Drs-compact Descriptionforgcp Revd

Protective Relaying with ELIN DRS

ProtectiveRelayingELINDRS_RevD.doc; 12.12.2006

VA TECH HYDRO-PRT / Proschek Document No: DIC-023-1.03 Rev: D (revising) 1/106


CONTENTS

1

2

3

4

5

6

7

DRS-WIN: Introduct ion ............................................................................... 6 1.1

Mode of operation..............................................................................................................6

1.2

Serial interfaces.................................................................................................................6

1.3

Display and Operation .......................................................................................................7

DRS-WIN: General ............................................ ........................................... 8 2.1

Establish a connection with DRS-COMPACT ....................................................................8

2.2

DRS-WIN Data Management...........................................................................................11

DRS-WIN: Protective Functions .............................................................. 12 3.1

Password.........................................................................................................................13

3.2

View Settings...................................................................................................................14

3.3

Change settings...............................................................................................................16

3.4

Trip Matrix........................................................................................................................18

DRS-WIN: Directory Structure ................................................................. 20 4.1

Directory: Plants ..............................................................................................................20

4.2

Directory: Commissioning ................................................................................................21

4.3

Directory: EventLists........................................................................................................21

4.4

Directory: Hist ..................................................................................................................21

DRS-WIN: Commissioning Tools ............................................................ 22 5.1

Binary I/O Preset .............................................................................................................22

5.2

Function Outputs .............................................................................................................24

5.3

Typical Commissioning – Window....................................................................................25 5.3.1 Internal measured values...................................................................................26

5.4

Save measurements in a file............................................................................................27

How to load a new software to the DRS ................................................. 30 6.1

Load a new software with the same label.........................................................................30

6.2

Load a new software with a different label .......................................................................33

Pre – Commissionin g Tests......... ............................................................ 36 7.1

CT secondary wiring test .................................................................................................36

7.2

PT secondary wiring test..................................................................................................38




8

9

Tripping Outputs ....................................................................................... 40 8.1

Lockout relays..................................................................................................................40

8.2

Bistable relays .................................................................................................................41

DRS Features. ................................................. ........................................... 42 9.1

Analog Inputs...................................................................................................................42

9.2

Digital Inputs....................................................................................................................43 9.2.1 Hardware Inputs.................................................................................................43 9.2.2 Blocking Input ....................................................................................................43 9.2.3 Copy Inputs........................................................................................................43 9.2.4 Special Inputs ....................................................................................................44

9.3

Digital Outputs .................................................................................................................44 9.3.1 Hardware Outputs..............................................................................................44 9.3.2 Copy Outputs .....................................................................................................44 9.3.3 Special Outputs..................................................................................................44

9.4

MODBUS Interface ..........................................................................................................45 9.4.1 MODBUS RTU Protocol.....................................................................................45 9.4.2 MODBUS Interface Data....................................................................................45 9.4.3 DRS MODBUS Addresses .................................................................................45 9.4.4 Binary Outputs ...................................................................................................46 9.4.5 Analog Outputs ..................................................................................................46 9.4.6 Analog Outputs: Maximum Values .....................................................................47

10 Protective Functions ................................................................................ 48 10.1 General............................................................................................................................48 10.2 Alarm and Trip Philosophy...............................................................................................49 10.3 Generator Differential (87G).............................................................................................50 10.3.1 General..............................................................................................................50 10.3.2 Commissioning ..................................................................................................52 10.4 Inadvertent Energization (50G/27) ...................................................................................53 10.4.1 General..............................................................................................................53 10.4.2 Inadvertent Energization with Current Memory...................................................54 10.4.3 Inadvertent Energization without Current Memory..............................................55 10.4.4 Commissioning ..................................................................................................55 10.5 Generator Inverse Time Overcurrent (51Ginv).................................................................56 10.5.1 General..............................................................................................................56 10.5.2 10.5.3 10.5.4 10.5.5 10.5.6

Commissioning ..................................................................................................56 Long inverse curve characteristic .......................................................................57 Normal inverse curve characteristic ...................................................................58 Very inverse curve characteristic........................................................................59 Extremely inverse curve characteristic ...............................................................60

10.6 Generator Overcurrent Voltage Restrained (51V) ............................................................61 10.6.1 General..............................................................................................................61 10.6.2 Commissioning ..................................................................................................62



Protective Relaying with ELIN DRS 10.7 Underimpedance (21G) ...................................................................................................63 10.7.1 General..............................................................................................................63 10.7.2 Commissioning ..................................................................................................64 10.8 Negative Sequence Overcurrent (46G)............................................................................65 10.8.1 General..............................................................................................................65 10.8.2 Commissioning ..................................................................................................66 10.9 Generator Overvoltage (59G) ..........................................................................................67 10.9.1 10.9.2

General..............................................................................................................67 Commissioning ..................................................................................................67

10.10Generator Undervoltage (27G) ........................................................................................68 10.10.1 General..............................................................................................................68 10.10.2 Commissioning ..................................................................................................68 10.11Under – Frequency (81G.u) .............................................................................................69 10.11.1 General..............................................................................................................69 10.11.2 Commissioning ..................................................................................................69 10.12Over – Frequency (81G.o)...............................................................................................70 10.12.1 General..............................................................................................................70 10.12.2 Commissioning ..................................................................................................70 10.13Load Rejection.................................................................................................................71 10.13.1 General..............................................................................................................71 10.14Frequency Gradient (81dF/dt)..........................................................................................73 10.14.1 General..............................................................................................................73 10.14.2 Commissioning ..................................................................................................73 10.15Reverse Power (32G) ......................................................................................................74 10.15.1 General..............................................................................................................74 10.15.2 Commissioning ..................................................................................................75 10.16Overfluxing (24G) ............................................................................................................76 10.16.1 General..............................................................................................................76 10.16.2 Commissioning ..................................................................................................76 10.17Underexcitation (40G)......................................................................................................77 10.17.1 General..............................................................................................................77 10.17.2 Commissioning ..................................................................................................78 10.18Out of Step (78G) ............................................................................................................79 10.18.1 General..............................................................................................................79 10.18.2 Commissioning ..................................................................................................82 10.19Stator Earth Fault (64G95)...............................................................................................83 10.19.1 General..............................................................................................................83 10.19.2 Commissioning ..................................................................................................83 10.20Stator Earth Fault (64G100).............................................................................................84 10.20.1 General..............................................................................................................84 10.20.2 Commissioning ..................................................................................................85 10.21Cable Earth Fault (64B) ...................................................................................................86 10.21.1 General..............................................................................................................86 10.21.2 Commissioning ..................................................................................................86 VA TECH HYDRO-PRT / Proschek Document No: DIC-023-1.03 Rev: D (revising) ProtectiveRelayingELINDRS_RevD.doc; 12.12.2006 4/106

Protective Relaying with ELIN DRS 10.22Breaker Failure (50BF) ....................................................................................................87 10.22.1 General..............................................................................................................87 10.22.2 Commissioning ..................................................................................................89 10.23Breaker opening too long (BF, 94GB) ..............................................................................90 10.23.1 General..............................................................................................................90 10.23.2 Commissioning ..................................................................................................91 10.24Voltage Balance (60) .......................................................................................................92 10.24.1 10.24.2 General..............................................................................................................92 Commissioning ..................................................................................................93 10.25Transformer Differential (87T) or Block Differential (87B).................................................94 10.25.1 General..............................................................................................................94 10.25.2 Commissioning ..................................................................................................97 10.26Main Transformer Restricted Earth Fault (64T.REF) ........................................................98 10.26.1 General..............................................................................................................98 10.26.2 Commissioning ................................................................................................100 10.27Trip Coil Supervision (TCS) ...........................................................................................103 10.27.1 General............................................................................................................103 10.27.2 Commissioning ................................................................................................104

11 Index ......................................................................................................... 105




1

DRS-WIN: Introduction U

The digital compact protection system DRS-COMPACT is a multifunctional protection relay for protection of synchronous machines and/or transformers. All components which are necessary for a complete protection system (interposing input transformers, measuring channels, various matrices, trip and alarm outputs) are installed in one case.

1.1

Mode of operation U

The signals generated in the plant (transformer current, transformer voltage, binary signals) are fed via appropriate interposing transformers and transducers into the system. The further operation is – except the methods of suppressing and filtering – fully digital. The advantages of this digital processing are the extensive insensitivity of the system concerning aging, temperature and also the possibility to reduce complex protection problems to relative simple algorithms, which can be computed easily. Thereby the characteristically computed values of the input signals can be used for further protective functions. The protective functions which are implemented in the relay are being processed sequentially by the software. In dependence of the working condition (fault-free running or fault case) the protection system gives out the equivalent alarm or trip signal. The signals are being distributed via a software matrix to the trip devices which corresponds to the tripping scheme. Optical indications signal the alarm and trip respectively of a protective function. With the PC there can be read out, displayed and processed further data about the fault event like alarm protocol and/or fault recording. Configuration and setting parameters are being saved in an E2PROM (fail safe): Each modification is being recorded and can be printed out in a reference protocol. The DRS-COMPACT has integrated following supervision functions:

• Self supervision • Check of integrity of the memories by supervision of check sum • Program execution supervision via watch dog feature • Plausibility control of the analog input signals by comparison with the minimal values • Supervision of the digital outputs by impulse monitoring the output driver stages

1.2

Serial interfaces U

The digital protection system DRS-COMPACT is equipped with 3 serial interfaces. The RS232C interface at the front is used for the local operation. This interface enables all writing and reading access. The writing access is protected with a password function. The RS485 interface at the back is used for remote operation or for connection of more DRSCOMPACT and DRS-LIGHT relays. The MODBUS interface at the back (RS485 interface) is used to connect the DRS-COMPACT to a control system.




1.3

Display and Operation U

With the 26 programmable and integrated LED's all protective function alarms and trips can be indicated. The LED indication can be reset by pressing the blue acceptance push button. The event list stores 265 events for later evaluation. Some or all protective functions (depending on options in the setting) makes a record in the fault record. All analog and digital inputs are stored in the moment when a function triggers. For detailed visualization (reading out of actual measured values, digital conditions, fault records, alarm protocol) or for parametering (reading out and setting of parameters, functional parameters, software matrices, specific plant data) the user operation software package DRS-WIN is used. With the integrated display and keypad all settings of the relay can be displayed and also changed.




2

DRS-WIN: General U

For the communication with the relay the following is necessary:

• DRS-WIN Software • DRS Communication cable The operation software DRS-WIN must be installed on a PC. The DRS communication cable is used to connect the PC with the DRS-COMPACT. If an optical interface is used, it must be plugged in on the PC side. The cable side can be plugged at the DRS. WARNING! It is strongly recommended NOT to connect the optical interface to the communication port of the DRS-COMPACT. This will cause a destroy of the communication port of the DRS-COMPACT.

2.1

Establish a connection with DRS-COMPACT U

Step 1: Start DRS-WIN

The software starts with an empty screen. No data's are loaded yet. The following choices are possible: • read out data from PC's hard disk – described later in this description • read out data from DRS – continue with step 2



Protective Relaying with ELIN DRS Step 2: Communication port configuration

The communication port with the connection to the DRS-COMPACT must be activated and the profile name must be "All". Close the window with "Ok" Step 3: Establish the connection PC – DRS with the communication cable Connect the communication cable between the PC and the DRS. If an optical interface is used, it must be plugged in on the PC side. It is strongly recommended NOT to connect the optical interface to the DRS-WIN, this will cause a destroy of the communication port of the DRS-COMPACT. Step 4: Automatically built up communication The communication PC – DRS will be built up automatically.

To read out all data from DRS the option "Read data from DRS" must be activated, this is the default selection. Press button "Continue" or wait the delay time which is displayed inside the button.



Protective Relaying with ELIN DRS Step 5: Read data from DRS All settings from DRS will be read out:

• Protective functions • Settings • Trip Matrix • LED Matrix

Step 6: Window with Protective Functions A window with all protective functions installed in the DRS is displayed.




2.2

DRS-WIN Data Management U

The following picture describes which DRS-WIN command loads the settings to which device. The middle is the memory of the PC (RAM). All settings which can be seen and changed are stored in this memory. The left box shows the PC's hard-disk. Only with a DRS-WIN command the settings from the PC's memory is stored or loaded out. The right box shows the DRS. Also only with a DRS-WIN command the settings from the PC's memory is sent or read out.

Save Data to File

PC's Hardisk VE - File

LoadDatafromFile

Read Data from DRS

DRS-WIN PC's Memory

DRS SendDatatoDRS

When starting communication with DRS, the setting data is read out from DRS to PC's memory. After changing some data, the setting must be sent to DRS with the button "Send Data to DRS". When withoutfrom connection to DRS, firstbutton the screen empty. ToFile". showThen the setting of a DRSstarting relay, itDRS-WIN must be loaded hard-disk with the "LoadisData from a VE-file will open, and the setting data will be stored in PC's memory.




3

DRS-WIN: Protective Functions U

After reading out the data from DRS the window with the protective functions installed in the DRS is displayed. Save data from PC on VE-file

Read Fault Record

Print out all setting data Measured Values Trip matrix LED matrix

DRS System time

Send data to DRS

Read data from DRS

DRS is Online DRS Label

1 Fault Record stored in DRS Protective Functions Event Records stored in DRS

After changing one of the settings the new value is only available in the PC's memory, both the DRS and the VE file on the hard disk still have the old setting. To change the setting in the DRS, use the button "Send data to DRS" To change the setting in the VE file, use the button "Save data from PC to VE-file"




3.1

Password U

All settings are protected by a password. The password can be entered as following:

• Menu: System – Password... • Username: • Password: or (default password)




3.2

View Settings U

To view settings of any DRS function simply click the function with the mouse:

A second window with the settings of the selected function will open: Triggersettings Internal measured values

Send data to DRS

Input matrix Read data from DRS

DRS is Online

DRS Label Settings of the protective function



Protective Relaying with ELIN DRS With the button "Input matrix" the following window will open: Send data to DRS

Read data from DRS

A n a lo g i n pu t s of t he fu nc t io n

D ig i ta l i np u ts of th e f u nct i o n

The analog inputs of the function are current and voltage inputs from CT's and PT's. The number of current and voltage inputs depend on the type of DRS function and the window adapts automatically. The digital inputs of the function are the following: • blocking inputs to block / unblock the function with a binary input • test input to force the function with a binary input




3.3

Change settings U

The change of the settings is protected by a password. To change the settings, press on the button with the setting to change:

In the new window change the setting and press "OK"

The setting window has a red triangle, which indicates that a setting was changed.



Protective Relaying with ELIN DRS By pressing on the triangle in the bottom of the window a new window with all modified data will be displayed:

IMPORTANT ! After changing of a setting the new value is only available in the PC's memory, both the DRS and the VE file still have the old setting. To change the setting in the DRS, use the button "Send data to DRS"




3.4

Trip Matrix U

In the "Protective Function – Window" the button "Trip Matrix" will open the "Trip Matrix" window:

The left column shows all outputs of all DRS functions. The top row shows all digital outputs of the DRS-COMPACT. The dots show which DRS function output is connected with which digital output. All dots in one column are logical OR connected. One click with the mouse on a dot removes it or makes a new one. The red circle shows the modified data The following symbols are possible: • black dot: connection between DRS function output and digital output, no difference with the reference file • black dot and red circle: connection between DRS function output and digital output, the reference file shows no connection • red circle: no connection between DRS function output and digital output, the reference file shows a connection







4

DRS-WIN: Directory Structure U

The software DRS-WIN is located on the hard disk in the directory DrsWin4. The subdirectory has the following structure:

4.1

Directory: Plants U

The directory "Plants" stores the setting data from DRS. If you press the button "Save Data to File" this is the directory where the file is stored. The name of the file is according the rule: DRS_XXXX.VE XXXX means the label of the DRS (ARZ1). Every DRS-COMPACT in the plant has its unique label. The settings and files of different DRS-COMPACT cannot be mixed. VE is the type of the file




4.2

Directory: Commissioning U

The directory "Commissioning" contains the text files with the stored measurements during commissioning. The name of the file is according the rule: [XXXX] yyyyyy.tpc XXXX means the label of the DRS (ARZ1). yyyyyy means the plant specific name of the DRS TPC is the type of the file

4.3

Directory: EventLists U

The directory "EventLists" stores the event records of the DRS

4.4

Directory: Hist U

The directory "Hist" stores the fault records of the DRS




5

DRS-WIN: Commissioning Tools U

For commissioning the following DRS-WIN features are very useful:

5.1

Binary I/O Preset U

Menu: System – Binary I/O Preset ...

With this window all binary inputs and outputs can be checked. Additional all inputs and outputs can be forced to "0" or "1"



Protective Relaying with ELIN DRS A click with the mouse on the input or output to force will open a new window:

This feature is very usefull for the following • check of inputs according the actual situation on the plant • check of outputs, e.g. CB trips • force of inputs according commissioning simulation (e.g. CB open) • force of outputs to 0 during commissioning not to make real trips The forced signals don't need to be reset, after closing of the window all forced outputs are changed back to normal operation.




5.2

Function Outputs U

Menu: System – Function Outputs ...

With this function the actual status of a whole protective function can be shown. The outputs of a whole function can be disabled. The LED indication is still active, but no outputs (trips and alarms) are activated. This is very usefull to disable functions which are not under test. All simulations don't need to be reset, after closing of the window all simulations are changed back to normal operation.




5.3

Typical Commissioning – Window U

During commissioning several windows can be open at the same time. The binary I/O preset window is used to check the inputs and outputs and to disable unwanted trips. The several measurement windows are used to check the current and voltage inputs and the calculated values.




5.3.1 Internal measured values Every function window has an icon which is called "Internal Measured Values". Pressing this button opens an additional window which shows internal calculated values from this function.

Some functions do not calculated internal values, they just work with the direct measured values. Nevertheless it is possible to open the "Internal Measured Values" window, but it does not show any value. The sense of the windows is to use the button "Save" to store the measurements of the function in a file, please refer to the according chapter in this document.




5.4

Save measurements in a file U

Actual and internal measurements can be saved in a text – file for later evaluation. Open the window "Measured values" and press the button "Save".

All measurements are saved in a TPC-file additional to the old content.



Protective Relaying with ELIN DRS With a text editor the file can be displayed:

The "Internal Measured Values" of any protective functions have also the possibility to save the measurements.



Protective Relaying with ELIN DRS The analog inputs of the functions and the internal computed values of the protective function is recorded additional to the old content of the file:




6

How to load a new software to the DRS U

The DRS can be loaded with a new software with DRS-WIN. New software means a new VE-file with different settings or also with different protective functions. A new VE-file can only be produced by VA TECH SAT. Every DRS has its unique label (ARZ1 for ARZEW Unit 1). That means only a VE file for ARZ1 can be loaded into the DRS (DRS_ARZ1.VE). If it is necessary to change the label, first the DRS has to cleared to a SPARE PART. Then every VEfile can be loaded into the DRS. The DRS takes the label from the new VE-file.

6.1

Load a new software with the same label U

The label of the DRS can be shown on the main window with the protective functions in DRS-WIN. The new software means a new VE-file with the same label. All other VE-files are not allowed to be send to the DRS. Step 1: New VE-file Copy the new VE-file to the "Plants" subdirectory in the DRS-WIN directory. It is recommended to save the "old" VE-file anywhere in your project directory for backup purpose. Step 2: Establish a communication with the DRS Please refer to the corresponding chapter in this documentation.

DRS-WIN asks to read data from DRS. As this is the default, it is possible to choose this option. Please note that now the DRS settings are stored in the computer's memory.



Protective Relaying with ELIN DRS The better option is to choose "Read data from file" and open the new VE-file. Only the correct VEfile (with the same label) can be selected. Now the new VE-file settings are stored in the computer's memory.

Step 3: Load the new VE-file in the computer's memory This step can be skipped, if the option "Read data from file" was used in "Step 2" ! Otherwise the new VE-file must be opened with the following command: DRS Data – Load Data from File ...

Select the correct VE-file, the label must fit to the DRS-label.




DRS-WIN asks to overwrite the setting data in the computer's memory (DRS data) with the data of the selected file (new VE-file). Push YES. In case of NO, the old DRS data is still in the computer's memory. The file has to be opened again. Now the settings of the new VE-file is copied to the computer's memory Step 4: Send Data to DRS The settings from the computer's memory must be sent to the DRS with the command: DRS Date – Send Data to DRS... or the equivalent button on the main window in DRS-WIN. If not done before, you have to enter the password first.

After initialising the DRS, the relay has the new software stored. Step 5: Check the correct working of the relay Check measurement display Check trip outputs with Binary I/O Preset Check protective functions with test inputs (Binary I/O Preset)




6.2

Load a new software with a different label U

This chapter is only for experienced users. With this commands all the settings and programming in the DRS is deleted. The operation of the DRS is stopped, no protective functions are working and the watchdog output will change to "Relay Fault". The following commands may only be executed after agreement of VA TECH SAT. Because of the unique DRS label it is only possible to load a VE file with the same label to the DRS. If for any circumstances another file with a different label must be stored in the relay, the DRS relay must be cleared to a "SPARE PART" Step 1: No Communication DRS-WIN with DRS The DRS shall not have a communication with DRS-WIN. Step 2: Clear a DRS to a SPARE PART To clear a DRS to a SPARE PART, this can be done with the DRS-keyboard and display. ATTENTION ! After finishing this step all data in the DRS will clear and the DRS will stop working ! DRS – Keyboard

Display

Enter the Menu: System Functions

Menu System Functions

Press 4 times the Button "down" until Menu "Spare Part"

System Functions Spare Unit

Press the Button "OK" to start the functions

Spare Unit Enter Password

Enter the Password for the Spare Part Function. ATTENTION ! There is a time supervision. If you enter too slow you must start again !


SPARE Vx.xx/xx SETUP REQUIRED



Step 3: Start DRS-WIN The DRS-WIN software will start with an empty screen. Step 4: Connect DRS to the PC Connect the DRS to the PC

DRS-WIN found a not programmed DRS, it is called SPARE PART. The software asks to initialize the DRS with a VE-file. Answer with OK

The system asks for a VE-file to initialize the DRS. Make the correct selection and answer with OK

DRS-WIN asks to reconfirm the selection. If the selection is correct, answer with OK.




The DRS is cleared and will be initialized with the selected data.

After initialising the DRS, the relay has the new software stored. Step 5: Check the correct working of the relay Check measurement display Check trip outputs with Binary I/O Preset Check protective functions with test inputs (Binary I/O Preset)




7

Pre – Commissioning Tests U

The following test are carried out before hot commissioning, that means before FSNL (full speed no load).

7.1

CT secondary wiring test U

The secondary wiring of the CT has to be tested. Step 1: CT data The technical data of the CT has to be checked according the type plate. The protection has to be connected to the core with the correct data. Sometimes the data of the cores do not fit to the drawings. The correct core with the correct data (protection characteristic) has to be used. Record the CT's data in the commissioning report. Step 2: Earthing on secondary side The earthing of the secondary side of the CT has to be checked. Every secondary wiring has to be earthed on one point, mainly on the CT connection. Also check the correct point of the earthing according the drawings in connection with the position of the CT. For example if the earthing must be on the line side, check the primary indication of the CT on the line side, the earthing must be on the adequate secondary side. Step 3: Secondary wiring test The secondary wiring to the protection must be checked. The connection must fit to the correct terminals according the drawing.



Protective Relaying with ELIN DRS Therefore the following test has to be performed: about 1 AAC ~

~

A1

1s1

DC

A2DC

Display -1ADC +

P1

1s2 P2

Open the terminals in the protection cubicle between internal and external side, very easy with a screw-breaker in the terminals. Connect an AC – Current – Supply to the external side of terminals in the protection cubicle. Because of the diode only the positive pulses of the AC current supply the wiring to the CT. The CT don't need to be disconnected because of the high burden. Only a very small current flow through the CT. Nearly no current is indicated on the measurement A1. A second person will measure with a second measurement A2 direct on the secondary terminals of the CT in the direction shown on the picture in coordination with the diode. The measurement setting must be ADC, that means DC measurement. If the display is negative, the connection CT – secondary side and protection terminals is correct. B

B




7.2

PT secondary wiring test U

The secondary wiring of the PT has to be tested. Step 1: PT data The technical data of the PT has to be checked according the type plate. The protection has to be connected to the corecore with with the the correct data. Sometimes data of the has cores fit Record to the drawings. The correct correct data (protectionthe characteristic) to do be not used. the PT's data in the commissioning report. Step 2: Earthing on secondary side The earthing of the secondary side of the PT has to be checked. Every secondary wiring has to be earthed on one point, mainly on the PT connection. Take special care with an open delta winding. Only one phase must be earthed, if all three phases are earthed, the PT secondary side is short circuit. Step 3: Secondary wiring test The secondary wiring to the protection must be checked. The connection must fit to the correct terminals according the drawing.



Protective Relaying with ELIN DRS Therefore the following test has to be performed: about 30 VAC ~

~

disconnect

VDC

The terminals in the protection cubicle don'tneed to be disconnected between internal and external side. The secondary PT connection must be removed during this test. Connect an AC – Voltage – Supply to the terminals in the protection cubicle. A second person will measure with a voltage measurement direct on the secondary terminals of the PT. Only the correct phase should indicate a voltage.




8

Tripping Outputs U

The tripping outputs have to realize the following features: • Each tripping output has to be able to carry the whole current from the connected tripping device (circuit breaker, shutdown valves). • After initiating a trip, the output must keep closed until a person made a reset which is possible only locally at the cubicle At the moment the following realizations had been made • bistable relays • lockout relays

8.1

Lockout relays U

The classic realization is the use of lockout relays. Every relay combines a complete tripping scheme as following: • Lockout #1: 52G + 41 • Lockout #2: 52G + 41 + 86N • Lockout #3: 52G + 41 + 86TGT • Lockout #4: 52L Every relay is directly tripped with one output from DRS. The contacts of the lockout relay makes the trip to the according devices. A protective function in the DRS can trip all necessary devices with only one output. The reset of the relay is made by hand with the big handle. The trip coil of the relay carries a big current only for a short time. Therefore internal NC contacts are used to switch off the current when the relay has tripped. Attention ! Never hold the handle when the trip circuit is energized, otherwise the trip coil burns. Also the DRS internal trip contacts are not able to switch off the trip current. The lockout relay (GE, type HSA) is shown in the picture below.




8.2

Bistable relays U

The lockout scheme is realized with a bistable relay, which has two coils, one trip coil and one reset coil. The trip coil is connected to one DRS output. Every relay makes only one trip to one device, that means one coil of one circuit breaker. A protective function in the DRS has to set several outputs to trip all necessary devices. The reset of the relay(s) is made by a pushbutton in front of the cubicle, which energizes the reset coil. The bistable relay (Telemecanique, type RHK) is shown in the picture below.




9 9.1

DRS Features U

Analog Inputs U

The DRS-COMPACT has 15 analog inputs which consist of 10 current inputs and 5 voltage inputs. All ten current inputs and all five voltage inputs are completely equivalent and can be used by all protective functions if possible. The next picture shows a typical configuration

Every protective function has an input matrix which makes the arrangement of the analog current and voltage inputs to the function. In principal all current and voltage inputs can be arranged to the function. It is the task of the design engineer and commissioning engineer to make and check the correct arrangement.




9.2

Digital Inputs U

The DRS has 32 digital inputs which have different properties. The different properties can be seen by the type of the input declared with 3 characters: AXI .........signal input can be used for signal function VAX........virtual signal input can be used for signal function ALL.........general input can be used for all type of inputs VAL ........virtual general input can be used for all type of inputs BLK ........blocking input can be used to block functions VBK........virtual blocking input can be used to block functions NON .......input not used VCK........virtual check input can be used to test functions EQT........input to reset LED indication (same as blue button in front of relay) The word "virtual" means that the input is not available physically, but with use of the "Binary I/O Preset" feature of the DRS-WIN the input can be set or reset temporary. Every protective function has an input matrix which makes the arrangement of the digital inputs to the function.

9.2.1 Hardware Inputs The inputs number 01 to 08 are hardware inputs. External signals can be connected to the terminals of the relay and the corresponding input show the actual situation.

9.2.2 Blocking Input The input number 28 "BLK ON" is always active. It is mainly used to always block protective functions. This can be used either for not needed stages of multiple stage function or during commissioning to prevent unwanted trips.

9.2.3 Copy Inputs The inputs 25, 26 and 27 are the copy - feedback of the digital outputs 25, 26 and 27. Sometimes they are inverted. This depends on the VE file and is not changeable by the commissioning engineer. This feature can be tested very easily with the "Binary I/O Preset" feature of the DRS-WIN; attention, a trip could appear! This input is used if a digital output has to be connected to a digital input This input is used by the following functions:

• Breaker Failure • Blocking of Overfrequency at load rejection




9.2.4 Special Inputs The input number 29 "Minute Pulse" is used to reset the DRS system time to the next full minute. The input number 30 "LED Quit" is used to reset the LED indication, it is the same function as pressing the blue button in front of the relay The input number 31 "NMI 1" and 32 "NMI 2" is internal use for older version of the DRS protection.

9.3

Digital Outputs U

The DRS has 32 digital outputs which have different properties. The different properties can be seen by the type of the input declared with 3 characters: TRP........trip output WNG ......warning output NON .......output not used VRT........virtual trip output AXO........ general output The "Trip Matrix" makes the arrangement between the protective functions and the digital outputs.

9.3.1 Hardware Outputs The outputs number 01 to 24 and 31, 32 are hardware outputs. External signals can be connected to the terminals of the relay and the contact is closed if the output is active. All 26 contacts have the same electric data. The outputs number 01 to 24 are used for trip or alarm circuits. The outputs number 31 and 32 are used to supervise the DRS fault and watchdog. See the next chapter "Special Outputs".

9.3.2 Copy Outputs The outputs 25, 26 and 27 are copies to the digital inputs 25, 26 and 27. Sometimes they are inverted. This depends on the VE file and is not changeable by the commissioning engineer. This feature can be tested very easily with the "Binary I/O Preset" feature of the DRS-WIN; attention, a trip could appear!

9.3.3 Special Outputs The output number 31 is the "DRS – fault" output. The output number 32 is the "DRS – watchdog" output. Both outputs are active, if the relay is working properly. Because the internal connected relay works with a N/C contact, a closed contact indicates a fault at the relay.




9.4

MODBUS Interface U

9.4.1 MODBUS RTU Protocol The DRS implements a subset of the AEG Modicon Modbus RTU serial communication standard. The DRS provides a special MODBUS interface on terminals of the relay. The DRS is always a slave. It cannot be programmed as a master. Computers or PLCs are commonly programmed as masters. The MODBUS protocol exists in two versions. Remote Terminal Unit (RTU, binary) and ASCII. Both versions are provided by the DRS. Two types of information are provided via MODBUS. The first are the binary outputs of all functions, which are mainly alarm and trip outputs. The second are analog current and voltage outputs. The interface data depends on the functions in the VE file. The plant specific data can be seen in the MODBUS memory map in the plant specific MODBUS interface list. The MODBUS interface data and the MODBUS addresses can be changed with DRS-WIN as following: Menu: DRS Functions – Modbus Settings

9.4.2 MODBUS Interface Data The MODBUS interface connection to the DRS-COMPACT is with RS485. The following terminals are used: • X2 – 8:TX+ • X2 – 9:TXGND • X2 – 10: The interface data for the MODBUS RS485 are as following: 9600 bd (alternatively: 2400, 4800, 19200, 38400) • communication speed: data bits: 8 (alternatively:7) • stop• bits: 1 (alternatively: 2) parity: • odd (alternatively: no, even) protocol: RTU (alternatively: ASCII) •

9.4.3 DRS MODBUS Addresses In GCP cubicles usually the MODBUS addresses for DRS-COMPACT starts with 3 for the first device, 4 for the second device and so on. The MODBUS addresses 1 and 2 are reserved for the excitation system.




9.4.4 Binary Outputs All binary outputs of all DRS functions are provided via MODBUS by reading the MODBUS function: input status. The address can be found in the MODBUS memory map. The address depends on the sequence of the DRS functions, which can be seen in the main window of DRS-WIN. The first function uses the first 15 bit (one word) of the input status. Within this word the first bit (LSB) gives the status of the alarm of stage 1, the second bit gives the status of the trip of stage 1, the third bit gives the status of the alarm of stage 2 and so on. For each protective function one data word is supplied and the bits represent the actual status of the binary outputs. Find below an example of a single stage overcurrent function: Data word: 0000 0000 0000 00yx The alarm status of the function is represented by bit "x" The trip status of the function is represented by bit "y"

9.4.5 Analog Outputs All analog current and voltage inputs are provided via MODBUS by reading the MODBUS function: input registers. The address can be found in the MODBUS memory map. The address depends on the sequence of the 15 analog inputs. The first analog input (current) has the address 0 or 1, depending on the base value of the master's MODBUS settings. The last analog input (voltage) has the address 14 or 15. For each analog measurement one data word is supplied which must be interpreted as unsigned decimal. Additional this integer value must be multiplied by the following factor : Current:

Current := Integer *

Voltage:

Voltage := Integer *

15 8191

* CT

5 65528

sec

* VT

ondary

sec

* CTratio

ondary

* VTratio

"Integer" means the word supplied by the input register, but only 15 bit. Bit #16 is not the sign bit. It is used to identify the validity of the data. If the bit is 1, the data is not valid because of an internal problem of the DRS. B

B

B

B

"CTsecondary and VTsecondary the for nominal inputs of the DRS. For CT the" standard valuemeans is 1A and VT 100V. "CTratio" and "VTratio" means the ratio of the current respectively voltage transformer. B

B

B

B




9.4.6 Analog Outputs: Maximum Values The maximum analog values are calculated as following: Current:

MaxCurrent := 32767 *

Voltage:

MaxVoltage := 32767 *

15 8191

* 1A = 60 A

5

* 100V

= 250V

(secondary value !) (secondary value !)

65528




10 Protective Functions U

10.1 General U

The following describes the protective functions used in the GCP. They are part of the library of DRS functions. Please consult the manual DID-001-1 for description of these DRS functions. Every DRS function has a unique DRS function identification, which can be found in DRS-WIN as following: Menu: View – Treeview

In the picture above the first item is as following: Protective function: 64G95 • DRS function: Current 1-ph. 1-st. • S function identification: MI111 • DR Some protective functions needs more than one DRS function. The belonging DRS functions are not necessarily one after the other. To enable maximum CPU speed the DRS functions have to be sorted in a specific order. Not all protective functions are implemented in all GCPs. This information is only an overview and will assume basic protection knowledge. The calculation of the setting values is not the task of this document. Please refer to the plant specific calculation note. VA TECH HYDRO-PRT / Proschek Document No: DIC-023-1.03 Rev: D (revising) ProtectiveRelayingELINDRS_RevD.doc; 12.12.2006 48/106


10.2 Alarm and Trip Philosophy U

Every DRS function has an alarm and a trip output per stage. Both outputs can be used for the activation of the binary outputs (trip matrix) and the activation of the LED's in front of the device (LED matrix). The alarm output will be set by the function immediate after the setpoint is reached. Now the time delay is started and after the end of the time delay the trip output will be set. The exception to this is the differential relay which has no time delay and no alarm output. This is the DRS internal working philosophy. In the GCP an alarm shall be sent to the control system after the time delay together with the activation of the trip. The realization is very easy. With the trip matrix the binary outputs with the alarms to the control system are connected to the trip output of the function. Also the yellow LED of the function should be connected to the trip output.




10.3 Generator Differential (87G) U

10.3.1 General The Generator Differential function protects the generator between the CT's connected to system 1 and system 2. System1 is the "base system" and should be connected to the CT's on the generator output side. System 2 is connected to the CT's on the neutral end side.



Protective Relaying with ELIN DRS The difference current is calculated by the function, it is the phasor – addition of the currents of system 1 and system 2, phase by phase. Therefore the CT's of system 1 and system 2 must be connected in 180 degrees phase shift. I difference

=

I system1

+ I system 2

The restrained current is the scalar value (magnitude) - addition of the currents of system 1 and system 2, phase by phase: r

I restrained

=

I system1

r

+

I system 2

The differential function has a stabilizing feature. Depending on the restrained current the setting increases according the following picture. The slope of the rising curve is selectable with the parameter "Bias". Differential Current / Rated Current (of Prot. Relay)

6,0

Set Value „BIAS“

5,0 OPERATE REGION

4,0

3,0

2,0

1,0

Set Diff 0,6 0,5 0,4 0,3 0,2 0,1

1,0

% 60 BIAS =

BASIC SET VALUE „OPERATE VALUE“

S= B IA

SLOPE ACC. TO SET VALUE „BIAS“

S= BIA = BIAS

% 50 40% 30%

FIXED SLOPE (BIAS= 0,3)

2,0

3,0

FIXED SLOPE (BIAS= 0)


4,0

5,0

6,0

7,0

8,0

9,0

10,0

Restraint Current / Rated Current



10.3.2 Commissioning For commissioning it is necessary to carry out two tests: • Trip test • Stability test For both tests the measurement display of the differential function of DRS-WIN is necessary. It shows both the difference current and the restrained current. For the tests it is good practice to use the display in secondary value modus. The first test is a trip test with a fault inside the protection range, one system leads current and the other system is zero. Increase the current; which is the same as the difference current, until the function trips. The second test is a stability test with no fault inside the protection range. Both systems have the same current but with opposite phase angle, the phasor - addition must be zero. The difference current must be close to zero, the restraint display must show the scalar value (magnitude) - addition of the current of both systems which is twice the value of one system. The measurements should be similar to the picture below.




10.4 Inadvertent Energization (50G/27) U

10.4.1 General The Inadvertent Energization function is an Overcurrent function with a current setting below the nominal current. Additional the function is blocked with the voltage level. If the voltage is higher than the setting level, the Overcurrent function is blocked. The Overcurrent function is active during generator standstill (voltage about zero volts), and blocked during normal operation with nominal voltage.

The following settings should be as used: Current • Memory: No • End of Current Memory: Block. Signal Blocking inputs: Unused •




10.4.2 Inadvertent Energization with Cur rent Memory Iactual

I set

t V actual

V set

t (I>) & (V<) [„CURR. MEMORY“=„YES“] 2

1

t

ALARM

CURR. MEMORY (=“YES“) takes over

(I>) & (V<) fulfilled

2

1

t

TRIP

DELAY TIME (set value) 1

t

BLOCK I (opt.)

fixed length (by firmware) 3

t

LEGEND: 1

Termination of „CURRENT MEMORY“ feedback circuit by „END OF TRIP PULSE“ acc. to set value: „END OF CURRENT MEMORY“ = „End of T rip Pulse“ Note: Length of trip pulse is fix ed (DRS firmware).

2

Termination of „CURRENT MEMORY“ - feedback circuit by external applied „BLOCK SIGNAL“ Note: „BLOCK SIGNAL“ usually to be derived from ®

3

® “CB = OFF“ - aux. contact.

The function starts, if both Overcurrent and Undervoltage criteria is fulfilled. This starts the alarm output. and after the delay time the trip output. The trip output has a fixed length. The current memory keeps the function active, even if the current decreases below the setpoint. If the parameter "End of Current Memory" is set to "End of Trip Pulse", the function terminates with the end of the trip pulse according to mark 1 in the picture above. If the parameter "End of Current Memory" is set to "Block Signal", the function terminates with an external input according to mark 2 in the picture above. The external signal is normally the CB-Off contact.




10.4.3 Inadvertent Energization without Current Memory Iactual

I >

Iset In

t Vactual Un

Vset V <

t (I>) & (V<) [„CURR. MEMORY“=„NO“] (I>) & (V<)

t

ALARM

(I >) & (V<) fulfilled

t

TRIP

DELAY TIME (set value)

t

fixed length (by firmware)

Without current memory the current must be above the setpoint and the voltage must be below the setpoint to start the function.

10.4.4 Commissioning For commissioning the function must be checked during the current tests. Because the voltage is about zero, the function must trip if the value exceeds the setpoint. During the voltage tests or load tests the function can be tested for stability.




10.5 Generator Inverse Time Overcurrent (51Ginv) U

10.5.1 General The first stage of the Inverse Time Overcurrent function has a selectable curve characteristic: extremely, very, normal, long inverse. The second stage has a definite characteristic. If this stage is active, the first stage is blocked.

10.5.2 Commissioning For commissioning the function must be checked during current tests. In most cases the setting values have to be reduced for test.




10.5.3 Long inverse curve characteristic The formula for the time delay is as following: t

= TMS *

120

 I  I

set

1

  − 1 

The graph for different TMS values is as following:

Long Inverse

1.000,000

100,000

10,000

c e s / t

TMS=1,0 1,000

TMS=0,5 TMS=0,1

0,100

0,010

0,001 1,00

10,00

100,00

I / Iset




10.5.4 Normal inverse curve characteristic The formula for the time delay is as following: t

= TMS *

0,14

 I  I

set

  

0 , 02

−1


Normal Inverse

1.000,000

100,000

10,000

c e s / t

TMS=1,0 1,000

TMS=0,5 TMS=0,1

0,100

0,010

0,001 1,00

10,00

100,00

I / Iset




10.5.5 Very inverse curve characteristic The formula for the time delay is as following: t

= TMS *

13,5

 I  I

set

1

  − 1 


Very Inverse

1.000,000

100,000

10,000

c e s / t

TMS=1,0 1,000

TMS=0,5 TMS=0,1

0,100

0,010

0,001 1,00

10,00

100,00

I / Iset




10.5.6 Extremely inverse curve characteristic The formula for the time delay is as following: t

= TMS *

80

 I  I

set

2

  − 1 


Extremely Inverse

1.000,000

100,000

10,000

c e s / t

TMS=1,0 1,000

TMS=0,5 TMS=0,1

0,100

0,010

0,001 1,00

10,00

100,00

I / Iset




10.6 Generator Overcurrent Voltage Restrained (51V) U

10.6.1 General The setting of the Overcurrent Voltage Restrained function is dependent on the measured voltage. Below 10% of nominal voltage the setting value is constant 10% of the "Operate Value". Above 90% of nominal voltage voltage the the setting setting value valueisismultiplied constant by equal to the "Operatethe Value". of nominal a factor according graphBetween below. 10 and 90%



Protective Relaying with ELIN DRS The following picture shows the multiplier of the setting value over the voltage level. OPERATE VALUE MULTIPLIER

1,0 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1,0

PHASE-PHASE VOLTAGE (ACTUAL) RATED PHASE-PHASE VOLTAGE (SET VALUE)

10.6.2 Commissioning For commissioning the function must be checked during current tests. In most cases the setting values have to be reduced for test.




10.7 Underimpedance (21G) U

10.7.1 General The Underimpedance function consists of 2 stages. The first stage is the Underimpedance function. In the impedance area it has a circle characteristic around the srcin. The stage will be active if the locus is inside this circle. The second stage is an Overcurrent function. It will block the first stage if the current is below the "Current Interlock" value. Additional with the setting "Time Delay Current" it can also be used as a definite time Overcurrent function.




10.7.2 Commissioning For commissioning it is necessary to carry out two tests: • Trip test • Stability test For both tests the measurement display of the differential function of DRS-WIN is necessary. It shows the impedance of all 3 phases in ohm. For the tests it is good practice to use the display in secondary value modus.

The first test is a trip test with a fault inside the protection range, a short circuit at the generator terminals. The impedance is about zero, because the voltage is zero Volts. The current must be higher than the setpoint, otherwise the impedance stage is blocked. For this test the setpoint of the current stage must be reduced. The second test is a stability test with a fault outside the protection range, a short circuit at the high voltage side of the transformer. The measured impedance should be slightly higher than the setpoint and the function should not trip.




10.8 Negative Sequence Overcurrent (46G) U

10.8.1 General The Negative Sequence Overcurrent function calculated the negative sequence of the current. The values in the DRS are based on the DRS nominal values which are 1A (or 5A). The generator has a different nominal value (e.g. 0,75A). Therefore the value of the generator must be multiplied with a compensation factor to get the DRS value.




10.8.2 Commissioning For commissioning it is necessary to carry out two tests: • Trip test • Stability test For both tests the measurement display of the differential function of DRS-WIN is necessary. It shows both the difference current and the restrained current. For the tests it is good practice to use the display in secondary value modus. The first test is a trip test with negative phase sequence current during the current tests. There are several possibilities to carry out this test and to simulate negative phase sequence current. • Modify the input matrix of the function by exchanging two phases of the CT (software solution) t e terminals of the GCP (secondary • Exchange two phases of secondary CT wiring at h hardware solution) • Make a single phase short circuit with a copper bar on the output terminals of the generator (primary hardware solution) The second test is a stability test with no negative phase sequence current during the current tests. The internal calculated negative phase sequence current should be close to zero. The display of the internal measured values should be similar to the picture below.




10.9 Generator Overvoltage (59G) U

10.9.1 General The Overvoltage function measures all 3 phase – phase voltages. The DRS nominal value is always 100V. Plants with different nominal values (110V or 120V) have to be adjusted with the setting value.

10.9.2 Commissioning For commissioning the function must be checked during voltage tests. In most cases the setting values have to be reduced for test.




10.10 Generator Undervoltage (27G) U

10.10.1 General The Undervoltage function measures all 3 phase – phase voltages. The DRS nominal value is always 100V. Plants with different nominal values (110V or 120V) have to be adjusted with the setting value. With the input matrix the function is blocked with "52G open".

10.10.2 Commissioning For commissioning the function must be checked during voltage tests. In most cases the setting values have to be reduced for test.




10.11 Under – Frequency (81G.u) U

10.11.1 General The Underfrequency function takes the measured frequency from the internal sampling frequency. The DRS has 2 channels which frequency it follows. The first channel is one of the voltage inputs and the second channel to is the onesecond of the current inputs. default channel is thethe first andsamples if the first is the not available it changes channel. If bothThe inputs are not available, DRS with DRS nominal frequency (50Hz or 60Hz). The function is automatically blocked if the measured voltage on the sampling input is lower or higher than the set value of the corresponding parameters of the function. With the input matrix the function is blocked with "52G open". Not used stages of the function are always blocked with the digital input number 28 "BLK ON" which is always active.

10.11.2 Commissioning For commissioning the function must be checked during voltage tests. The speed of the turbine has to be decreased. In most cases the setting values have to be reduced for test.




10.12 Over – Frequency (81G.o) U

10.12.1 General The Overfrequency function takes the measured frequency from the internal sampling frequency. The DRS has 2 channels which frequency it follows. The first channel is one of the voltage inputs and the second is one of second the current inputs. Theinputs default channel is the first and if the firstwith is not availablechannel it changes to the channel. If both are not available, the DRS samples the DRS nominal frequency (50Hz or 60Hz). The function is automatically blocked if the measured voltage on the sampling input is lower or higher than the set value of the corresponding parameters of the function. With the input matrix the function is blocked with the virtual input number 27 "Load Rejection". Please refer to the according chapter in this document. Not used stages of the function are always blocked with the digital input number 28 "BLK ON" which is always active.

10.12.2 Commissioning For commissioning the function must be checked during voltage tests. The speed of the turbine has to be decreased. In most cases the setting values have to be increased for test.




10.13 Load Rejection U

10.13.1 General The Load Rejection function is used to make a logical pulse at the moment when the generator gets offline. The duration of the pulse is 60 seconds, selectable by the signal function "Load Rejection t". This feature is used to block the Overfrequency protection to prevent a tripping of the generator when it gets offline.



Protective Relaying with ELIN DRS The following picture shows the logic for the Load Rejection: BI.04: Generator Offline Signal

Alarm

Signal function "Load Rejection“ raising: 0sec

VI.26: Load Rejection t Blocking

VO.27: Load Rejection Trip

Signal

Alarm

Signal function "Load Rejection t“ raising: 60sec Blocking

VO.26: Load Rejection t Trip

The event "Generator Offline" is detected by opening one of the breakers 52G or 52L. This information is connected to the binary input BI.04 "Generator Offline". This binary input starts two signal functions: "Load Rejection" and "Load Rejection t". The first signal function "Load Rejection" sets both the output and input "Load Rejection" VO27 and VI27 without time delay. The input VI27 is the direct copy of the output VO27. Please refer to the chapter "Copy Inputs" in this document. The second signal function "Load Rejection t" sets both the output and input "Load Rejection t" VO26 and VI26 after the time delay of 60 seconds. This signal blocks (stops) the first signal function "Load Rejection". The input "Load Rejection" VI27 can be used to block a protective function for a duration of 60 seconds.

BI.04: Generator Offline

VO.26: Load Rejection t

VO.27: Load Rejection

60 sec




10.14 Frequency Gradient (81dF/dt) U

10.14.1 General The Frequency Gradient function takes the measured frequency from the internal sampling frequency. The DRS has 2 channels which frequency it follows. The first channel is one of the voltage inputs and seconditchannel the current inputs. Theinputs default is the first and if the first is notthe available changesistoone theofsecond channel. If both arechannel not available, the DRS samples with the DRS nominal frequency (50Hz or 60Hz). The function is automatically blocked if the measured voltage on the sampling input is lower or higher than the set value of the corresponding parameters of the function. The function starts if the frequency change level is higher than the setting. The frequency change is calculated from the number of periods given in the setting "Average Time Constant". This setting shall be as big as possible to avoid faulty calculations.

10.14.2 Commissioning For commissioning the function must be checked during voltage tests. The speed of the turbine has to be decreased or increased within short time. In most cases the setting values have to be reduced for test.




10.15 Reverse Power (32G) U

10.15.1 General The Reverse Power function prevents the generator of working as motor- The function measures the active power calculated of the three current and three voltage inputs. The function has the setting input "Power Direction" which has to be checked during commissioning.




10.15.2 Commissioning For commissioning this function must be checked shortly after synchronizing the generator to the grid. For the test the measurement display of the reverse power function of DRS-WIN is necessary. It shows the apparent, real and reactive power. For the tests it is good practice to use the display in primary value modus.

Because the function was not properly tested before, the synchronization should be done with disabled trip outputs of this function. After synchronizing the generator to the grid check the display of the function for correct values of real and reactive power. If the display is wrong change the setting of "Power Direction". Reduce the speed or active power until the function trips, there is no real trip because of disabled trip outputs. After checking the function enable the trip outputs.




10.16 Overfluxing (24G) U

10.16.1 General The Overfluxing function protects electric equipment from operating with too high magnetic flux.

10.16.2 Commissioning For commissioning the function must be checked during voltage tests. The speed of the turbine has to be decreased and / or the voltage level in creased. In some cases the setting values have to be reduced for test.




10.17 Underexcitation (40G) U

10.17.1 General The Underexcitation function detects failures in the excitation system. The function measures a virtual rotor angle θ. This angle is compared with the setpoint and by exceeding the setpoint, the function starts. The function has the setting input "Voltage Direction" which has to be checked during commissioning.



Protective Relaying with ELIN DRS The virtual rotor angle θ is the angle of a line between a base point (represented by the quadrature axes reactance) and the actual load point (locus). Active Po wer (p.u.)

1,0 0,9

0,9

0,8

0,8

0,7 0,6 0,5

T

p ri

0,4

o N

0,3

a rm

l

p O

ra e

ti

o

n

-1,0 -0,9 -0,8

0,8 0,7

0,7

0,6

0,6

0,5

0,5

0,4

0,4

0,3

0,3

0,2 0,1

0,9

0,2

ϑ

0,2

0,1

0,1

-0,6 -0,5 -0,4 -0,3 -0,2 -0,1 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0

Reactive Powe r (p.u.)

10.17.2 Commissioning For commissioning the function must be checked during load tests. For the test the measurement display of the underexcitation function of DRS-WIN is necessary. It shows the rotor angle θ. The window also shows the rotor current, but this feature is currently not used in GCP applications.

Because the function was not properly tested before, the synchronization should be done with disabled trip outputs of this function. After synchronizing the generator to the grid check the display of the function for correct values of the rotor angle θ. Reduce the excitation or reactive power and check that the angle gets bigger, then increase the excitation or reactive power and check that the angle gets smaller. If the display is wrong change the setting of the "Voltage Direction". The trip (with disabled trip outputs) can be checked with reversed "Voltage Direction" in overexcitation modus. After checking the function enable the trip outputs and change the "Voltage Direction" to the correct value.




10.18 Out of Step (78G) U

10.18.1 General The Out of Step function calculates the impedance vector with the positive sequence voltages and currents. The function supervises the movement of the vector. The function has the setting input "Current Direction" which has to be checked during commissioning.



Protective Relaying with ELIN DRS The function uses the following setpoints according the following picture: • two blinders R 1 and R2, represented by the real (x) value of R1 and the real (x) offset to R2 • one impedance circle; represented by the center and the diameter. B

B

B

B

B

B

B

B

IMPEDANCE DIAGRAM

X [p.u.]

zS

. T P A D A T

xT δ -0.5

x 2

ϕp

δ

R [p.u.] 0.5

xd ’ BASE POINT (R1)

E L C IR C . P IM

R E T N E C

R E T E M A I D E L C R I C .

IMPEDANCE CIRCLE -0.5

D E T P A D A

’d x 3

P M I

OFFSET (R1-R2)

-1.0 VERTICAL BLINDER R2

VERTICAL BLINDER R1

LEGEND x d’ xT zS

δ ϕp R1 R1-R2 [p.u.]

adapted transient generator reactance adapted transformer reactance adapted external system impedance (line) rotor angle (between E p and Uline): 120°/240° phase angle (between E p-U line and Igenerator) distance between coordinate zero-point and blinder R1 distance between blinder R1 and blinder R2 refered to RELAY NOM. VALUES/ all imp. set values to be adapted to RELAY NOM. VALUES



Protective Relaying with ELIN DRS The following picture shows a movement of the locus which initiates a trip of the function: • Point 1 shows the normal operation point before a fault • At point 2 the locus reaches the impedance circle • At point 3 when the locus passes the first blinder R1, the function activates the alarm output • If the locus passes the second blinder R2 at point 4, the fault is definitive an out of step situation. If the setpoint "Slip pulse numbers = 1" and the setpoint "Trip = instantaneous ", the function activates the trip output. At this point the stator current is very high. • It is better to delay the trip until the locus leaves the impedance circle at point 5, setpoint B

B

•

B

B

"Trip = delayed" If the setpoint " Slip pulse numbers > 1" then the function waits for a second slip by reaching point 6 and 7 X

6

1

7 5

LOCUS (IMP. VECTOR)

2 4

3

R

IMP. CIRCLE

VERTICAL BLINDER R2

VERTICAL BLINDER R1

1

LOCUS AT NOM. OPERATION OF GENERATOR

2

LOCUS LOCUS LOCUS LOCUS LOCUS LOCUS

3

4

5

6

7

ENTERS IMPEDANCE CIRCLE CROSSES BLINDER R1 (1. SLIP STARTS) CROSSES BLINDER R2 („INSTANTANEOUS TRIP“) LEAVES IMPEDANCE CIRCLE (DELAYED TRIP“) ENTERS IMPEDANCE CIRCLE CROSSES BLINDER R1 (1. SLIP ENDS; 2. SLIP STARTS)




10.18.2 Commissioning For commissioning this function must be checked shortly after synchronizing the generator to the grid. For the test the measurement display of the out of step function of DRS-WIN is necessary. It shows the position of the locus.

Because the function was not properly tested before, the synchronization should be done with disabled trip outputs of this function. After synchronizing the generator to the grid check the display of the function for correct values of the position of the locus. For normal load the angle should be close to zero degree. If the angle is close to 180 degree, the setting "Current Direction" must be changed. After checking the function enable the trip outputs.




10.19 Stator Earth Fault (64G95) U

10.19.1 General The Stator Earth Fault 90% function is an single phase Overcurrent function which measures the current trough the neutral point of the generator.

10.19.2 Commissioning For commissioning it is necessary to carry out two tests: • Trip test • Stability test The first test is a trip test with a single phase earth fault at the generator terminals. The second test is stability test with no earth fault during the voltage test. Check the current through the neutral point of the generator for a value close to zero Amps (secondary value).




10.20 Stator Earth Fault (64G100) U

10.20.1 General rd The Stator Earth Fault 100% function measures the 3 harmonic of the zero sequence voltage at the generator terminals and the 3rd harmonic of the voltage at the generator neutral point. P

P

P

P

rd In case of a stator earth fault at the generator, 3 harmonics in the voltage are produced. If the both voltages are same level, the difference is zero. If the earth fault is close to the neutral point of the generator, the 3rd harmonic at this point is zero, while the 3rd harmonic at the output of the generator is not zero. If the difference voltage is higher than the setpoint, the function trips. P

P

P


P

P

P



10.20.2 Commissioning For commissioning the function can be checked for stability. For the test the measurement display of the stator earth fault function of DRS-WIN is necessary. It shows the 3rd harmonic at the output and at the neutral of the generator. Also the triggervoltage, which is the difference between the two voltages is shown. The triggervoltage must be very close to zero Volts. P

P




10.21 Cable Earth Fault (64B) U

10.21.1 General The Cable Earth Fault function is a single phase Overvoltage function which measures the zero sequence voltage at the low voltage side of the main transformer.

10.21.2 Commissioning For commissioning it is necessary to carry out two tests: • Trip test • Stability test The first test is a trip test with a single phase earth fault at the generator terminals. The second test is stability test with no earth fault during the voltage test. Check the zero sequence voltage for a value close to zero Volts (secondary value).




10.22 Breaker Failure (50BF) U

10.22.1 General The Breaker Failure function is an Overcurrent function with very low setting which is blocked during normal operation. A trip of another protective function inside the same DRS will activate the function. Then function theopen, generator current, which shall decrease closefailure to 0A if the the CB Breaker opens allFailure 3 poles. If the supervises CB does not the current keeps high and the breaker function will trip another CB. The blocking of the Breaker Failure function is done with the input VI.25. This is a virtual input, it is not physically available, but it can be used for internal use. This input is an inverted copy of the output VO.25, that means output logic 0 will copy to the input logic 1. This is normal operation. If a protective function will activate the breaker failure function it sets the output to logic 1, which copies to the input logic 0 and the Breaker Failure function is active.



Protective Relaying with ELIN DRS The next picture shows the internal copy of output VO.25 to VI.25 in normal operation. This copy is inverted, which means output logic 0 copies to input logic 1.

[ V I . 2 5 ] :B FS t ar t

[ V O . 2 5 ] :B FS t ar t INVERSION 1 = NOT(0)

The next picture shows the flow chart of the Breaker Failure function. No Trip: VO.25 logic 0 – copy to VI.25 logic 1 – Overcurrent function blocked Trip of any protective function: VO.25 logic 1 – VI.25 logic 0 – Overcurrent function active If CB opens in time, Breaker Failure function makes no trip If CB does not open, Breaker Failure function makes a trip to another CB




50BF

NO

TRIP ?

YES

VO.25 = 0 VI.25 = 1

VO.25 = 1 VI.25 = 0

Overcurrent blocked

Overcurrent free

OK YES

50BF Alarm

OK

52G opened

NO

50BF Trip

52L - TRIP

10.22.2 Commissioning For commissioning the function must be checked during the current tests.




10.23 Breaker opening too long (BF, 94GB) U

10.23.1 General The Breaker opening too long function is a logical function which detects the circuit breaker tripping command and waits for the opening of the breaker. The realization is done with a signal function. With every trip command of the circuit breaker the function starts. The trip has a time delay of 250 ms. A trip is only issued if the circuit breaker does not open within this time.



Protective Relaying with ELIN DRS The following picture shows the logic for the Breaker opening too long: BI.05: 52G tripped

BF.Alarm Signal

Alarm

Signal function "BF“ raising: 250 ms

BI.01: 52G open Blocking

BF.Trip Trip

Both trip commands to the circuit breaker are connected to one binary input BI.05 "52G tripped". This input starts the signal function "BF". The time delay for the trip is 250 ms. Within this time delay the signal function must be blocked with the input BI.01 "52G open". If the circuit breaker does not open, the input will not block the function and a trip is issued. For the case of properly opening circuit breaker the following timing diagram is valid (no Trip):

BI.05: 52G tripped

BI.01: 52G open

BF.Alarm

BF.Trip

For the case of not properly opening circuit breaker the following timing diagram is valid (Trip):

BI.05: 52G tripped

BI.01: 52G open

BF.Alarm

BF.Trip

250 ms

10.23.2 Commissioning There are no special tests necessary for commissioning.




10.24 Voltage Balance (60) U

10.24.1 General The Voltage Balance function checks the voltage for negative phase sequence. If the level is higher than the setpoint, the function trips. Additional the function is blocked if the negative sequence current is higher than the setpoint,




10.24.2 Commissioning For commissioning the function can be checked during the voltage tests. For the test the measurement display of the voltage balance function of DRS-WIN is necessary. It shows both the negative phase sequence voltage and the negative phase sequence current. For the tests it is good practice to use the display in secondary value modus.

Check the display of the function for a negative sequence voltage close to zero Volts (secondary values).




10.25 Transformer Differential (87T) or Block Differential (87B) U

10.25.1 General The Transformer Differential function or Block Differential function protects the transformer between the CT's connected to system 1, system 2 and system 3. The function covers 2 or 3 systems. The theory is always the same. System 1 is the "base system" and should be connected to the CT's at the high voltage side of the transformer.

The difference current is calculated by the function, it is the phasor – addition of the currents of system 1, system 2 and system 3, phase by phase, with vector group correction and CT ratio compensation. Therefore the CT's of system 1, system 2 and system 3 must be connected in 180 degrees phase shift. If this is not possible it can be corrected by turning the vector group 180 degrees. r

I difference

= I system + I system 1

2 *

CT2−1

+ I system

3

*

CT3−1

The restrained current is the scalar value (magnitude) - addition of the currents of system 1, system 2 and system 3, phase by phase: r

I restrained

=

I system1

r

+

I system 2

r

*


CT2 −1

+

I system 3 * CT3−1


Protective Relaying with ELIN DRS The differential function has a stabilizing feature. Depending on the restrained current the setting increases according the following picture. The slope of the rising curve is selectable with the parameter "Bias". Differential Current / Rated Current (of Prot. Relay)

6,0

Set Value „BIAS“

5,0 OPERATE REGION

4,0

3,0

2,0

1,0

S= B IA

BASIC SET VALUE

Set Diff 0,6 0,5 0,4 0,3 0,2 0,1

1,0 FIXED SLOPE (BIAS= 0)

S= B IA

SLOPE ACC. TO SET VALUE „BIAS“

„OPERATE VALUE“

S= BIA = BIAS

% 60 % 50 40% 30%

FIXED SLOPE (BIAS= 0,3)

2,0

3,0

4,0

5,0

6,0

7,0

8,0

9,0

10,

0

Restraint Current / Rated Current

The function also has a zero sequence filter. It is used to eliminate the zero sequence system from the calculation. If this filter is ON, the current is reduced by its zero sequence current. The zero sequence filter can be selected separately for every system. It should be turned ON for solidly grounded systems. ATTENTION! During secondary injection tests all zero sequence filters should be turned off, for checking of setpoints. If the zero sequence filter is turned ON and only one phase is injected by secondary tests, the display of the internal measurements shows a current for all three phases.



Protective Relaying with ELIN DRS The following drawing shows the internal logic for a 2 legs 3 phase differential function: High Set OC

2,00 A

FFT 1H>> HIGH SET 5 Zero Sequ.Fil.Sys. 1

1

On

Bias

ISYSTEM1 L1- I0

ISYSTEM1 L1 I SYSTEM1 L2 I SYSTEM1 L3

ZERO

FFT 1H

SEQUENCE

45 %

|IA|+|Ia| 1 CALCULATION OF RESTRAINT

2

SYSTEM1

Remark: I 0 = (IL1+IL2+IL3)/3

BIAS

.O A T L V C A

CURRENT3

Operate Value

. R E E P U

4

0,30 A RESTR. CURR.

CALC. OF ACT. ?I-SET VALUE & TRIP DECISION

FFT 1H

CALCULATION OF DIFF. CURRENT

2nd Harmonic

25 %

FFT 2H > set 5th Harmonic Zero Sequ.Fil.Sys. 2

Off

15 %

>=1

FFT 5H > set

ISYSTEM2 L1- I0

I SYSTEM2 L1 I SYSTEM2 L2 I SYSTEM2 L3

ZERO SEQUENCE SYSTEM2

Remark: I0 = (IL1+IL2+IL3)/3

Vector Group 1-2

&

5

VECTOR

TRIP &

GROUP 1-2

CT Ration Comp. 2-1

CT RATIO

1.00

FFT 1H

2

COMPENSATION 2-1

L1 L2 L3

LEGEND RELAY PARAMETERS (SET VALUES) FFT 1H...FOURIER TRANSFORM./ 1st HARM. RESTRAINT CURRENT...USED FOR BIAS CALC. |IA|...HV-SIDE OF TRANSF. |Ia|...LV-SIDE OF TRANSF. (COMPENSATED) 4 ANGLE OF SLOPE OF BIAS CHARACTERISTIC nd 5 BLOCKING BY 2 HARM. OR 5th HARM. IS CANCELLED IN CASE: ? I > HIGH SET. 1 2 3




10.25.2 Commissioning For commissioning it is necessary to carry out two tests: • Trip test • Stability test For both tests the measurement display of the differential function of DRS-WIN is necessary. It shows both the difference current and the restrained current. For the tests it is good practice to use the display in secondary value modus. The first test is a trip test with a fault inside the protection range, one system leads current and the other systems are zero. Increase the current; which is the same as the difference current, until the function trips. The second test is a stability test with no fault inside the protection range. All systems have the same current, with respect to the vector group and the CT ratio, but with opposite phase angle, the phasor addition must be zero. The difference current must be close to zero, the restraint display must show the scalar value (magnitude) - addition of the current of all systems. The measurements should be similar to the picture below.




10.26 Main Transformer Restricted Earth Fault (64T.REF) U

10.26.1 General A simple overcurrent and earth fault system will not give good protection coverage for a star connected primary winding. The degree of protection is very much improved by the application of a restricted fault The residualin current of three line current transformers is balanced against theearth output of asystem. current transformer the neutral conductor. The Main Transformer Restricted Earth Fault function protects the transformer in case of an earth fault between the CT's connected to system 1 and system 2. Outside this area the function is stable. For the realization a transformer differential function with 2 inputs and 3 phases is used. The advantage of this is the bias characteristic which makes the system more stable against outside faults. The setting "Vector group" is used to make a simple 180 degree rotation of one of the current systems. In that case the vector group setting is 6. In case of a different situation on site it is also possible to change the setting to 0. All other choices (vector group 1, 5, 7 and 11) should not be used. All 3 phases of a system are connected to the same current inputs. The setting ratios. "CT ratio compensation" is set to 1,0 in case of equal CT ratio, but can also be adapted to different



Protective Relaying with ELIN DRS In the example below the restricted earth fault function share the high voltage current transformers with the transformer or block differential function. The high voltage current transformers are first used by the differential protection 87T or 87B, the zero sequence part of the current is connected to a separate current input which is system 1 of the 64REF protection. System 2 of the 64REF protection is the neutral CT of the transformer.

The calculation of the difference current and restrained current is explained in the chapter "Transformer Differential" in this document.




10.26.2 Commissioning For commissioning it is necessary to carry out two tests: • Trip test • Stability test For both tests the measurement display of the differential function of DRS-WIN is necessary. It shows both the difference current and the restrained current. For the tests it is good practice to use the display in secondary value modus. The trip of 64REF can be checked by applying a single phase earth fault inside the protection range according the following picture. 87T System 1

64REF ∆I > 0

One system carries a current and the other system is zero. If the differential current exceeds the setpoint the function will trip.



Protective Relaying with ELIN DRS The stability of 64REF can be checked by applying a single phase earth fault outside the protection range according the following picture. 87T System 1

64REF ∆I = 0

Both systems have the same current but with the same phase angle, the phasor - addition must be zero with correction of vector group 180 degrees. The difference current must be close to zero, the restraint display must show the scalar value (magnitude) - addition of the current of both systems which is twice the value of one system. The measurements should be similar to the picture below.



Protective Relaying with ELIN DRS If the differential current shows a value equal to the restraint current check that both current inputs shows a current (with the measurement display). If YES, then it seems that one system has the wrong current direction. To avoid wiring changes inside or outside the cubicle, there is a possibility to change the setting "Vector Group" from 6 to 0 or reverse.




10.27 Trip Coil Supervision (TCS) U

10.27.1 General The Trip Coil Supervision function detects a fault in the electrical circuit of the trip coil of a circuit breaker. The same function can also be used to supervise the electrical circuit of the trip coil of a lockout relay.



Protective Relaying with ELIN DRS The electrical connection is according the picture below. The binary input of the DRS is in parallel to the trip contacts of the supervised trip circuit which is one input of the TCS function. The second input is the CB-open input to block the function. trip circuit supervision of a circuit breaker

trip circuit supervision of a lockout relay

The following conditions are possible: CB open: If the circuit breaker is open, the supervision is not possible because the internal NC contact of the breaker is open. As a result the input "CB open" is active and the function is blocked. In case of a lockout relay the function is also blocked with the generator circuit breaker because there is a possibility that the lockout relay is tripped. CB closed and no trip: If the circuit breaker is closed, the supervision is active and the internal NC contact of the circuit breaker is closed. If the trip circuit of the circuit breaker or lockout relay is closed properly, the full voltage can be measured at the binary input of DRS, which shows logical 1. Otherwise the binary input is logical 0. CB closed and trip In the first moment of a trip when the circuit breaker is still closed, the input of the DRS shows logic 0 because of the closed trip contact. The TCS function starts working, but within the time delay (1 second) the breaker opens and the CB open feedback blocks the function.

10.27.2 Commissioning There are no special tests necessary for commissioning.




11 Index U

—A— alarm output, 49 analog inputs, 42 —B— Binary I/O Preset, 22

minute pulse, 44 MODBUS, 6, 45 MODBUS addresses, 45 MODBUS interface, 45 Modicon, 45

bistable relay, 41 BLK ON, 43 Block Differential, 94 Breaker Failure, 87 Breaker opening too long, 90 —C— Cable Earth Fault, 86 commissioning, 25 communication cable, 8, 9 communication port, 9 CPU speed, 48 —D— difference current, 51, 94, 99 digital inputs, 43 digital outputs, 44 DRS – fault, 44 DRS – watchdog, 44

modified data, 17, 18 multifunctional protection relay, 6 —N— Negative Sequence Overcurrent, 65 NMI 1, 44 NMI 2, 44 —O— Out of Step, 79 Overcurrent Voltage Restrained, 61 Overfluxing, 76 Overfrequency, 70 Overvoltage, 67 —P— password, 13 protective functions, 48 —R— red triangle, 16

DRS function identification, 48 DRS functions, 48 DRS-WIN, 8 —E— E2PROM, 6 event list, 7 —F— fault record, 7 Frequency Gradient, 73 Function Outputs, 24 —G— Generator Differential, 50 —I— Inadvertent Energization, 53 input matrix, 15 interposing transformers, 6 Inverse Time Overcurrent, 56

Remote Terminal Unit, 45 restrained current, 51, 94, 99 Reverse Power, 74 RS485, 6 —S— secondary wiring, 36, 38 serial interfaces, 6 settings, 14 spare part, 30, 33 stabilizing feature, 51, 95 Stator Earth Fault 100%, 84 Stator Earth Fault 90%, 83 supervision functions, 6 synchronous machines, 6 —T— transducers, 6 Transformer Differential, 94

—L— LED, 7 LED Quit, 44 Load Rejection, 71 lockout relays, 40 —M— Main Transformer Restricted Earth Fault, 98 Measured values, 27

transformers, 6 trip matrix, 18 trip output, 49 tripping outputs, 40 —U— Underexcitation, 77 Underfrequency, 69 Underimpedance, 63



Protective Relaying with ELIN DRS Undervoltage, 68 —V— VE-file, 30


—Z— zero sequence filter, 95


Drs-compact Descriptionforgcp Revd

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