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Manual MRI3 GB 

Woodward 

DOK-TD-MRI3 Rev.A 

59 

7.4  Inverse time characteristics 

 

 

Figure 7.1: Normal Inverse (Type A) 

 
 

 

Figure 7.2: Very Inverse (Type B) 

 
 

 

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Summary of Contents for MRI3

Page 1: ...MRI3 Digital multifunctional relay for overcurrent protection Manual MRI3 Revision A...

Page 2: ...the right to update any portion of this publication at any time Information provided by Woodward Governor Company is believed to be correct and reliable However no responsibility is as sumed by Woodw...

Page 3: ...y of residual voltage UE as primary quantity Uprim Usec 31 5 3 4 Voltage transformer connection for residual voltage measuring 3pha e n 1 1 31 5 3 5 Nominal frequency 31 5 3 6 Display of the activatio...

Page 4: ...ple of test circuit for MRI3 relays without directional feature 47 6 4 3 Checking the input circuits and measured values 48 6 4 4 Checking the operating and resetting values of the relay 48 6 4 5 Chec...

Page 5: ...o element low and high set earth fault protection with definite or inverse time characteristics integrated determination of earth fault direction for application to power system networks with isolated...

Page 6: ...nsitive earth fault current measuring with or without directional feature X and XR relay type determination of earth short circuit fault direction for systems with solidly earthed or resistance earthe...

Page 7: ...ring Figure 3 1 Measuring of the phase currents for over current and short circuit protection I I Figure 3 2 Earth fault measuring by means of ring core C T IE When phase and earth fault current measu...

Page 8: ...required Disadvantage of holmgreen circuit At saturation of one or more C Ts the relay detects seeming an earth current This arrow shows the current flow in forward direction for this LED lights up g...

Page 9: ...erter For the unit type with earth fault directional features ER XR relay type the residual voltage UE in the secondary circuit of the voltage transformers is internally formed In case no directional...

Page 10: ...3 1 3 Blocking input The blocking functions adjusted before will be blocked if an auxiliary voltage is connected to terminals D8 E8 See chapter 5 7 1 3 1 4 External reset input Please refer to chapte...

Page 11: ...of par tial segments If this max number of fault event has been exceeded the fault recorder block any further recordings in order to prevent that the stored data are written over After the data have b...

Page 12: ...IX IRE IRX IR IER IXR IRER IRXR ER XR EX ISR IRSR SR Display of measuring val ues as primary quantities Iprim phase X X X X X X X X Display of earth current as primary quantities Iprim earth X X X X...

Page 13: ...ifferent relay types 2 Reset setting for inverse time characteristics in phase current path 3 Reset setting for inverse time characteristics in earth current path Parameter for the fault recorder Rela...

Page 14: ...Woodward Manual MRI3 GB 14 DOK TD MRI3 Rev A Front plates Figure 3 9 Front plate MRI3 I Figure 3 10 Front plate MRI3 E X...

Page 15: ...Manual MRI3 GB Woodward DOK TD MRI3 Rev A 15 Figure 3 11 Front plate MRI3 IR Figure 3 12 Front plate MRI3 ER XR...

Page 16: ...Woodward Manual MRI3 GB 16 DOK TD MRI3 Rev A Figure 3 13 Front plate MRI3 SR Figure 3 14 Front plate MRI3 IRER IRXR and MRI3 IER IXR...

Page 17: ...n LED lights up to indicate the forward direction the red LED indicates the backward direction The LED marked with letters RS lights up during setting of the slave address of the device for serial dat...

Page 18: ...ram is located in an EPROM Electrically Programmable Read Only Memory With this program the CPU of the microcontroller calculates the three phase currents and ground current in order to detect a possi...

Page 19: ...ses 4 3 1 Reversal in direction during the activation phase Reversal of the current direction during the activation phase can lead to hyper functions This main ly applies to installations where parall...

Page 20: ...elation to the forward direction of the line The critical point here is the MRI3 No 1 Using delay action in directional recognition it is possible to prevent shut down of the fault free line The follo...

Page 21: ...D MRI3 Rev A 21 If line impedance and internal resistance of the generator is only ohmic If line impedance and internal resistance of the generator is only inductive The maximum sensitivity angle corr...

Page 22: ...sturbances at least 2 periods 40 ms at 50 Hz are evaluated For the MRI3 overcurrent relays with directional feature different time delays or time multipliers can be set for forward and backward faults...

Page 23: ...mers supplying the relay Earth faults beyond the current transformers i e on the consumer or line side will not be detected Figure 4 7 Generator stator earth fault protection 4 4 2 System earth fault...

Page 24: ...nt ways depending on the voltage transformer connections refer to Table 4 1 Connection of the voltage transformers Total current can be measured by connecting the unit either to a ring core C T or to...

Page 25: ...current IC b lags behind the residual voltage at 90 Figure 4 10 Phase position between the residual voltage and zero sequence current for faulted and non faulted lines in case of compensated systems...

Page 26: ...and therefore also on the coincidence time measurement between earth cur rent and zero sequence voltage The zero sequence voltage U0 required for determining the earth short circuit fault direction is...

Page 27: ...at 170 in relation to the zero sequence voltage U0 see Figure 4 12 Figure 4 12 Characteristic angle in resistance earthed systems RESI The pickup range of the directional element is set by turning th...

Page 28: ...uch a way that a saturation should not occur within the following operating current ranges Independent time overcurrent function K1 2 Inverse time overcurrent function K1 20 High set function K1 1 2 1...

Page 29: ...eature RCA in Grad SELECT RESET LED green Warning or trip at earth fault measuring E and ER XR types TRIP WARN SELECT RESET IE Measured method of the residual voltage UE 1 3 PHA E N 1 1 SELECT RESET U...

Page 30: ...ESET System reset WW SELECT RESET for about 3 s Table 5 1 possible indication messages on the display 1 refer to 4 4 2 only Modbus 5 2 Setting procedure After push button SELECT RESET has been pressed...

Page 31: ...o that the measuring value is shown as primary current in ampere Apart from that the indication refers to of IN 5 3 3 Display of residual voltage UE as primary quantity Uprim Usec The residual voltage...

Page 32: ..._FR Ext Triggering of the FR Reset input R_FR Blocking input Ext Trigger for FR S2_FR Parameter switch Ext Trigger for FR With the settings SET1 or SET2 the parameter set is activated by software Term...

Page 33: ...f flashing LED tI The most sensitive time setting value means the fastest tripping for the selected relay characteristic If a definite time characteristic has been se lected the display shows the trip...

Page 34: ...d The high set element can be blocked via terminals E8 D8 if the corresponding blocking parameter is set to bloc refer to chapter 5 7 1 5 4 6 Trip delay for high set element tI Independent from the ch...

Page 35: ...characteristics can be chosen by using pushbuttons and can be stored by using ENTER pushbutton 5 4 12 Trip delay or time multiplier for earth fault element tIE Similar to chapter 5 4 3 5 4 13 Reset mo...

Page 36: ...d on supervision of phase currents during tripping events Only af ter tripping this protective function becomes active The test criterion is whether all phase currents are dropped to 1 x IN within tCB...

Page 37: ...s with 60 Hz 7 8 recordings for a duration of 2 s with 50 Hz 1 66 s with 60 Hz is written over at new trigger signal 5 5 3 5 5 3 Adjustment of trigger occurrences There is a choice between four diffe...

Page 38: ...s are excited and the set tripping time expires Tripping only takes place when a the voltage at the blocking input D8 E8 is reduced b the voltage at the blocking input D8 E8 is applied the tripping ti...

Page 39: ...only activated after elapse of the tripping delay After the assignment mode has been activated first LED I lights up green Now one or several of the four output relays can be assigned to current elem...

Page 40: ...ut relays default settings 5 8 Setting value calculation 5 8 1 Definite time overcurrent element Low set element I The pickup current setting is determined by the load capacity of the protected object...

Page 41: ...ependent to the fault current 5 9 Indication of measuring and fault values 5 9 1 Indication of measuring values The following measuring quantities can be indicated on the display during normal service...

Page 42: ...k0 100k 999k 1M00 2M00 A kA kA kA kA MA Active portion IP 00 999 k00 k99 1k0 9k9 10k 99k M10 M99 1M0 2M0 A kA kA kA MA MA Reactive portion IQ 00 999 k00 k99 1k0 9k9 10k 99k M10 M99 1M0 2M0 A kA kA kA...

Page 43: ...ent 000 999 k000 k999 1k00 9k99 10k0 99k0 100k 999k 1M00 2M00 A kA kA kA kA MA Active portion IP 00 999 k00 k99 1k0 9k9 10k 99k M10 M99 1M0 2M0 A kA kA kA MA MA Reactive portion IQ 00 999 k00 k99 1k0...

Page 44: ...bbreviations FLT1 FLT2 FLT3 are displayed FLT1 means the latest fault data set recorded At the same time the parameter set active at the occurrence is shown By pressing SELECT RESET the fault measurin...

Page 45: ...applying auxiliary voltage to C8 D8 Software Reset The software reset has the same effect as the SELECT RESET push button see also communication protocol of RS485 interface The display can only be res...

Page 46: ...uit to the circuit breaker if tripping is not desired By pressing the push button TRIP once the display shows the first part of the software version of the relay e g D08 By pressing the push button TR...

Page 47: ...tage supply unit adjustable from 0 to 1 2 x Un Only for relays with directional feature timer to measure the operating time Accuracy class 10 ms switching device and test leads and tools 6 4 2 Example...

Page 48: ...and earth current input circuits in the same manner Accuracy of earth current measuring 3 of measuring value or 0 1 of In for E type 0 01 of In for X type 6 4 5 Checking the relay operating time To c...

Page 49: ...t relay with relay connection angle of 0 The re lay input currents and their corresponding reference voltages are shown in Table 6 1 also refer to 4 3 If the single phase test circuit as illustrated i...

Page 50: ...upon the current input I1 The voltage source is to be con nected as provided for in Table 6 1 With an angle setting of 49o leading relay 2 must respond and LED lights up green If the angle is now cha...

Page 51: ...or testing a relay with earth fault directional feature one of the input energizing quantity voltage shall be applied to the relay with a constant value within its effective range The other input ener...

Page 52: ...e set to TR_B first value in the blocking menu of the protection functions Chapter 5 7 1 The appertaining Block Trip time should be longer than the set tripping time tI see chapter 5 4 18 Here too a c...

Page 53: ...ked and the actual power factor may be calculated and compared it with the cos meter indication on the switchboard to verify that the relay is connected to the power system with the correct polarity 6...

Page 54: ...nd in voltage circuit continuously 1 5 x UN 7 2 Common data Dropout to pickup ratio 97 Dropout to pickup ratio for phase current in range 0 2 x IN to 0 5 x IN 100 Returning time 30 ms Time lag error c...

Page 55: ...05 10 EXIT inverse time 0 001 0 002 0 005 0 01 0 02 0 05 x IN 0 01 0 02 0 05 IN 0 01 0 02 0 05 0 1 0 2 0 5 1 0 2 0 5 0 10 20 s 0 01 0 02 0 05 0 1 0 2 5 from set value or 0 3 IN 0 3 IN SR 0 03 IN YR 3...

Page 56: ...2 300 V UN 400 V 3 PHA e n 5 300 V 1 1 5 500 V 1 V 1 V 2 V 2 V 5 V 5 V 5 from set value or 0 5 UN 7 3 5 Block Trip time Block Trip 0 1 2 0 s EXIT 0 01 0 02 0 05 0 1 s 1 or 10 ms 7 3 6 Switch failure...

Page 57: ...IEC 255 4 or BS 142 Normal Inverse Type A 0 14 1 Very Inverse Type B 13 5 1 Extremely Inverse Type C 80 1 Long Time Inverse 120 1 RI Inverse Time 1 0 339 0 236 RXIDG characteristic 5 8 1 3 Where t tri...

Page 58: ...1 Determination of earth fault direction MRl3 ER XR Measurement of active current component for compensated systems IE x cos Measurement of reactive current component for isolated systems IE x sin Ang...

Page 59: ...ormal Inverse Type A Figure 7 2 Very Inverse Type B 1 2 3 4 5 6 7 8 910 20 I IS 0 1 1 10 100 1000 t s tI 0 05 0 1 0 2 0 3 0 4 0 5 0 6 0 8 1 0 1 4 2 0 3 0 4 0 6 0 8 0 10 0 1 2 3 4 5 6 7 8 910 20 I IS 0...

Page 60: ...C Figure 7 4 RI Inverse 1 2 3 4 5 6 7 8 910 20 I IS 0 01 0 1 1 10 100 1000 t s tI 0 05 0 05 0 1 0 1 0 2 0 3 0 4 0 5 0 6 0 8 1 0 10 0 1 4 2 0 3 0 4 0 6 0 8 0 1 2 3 4 5 6 7 8 910 20 I IS 0 1 1 10 100 t...

Page 61: ...gure 7 6 RXIDG characteristic 1 2 3 4 5 6 7 8 910 20 I IS 0 1 1 10 100 1000 10000 t s tI 1 0 2 0 10 0 8 0 6 0 5 0 4 0 3 0 0 8 0 6 0 5 0 4 0 3 0 2 0 1 0 05 1 2 3 4 5 6 7 8 910 20 I IS 0 1 1 10 100 t s...

Page 62: ...ntacts Number of relays dependent on relay type Contacts 2 change over contacts for trip relay 1 change over contact for alarm relays Technical data subject to change without notice 1 10 I IN 0 01 0 1...

Page 63: ...tive 1 A 5 A 1 solid grounded 1 A 1 5 A 1 solid grounded 1 A sensitive 5 A E1 E5 X1 X5 S1 S5 Y1 Y5 Directional feature in earth path none Rated voltage2 100 V in earth circuit 230 V 400 V R1 R2 R4 Hou...

Page 64: ...tion parameter Relay type MRI3 I IE IX IRE IRX IR IER IXR IRER IRXR ER XR E X ISR IRSR SR Default settings Actual settings 2 parameter sets X X X X X X X X X X X Set 1 Set 2 Set 1 Set 2 I X X X X X X...

Page 65: ...setting Actual settings Plugged No plugged X No function X Code jumper Low High range for reset input Low High range for blockage input Default settings Actual settings Default settings Actual settin...

Page 66: ...Parameter set Set 1 Set 2 Set 1 Set 2 Set 1 Sete 2 Set 1 Set 2 I X X I X X IE X X IE X X tCBFP X X This technical manual is valid for Software version D01 9 03 MRI3 ER IER IRER D20 3 03 MRI3 XR IXR IR...

Page 67: ...Manual MRI3 GB Woodward DOK TD MRI3 Rev A 67...

Page 68: ...ermany Postfach 10 07 55 P O Box D 47884 Kempen Germany Phone 49 0 21 52 145 1 Internet www woodward com Sales Phone 49 0 21 52 145 216 or 342 Telefax 49 0 21 52 145 354 e mail salesEMEA_PGD woodward...

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