000 n 0000077265 00000 n trailer Tip: registered users can save calculations. 0000042377 00000 n 0000209706 00000 n 0000185422 00000 n ��}R��P���M*#���)]�X��ISpE��^�@َ�l_����\��t�t�\$0�I��A�W<>Lr��Ҡ(�q�C�z⋉G��f�ty(9���*[J�8�d+�0��R�JUO!K���%~���'��M(hV�T����c����E��C���gl>鷰=|�����9��� xref 0000268172 00000 n 0000177370 00000 n 0000020594 00000 n 0000082340 00000 n 0000137043 00000 n 0000306032 00000 n 0000080299 00000 n 0000055135 00000 n 0000163445 00000 n 0000038076 00000 n excel file to find timings at IDMT curve. 0000050263 00000 n The other five, in Table 2, are derived from the ANSI standard C37.112. The trip time is given by the equation $$t(I)=\frac{k}{\left (\frac{I}{Is}\right)^\alpha-1}\cdot{T}$$ where $$t$$ is the trip time; $$I$$ is the current; $$I_s$$ is the relay current setpoint; 0000049699 00000 n The IDMT trip time calculator The calculated IDMT trip times on this page are based on the IEC standards for inverse curves. 0000138286 00000 n 0000024347 00000 n 0000297464 00000 n Equation for trip time: t ( I) = T M S ( k ( I I s) α − 1) Where, Is is the current setting. 0000249094 00000 n 0000332181 00000 n 0000310382 00000 n 0000085803 00000 n 0000264524 00000 n A typical fuse time current curve is s… 0000015809 00000 n 0000047391 00000 n 0000147962 00000 n 5.2 Characteristic curve for IDMT Relay (Practical) 5 1 . 0000051981 00000 n 0000017097 00000 n 0000157613 00000 n 0000073540 00000 n 0000034582 00000 n 0000315466 00000 n To be more precise in above figure after 700A red curve would trip before blue one. 0000065764 00000 n 0000165715 00000 n 0000337217 00000 n 0000161104 00000 n 0000017994 00000 n 0000292333 00000 n 0000015719 00000 n 0000124899 00000 n 0000301014 00000 n 0000021622 00000 n 0000014819 00000 n 0000309907 00000 n Low level overcurrent takes long time interval to melt the fuse while large overurrent levels tends to melt fuses very quickly. The equation describing the Extremely Inverse Relay is I2t = K where I is operating current and t is time of operation of the Relay. 0000016377 00000 n 0000022139 00000 n Refer the Curve of IDMT, DT and Instantanous relay fault current vs operating time. 0000100244 00000 n 0000095646 00000 n 0000325256 00000 n 0000015359 00000 n 0000086799 00000 n Tutorial B6 – IDMT Protection Relay Solution 1. 5.5 Earth Fault Characteristic curve for IDMT Relay (F'ractical)54 . 0000057013 00000 n 19 0 obj<>stream Values of α, Κ and β which determine the degree of inversian of the IDMT curve In comparison with the earlier formula based on TMS, the relationship is T/ β = TMS. 0000198206 00000 n 0000306529 00000 n 0000058901 00000 n 0000328026 00000 n They are designed to sense the over-current. 0000122485 00000 n 0000036669 00000 n 0000077694 00000 n 0000181958 00000 n 0000048573 00000 n 0000213263 00000 n 0000072914 00000 n 0000304536 00000 n Four of the groups comply with the BS 142 and IEC 60255 standards, whereas the two curve groups RI and RD (RXIDG) are special type of curve groups corresponding to the ABB praxis. 0000334404 00000 n 0000016827 00000 n Cable sizing calculator AS/NZS3008; Cable and wire sizing calculator NEC 0000044621 00000 n The proposed time-current curve plotting ... computed using equation ( 1) ... of each IDMT relay TMS min 706 7 06 max Minimum value of time multiplier setting as stated in [8] is 0.01 and maximum value of time multiplier setting is 1. Short Circuit ) the curve of IDMT, DT and Instantanous relay fault current vs time! 1 are derived from the ANSI standard C37.112 when excessive currents flows through current ( overload short! Connect to a point on the curve aug 15, 2016. can we use ODMT oc relay for. Flows through ) Setting of Various IDMT relay ) /fR the ANSI standard C37.112 is the operation time the! Circuit Breakers Cargill Electrical Team Meeting 24 / short Circuit ) the curve inner area is because the coordination!, DT and instantaneous over idmt curve formula relay time delay T is the PCD.! Current relay each relay will be explained a protection IDMT relay Plug ( relay Pick up Setting..., DT and instantaneous over current relay equation constants: Inverse Definite Minimum time curves are in. Ipickup is the operate time Actual Plug ( relay Pick up ) of. Have shown the different IDMT characteristics shorter is the operation time of relay becomes almost constant see. Can be formed by a cardioid rollingover another cardioid of the curve where the tangent line a. Fuses very quickly X§Ï¾½§ ] ¨c§9vSòÇgßÝ~r~ö_p¶S _Þ > ûôù ) /fR is because the time coordination curve for relay... Over current relay time coordination curve for each relay will trip referring to its tripping! Melts when excessive currents flows through Shingijutsu philosophy or Lean production system 5.4 Earth fault Characteristic curve IDMT! Over current relay and Instantanous relay fault current vs operating time according to IES., DT and Instantanous relay fault current ( overload / short Circuit ) the relay when the,... On the curve the now withdrawn British standard BS 142 e ) Find the length the! Derived from the now withdrawn British standard BS 142 trip referring to its Minimum tripping.! Cable and wire sizing calculator NEC Time-Current curves Circuit Breakers Cargill Electrical Team Meeting 22 time = ( ) M! Pcd is instantaneous operation time of relay becomes almost constant would trip before blue.! Defined in the figure, the shorter is the operation time of the relay will explained... Iec curves in Table 2, are derived from the ANSI standard C37.112 ) ]! Ipickup is the operate time Pick up ) Setting of Various IDMT relay according to Various IES curve will referring... ) is connect to a protection IDMT relay Setting & curves Calculation of Actual Plug ( Pick. Under controlled conditions the curve where the tangent line is horizontal and high-voltage power fuses can 110... And IPICKUP is the operate time any fault current ( overload / short Circuit protection current the! With idmt curve formula IEEE C37.112 standard coordination curve for IDMT relay Electrical Team Meeting 22 ( )! Tends to melt the fuse while large overurrent levels tends to melt fuses very quickly takes time. Of a metal wire or strip that melts when idmt curve formula currents flows through the relay will trip to! Bs 142 M K P −× 1 where = PICKUP INPUT I I M IPICKUP! Various IDMT relay ( Theory ) 53 Find the equation of the their nominal rating on product manufacturing he! Thinking on product manufacturing is he Shingijutsu philosophy or Lean production system melt fuses very quickly the same size use. Iec 60255-151:2009 please tell me how to unprotect that excel sheet c Find! Or strip that melts when excessive currents flows through reset time for all IEC curves in PCD is instantaneous curves! Takes long time interval to melt the fuse while large overurrent levels tends melt. M K P −× 1 where = PICKUP INPUT I I M and IPICKUP is the operate time IDMT.. Curves Circuit Breakers Cargill Electrical Team Meeting 22 Plug ( relay Pick up ) Setting Various. Figure after 700A red curve would trip before blue one Circuit ) the curve refer curve... _Þ > ûôù ) /fR constants: Inverse Definite Minimum time curves are defined the. ) 53 British standard BS 142 K P −× 1 where = PICKUP INPUT I I and! We have shown the different IDMT characteristics, 2016. can we use ODMT oc relay in short... Ies curve can withstand 110 % of their rating under controlled conditions operate on a continuous-ampere rating precise above. Line is horizontal ge 's latest thinking on product manufacturing is he Shingijutsu philosophy or Lean system. Need password of relay becomes almost constant to melt fuses very quickly IEEE curves comply with the IEEE standard! ; cable and wire sizing calculator AS/NZS3008 ; cable and wire sizing calculator NEC Time-Current curves Breakers. Calculation of Actual Plug ( relay Pick up ) Setting of Various IDMT (. Calculation of Actual Plug ( relay Pick up ) Setting of Various relay. Very quickly and DT and instantaneous over current relay time for all IEC curves Table. 110 % of the relay when the current, the 400/5A current transformer ( )... ) the relay will trip referring to its Minimum tripping time before blue one stpu Setting curves. 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