Page 1 Protection Relay REX 521 Technical Reference Manual, Standard Configurations...
Page 3: Table Of Contents
3.3.3. Standard configuration H03 ..........41 3.3.3.1. Features .............41 3.3.3.2. Application ............42 3.3.4. Standard configuration H04 ..........44 3.3.4.1. Features .............44 3.3.4.2. Application ............45 3.3.5. Standard configuration H05 ..........47 3.3.5.1. Features .............47 3.3.5.2. Application ............48 © Copyright 2005 ABB Oy, Distribution Automation, Vaasa, FINLAND...
Page 4 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 3.3.6. Standard configuration H06 ..........50 3.3.6.1. Features ............. 50 3.3.6.2. Application ............51 3.3.7. Standard configuration H07 ..........53 3.3.7.1. Features ............. 53 3.3.7.2. Application ............54 3.3.8. Standard configuration H08 (No sensors) ....... 56 3.3.8.1.
Page 5 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 5.2.1. Interlocking options ............75 6. Default settings ...............79 7. Function block descriptions ..........87 7.1. Protection ..................87 7.1.1. 3I>, 3I>> and 3I>>> ............87 7.1.2. Io>, Io>> and Io>>> ............89 7.1.3. Io>->, Io>>-> and Io>>>-> ..........90 7.1.4.
Page 6 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 7.4.2. TCS1 ................123 7.4.3. MCS 3I ................123 7.4.4. MCS 3U ................. 123 7.4.5. TIME1 ................124 7.5. Power quality ................124 7.5.1. PQ 3Inf ................124 7.5.2. PQ 3Unf ................. 125 7.6.
Page 7 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 9.2.4.1. Blocking signal received from the outgoing feeder ...............152 9.2.4.2. Outgoing blocking signal to the overcurrent relay on the HV side .........152 9.2.4.3. Earth fault stage Io>>> used to trip the breaker on the HV side of the transformer ....153...
Page 8 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 10.1.4.2.Outgoing blocking signal to the incoming feeder ............... 178 10.1.4.3.Trip-alarm signals from overcurrent and earth fault ............178 10.1.4.4.Circuit-breaker failure protection ...... 178 10.1.4.5.Trip-circuit supervision ........179 10.2.Incoming feeder, Medium M01 ..........180 10.2.1.Features ................
Page 9 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 11.1.3.2.Synchro-check function ........201 11.1.4.Connections ..............202 11.1.4.1.Protection signal routing ........202 11.1.4.2.Indication and control connections ....202 11.1.5.Implementations .............202 11.1.6.Blocking principles ............203 11.1.6.1.Circuit-breaker failure protection ......203 11.1.6.2.Trip-circuit supervision ........203 11.2.Incoming feeder, High H02 ............204 11.2.1.Features .................204...
Page 10 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 11.5.1.Features ................ 220 11.5.2.Measurements ............... 222 11.5.3.Protection ..............222 11.5.3.1.Phase overcurrent protection ......222 11.5.3.2.Earth fault protection ........222 11.5.3.3.Overvoltage and undervoltage protection ..222 11.5.4.Connections ..............223 11.5.4.1.Protection signal routing ........223 11.5.4.2.Indication and control connections ....
Page 11 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 11.7.3.8.Fuse fail protection ...........239 11.7.4.Condition monitoring ............239 11.7.4.1.Operation time counter ........239 11.7.5.Connections ..............240 11.7.5.1.Protection signal routing ........240 11.7.5.2.Indication and control connections ....240 11.7.5.3.Indication of motor status .........240 11.8.Incoming feeder, High H08/H09 ..........241 11.8.1.Features .................241...
Page 13: About This Manual
This document and parts thereof must not be reproduced or copied without written permission from ABB Oy, and the contents thereof must not be imparted to a third party nor used for any unauthorized purpose.
Page 14: Abbreviations
• Operator’s Manual 1MRS751107-MUM • Installation Manual 1MRS750526-MUM • Technical Descriptions of Functions (CD-ROM) 1MRS750889-MCD • Modbus Remote Communication Protocol for REX 521, 1MRS755017 Technical Description • DNP 3.0 Remote Communication Protocol for REF 54_ 1MRS755260 and REX 521, Technical Description...
Page 15: Document Revisions
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Parameter and event lists for REX 521 • Parameter List for REX 521 1MRS751999-RTI • Event List for REX 521 1MRS752000-RTI • General Parameters for REX 521 1MRS752156-RTI • Interoperability List for REX 521...
Page 16: Safety Information
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 1.7. Safety information Dangerous voltages can occur on the connectors, even though the auxiliary voltage has been disconnected. National and local electrical safety regulations must always be followed. The device contains components which are sensitive to electrostatic discharge.
Page 17: Introduction
Config. name parameter, for example H02S. Differences between REX 521 and RED 500 platform in the function block descriptions The REX 521 and the RED 500 platform differ in some respects concerning the function block descriptions in the CD-ROM Technical Descriptions of Functions (see Section 1.5.
Page 18 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Table 2.-1 Standard configurations for REX 521 (Continued) HW versions Basic Medium High/Sensor 1,6,7 Standard configurations B01 B02 M01 M02 H01 H06 H07 H08 IEEE Function FB name device blocks...
Page 19 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Table 2.-1 Standard configurations for REX 521 (Continued) HW versions Basic Medium High/Sensor 1,6,7 Standard configurations B01 B02 M01 M02 H01 H06 H07 H08 IEEE Function FB name device blocks...
Page 20 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Table 2.-2 Protection functions available in the different standard configurations of REX 521 Function Description 3U<< Three-phase undervoltage protection, high-set stage 3I2f> Three-phase transformer inrush and motor start-up current detector Iub>...
Page 21 MCS 3U Supervision function of the energizing voltage input circuit TIME1 Operation time counter Table 2.-6 Power quality monitoring function available in the different standard configurations of REX 521 Function Description PQ 3Inf Current waveform distortion measurement PQ 3Unf Voltage waveform distortion measurement...
Page 23: Standard Configurations
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Standard configurations 3.1. HW version: Basic 3.1.1. Standard configuration B01 3.1.1.1. Features • Three-phase non-directional overcurrent protection with three stages • Non-directional earth fault protection with three stages • Phase discontinuity protection for three phases •...
Page 24: Application
Fig. 3.1.1.1.-1 Block diagram of B01 3.1.1.2. Application The B01 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective short-circuit, time overcurrent and earth fault protection of radial isolated neutral networks, solidly earthed networks, resistant earthed networks and resonant earthed networks.
Page 25 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations ConfB01_b Fig. 3.1.1.2.-1 Block diagram of the standard configuration B01 for REX 521...
Page 26: Standard Configuration B02
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 3.1.2. Standard configuration B02 3.1.2.1. Features • Three-phase non-directional overcurrent protection with three stages • Three-phase transformer inrush and motor start-up current detector • Non-directional earth fault protection with three stages •...
Page 27: Application
Fig. 3.1.2.1.-1 Block diagram of the standard configuration B02 3.1.2.2. Application The B02 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective short-circuit protection, time- overcurrent protection, earth fault protection and automatic reclosing. The...
Page 28 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations ConfB02_b Fig. 3.1.2.2.-1 Block diagram of the standard configuration B02 for REX 521...
Page 29: Hw Version: Medium
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 3.2. HW version: Medium 3.2.1. Standard configuration M01 3.2.1.1. Features • Three-phase non-directional overcurrent protection with three stages • Three-phase transformer inrush and motor start-up current detector • Directional earth fault protection with three stages •...
Page 30: Application
Fig. 3.2.1.1.-1 Block diagram of the standard configuration M01 3.2.1.2. Application The M01 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective short-circuit, time overcurrent and directional earth fault protection of radial isolated neutral networks, solidly earthed networks, resistant earthed networks and resonant earthed networks.
Page 31 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations ConfM01_b Fig. 3.2.1.2.-1 Block diagram of the standard configuration M01 for REX 521...
Page 32: Standard Configuration M02
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 3.2.2. Standard configuration M02 3.2.2.1. Features • Three-phase non-directional overcurrent protection with three stages • Three-phase transformer inrush and motor start-up current detector • Directional earth fault protection with three stages •...
Page 33: Application
Fig. 3.2.2.1.-1 Block diagram of the standard configuration M02 3.2.2.2. Application The M02 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective short-circuit protection, time- overcurrent protection, directional earth fault protection and automatic reclosing.
Page 34 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations ConfM02_b Fig. 3.2.2.2.-1 Block diagram of the standard configuration M02 for REX 521...
Page 35: Hw Version: High/Sensor
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 3.3. HW version: High/Sensor 3.3.1. Standard configuration H01 (Sensor) 3.3.1.1. Features • Three-phase directional overcurrent protection with two stages • Three-phase non-directional overcurrent protection with one stage • Three-phase transformer inrush and motor start-up current detector •...
Page 36: Application
Fig. 3.3.1.1.-1 Block diagram of standard configuration H01 3.3.1.2. Application The H01 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective directional and non-directional short- circuit protection, directional time-overcurrent protection, directional earth fault protection and automatic reclosing with synchro- and voltage-check functionality.
Page 37 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations ConfH01_b Fig. 3.3.1.2.-1 Block diagram of the standard configuration H01 for REX 521...
Page 38: Standard Configuration H02
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 3.3.2. Standard configuration H02 3.3.2.1. Features • Three-phase directional overcurrent protection with two stages • Three-phase non-directional overcurrent protection with two stages • Three-phase transformer inrush and motor start-up current detector •...
Page 39: Application
Fig. 3.3.2.1.-1 Block diagram of the standard configuration H02 3.3.2.2. Application The H02 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective directional and non-directional short- circuit protection, directional and non-directional time-overcurrent protection, directional earth fault protection and automatic reclosing.
Page 40 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations ConfH02_a Fig. 3.3.2.2.-1 Block diagram of the standard configuration H02 for REX 521...
Page 41: Standard Configuration H03
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 3.3.3. Standard configuration H03 3.3.3.1. Features • Three-phase non-directional overcurrent protection with three stages • Three-phase transformer inrush and motor start-up current detector • Directional earth fault protection with three stages •...
Page 42: Application
Fig. 3.3.3.1.-1 Block diagram of the standard configuration H03 3.3.3.2. Application The H03 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective non-directional short-circuit protection, non-directional time-overcurrent protection, directional earth fault protection and automatic reclosing with synchro- and voltage-check functionality.
Page 43 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations ConfH03_a Fig. 3.3.3.2.-1 Block diagram of the standard configuration H03 for REX 521...
Page 44: Standard Configuration H04
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 3.3.4. Standard configuration H04 3.3.4.1. Features • Three-phase non-directional overcurrent protection with three stages • Three-phase directional overcurrent protection with one stage • Underfrequency or overfrequency protection with one stage •...
Page 45: Application
Fig. 3.3.4.1.-1 Block diagram of the standard configuration H04 3.3.4.2. Application The H04 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective non-directional short-circuit protection, non-directional time-overcurrent protection, directional and non- directional earth fault protection and automatic reclosing.
Page 46 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations ConfH04_a Fig. 3.3.4.2.-1 Block diagram of the standard configuration H04 for REX 521...
Page 47: Standard Configuration H05
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 3.3.5. Standard configuration H05 3.3.5.1. Features • Three-phase non-directional overcurrent protection with three stages • Non-directional earth fault protection with three stages • Three-phase overvoltage protection with two stages • Three-phase undervoltage protection with two stages •...
Page 48: Application
Fig. 3.3.5.1.-1 Block diagram of the standard configuration H05 3.3.5.2. Application The H05 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective non-directional short-circuit protection, non-directional time-overcurrent protection, non-directional earth fault protection, overvoltage protection, undervoltage protection and residual overvoltage protection.
Page 49 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations ConfH05_c Fig. 3.3.5.2.-1 Block diagram of the standard configuration H05 for REX 521...
Page 50: Standard Configuration H06
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 3.3.6. Standard configuration H06 3.3.6.1. Features • Three-phase non-directional overcurrent protection with two stages • Three-phase overvoltage protection with two stages • Three-phase undervoltage protection with two stages • Residual overvoltage protection with three stages •...
Page 51: Application
Fig. 3.3.6.1.-1 Block diagram of the standard configuration H06 3.3.6.2. Application The H06 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective non-directional short-circuit protection, non-directional time-overcurrent protection, overvoltage protection, undervoltage protection, residual overvoltage protection, underfrequency protection and overfrequency protection.
Page 52 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations ConfH06_a Fig. 3.3.6.2.-1 Block diagram of the standard configuration H06 for REX 521...
Page 53: Standard Configuration H07
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 3.3.7. Standard configuration H07 3.3.7.1. Features • Three-phase non-directional overcurrent protection with three stages • Non-directional earth fault protection with two stages • Directional earth fault protection with two stages •...
Page 54: Application
Fig. 3.3.7.1.-1 Block diagram of the standard configuration H07 3.3.7.2. Application The H07 standard configuration for REX 521 is designed for protection of large or medium-size three-phase AC motors in circuit breaker controlled motor drives. Due to large number of protective functions integrated, the relay provides a complete protection against motor damage caused by electrical faults.
Page 55 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations ConfH07_b Fig. 3.3.7.2.-1 Block diagram of the standard configuration H07 for REX 521...
Page 56: Standard Configuration H08 (No Sensors)
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 3.3.8. Standard configuration H08 (No sensors) 3.3.8.1. Features • Three-phase non-directional overcurrent protection with three stages • Non-directional earth fault protection with three stages • Three-phase overvoltage protection with two stages •...
Page 57: Application
Fig. 3.3.8.1.-1 Block diagram of the standard configuration H08 3.3.8.2. Application The H08 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective non-directional short-circuit protection, non-directional time-overcurrent protection, non-directional earth fault protection, overvoltage protection, undervoltage protection and residual overvoltage protection.
Page 58 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations ConfH08_c Fig. 3.3.8.2.-1 Block diagram of the standard configuration H08 for REX 521...
Page 59: Standard Configuration H09 (No Sensors)
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 3.3.9. Standard configuration H09 (No sensors) 3.3.9.1. Features • Three-phase non-directional overcurrent protection with three stages • Non-directional earth fault protection with three stages • Three-phase overvoltage protection with two stages •...
Page 60: Application
Fig. 3.3.9.1.-1 Block diagram of the standard configuration H09 3.3.9.2. Application The H09 standard configuration for REX 521 is designed to be used in single busbar systems using one circuit breaker for selective non-directional short-circuit protection, non-directional time-overcurrent protection, non-directional earth fault protection, overvoltage protection, undervoltage protection, residual overvoltage protection, underfrequency protection and overfrequency protection.
Page 61 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations ConfH09_a Fig. 3.3.9.2.-1 Block diagram of the standard configuration H09 for REX 521...
Page 63: Reading Of The Overview Diagrams Of The Signal Routings
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Reading of the overview diagrams of the signal routings The signals in a standard configuration can be programmed to perform various functions. Digital inputs can be connected to the different input signals (for example Blocking 1) by using selectors.
Page 64: Input Selectors
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Function blocks Input selectors Switchgroups SWGRP I> I>> Selector I>>> SWGRP Reset OC Reset EF Io> Io>> Selector Io>>> Reset Iub SWGRP Selector Selector etc. Selector Master trip Lockout reset...
Page 65: Input Switchgroups (Swgrp)
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Selector Selector Reset 1 Reset 2 Selector Blocking 1 Selector Blocking 2 Selector Selector etc. Fig. 4.1.1.-1 Use of input selectors 4.1.2. Input switchgroups (SWGRP) Switchgroups are used for connecting input signals to the inputs of the function blocks.
Page 66: Input Signals
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 4.1.3. Input signals The figure below shows a part of the overview diagram focusing on input signals. Input signals SWGRP Selector Reset 1 Iub> 3Ith> PQ 3Inf Iub> Reset 2 3Ith>...
Page 67: Function Blocks In The Overview Diagrams Of The Signal Routings
CBFP, available in the function. For further information, refer to the CD- Technical Descriptions of Functions (see Section 1.5. Related documents). See also Chapter 2. Introduction for differences between the REX 521 and the RED 500 platform in the function block descriptions of the CD-ROM.
Page 68: Output Switchgroups (Swgrp)
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Protection function name Time characteristics 3I>>> CBFP BSOUT Outputs Inputs GROUP START DOUBLE TRIP RESET CBFP CBFP = circuit breaker failure protection Fig. 4.2.1.-1 Description of function block symbols More information concerning function blocks in this manual, refer to Chapter 7.
Page 69: Other Functions Described In Signal Overview Diagrams
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 4.4. Other functions described in signal overview diagrams 4.4.1. Lockout function The lockout function is used for increasing the safety when performing control operations. Lockout function can be reset by using the input selector to connect one of the digital inputs (DI1...DI9) to the Lockout reset signal.
Page 70 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Trip signal Lockout Lockout reset Lockout (Normally closed) Close command Lockout2 Fig. 4.4.1.-3 The other option how to use the lockout function Note that when the lockout function is in use and an auxiliary power failure occurs, the output relays return to off-state.
Page 71 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations High speed tripping contact 3I> HSPO1 Master trip Open 3I>> (X4.2.3/4/1/2) 3I>>> Io>--> Trip 1 ³1 ³1 Io>>--> Io>>>--> Lockout Iub> 3Ith> HSPO1 Lockout working Lockout reset Lockout 3I> 3I>>...
Page 73: Parametrization Of The Digital Inputs
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Parametrization of the digital inputs Digital inputs can be used for performing different functions like resetting the desired function block by programming the selectors and switchgroups accordingly. Selectors Output Input...
Page 74: Power Quality Trigger
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 5.1.5. Power quality trigger Any of the inputs DI1...DI9 can be used to start the power quality recording measurements. 5.1.6. Master trip An external trip signal can be routed to the heavy duty tripping contact via DI1...DI9.
Page 75: Time Synchronization
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 5.1.13. Time synchronization Digital input 9 can be used as a GPS time synchronization input. 5.1.14. AR inhibit, AR on input, start AR Auto-reclosure function O->I can be started, inhibited or turned on via DI1...DI9.
Page 76 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Using a digital input directly One of the digital inputs (DI1...DI9) can be selected directly to permit close operations. Use the selector named Close enable in the relay menu or the Relay Setting Tool to select the input.
Page 77 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations DC pos. open ≥1 & Interlocking_A DC pos. close ES pos. open & & Interlocking_B ES pos. close Fig. 5.2.1.-3 Interlocking using disconnector and/or earth-switch state Using disconnector, earth-switch and logical inputs In the cases mentioned above, additional signals, such as SF6 gas low, may be used to block close operations.
Page 78 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Example of customized interlocking DC pos. close = station L/R-switch in remote & ES pos. open = Earth switch open & Interlocking_D = Close enable Logic input 1 = SF6 gas alarm Logic input 2 = Spring not charged &...
Page 79: Default Settings
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Default settings These settings can be found in Main menu\Configuration\. Table 6.-1 Input signals HW versions Basic Medium High/Sensor Standard configuration Input Signals Digital inputs connected Reset 1 Reset 2...
Page 80 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Table 6.-2 Input SWGRP (Basic and Medium) HW versions Basic Medium Standard configuration Group Iub> Iub> Iub> Iub> 3Ith> 3Ith> 3Ith> 3Ith> Blocking 1 BS1 3I> BS1 3I> BS1 3I>...
Page 81 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Table 6.-3 Input SWGRP (High/Sensor) (Continued) HW versions High/Sensor Standard conf. Is2t n<->BS2 FUSEF -> BS2 O->I/3I> O->I/3I>> O->I/3I>>> O->I/3I>-> O->I/3I>>-> O->I/3I>>>-> O->I/Io> O->I/Io>> O->I/Io>>> O->I/Io>-> O->I/Io>>-> O->I/Io>>>-> O->I/3U> O->I/3U>>...
Page 82 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Table 6.-4 Output SWGRP (Basic and Medium) (Continued) HW versions Basic Medium Standard configuration Trip 2 3I> 3I> 3I> 3I> 3I>> 3I>> 3I>> 3I>> 3I>>> 3I>>> 3I>>> 3I>>> Io> Io>...
Page 83 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Table 6.-5 Output SWGRP (High/Sensor) High/Sensor versions Standard conf. Output Output Signals SWGRP Trip 1 3I>--> 3I>--> 3I> 3I> 3I> 3I> 3I> 3I>>--> 3I>>--> 3I>> 3I>> 3I>> 3I>> 3I>> 3I>>>...
Page 84 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Table 6.-5 Output SWGRP (High/Sensor) (Continued) High/Sensor versions Standard conf. Trip 2b 3I() f2 Trip2 U1<U1U2> f1 Trip1 f1 Trip2 Trip 3 3I>--> 3I>--> 3I> 3I> 3I> 3I> 3I> 3I>>-->...
Page 85 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Table 6.-5 Output SWGRP (High/Sensor) (Continued) High/Sensor versions Standard conf. Start 1a 3I> 3I> 3I>> 3I>> 3I>>> 3I>>> Io>--> Io> Io>>--> Io>> 3Ithdev> Io>>> Io> 3U> Io>> 3U>> 3I< 3U<...
Page 86 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Table 6.-6 Output signals HW versions Basic, Medium, High and Sensor Standard B01, B02, M01, M02, H01, H02, H03, H04, H05, H06, H07, H08, H09 configuration Output relays Output signals...
Page 87: Function Block Descriptions
(Section 1.5. Related documents). Technical Descriptions of Functions See also Chapter 2. Introduction for differences between the REX 521 and the RED 500 platform in the function block descriptions of the CD-ROM. In this chapter, the function blocks are called by their IEC names. The corresponding ABB names for the function blocks can be found in Table 2.-1.
Page 88 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Three-phase non-directional overcurrent protection, low-set stage, 3I> Start current 0.10…5.00 x In Operate time in DT mode 0.05…300.00 s Time multiplier in IDMT mode 0.05…1.00 IEEE time dial in IDMT mode 0.5...15.0...
Page 89: Io>, Io>> And Io
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 7.1.2. Io>, Io>> and Io>>> The non-directional earth fault protection function blocks are designed for non- directional earth fault protection whenever the DT characteristic or, as concerns I >, the IDMT (Inverse Definite Minimum Time) characteristic is appropriate.
Page 90: Io>->, Io>>-> And Io
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Non-directional earth fault protection, high-set stage, Io>>, and instantaneous stage, Io>>> Start current 0.10…12.00 x In Operate time 0.05…300.00 s Operation mode Not in use Definite time Instantaneous Measuring mode...
Page 91 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Directional earth fault protection, low-set stage, Io>-> Start current 1.0…25.0% of In Start voltage 2.0…100.0% of Un Operate time in DT mode 0.1…300.0 s Time multiplier in IDMT mode 0.05…1.00...
Page 92 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Directional earth fault protection, high-set stage, Io>>-> and instantaneous stage, Io>>>-> Start current 1.0…200.0% of In Start voltage 2.0…100.0% of Un Operate time 0.1…300.0 s Operation mode Not in use...
Page 93: 3I>-> And 3I
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 7.1.4. 3I>-> and 3I>>-> The directional overcurrent function blocks are designed for directional single- phase, two-phase and three-phase overcurrent and short-circuit protection whenever the DT characteristic or, as concerns 3I>->, the IDMT (Inverse Definite Minimum Time) characteristic is appropriate.
Page 94: 3U> And 3U
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Three-phase directional overcurrent protection, high-set stage, 3I>>-> Start current 0.05…40.00 x In Operate time 0.05…300.00 s Operation mode Not in use Definite time Instantaneous Basic angle ϕ 0...90 Oper. Direction...
Page 95 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Three-phase over voltage protection, low-set stage, 3U> Start voltage 0.10...1.60 x Un Operate time 0.05...300.00 s Operation mode Not in use Definite time A curve B curve Time multiplier 0.05...1.00 Measuring mode Mode 1 (Phase-to-phase voltages / Peak-to-peak meas.)
Page 96: And 3U
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 7.1.6. 3U< and 3U<< Abnormal busbar voltages can be caused by faults in the network or a faulty tap changer or voltage regulator of a power transformer. The function blocks are designed for the single-phase, two-phase and three-phase undervoltage protection whenever the DT characteristic or, as concerns 3U<, the IDMT (Inverse Definite...
Page 97: 3I2F
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Three-phase under voltage protection, high-set stage, 3U<< Start voltage 0.10...1.20 x Un Operate time 0.1...300.0 s Operation mode Not in use Definite time C curve Measuring mode Mode 1 (Phase-to-phase voltages / Peak-to-peak meas.) Mode 2 (Phase-to-phase voltages / Fundam.freq.)
Page 98: Iub
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 7.1.8. Iub> The phase discontinuity protection function block Iub> is designed to be used for protection against broken phase conductors in distribution networks. Definite-time (DT) characteristic is always used. Iub>...
Page 99: O->I
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Three-phase thermal overload protection for cables, 3Ith> Time constant for the cable 1…999 min Maximum load current for the cable 1.0…5000.0 A Maximum temperature of conductor 40.0…150.0°C Reference temperature -50.0…100.0°C Trip temperature 80.0…120.0%...
Page 100 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Auto-reclosure function, O->I Number of reclosures 0…5 Initiation mode Trip Start AR1, AR2, AR3, AR4 starting line operation No operation mode AR shot initiated Initiation of AR shot blocked AR1 AR2, AR3, AR4 start delay 0…10.00 s...
Page 101: Uo>, Uo>> And Uo
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Input SWGRP Output SWGRP O->1 Active SHOT1 O->I 3I> Start SHOT2 O->I 3I>> Start SHOT3 O->I 3I>>> Start SHOT4 SHOT5 TRDUE Initiation signals TDDUE O-->I DI1...DI9 Ext. start ACTIVE DEFTRIP...
Page 102: F1 And F2
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Residual over voltage protection, low-set stage, Uo>, high-set stage, Uo>> and instantaneous stage, Uo>>> (Continued) Start time Injected voltages > 2.0 x start voltage: internal time < 32 ms total time < 40 ms Reset time 40...1000 ms...
Page 103: Sync1
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations System frequency protection, f1 and f2 (Continued) Reset time 140...1000 ms (Depends on the minimum pulse width set for the trip output) Operate time accuracy ±2.0% of set value or ±30 ms 7.1.13.
Page 104: Is2T N
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 7.1.14. Is2t n< The motor start-up supervision protection function block Is2t n< is designed to monitor thermal stress during a single motor start-up. Is 2t n< S TART GROUP S TALL_IND...
Page 105: 105
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 7.1.15. 3I() The function block 3I() is designed for the phase-reversal protection of motors 3I() BLOCK S TART TRIP GROUP RES ET CBFP Fig. 7.1.15.-1 Function block symbol of 3I()
Page 106: I2> And I2
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 7.1.16. I2> and I2>> The function blocks I2> and I2>> are designed for negative phase sequence protection whenever the operating characteristic is appropriate. The function blocks are applied in protecting power generators or synchronous motors against thermal stress and damage I2>...
Page 107: 107
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 7.1.17. 3I< The undercurrent function block is designed to be used for non-directional three- phase undercurrent protection. Usually the undercurrent function block indicates loss of load for pumps, fans and conveyors. Protection is important if the pump is cooled by the liquid it pumps, or if a broken conveyor belt may cause damage for the process.
Page 108: Fusef
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 7.1.18. FUSEF Some voltage-based protection functions may maloperate if a voltage measurement circuitry is damaged or if the miniature circuit breaker (MCB) of the measurement circuitry has opened for example due to an operation of the short-circuit protection.
Page 109: 3Ithdev
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 7.1.19. 3Ithdev> The function block protects a motor both from short- and long-duration overloads. The start situation is a good example of short-duration overload since particularly at start-up the rotor is in danger to be overloaded by the starting current. The starting current can be in the range of five to seven times the rated current of the motor.
Page 110: U1
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Three-phase thermal overload protection for devices, 3Ithdev (Continued) Operation accuracies Current measurement: f/fn = 0.95...1.05: ±1.0%, I = 0.1...10.0 x In Operate time accuracy ±2% or ±0.5 s Reset ratio TRIP: (TEMP(%) -0.1)/Trip temperature...

Page 111: Control
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Phase sequence voltage protection (Continued) Start value U1< 0.01...1.20 x Un Start value U1> 0.80...1.60 x Un Operate time U2> 0.04...60.00 s Operate time U1< 0.04...60.00 s Operate time U1>...
Page 112: I<->O Ind1 And I<->O Ind2
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 7.2.2. I<->O IND1 and I<->O IND2 The object indication function blocks I<->O IND1 and I<->O IND2 indicate the open, close and undefined states of a disconnector or an earthing switch.
Page 113 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Table 7.2.5-3 Medium M01 LED1 LED2 LED3 LED4 LED5 LED6 LED7 LED8 3I> Start Io>-> Start Iub> Start MEAS HI ALARM MEAS LO ALARM CB Wear 3I> Trip Io>->Trip Iub> Trip...
Page 114 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Table 7.2.5-8 High/Sensor H04 LED1 LED2 LED3 LED4 LED5 LED6 LED7 LED8 3I> Start Io>-> Start Io> Start f1 Start 1 O->I OPEN MEAS HI ALARM MEAS LO ALARM CB Wear 3I>...
Page 115: Measurement
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Table 7.2.5-13 High H09 LED1 LED2 LED3 LED4 LED5 LED6 LED7 LED8 3I> Start Io> Start 3U> Start Uo> Start MEAS HI ALARM MEAS LO ALARM CB Wear 3I> Trip Io>...
Page 116: Drec
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 7.3.2. The neutral current measurement function block Io measures the true RMS neutral current, that is, harmonics are not suppressed. The current values are updated once a fundamental frequency cycle, that is, the integration time for the true RMS calculation is one fundamental cycle Fig.
Page 117 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Recording can be triggered on the rising or falling edge of any or several of the digital inputs, on an adjustable level of overcurrent, overvoltage or undervoltage, or the recording can be triggered manually via the HMI, via serial communication or a parameter, or using a periodic triggering.
Page 118 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Transient disturbance recorder, DREC Operation mode Saturation Overwrite Extension Pre-trg time 0…100% Over limit ILx 0.00…40.00 x In Over limit Io 0.00…40.00 x In Over limit Uo 0.00…2.00 x Un AI filter time 0.000…60.000 s...
Page 119: 119
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations DREC digital inputs: (Trip 1, Trip 2, and Trip 3 are the Output SWGRP signals.) Input B01/B02 M01/M02 H05/H08 Start 3I> Start 3I> Start 3I>-> Start 3I>-> Start 3I> Start 3I>...
Page 120: 3U_B
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Three-phase voltage measurement, 3U UL1_U12 0.00...999.99 kV UL2_U23 0.00...999.99 kV UL3_U31 0.00...999.99 kV UL1_U12 0.00...2.00 x Un UL2_U23 0.00...2.00 x Un UL3_U31 0.00...2.00 x Un UL1_U12 average 0.00...999.99 kV UL2_U23 average 0.00...999.99 kV...
Page 121: Pqe
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 7.3.7. The measurement function block f measures the frequency of the network. Fig. 7.3.7.-1 Function block symbol of f System frequency measurement, f Frequency 10.00...75.00 Hz Average Freq. 10.00...75.00 Hz Voltage U 0.0...2.0 x Un...
Page 122: Ai1
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 7.3.9. The analog measuring block is used for supervising current limits and for determining the state of the motor (running/stopped) in H07. LOW ALARM HIGH ALARM Fig. 7.3.9.-1 Function block symbol of AI1...
Page 123: Tcs1
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations CB wear ALARM OPEN BINOPEN BINCLOSE Fig. 7.4.1.-1 Function block symbol of CB wear 7.4.2. TCS1 The trip-circuit supervision function block TCS1 does not perform the supervision itself but it is used as an aid for configuration. The functional part belongs mainly to the self-supervision tasks of the PS_ card.
Page 124: Time1
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations The function block supervises the energizing circuits by comparing the measured voltages. If one or two voltages exceed the setting “High limit”, while the measured values of the remaining one or two voltages are below the “Low limit”, the output ALARM is activated after the set alarm delay.
Page 125: Pq 3Unf
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Current waveform distortion measurement, PQ 3Inf The current waveform distortion measurement PQ 3Inf is used for measurement and statistical analysis of current waveform distortion. The standards concerning voltage distortion measurement are applied to current distortion measurement in PQ 3 Inf.
Page 126 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Distortion measurement does not include rapidly changing harmonics, interharmonics or other spurious components. PQ 3Unf TRIGG HAR_HIGH RESET CUM_HIGH Fig. 7.5.2.-1 Function block symbol of PQ 3Unf Voltage waveform distortion measurement, PQ 3Unf The voltage waveform distortion measurement PQ 3Unf is used for measurement and statistical analysis of voltage waveform distortion.
Page 127: Standard Functions
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 7.6. Standard functions 7.6.1. Switchgroups (SWGRP) The switchgroups are used for changing the functionality of the standard configuration via the HMI or using the Relay Setting Tool. 7.6.2. Selectors The selectors are used for routing signals and connecting inputs. Every digital input can be connected to an input signal (for example Blocking 1, Master trip) via a selector.
Page 129: Example Substations
Technical Reference Manual, Standard Configurations Example substations All the application examples are designed for typical HV/MV substations like below. 3I > 50/51 > CBCM CBFP 3I~harm REX 521 B01 3I > 50/51 I > 50N/51N CBCM CBFP 3I~harm REX 521 B01 3I >...
Page 130 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 3I > 50/51 U > 59N (67N) CBCM CBFP 3I~harm REX 521 M01 3I > 50/51 3I > 50/51 I > I > CBCM CBCM I > I > 3I~harm...
Page 131 Technical Reference Manual, Standard Configurations 3I> 3I> 3I > 50/51 3I > 50/51 CBFP */62 CBFP */62 REX 521 H02 REX 521 H02 Incoming feeder, Incoming feeder, High H02 High H02 U > 3I > 50/51 U > 3I >...
Page 133: Application Examples, Basic
50N/51N CBCM I > 3I~harm CBFP Application Example 1 REX 521 B01 Fig. 9.1.1.-1 B01 is used for protection, measuring and supervision on an outgoing feeder in a single busbar system. The supplying network is either solidly or resistance earthed.
Page 134 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations TRIP circuit breaker CLOSE circuit breaker Blocking signal to the incoming feeder (START 3I>>) Circuit-breaker failure protection Breaker wear alarm Internal relay fault Blocking signal from the residual voltage relay to the Io>...
Page 135: Measurement Connections
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 9.1.2. Measurement connections The three-phase current transformers are connected to the connector X1.1 on the rear panel. The rated currents of the measuring input are 1 A and 5 A.
Page 136: Earth Fault Protection
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations For more information about the phase overcurrent blocking signals between the first and the third application example, refer to the overview diagram on Fig. 9.3.5.-1. The operation of the low-set overcurrent stage 3I> of the relay can be based on a definite- or on an inverse-time characteristic.
Page 137: Phase Discontinuity Protection
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations While using the sensitive non-directional earth fault it is recommended to secure the earth fault functionality by using the start signal from a residual voltage relay to release blocking of the earth fault protection. By doing this, unnecessary trips are avoided due to disturbances in the measured earth fault current.
Page 138: Connections And Signal Routings
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations highest phase current value. The 3Ith> applies the thermal model of one time- constant for temperature measurement, which means that both the temperature rise and the cooling follow an exponential curve.
Page 139 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations As the HSPO1 is always routed to the “Trip 1” output signal, the settings are made directly in Main menu\Configuration\Output SWGRP\Trip 1 where the checksum for the settings is displayed (255 by default).
Page 140: Indication And Control Connections
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Using Graphical I/O Setting Tool To change settings for Trip 1, go to the Output Matrix. Route the Trip 1 signals to HSPO1 with a mouse-click in the graphical matrix.
Page 141 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations The status-indication signals are also routed from the digital inputs to the circuit breaker function (I<->O CB1) via the input signal selectors. These settings can be found in: Main menu\Configuration\Input Signals\, where the different input signal names are displayed and the specific inputs selected.
Page 142: Implementations
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations via push buttons are also disabled when the relay is set to remote mode, and vice versa when the relay is in local mode, the remote control is disabled. If the breaker is interlocked and the interlocking scheme is used with one or more digital inputs configured to the “CLOSEENA”...
Page 143: Outgoing Blocking Signal To The Incoming Feeder
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 9.1.5.1. Outgoing blocking signal to the incoming feeder The start signals from any protection function can be routed to an output relay to provide a blocking signal to the incoming feeder. The overcurrent stages 3I>> and 3I>>>...
Page 144: Trip-Circuit Supervision
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations The CBFP signals from the protection functions are routed to the output signals via the output switchgroups. These settings can be found in Main menu\Configuration\Output SWGRP\CBFP. When the three-stage overcurrent, the two-stage earth fault, the unbalance and thermal overload protection are selected the checksum for the CBFP is 223.
Page 145: Disconnector And Earth-Switch Indication
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations The Alarm 1 signal is then connected to an output relay via Main menu\Configuration\Output Signals\, and in this example, the breaker wear alarm signal is connected to the signal output 1, SO1.
Page 146: Incoming Feeder, Basic B01
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Breaker wear alarm Circuit-breaker failure protection Blocking signal from the residual voltage relay Blocking signal to the incoming feeder to Io> (START 3I>>) CLOSE circuit breaker TRIP circuit breaker REX521 Fig.
Page 147 Protection Relay REX 521 Technical Reference Manual, Standard Configurations 3I > 50/51 I > 50N/51N CBCM CBFP 3I~harm Application Example 2 REX 521 B01 3I > 50/51 I > 50N/51N CBCM I > 3I~harm CBFP Application Example 1 REX 521 B01 Fig.
Page 148 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations TRIP circuit breaker CLOSE circuit breaker Io>>> TRIP to breaker on HV side of transformer Circuit-breaker failure protection OC blocking signal to the HV relay (3I>> START) Internal relay fault...
Page 149: Measurement Connections
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 9.2.2. Measurement connections The three-phase current transformers are connected to the connector X1.1 on the rear panel. The rated currents of the measuring input are 1 A and 5 A.
Page 150: Phase Overcurrent Protection
A few examples of how the described application can be changed using some of the features of REX 521 are described below. The back-up protection can be made with the circuit-breaker failure protection function of the protection relay of the outgoing feeder.
Page 151: Earth Fault Protection
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations instantaneous trip of the busbar system. On the other hand, it is difficult to find the right setting value since a close-up fault in a feeder can cause the circuit breaker of the in-feeder to trip instead of the feeder protection relay.
Page 152: Indication And Control Connections
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Using the HMI: To change the settings for Trip 1 go to Output SWGRP\Trip 1 and press the [E]-button. The different protection functions are displayed one at a time. By →...
Page 153: Earth Fault Stage Io>>> Used To Trip The Breaker On The Hv Side Of The Transformer
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations As mentioned above the start signal from the high-set overcurrent stage 3I>> can be routed to the high-set stage 3I>> of the HV relay. To use the start signal of a protection function, the signal has to be routed via Main menu\Configuration\Output SWGRP\Start 1 or \Start 2.
Page 154: Power Quality
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations The recording can be triggered by any of the alternatives listed below: • Triggering on the rising or falling edge of the protective start signals • Triggering on current measurement •...
Page 155: Transformer Feeder, Basic B01
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations OC-blocking signal to HV-relay (3I>> START) Circuit breaker failure protection OC-blocking signal from outgoing-feeders Io>>> TRIP to breaker on to 3I>>> stage HV side of transformer CLOSE circuit breaker TRIP circuit breaker REX 521 Fig.
Page 156 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 3I > 50/51 > CBCM CBFP 3I~harm Application Example 3 REX 521 B01 3I > 50/51 I > 50N/51N CBCM CBFP 3I~harm Application Example 2 REX 521 B01 3I >...
Page 157 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations TRIP circuit breaker CLOSE circuit breaker Circuit-breaker failure protection Internal relay fault OC blocking signal from the MV relay to the 3I>> stage Fig. 9.3.1.-2 Connection overview diagram of the incoming feeder...
Page 158: Measurement Connections
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 9.3.2. Measurement connections The three phase current transformers are connected to the connector X1.1 on the rear panel. The rated currents of the measuring input are 1 A and 5 A.
Page 159: Transformer Inrush
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations The high-set overcurrent stage 3I>> is configured to operate in case of a short-circuit in the poles of the LV side. The stage serves also as back-up at short-circuits in the MV busbar system.
Page 160: Protection Signal Routing
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations The signal from the inrush function is configured as an input signal to the standard configuration and has to be routed to the overcurrent functions when taken into use. The settings, for which overcurrent stage to double, are made in Main menu\Input SWGRP\Double\.
Page 161: Circuit-Breaker Failure Protection
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations On the overcurrent stages 3I>, 3I>> and 3I>>>, the Blocking 1 input signal is connected to the BS1 input and the Blocking 2 input signal is connected to the BS2 input of the function.
Page 162: Blocking Signal Overview
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Circuit breaker failure protection OC-blocking signal from MV-relay to 3I>> stage CLOSE circuit breaker TRIP circuit breaker REX 521 Fig. 9.3.4.2.-1 Connection diagram for the standard configuration B01 with breaker status indication, blocking, control and breaker failure signals.
Page 163: Outgoing Feeder, Basic B02
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Application REX521 example 3 3I> (8.3.) 3I>> 3I>>> REX521 Application example 2 3I> (8.2.) 3I>> 3I>>> Application REX521 example 1 3I> (8.1.) 3I>> 3I>>> Fig. 9.3.5.-1 Phase overcurrent blocking signal overview diagram for the first...
Page 164 50N/51N CBCM I > 3I~harm CBFP Application Example 4 REX 521 B02 Fig. 9.4.1.-1 B02 is used for protection, measuring and supervision on an outgoing feeder in a single busbar system. The supplying network is either solidly or resistance earthed.
Page 165 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations TRIP circuit breaker CLOSE circuit breaker Blocking signal to incoming feeder (START 3I>>) Circuit-breaker failure protection Definite trip alarm Internal relay fault Blocking signal from the residual voltage relay to the Io>...
Page 166: Measurement Connections
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 9.4.2. Measurement connections The three-phase current and neutral current transformers are connected to the connector X1.1 on the rear panel. The rated currents of the measuring input are 1 A and 5 A.
Page 167: Auto-Reclosure Function
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 9.4.3.1. Auto-reclosure function The auto-reclose function (O->I) enables different types of auto-reclosing. An auto- reclose sequence is initiated either by a start signal or by a trip signal. In the following example two auto-reclosures initiated by the start of the protection are carried out.
Page 168 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Instant of fault Start Protection operation time (Trip signal from protection) Circuit breaker Shot 2 Shot 1 Dead time Dead time Close signal Discrimination Time Alarm Definite Trip Fig. 9.4.3.1.-2 Auto-reclose sequence, when AR is initiated by the trip signal.
Page 169: Protection Signal Routing
Local control can be executed via the HMI according to the instructions in (see Section 1.5. REX 521 Operator’s Manual Related documents).
Page 170: Implementations
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations CLOSE circuit breaker TRIP circuit breaker REX 521 Fig. 9.4.5.-1 Connection diagram for the standard configuration B02 with breaker status indication and the control signals for opening and closing of the circuit breaker 9.4.6.
Page 171: Digital Input To Initiate Auto-Reclosing Function
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations [↓] push buttons. The checksum for O->I Alarm 1 will then be 32. The O->I Alarm 1 signal can then be routed to an output contact, in this example SO2, in Main menu\Configuration\Output Signals\.
Page 173: Application Examples, Medium
3I~harm CBFP Application Example 5 REX 521 M01 Fig. 10.1.1.-1 REX 521 M01 used for protection, measuring and supervision on an outgoing feeder in a single busbar system. The system earthing of the supplying network is either compensated or isolated.
Page 174 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations TRIP circuit breaker CLOSE circuit breaker Blocking signal to incoming feeder (START 3I>>) Circuit-breaker failure protection Earth-fault TRIP Alarm Overcurrent TRIP Alarm Internal relay fault Control signal for selecting the basic angle of Io>-->...
Page 175: Measurement Connections
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 10.1.2. Measurement connections The three-phase current, neutral current transformers and residual voltage transformer are connected to the connector X1.1 on the rear panel. The rated currents of the measuring input are 1 A and 5 A and additionally, for earth fault, 0.2 A and 1 A.
Page 176: 1.Directional Earth Fault Protection
In the REX 521 M01 it is suitable to use the directional earth fault protection with the sensitive current input. The rated values are 0.2 A/1 A.
Page 177: Implementations
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations CLOSE circuit breaker TRIP circuit breaker REX 521 Fig. 10.1.3.3.-1 Connection diagram for the standard configuration M01 with breaker status indication and control signals for opening and closing of the circuit breaker 10.1.4.
Page 178: 2.Outgoing Blocking Signal To The Incoming Feeder
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations In this example the digital input DI8 is connected to the input signal BACTRL and then routed to the BACTRL input of the directional earth fault functions. The BACTRL signal can be found in Main menu\Configuration\Input Signals\BACTRL\ where DI8 is selected.
Page 179: 5.Trip-Circuit Supervision
Main menu\Configuration\Input SWGRP\TCS1\. The default setting of the parameter is ”Not in use”. Another solution is to use an external resistor to prevent the TCS1 alarm. Refer to (see Section 1.5. Related REX 521 Technical Reference Manual, General documents) for more information about the trip-circuit supervision.
Page 180: Incoming Feeder, Medium M01
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Overcurrent TRIP Alarm Earth-fault TRIP Alarm Control signal for selecting the basic angle of Io>--> (BACTRL) Circuit breaker failure protection Blocking signal to incoming feeder (START 3I>>) CLOSE circuit breaker...
Page 181 CBCM CBFP 3I~harm Application Example 6 REX 521 M01 Fig. 10.2.1.-1 REX 521 M01 used for protection, measuring and supervision on an incoming feeder in a single busbar system. The system earthing on the supplying network is compensated or isolated.
Page 182 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations TRIP circuit breaker CLOSE circuit breaker Uo>> TRIP to the outgoing feeders Circuit-breaker failure protection Uo>> Start to release blocking of outgoing feeders OC blocking signal to the HV relay (3I>> START)
Page 183: Measurement Connections
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 10.2.2. Measurement connections The three-phase current transformers and residual voltage transformers are connected to the connector X1.1 on the rear panel. The rated currents of the measuring input are 1 A and 5 A. The rated values for the voltage are 100 V, 110 V, 115 V and 120 V.
Page 184: Protection
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 10.2.3. Protection All the necessary settings for the protection functions can be set via the Relay Setting Tool or the local HMI. The settings can be found in Main menu\Protection\.
Page 185: 2.Indication And Control Connections
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 10.2.4.2. Indication and control connections The connections for the indication and the control signals of the circuit breaker and the disconnector for the incoming feeder can be set as described in the first application example on Section 9.2.
Page 186: 3.Outgoing Blocking Signal To The Overcurrent Relay On The Hv Side
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 10.2.5.3. Outgoing blocking signal to the overcurrent relay on the HV side The start signals from the overcurrent protection function can be routed to an output relay to provide a blocking signal. The overcurrent stages 3I>> and 3I>>> have also a separate BSOUT signal for blocking purpose.
Page 187: 6.Circuit-Breaker Failure Protection
Main menu\Input SWGRP\TCS1\. The default setting of the parameter is ”Not in use”. Another solution is to use an external resistor to prevent the TCS1 alarm. Refer to REX 521 Technical Reference Manual, General (see Section 1.5. Related documents) for more information about the trip-circuit supervision.
Page 188: Outgoing Feeder, Medium M02
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations Second settings OC-blocking signal to HV-relay (3I>> START) Uo>> Start to release blocking of outgoing feeders Circuit-breaker failure protection OC-blocking signal from outgoing-feeders Uo>> TRIP to outgoing feeders to 3I>>> stage...
Page 189 I > CBCM I > 3I~harm CBFP Application Example 7 REX 521 M02 Fig. 10.3.1.-1 REX 521 M02 used for protection, measuring and supervision on an outgoing feeder in a single busbar system. The supplying network is either compensated or isolated.
Page 190 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations TRIP circuit breaker CLOSE circuit breaker Blocking signal to incoming feeder (START 3I>>) Circuit-breaker failure protection Definite trip alarm Internal relay fault Control signal for selecting the basic angle of Io>-->...
Page 191: Measurement Connections
Relay Setting Tool or the local HMI. The settings can be found in Main menu\Configuration\Meas. devices\. Refer to REX 521 Technical Reference Manual, General (see Section 1.5. Related documents) for further information about how to set the rated currents and voltage.
Page 192 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations In the following example two auto-reclosures initiated by the start of the protection are carried out. The auto-reclosures are subject to a preset start-delay time initiated from the start signal of the protection. The first auto-reclosure is delayed only slightly to avoid unwanted auto-reclosures (100 ms).
Page 193 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Instant of fault Start Protection operation time (Trip signal from protection) Circuit breaker Shot 2 Shot 1 Dead time Dead time Close signal Discrimination Time Alarm Definite Trip Fig. 10.3.3.1.-2 An auto-reclose sequence, when AR is initiated by the trip signal The reclaim time is always started or restarted at a circuit breaker close operation.
Page 194: Protection Signal Routing
Local control can be executed via the HMI according to the instructions in (see Section 1.5. REX 521 Operator’s Manual Related documents).
Page 195: Implementations
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations CLOSE circuit breaker TRIP circuit breaker REX 521 Fig. 10.3.5.-1 Connection diagram for the standard configuration M02 with breaker status indication and control signals for opening and closing of the circuit breaker 10.3.6.
Page 196: 2.Digital Input To Initiate Auto-Reclosing Function
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 10.3.6.2. Digital input to initiate auto-reclosing function If an external start or trip signal is available for initializing the auto-recloser, the signal can be connected to a digital input of the relay. Set the digital input, in this example DI7, for the O->I Ext.
Page 197 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations External reclosure initialization signal Definite trip alarm Control signal for selecting the basic angle of Io>--> (BACTRL) Circuit-breaker failure protection Blocking signal to the incoming feeder (START 3I>>) CLOSE circuit breaker...
Page 199: Application Examples, High
Application Example 8 REX 521 H01 Fig. 11.1.1.-1 REX 521 High H01 used for protection, measuring and supervision on an incoming feeder in a single busbar system with parallel generator feeder. The system earthing on the supplying network is compensated or isolated.
Page 200 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations TCS1 TRIP1 circuit breaker CLOSE circuit breaker 3I> -> TRIP2 to the HV side circuit breaker Circuit-breaker failure protection OC blocking signal to the HV-side 3I>> stage (3I>>-> START) OC blocking signal to the 3I>>>...
Page 201: Measurements
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 11.1.2. Measurements Following measurements are supported in this application example: • True RMS measurement of phase currents • True RMS measurement of phase-to-earth voltages • True RMS measurement of residual voltage (calculated value from phase-to-earth voltages) •...
Page 202: Connections
(see Section 9.1. Outgoing feeder, Basic B01), except the signals for the open and close buttons that in this example are disconnected. Local control can be executed by HMI according to the instructions in REX 521 Operator’s (see Section 1.5. Related documents). Manual 11.1.5.
Page 203: Blocking Principles
Main menu\Input SWGRP\TCS1\. The default setting of the parameter is “Not in use”. Another solution is to use an external resistor to prevent the TCS1 alarm. Refer to (see Section 1.5. Related REX 521 Technical Reference Manual, General documents) for more information about the trip-circuit supervision.
Page 204: Incoming Feeder, High H02
*/62 3I~harm 3U~harm Application Example 9 REX 521 H02 Fig. 11.2.1.-1 H02 used for protection, measuring and supervision on an incoming feeder in a single busbar system with parallel feeders. The system earthing on the supplying network is compensated or...
Page 205 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations TCS1 TRIP1 circuit breaker CLOSE circuit breaker 3I> -> TRIP2 to the HV side circuit breaker Circuit-breaker failure protection OC blocking signal to the HV-side 3I>> stage (3I> START) OC blocking signal to the 3I>>...
Page 206: Measurement Connections
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 11.2.2. Measurement connections Following measurements are supported in this application example: • True RMS measurement of phase currents • True RMS measurement of phase-to-phase voltages • True RMS measurement of residual voltage •...
Page 207: Connections
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations The needed time for blocking includes: Start time of the relay Input delay on the relay + Retardation time Margin (40 ms) to be blocked (30 ms) (20 ms) (10 ms) The set operate time of a back-up protection stage 3I>...
Page 208: 2.Indication And Control Connections
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 11.2.4.2. Indication and control connections The connections for indication and control can be implemented as described in the first application example (see Section 9.1. Outgoing feeder, Basic B01), except the signals for the open and close buttons that in this example are disconnected.
Page 209: 2.Blocking Signal From 3I>-> Stage To 3I>> Stage
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations REX 521 REX 521 3I> 3I> 3I>> 3I>> 3I>>> 3I>>> REX 521 REX 521 3I> 3I> Incoming feeder Incoming feeder 3I> 3I> (H02) (H02) 3I>> 3I>> REX 521 REX 521 3I>...
Page 210: 4.Trip-Circuit Supervision
The High H03 variant of REX 521 is selected to be used in this application because of the synchro-check and voltage-check functionality. This selection makes it possible to extend the automatic supervision functionality in the substation.
Page 211 CBCM 3I > 3I~harm SYNC 3U~harm REX 521 H03 Application Example 10 Fig. 11.3.1.-1 H03 is used for protection, measuring and supervision on a bus sectionalizer in a single busbar system. The supplying network can be compensated, isolated, solidly or resistance earthed.
Page 212 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations TCS1 TRIP circuit breaker CLOSE circuit breaker Blocking signal to incoming feeder (START 3I>>) Circuit-breaker failure protection Definite trip alarm Internal relay fault TempAlarm Mains ACFail Blocking signal from outgoing feeders Fig.
Page 213: Measurements
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 11.3.2. Measurements Following measurements are supported in this application example: • True RMS measurement of phase currents • True RMS measurement of phase-to-phase voltages • System frequency measurement 11.3.3. Protection All the necessary settings for the protection functions can be set via the Relay Setting Tool or the local HMI.
Page 214: 2.Synchro-Check Function
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations The time grading includes (definite time): 2 X Tolerance of the + Operation time + Retardation time Saturation and delay relays’ operate times of the CB of the relay margin...
Page 215: Connections
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Before the function block allows the closing of the CB, it ensures that the phase difference remains within the setting range until the CB closes. The command mode is used as a basic control principle of the synchro-check function.
Page 216 3I~harm I > 3U~harm CBFP */62 REX 521 H04 Application Example 11 Fig. 11.4.1.-1 REX 521 H04 used for protection, measuring and supervision on an outgoing feeder in a single busbar system. The supplying network is either compensated or isolated.
Page 217 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations TCS1 TRIP circuit breaker CLOSE circuit breaker Blocking signal to incoming feeder (START 3I>>) Circuit-breaker failure protection Definite trip alarm Internal relay fault TempAlarm Mains ACFail Control signal for selecting the basic angle of Io>-->...
Page 218: Measurements
Relay Setting Tool or the local HMI. The settings can be found in Main menu\Configuration\Meas. devices\. Refer to (see Section 1.5. Related REX 521 Technical Reference Manual, General documents) for further information about how to set the rated currents and voltage. 11.4.4. Protection All the necessary settings for the protection functions can be set via the Relay Setting Tool or the local HMI.
Page 219: 2.Auto-Reclosure Function
Local control can be executed via the HMI according to the instructions in (see Section 1.5. REX 521 Operator’s Manual Related documents).
Page 220: Implementations
3U> 3I~harm 3U< 3U~harm CBFP */62 REX 521 H05 Application Example 12 Fig. 11.5.1.-1 H05 is used for protection, measuring and supervision on an incoming feeder in a single busbar system. The supplying network is either solidly or resistance earthed...
Page 221 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations TCS1 TRIP circuit breaker CLOSE circuit breaker Io>>> TRIP to breaker on HV side of transformer Circuit-breaker failure protection OC blocking signal to the HV relay (3I>> START) Internal relay fault...
Page 222: Measurements
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 11.5.2. Measurements Following measurements are supported in this application example. • True RMS measurement of phase currents • True RMS measurement of neutral current • True RMS measurement of phase-to-phase voltages •...
Page 223: Connections
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 115% t(s) 130% DT operation 60 s 60 s IDMT operation 0.1 s 70 80 90 100 110 120 130 U/Un(%) UNDERVOLTAGE U< = 0.85 x Un, t> = 60 s, DT U<<...
Page 224: 2.Indication And Control Connections
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 11.5.4.2. Indication and control connections All the necessary settings for the indication and control signals of the circuit breaker and the disconnector for the incoming feeder can be set as described in the first application example on Section 9.1.
Page 225: 6.Power Quality
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations • Manual triggering via the HMI or with the external input signal • Triggering via communication parameter • Periodic triggering Regardless of the triggering type, each recording generates the event E31. The triggering time and reason are included in the recording.
Page 226: Measurement Cubicle, High H06
U > 3U> 3U~harm 3U< f< Application Example 13 REX 521 H06 Fig. 11.6.1.-1 H06 is used for protection, measuring and supervision in a measurement cubicle in a single busbar system. The supplying network is either compensated or isolated.
Page 227 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations TCS1 TRIP1 to the incoming feeder Uo>>>,Uo>> TRIP3 to all outgoing feeders Uo>>>,Uo>>, U<, U<<, U>, U>> and f<< TRIP2 to the load shedding group 1 f< Earth-fault alarm Uo>...
Page 228: Measurements
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 11.6.2. Measurements Following measurements are supported in this application example: • True RMS measurement of phase-to-phase voltages • True RMS measurement of residual voltage • System frequency measurement 11.6.3. Protection All the necessary settings for the protection functions can be set by means of the Relay Setting Tool or the local HMI.
Page 229: 3.Underfrequency Protection
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 115% t(s) 130% DT operation 60 s 60 s IDMT operation 0.1 s 70 80 90 100 110 120 130 U/Un(%) UNDERVOLTAGE U< = 0.85 x Un, t> = 60 s, DT U<<...
Page 230: 2.Indication And Control Connections
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations The trip signal (Trip 2) of the underfrequency stage f< protection function is routed to the power output PO2 (x4.2.14/15). The trip signals (Trip 3) of the residual voltage stages Uo>>> and Uo>>, undervoltage, overvoltage and underfrequency stage f<<...
Page 231: Implementations
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations The settings are made by means of the Relay Setting Tool or the local HMI. The settings can be found in: Main menu\Configuration\Input Signals\ Main menu\Configuration\Input SWGRP\ Main menu\Configuration\Output Signals\ Main menu\Configuration\Output SWGRP\ 11.6.5.
Page 232: Motor Protection, High H07
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations External triggering can be made by means of the reserved input signal “PQ 3Unf trig” connected to digital input. The settings can be found in Main menu\Configuration\Input Signals\PQ 3Unf trig.
Page 233 I s 2t , n< 48, 14, 66 3U~har m I 2> 3I < CBFP * / 62 Application example 14 REX 521 H07 Fig. 11.7.1.-1 H07 is used for protection, measuring, and supervision of a single busbar motor feeder...
Page 234 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations TCS1 TRIP circuit breaker CLOSE circuit breaker RESTART enable Circuit-breaker failure protection Definite trip alarm Prior alarm Internal relay fault TempAlarm Mains ACFail Speed Switch Fig. 11.7.1.-2 Connection overview diagram of the single busbar motor feeder...
Page 235: Measurements
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 11.7.2. Measurements The following measurements are supported in this application example: • True RMS measurement of phase currents • True RMS measurement of phase-to-phase voltages • True RMS measurement of neutral current •...
Page 236: 2.Start-Up Supervision (Stall Protection)
Refer to Fig. 11.7.1.-2 for an example of speed switch connection to the inputs of REX 521. The speed switch information is used to control the stall protection (the operation mode of Is2t n<...
Page 237 1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations The equation for Countdown rate setting is: ---------- - reset where =starting time (in seconds) =time (in hours) to reset one start-up stress reset If it is assumed that the motor is recommended to be started at most three times within eight hours, and that the start-up time is 20 seconds each, the situation described in the diagram (see Fig.
Page 238: 4.Short-Circuit (High-Set Overcurrent) Protection
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations 11.7.3.4. Short-circuit (high-set overcurrent) protection The high-set overcurrent protection (3I>> or 3I>>>) constitutes an interwinding short-circuit protection for the motor and a phase-to-phase short circuit protection for the feeder cable.
Page 239: 6.Phase Reversal Protection
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Example: Motor start-up current is 5.2 x FLC and thereby the estimated K-setting is 175/(5.2) = 6.5%. The most severe unbalance is caused by an broken phase. It should be checked that in case of broken (open) phase the operation time of the unbalance protection is shorter than the permissible locked-rotor jam time.
Page 240: Connections
Section 9.2.3.4. Indication and control connections with the exception of the signals for the open and close buttons that are disconnected in this example. Local control can be executed via HMI according to the instructions in REX 521 Operator's Manual (see Section 1.5. Related documents).
Page 241: Incoming Feeder, High H08/H09
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations For logical operation of motor status indication, the “Stop” and “Runs” indications must be selected in pairs and the corresponding checksums must be added together, for example: STOP:Ind. and RUNS:Ind. checksum = 24.
Page 242 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations TC S1 TRIP circuit breaker CLOSE circuit breaker Io>>> TRIP to breaker on HV side of transformer Circuit-breaker failure protection OC blocking signal to the HV relay (3I>> START) Internal relay fault...
Page 243: Measurements
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 11.8.2. Measurements Following measurements are supported in this application example. • True RMS measurement of phase currents • True RMS measurement of neutral current • True RMS measurement of phase-to-earth voltages •...
Page 244: Connections
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations An operational characteristic example on overvoltage and undervoltage protection is presented in the picture below (Fig. 11.5.3.-1). 115% t(s) 130% DT operation 60 s 60 s IDMT operation 0.1 s...
Page 245: 2.Indication And Control Connections
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations 11.8.4.2. Indication and control connections All the necessary settings for the indication and control signals of the circuit breaker and the disconnector for the incoming feeder can be set as described in the first application example on Section 9.1.
Page 246: 6.Power Quality
REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations • Manual triggering via the HMI or with the external input signal • Triggering via communication parameter • Periodic triggering Regardless of the triggering type, each recording generates the event E31. The triggering time and reason are included in the recording.
Page 247: Symbol Notations
1MRS751802-MUM Protection Relay REX 521 Technical Reference Manual, Standard Configurations Symbol notations = multiple-stage three-phase overcurrent protection, low-set, high-set and instantaneous 3I > 50/51 stage available = multiple-stage three-phase directional overcurrent protection, low-set, high-set and 3I> instantaneous stage available >...
Page 248 REX 521 Protection Relay 1MRS751802-MUM Technical Reference Manual, Standard Configurations = energy counter, forward or reverse active / reactive energy = measuring circuit supervision = trip circuit supervision = circuit-breaker condition monitoring CBCM = voltage waveform distortion measurement 3U~harm = current waveform distortion measurement...
Page 250 ABB Oy Distribution Automation P.O. Box 699 FI-65101 Vaasa FINLAND Tel. +358 10 22 11 Fax. +358 10 224 1094 www.abb.com/substationautomation...

ABB REX 521 Technical Reference Manual, Standard Configurations

1 About this Manual

2 Introduction

3 Standard Configurations

4 Reading of the Overview Diagrams of the Signal Routings

5 Parametrization of the Digital Inputs

6 Default Settings

7 Function Block Descriptions

8 Example Substations

9 Application Examples, Basic

10 Application Examples, Medium

11 Application Examples, High

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