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Seg High Tech MRI3-ITE Manual

Time overcurrent relay with thermal replica and earth current measuring
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MRI3-ITE(R)
Time overcurrent relay with thermal replica
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and earth current measuring

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Summary of Contents for Seg High Tech MRI3-ITE

  • Page 1 MRI3-ITE(R) Time overcurrent relay with thermal replica and earth current measuring...

  • Page 2: Table Of Contents

    Contents 1 Introduction and Application 2 Features and characteristics 3 Design Connections 5.4.6 Trip delay or time multiplier for phase 3.1.1 Analog input circuits overcurrent element (t I> 3.1.2 Output relays 5.4.7 Reset setting for inverse time tripping Relay output contacts characteristics in the phase current path 3.2.1 Blocking input...
  • Page 3 6 Relay testing and commissioning Power-On Testing the output relays and LEDs Checking the set values Secondary injection test 6.4.1 Test equipment 6.4.2 Example of test circuit for MRI3-ITE 6.4.3 Checking the input circuits and measured values 6.4.4 Example of a test circuit with earth fault directional feature 6.4.5 Checking the operating and resetting...

  • Page 4: Introduction And Application

    • recording of up to eight fault occurences with time stamp, • switch failure protection, • serial data exchange via RS485 interface possible; alternatively with SEG RS485 Pro-Open Data Proto- col or Modbus Protocol, Important: • Display of date and time.

  • Page 5: Design

    Design Connections Figure 3.1: Connection diagram L1.1 L1.2 L2.1 L2.2 L3.1 L3.2 Figure 3.2: Phase current measuring and earth-current detection Figure 3.3: Earth-fault measuring by means of ring-core C.T. (I by means of Holmgreen-circuit. When phase-- and earth-fault current measuring are This connection can be used with three existing phase current transformers when combined phase and earth- combined, the connection has to be realized as per...

  • Page 6: Analog Input Circuits

    Voltage measuring for the directional detection: Relay output contacts Figure 3.4: Measuring of the phase voltages for the directional detection at earth-fault protection (I and I E> E>> 3.1.1 Analog input circuits Figure 3.5: Relay outputs The protection unit receives the analog input signals of the phase currents IL1 (B3-B4), IL2 (B5-B6), IL3 (B7-B8) and the residual current I (B1-B2) each via separate...

  • Page 7: Fault Recorder

    3.2.3 Fault recorder Memory space 6 to 4 is occupied. The MRI3-ITER has a fault value recorder which rec- Memory space 5 is currently being written in ords the measured analog values as instantaneous values. The instantaneous values are scanned at a raster of 1.25 ms (at 50 Hz) and 1.041 ms (at 60 Hz) and saved in a cyclic buffer.

  • Page 8: Front Plate

    Front plate The LED RS, ϑ and ϑ yellow light up yellow (MRI3-ITE) The LED RS, I and I light up yellow (MRI3-ITER). All other LEDs are two-coloured. LEDs left to the alpha- numerical display light-up green during measuring and red at alarm.

  • Page 9: Working Principle

    Working principle Analog circuits Digital circuits The incoming currents from the main current transform- The essential part of the MRI3-ITE relay is a powerful ers on the protected object are converted to voltage microcontroller. All of the operations, from the analog signals in proportion to the currents via the input trans- digital conversion to the relay trip decision, are carried formers and burden.

  • Page 10: Thermal Replica

    Thermal replica 4.3.1 Definitions Thermal time constant τ: Basic current I Set limiting value of the overload current at which the It indicates the time until the temperature of the electri- relay must not trip. This, in general, is the maximally cal equipment to be protected reaches 63% of the sta- permissible operating current in consideration of addi- tionary operating temperature.

  • Page 11: Algorithm

    Algorithm Based on the defined thermal model, one can deduce T (%) that an energy Q is stored in the electrical equipment. k ^2 * 100% After expiry of a long time and with a constant current load, a stationary condition will be achieved in which T(t) 'TRIP' the temperature of the electrical equipment does not...
  • Page 12 Analogous, for the temperature equivalent ϑ with ϑ Different time constants: the following formula is applied: After switching off the electrical equipment (I = 0) temperature will decrease and tend towards ϑ (environmental temperature).   − ϑ ⋅  ϑ...

  • Page 13: Earth Fault Protection

    Earth fault protection 4.5.1 Generator stator earth fault protection With the generator neutral point earthed earthed as shown in Figure 4.4 the MRI3-ITER picks up only to phase earth faults between the generator and the loca- tion of the current transformers supplying the relay. Earth faults beyond the current transformers, i.e.

  • Page 14: Earth-Fault Directional Feature (Er-Relay Type)

    Earth-fault directional feature (ER-relay type) The residual voltage U required for determining earth A built-in earth-fault directional element is available for fault direction can be measured in three different applications to power networks with isolated or with ways, depending on the voltage transformer connec- arc suppressing coil compensated neutral point.
  • Page 15 Figure 4.6: Phase position between the residual voltage and zero sequence current for faulted and non-faulted lines in case of isolated systems (sin ϕ ) By calculating the reactive current component (sin ϕ - residual voltage - zero sequence current adjustment) and then comparing the phase angle in - capacitive component of zero sequence cur- relation to the residual voltage U...

  • Page 16: Demand Imposed On The Main Current Transformers

    Demand imposed on the main current transformers The current transformers have to be rated in such a way, that a saturation should not occur within the fol- lowing operating current ranges: Independent time overcurrent function: K1 = 2 Inverse time overcurrent function: K1 = 20 High-set function: K1 = 1.2 - 1.5...

  • Page 17: Operation And Settings

    Operation and settings Display Function Display shows Pressed pushbutton Corresponding LED SEG Normal operation Measured operating values actual measured values, <SELECT/RESET> L1, L2, L3, E ϑ , ϑ related to I one time for each value Temperature equivalent in % ϑ...

  • Page 18: Leds

    5.1.1 LEDs LED-Name Mode Colour LED-Display Meaning L1, L2, L3, E Display of measuring green continuously Current measuring values (phase or earth current) ϑ and ϑ Display of measuring yellow continuously Measuring of the temperature values equivalent (%) L1, L2, L3, E Pickup flashing Overcurrent pickup...

  • Page 19: Setting Procedure

    Setting procedure 5.3.3 Display of residual voltage U as primary quantity (U prim After push button <SELECT/RESET> has been pressed, The residual voltage can be shown as primary measur- always the next measuring value is indicated. Firstly ing value. For this parameter the transformation ratio of the operating measuring values are indicated and then the VT has to be set accordingly.

  • Page 20: Parameter Switch/External Triggering Of

    5.3.7 Parameter switch/external Protection parameters triggering of the fault recorder 5.4.1 Pickup value of the thermal By means of the parameter-change-over switches it is overload protection I and I possible to activate two different parameter sets. Switching over of the parameter sets can either be For basic current I , the max.

  • Page 21: Time Current Characteristics For Phase Overcurrent Element (Char I>)

    5.4.5 Time current characteristics for 5.4.7 Reset setting for inverse time phase overcurrent element tripping characteristics in the phase (CHAR I>) current path By setting this parameter, one of the following 6 mes- To ensure tripping, even with recurring fault pulses sages appears on the display: shorter than the set trip delay, the reset mode for all DEFT...

  • Page 22: Warn/Trip Changeover

    5.4.12 WARN/TRIP changeover 5.4.18 COS/SIN Measurement (ER - relay type) An earth fault can be parameterized as follows: a) "warn" only the alarm relay trips Depending on the neutral earthing connection of the b) "TRIP" the trip relay trips and tripping values are protected system the directional element of the earth fault relay must be preset to cos ϕ...

  • Page 23: Setting Of Baud-Rate

    5.4.22 Setting of Baud-rate (applies for 5.5.3 Adjustment of trigger occurences Modbus Protocol only) There is a choice between four different occurences: Different transmission rates (Baud rate) can be set for P_UP (PickUP) Storage is initiated after recognition data transmission via Modbus Protocol. of a general activation The rate can be changed by push buttons <+>...

  • Page 24: Additional Functions

    Additional functions 5.7.1 Blocking of the protective functions Blocking of the protective functions: Function Display LED/Colour Temperature NO_B The MRI3-ITE(R) is equipped with a blocking function Temperature NO_B B, T that can be parameterized arbitrary. Connecting sup- I> Overcurrent NO_B I>...
  • Page 25 The assignment of output relays 1 - 4 can be changed by pressing <+> and <-> pushbuttons. The selected assignment can be stored by pressing pushbutton <ENTER> and subsequent input of the password. By pressing pushbutton <SELECT/RESET>, LED I> lights up red.

  • Page 26: Indication Of Measuring And Fault Values

    Indication of measuring and fault values 5.8.1 Indication of measuring values The following measuring quantities can be indicated Earth voltage on the display during normal service: • Aparent Current in phase 1 (LED L1 green) Indication as Range Unit • Aparent Current in phase 2 (LED L2 green) Sec.

  • Page 27: Fault Memory

    5.8.4 Fault memory Reset When the relay is energized or trips, all fault data and Unit MRI3-ITER has the following three possibilities to times are stored in a non-volatile memory manner. The reset the display of the unit as well as the output relay MRI3 is provided with a fault value recorder for max.
  • Page 28 Checking the set values Relay testing and commis- sioning By repeatedly pressing the pushbutton <SELECT>, all relay set values may be checked. Set value modifica- The test instructions following below help to verify the tion can be done with the pushbutton <+><-> and protection relay performance before or during commis- <ENTER>.
  • Page 29 6.4.2 Example of test circuit for MRI3-ITE For testing MRI3-ITE relays only current input signals are required. Figure 6.1 shows a simple example of a single phase test circuit with adjustable current energiz- ing the MRI3-ITE relay under test. Figure 6.1: Test circuit 6.4.3 Checking the input circuits and measured values General hint: When checking the individual tripping...
  • Page 30 6.4.4 Example of a test circuit with earth fault directional feature Figure 6.1: Test circuit The appropriate measuring value is selected via the For testing MRI3-ITER relays with earth fault directional feature, current and voltage sources are required, with <SELECT/RESET> key. The display must indicate 1/3 one of the two sources having to be equipped with a of the rated voltage (±0.5% Un).
  • Page 31 6.4.5 Checking the operating and 6.4.7 Checking the high set element resetting values of the relay of the relay Inject a current which is less than the relay set values in Set a current above the set operating value of I>>. In- phase 1 of the relay and gradually increase the cur- ject the current instantaneously and check that the rent until the relay starts, i.e.
  • Page 32 6.4.9 Testing the external blocking with Block/Trip function In order to simplify things, the short-circuit stage is to Because of its powerful combined indicating and be tested here as described in Chapter 6.4.7. For this measuring functions, the MRI3-ITER relay may be purpose, the parameter for the Block/Trip function tested in the manner of a primary injection test without must be set to "TR_B"...
  • Page 33 Technical data Measuring circuits Rated data: Nominal current I 1 A or 5 A Nominal frequency f 50/60 Hz adjustable Power consumption in current circuit: at I = 1 A 0.2 VA at I = 5 A 0.1 VA Power consumption in voltage circuit: <1 VA Thermal withstand capability...
  • Page 34 Setting ranges and steps 7.3.1 Systemparameter Setting range Step Tolerance Iprim (SEK) 0.002... 50.0 kA 0.001 kA (0.002...0.200) L1 L2 L3 E 0.002 kA (0.200...0.500) 0.005 kA (0.500...1.00) 0.01 kA (1.00...2.00) 0.02 kA (2.00...5.00) 0.05 kA (5.00...10.0) 0.1 kA (10.0...20.0) 0.2 kA (20.0...50.0) Ue>...
  • Page 35 7.3.2 Time overcurrent protection and thermal replica Setting range Step Tolerance ±3% from set value 0.4...3.5 x I (EXIT) 0.02 x I (0.4...1.0) B,Alarm or ±2.5% I 0.05 x I (1.0...3.5) 0.5...5 0.01 (0.5...1.0) 0.02 (1.0...2.0) 0.05 (2.0...5.0) ±3% from set value 0.4...3.5 x I (EXIT) 0.02 x I...
  • Page 36 7.3.3 Earth fault protection Setting range Step Tolerance ±3% from set value 0.01...2.0 x I (EXIT) (E) 0.001 (0.01...0.05) E> or ±0.3% I 0.01...0.45 x I (EXIT) (ER) 0.002 (0.05...0.1) 0.005 (0.1...0.2) 0.01 (0.2...0.5) 0.02 (0.5...1.0) 0.05 (1.0...2.0) ±3% or ±20 ms 0.04 - 260 s (EXIT) 0.02 (0.06...1.0) IE>...
  • Page 37 7.3.4 Earth fault protection (ER-Type) Setting range Step Tolerance ±5% from set value or = 100 V: E> 3 PHA/e-n: 1 - 70 V <0.5% U 1:1: 1- 120 V = 230 V: 3 PHA/e-n: 2 - 160 V 1:1: 2 - 300 V = 400 V: 3 PHA/e-n: 5 - 300 V...
  • Page 38 Tripping characteristics 7.4.1 Thermal characteristic From the equation for the temperature equivalent:   − ϑ ⋅  ϑ − ⋅  ⋅ τ 100% 100% ⋅ ⋅   it is possible to deduce the tripping characteristics according to IEC 155-8. The temperature equivalent of the preload ϑ...
  • Page 39 7.4.2 Preload factor The normal tripping characteristic according to IEC 255-8:      −        = ⋅ τ ln   TRIP     −     ...
  • Page 40 7.4.3 Inverse time overcurrent protection relay According to IEC 255-4 or BS 142 > Normal Inverse (type A) 0 02   −     > Very Inverse (type B)    −    > Extremely Inverse (type C) ...
  • Page 41 Tripping characteristics 10000 1000 1000 I> 20.0 10.0 t[s] t[s] I> 20.0 10.0 0.06 0.06 0.01 5 6 7 8 9 10 5 6 7 8 9 10 Figure 7.4: Extremely Inverse Figure 7.2: Normal Inverse 1000 I> I> 20.0 t[s] t[s] 10.0...
  • Page 42 10000 I> 10.0 1000 I> t[s] 10.0 t[s] 0.05 0.05 5 6 7 8 9 10 5 6 7 8 9 10 Figure 7.6: Long Time Inverse Figure 7.8: RI-Inverse I> 10.0 t[s] 0.05 5 6 7 8 9 10 Figure 7.7: RXIDG-characteristic 7.6 Output relays Contacts: 2 change-over contacts for relay 1 and 2;...
  • Page 43 Order form Time overcurrent- / earth fault current MRI3- relay with thermal replica 3-phase current I>, I>> Rated current Thermal replica Earth current none Rated current Directional feature in earth path none Rated voltage 100 V in earth path 230 V 400 V Housing (12TE) 19“-rack...
  • Page 44 Setting list MRI3-ITE(R) Project: SEG-job.-no.: Function group: = Location: + Relay code: - Relay functions: Password: Date: Note ! All settings must be checked at site and should the occasion arise, adjusted to the object/item to be protected. Setting of parameters...
  • Page 45 Assignment of the blocking function: Default setting Actual setting Parameter switch Set 1 Set 2 Set 1 Set 2 Blocking the protection function PR_B PR_B PR_B Blocking the trip step TR_B Default setting Actual setting Function Blocking No blocking Blocking No blocking Parameter set Set 1...
  • Page 46 Parameter for the fault recorder Default Actual Function Unit settings settings Number of recordings Saving of the recording at the occurrence TRIP Time prior to trigger impulse 0.05 Year settings Year Y=00 Month settings Month M=00 Day settings D=00 Setting of the hour Hour h=00 Setting of the minute...

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