Siemens 7SG12 DAD-N User manual

Reyrolle
Protection
Devices
7SG12 DAD-N
Numerical High Impedance Relay with CT Supervision
Answers for energy

7SG12 DAD-N Contents
The copyright and other intellectual property rights in this document, and in any model or article produced from it
(and including any registered or unregistered design rights) are the property of Siemens Protection Devices
Limited. No part of this document shall be reproduced or modified or stored in another form, in any data retrieval
system, without the permission of Siemens Protection Devices Limited, nor shall any model or article be
reproduced from this document unless Siemens Protection Devices Limited consent.
While the information and guidance given in this document is believed to be correct, no liability shall be accepted
for any loss or damage caused by any error or omission, whether such error or omission is the result of
negligence or any other cause. Any and all such liability is disclaimed.
©2010 Siemens Protection Devices Limited
Contents
Technical Manual Chapters
1 Description of Operation
2 Performance Specification
3 Relay Settings
4 Communication Interface
5 Applications Guide
6 Installation
7 Commissioning
8 Maintenance
9 Diagrams

7SG12 DAD N Description of Operation
The copyright and other intellectual property rights in this document, and in any model or article produced from it
(and including any registered or unregistered design rights) are the property of Siemens Protection Devices
Limited. No part of this document shall be reproduced or modified or stored in another form, in any data retrieval
system, without the permission of Siemens Protection Devices Limited, nor shall any model or article be
reproduced from this document unless Siemens Protection Devices Limited consent.
While the information and guidance given in this document is believed to be correct, no liability shall be accepted
for any loss or damage caused by any error or omission, whether such error or omission is the result of
negligence or any other cause. Any and all such liability is disclaimed.
©2010 Siemens Protection Devices Limited
7SG12 DAD N
Numerical High Impedance Relay with CT Supervision
Document Release History
This document is issue 2010/02. The list of revisions up to and including this issue is:
Pre release
2010/02 Document reformat due to rebrand
R4 26/08/2005 Clarified TCS operation.
R3 20/07/2005 Second stage differential element added.
R2 24/05/2004 General update
R1 06/06/2003 First Issue for Comment.
Software Revision History

7SG12 DAD N Description of Operation
Contents
1INTRODUCTION................................................................................................................................................ 3
2HARDWARE DESCRIPTION............................................................................................................................. 3
2.1 General .................................................................................................................................................... 3
2.2 Analogue Inputs ....................................................................................................................................... 4
2.3 Status Inputs ............................................................................................................................................ 4
2.4 Output Relays .......................................................................................................................................... 4
2.5 Fascia LEDS ............................................................................................................................................ 5
2.6 Self Monitoring ......................................................................................................................................... 5
2.6.1 Protection Healthy/Defective ............................................................................................................ 5
3PROTECTION FUNCTIONS.............................................................................................................................. 5
3.1 Overall Differential (87/50-1, 87/50-2) ...................................................................................................... 5
3.2 CT Supervision (CT 50) ........................................................................................................................... 5
3.3 Trip Circuit Supervision ............................................................................................................................ 5
4OTHER FEATURES .......................................................................................................................................... 6
4.1 Metering ................................................................................................................................................... 6
4.2 Data Storage............................................................................................................................................ 6
4.2.1 General ............................................................................................................................................ 6
4.2.2 Waveform Records. ......................................................................................................................... 6
4.2.3 Event Records.................................................................................................................................. 6
4.2.4 Fault Recording................................................................................................................................6
4.3 Time Synchronisation............................................................................................................................... 7
4.3.1 IRIG-B Time Synchronisation........................................................................................................... 7
4.3.2 IEC 60870-5-103 Time Synchronisation........................................................................................... 7
4.3.3 Real Time Clock Time Synchronisation............................................................................................ 7
4.4 Communications ...................................................................................................................................... 7
4.5 Settings Groups ....................................................................................................................................... 7
4.6 Password Feature .................................................................................................................................... 7
5USER INTERFACE............................................................................................................................................ 8
5.1 Liquid Crystal Display............................................................................................................................... 8
5.2 Back light Control..................................................................................................................................... 8
5.3 LED Indications........................................................................................................................................ 8
5.4 Keypad..................................................................................................................................................... 8
5.5 Relay Identifier ......................................................................................................................................... 8
5.6 Settings Mode .......................................................................................................................................... 8
5.6.1 Settings Adjustment ......................................................................................................................... 8
5.6.2 Settings And Displays ...................................................................................................................... 9
5.7 Instruments Mode .................................................................................................................................. 10
5.7.1 Hidden Instruments ........................................................................................................................ 10
5.8 Fault Data Mode.................................................................................................................................... 10
5.9 Default Instruments Screens.................................................................................................................. 10
6DIAGRAMS...................................................................................................................................................... 12
Figures
Figure 1 – DAD-N Numerical High Impedance protection........................................................................................ 3
Figure 2 – DAD-N in E8 case with front panel open............................................................................................... 12
Figure 3 – DAD-N Rear View ................................................................................................................................. 12
Figure 4 – High Impedance Differential Schematic ................................................................................................ 13
Figure 5 – DAD-N Menu Structure ......................................................................................................................... 14
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7SG12 DAD N Description of Operation
1 Introduction
The DAD-N relay represents an integration of the protection elements required to provide a complete
Numerical High Impedance protection, with additional auxiliary and backup elements available to provide
integrated scheme solutions. The basic relay is a single differential zone as shown below. Other models
are also available which incorporate multiple zones of protection which may be used together with logic
schemes to form more complex busbar protection zones with check zone capability.
High Impedence Differential
Protected Zone
N
A
B
C
1A
17
20
19
18
22
21
28
27
26
25
24
23
AN1
5A
Ia
Ib
Ic
R RR
DAD-N-101
High Impedence Numerical Differential
CT
50
87/50
-1
AN1C1 - C3
87/50
-2
1A
5A
1A
5A
Figure 1 – DAD-N-101 Numerical High Impedance protection
2 Hardware Description
2.1 General
The structure of the relay is based upon the Modular II hardware and software platform illustrated in Figure
2where the required cards plug in from the front after opening the front fascia. Modules are interconnected
by means of ribbon cable. The basic relay is supplied in a standard Epsilon case size E8. The Modular II
design provides commonality between products and spare parts across a range of protection and control
relays including Duobias, Ohmega, Delta, Tau and Iota.
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7SG12 DAD N Description of Operation
Configuration :
Analogue Inputs Status Inputs Output Relays Case Connections
3 11 13 E8 2621W11006
Each analogue module has up to four inputs; the first three are usually for measuring the CT secondary
line currents from each of the three phases A, B and C. The fourth channel is not used.
The unit consists of the following modules:
1) Analogue Input modules (4 x I )
2) One Controller CPU module
3) One Power Supply and Basic I/O module
4) Maximum of Four Output relay/Status Input Module
5) One Front Fascia
2.2 Analogue Inputs
One analogue module is used in the E8 case of 3 channels of current.
In order to ensure high accuracy true RMS measurements and accurate phase and slip frequency
calculations, the current signals are sampled at a minimum of 16 samples per cycle for both 50Hz and
60Hz system frequencies. This sampling rate also provides high accuracy and waveform storage records
2.3 Status Inputs
The relay may be fitted with up to 11 status inputs. The user can program the relay to use any status input
for any function. A timer is associated with each input and a pickup time setting may be applied to each
input. In addition each input may be logically inverted to allow easy integration of the relay within the user
scheme. Each input may be mapped to any front Fascia LED and/or to any Output Relay contact. This
allows the Relay to act as panel indication for alarms and scheme status without having to use additional
external flagging elements.
2.4 Output Relays
The relay may be fitted with 13 output relays, all of which are capable of handling circuit breaker tripping
duty. All relays are fully user configurable and can be programmed to operate from any or all of the control
functions. There are three relays on the Power Supply/Basic I/O module which have C/O contacts and 2
with N/O contacts. Additional modules may are fitted with 8 N/O contacts.
In their normal mode of operation output relays remain energised for a minimum of 100msec and a
maximum dependent on the energising condition duration. If required, however, outputs can be
programmed to operate as latching relays. These latched outputs can be reset by either pressing the
TEST/RESET button, or by sending an appropriate communications command.
The output relays can be used to operate the trip coils of the circuit breaker directly if the circuit breaker
auxiliary contacts are used to break the trip coil current and the contact rating of the relay output contacts
is not exceeded for 'make and carry' currents.
With a failed breaker condition the current 'break' may be transferred to the relay output contacts and
where this level is above the break rating of the contacts an auxiliary relay with heavy-duty contacts should
be utilised.
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7SG12 DAD N Description of Operation
2.5 Fascia LEDS
In the E8 case there are 16 user programmable red LED flag indicators. By opening the front panel it is
possible to insert a label strip into a slip in pocket, which provides legend information about the meaning of
each LED. The legend may be specified when ordering the relay or alternatively the user can create a
customized legend. The user can customise which LED is used for which purpose as well as being able to
program each LED as being latching or self –resetting.
2.6 Self Monitoring
The relay incorporates a number of self-monitoring features. Each of these features can initiate a
controlled reset recovery sequence, which can be used to generate an alarm output. In addition, the
Protection Healthy LED will give visual indication.
A watchdog timer continuously monitors the microprocessor. The voltage rails are also continuously
supervised and the microprocessor is reset if any of the rails falls outside of their working ranges. Any
failure is detected in sufficient time so that the microprocessor can be shut down in a safe and controlled
manner.
2.6.1 Protection Healthy/Defective
The normally closed contacts of relay 1 are used to signal protection defective, whilst the normally open
contacts are used to signal protection healthy. When the DC supply is not applied to the relay or a problem
is detected with the operation of the relay then this relay is de-energised and the normally closed contacts
make to provide an external alarm. When the relay has DC supply and it has successfully passed its self-
checking procedure then the Protection Healthy contacts are made and the Protection Defective contacts
are opened.
3 Protection Functions
3.1 Overall Differential (87/50-1, 87/50-2)
The Overall Differential protection uses the high impedance circulating current principle, a single line
diagram of such a scheme is shown in Figure 4 – High Impedance Differential Schematic. The protection
consists of a DTL over-current element 87/50 per phase which is used for tripping.
Transient stability under through fault conditions is a problem with many forms of differential protection,
due to variations in CT magnetising characteristics. When saturation is approached the current transformer
output waveforms become increasingly distorted with a high percentage of 3rd and other harmonics. The
algorithms employed in the Overall Differential protection ensure complete harmonic rejection thus
improving overall protection stability.
In addition the settings for high impedance differential protection are calculated assuming that one CT is
completely saturated. Using this worst case condition the voltage (determined by the value of the
stabilising resistor) and current settings for the 87/50 elements can be precisely calculated with known
stability margins. Intermediate conditions where the CT is only partially saturated increases the stability
margin. This approach enables schemes to be engineered with relatively low knee-point voltages.
There are two stages of protection, 87/50-1 and 87/50-2 both of which are identical.
3.2 CT Supervision (CT 50)
To check for CT continuity an overcurrent element (50) is available. During healthy CT conditions the
current in the differential circuit is zero. If one CT becomes open circuit the current contribution from that
CT will flow through the relay. If the setting is below this level of current the relay CT alarm will operate.
3.3 Trip Circuit Supervision
Status inputs on the relay can be used to supervise the trip circuit while the associated circuit breaker (CB)
is either open or closed. Each trip circuit monitored can independently be programmed to operate output
contacts, LEDs and events.
To use the function set ‘Trip Cct nPickup Delay’ to the required value in the Trip Circuit Supervision Menu
and then map the ‘Trip Cct Fail n’ settings in the Status Input Menu, Output Relay Menu and LED Menu as
required.
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7SG12 DAD N Description of Operation
The Trip Circuit Timer(s) are inhibited whenever one or more of the status inputs selected is energised.
4 Other Features
4.1 Metering
The metering feature provides real-time data available from the relay fascia in the ‘Instruments Mode’ or
via the communications interface.
The following displays are available:
Differential currents (Primary and secondary)
Digital input status
Output relay status
Time and Date
4.2 Data Storage
4.2.1 General
Details of relay operation are recorded in three forms, namely Waveform records, Event records and Fault
Data records. All records are time and date stamped with a resolution of one millisecond.
4.2.2 Waveform Records.
The waveform record feature stores analogue and digital information for the current inputs, status inputs
and output relays and LED’s. Waveforms may be returned to VA TECH Reyrolle ACP Ltd for analysis.
The waveforms are stored with a sampling resolution of at least 16 samples per cycle depending upon
relay model. The waveform recorder has the ability to store records for the previous four trip operations of
the relay. These are labelled 1-4 with 1 being the most recent record. This however, can be altered using
the ‘Record Duration’ setting, which offers the following selection:
•Five records of one second duration
•Two records of two seconds duration
•One record of five seconds duration
The waveform recorder will be triggered automatically when any protection element operates. It can also
be triggered by any of the following means:
Via the ‘Trigger Storage” status input signal.
Via the IEC870-5-103 communications interface.
The waveform recorder has a settable pre-fault triggering capability.
4.2.3 Event Records
The event recorder feature allows the time tagging of any change of state (Event) of the relay. As an event
occurs, the actual event condition is logged as a record along with a time and date stamp to a resolution of
1 millisecond. There is capacity for a maximum of 500 event records that can be stored in the relay and
when the event buffer is full any new record will over-write the oldest. The following events are logged:
Change of state of Output Relays.
Change of state of Status Inputs.
Change of Settings and Settings Group
Change of state of any of the control functions of the relay.
4.2.4 Fault Recording
The fault type, led flag configuration, date and time of the last five faults are recorded for display via the
Fascia LCD.
Note : the real-time clock, waveform records, fault records and event records are all maintained, in the
event of loss of auxiliary d.c. supply voltage, by the backup storage capacitor. This capacitor has the ability
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7SG12 DAD N Description of Operation
to maintain the charges on the real-time clock IC and the SRAM memory device for typically 2-3 weeks
time duration.
4.3 Time Synchronisation
Time and date can be set either via the relay fascia using appropriate commands in the System Config
menu, via an IRIG-B input or via the communications interface
4.3.1 IRIG-B Time Synchronisation
A BNC connector on the relay rear provides an isolated IRIG-B GPS time synchronisation port. The IRIG-B
input expects a modulated 3-6 Volt signal and provides time synchronisation to the nearest millisecond.
4.3.2 IEC 60870-5-103 Time Synchronisation
Relays connected individually or in a ring or star configuration can be directly time synchronised using the
IEC 60870-5-103 global time synchronisation. This can be from a dedicated substation automation system
or from REYDISP EVOLUTION communications support software.
4.3.3 Real Time Clock Time Synchronisation
In the absence of IRIG-B and IEC60870 time synchronisation the relay contains a real time clock circuit
which maintains real time in the absence of DC supply.
4.4 Communications
Two fibre optic communication ports, COM1 and COM 2b are provided at the rear of the relay, which give
superior EMC performance. An isolated RS232 port, COM 2a, is provided at the front of the relay for local
access using a PC.
Communication is compatible with the IEC870-5-103 FT 1.2 transmission and application standards. For
communication with the relay via a PC (personal computer) a user-friendly software package, REYDISP
EVOLUTION, is available to allow transfer of the following:
Relay Settings
Waveform Records
Event Records
Fault Data Records
Instrument and meters
Control Functions
Communications operation is described in detail in Section 4 of this manual. For information about all
aspects of the communications protocol used in the Modular II range of relays see Section 4.
4.5 Settings Groups
Depending upon the relay model then up to eight alternative setting groups are provided, making it
possible to edit one group while the relay protection algorithms operate using another ‘active’ group. An
indication of which group is being viewed is given by the ‘Gn’ character in the top left of the display.
Settings that do not indicate Gn in the top left corner of the LCD are common to all groups.
A change of group can be achieved either locally at the relay fascia or remotely via a communication
interface command or via a status input change.
4.6 Password Feature
The programmable password feature enables the user to enter a 4 character alpha numeric code to secure
access to the relay settings. The relay is supplied with the password set to ‘NOT ACTIVE’, which means
that the password feature is disabled. The password must be entered twice as a security measure against
accident changes. Once a password has been entered then it will be required thereafter to change
settings. It can, however, be de-activated by using the password to gain access and by entering the
password ‘NONE’. Again this must be entered twice to de-activate the security system.
As soon as the user attempts to change a setting the password is requested before any setting alterations
are allowed. Once the password has been validated, the user is ‘logged on’ and any further changes can
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7SG12 DAD N Description of Operation
be made without re-entering the password. If no more changes are made within 1 hour then the user will
automatically be ‘logged off’, re-enabling the password feature.
Note that the password validation screen also displays a numerical code. If the password is lost or
forgotten, this code should be communicated to VA TECH Reyrolle ACP Ltd and the password can be
retrieved.
5 User Interface
The user interface is designed to provide a user-friendly method of entering settings and retrieving data
from the relay. The E8 relay fascia includes a 20 character by 2 line, backlit, liquid crystal display (LCD), 16
light emitting diodes (LED) and 5 push buttons.
5.1 Liquid Crystal Display
The liquid crystal display is used to present settings, instrumentation and fault data in a textual format on a
2 lines by 20-character interface.
5.2 Back Light Control
To conserve power the display backlighting is turned off if no push buttons are pressed for 5 minutes.
After an hour the whole display is de-activated. A setting within the “SYSTEM CONFIG MENU” allows the
timeout to be adjusted from 1 to 60 minutes and “OFF”, which means the backlight is always on.
5.3 LED Indications
The following indications are provided:
Protection Healthy – Green LED.
This LED is solidly illuminated to indicate that DC volts have been applied to the relay and that the relay is
operating correctly. If the internal relay watchdog detects a protection relay unhealthy condition then this
LED will continuously flash.
Programmable – Red LED.
An LED MENU is provided to map any relay output or any status input to any LED.
5.4 Keypad
Five pushbuttons are used to control the functions of the relay. They are labelled ENTER and CANCEL.
Note that the ►button is also labelled TEST/RESET.
When the relay front cover is in place only the ▼and ►buttons are accessible. This allows read only
access to all the menu displays.
5.5 Relay Identifier
The Relay Identifier setting in the SYSTEM CONFIG MENU may be used to place a circuit identifier of up
to 16 alphanumeric characters onto the relay fascia. This information is also returned as part of the System
Information command from Reydisp Evolution Communications Support Software.
5.6 Settings Mode
5.6.1 Settings Adjustment
The push-buttons on the fascia are used to display the relay settings, display the operating signals, e.g.
currents, on the LCD and to reset the flag indication on the LCDs.
▼READ DOWN
In the Settings Display this push-button is used for scrolling down through a list of settings or signals.
In Settings Modification mode it is used for selecting the next value of (or decreasing) the displayed setting
or for deselecting a bit position in a particular control setting.
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7SG12 DAD N Description of Operation
▲READ UP
In Settings Display or Signal Displays this push-button is used for scrolling up through a list of settings or
signals.
In Settings Modification mode it is used for selecting the previous value of (or increasing) the displayed
setting or for selecting a bit position in a particular control setting.
ENTER
This push-button is used when the cover is removed to select between two modes of operation namely
Settings Display or Settings Modification.
When this push-button is pressed and a relay setting is being displayed part of the display will flash to
indicate that the setting being displayed can be modified by using the ▲READ UP or ▼ READ DOWN
keys on the facia.
When the required value of the setting has been established it may be entered into the relay and acted
upon by pressing the ENTER key again.
CANCEL
This push-button is used when the cover is removed to return the relay display to its initial status. It can be
used to reject any alterations to the setting being modified provided the ENTER key has not been pressed
to accept the changes.
►TEST/RESET
This push-button is used to reset the fault indication on the LEDs on the fascia. It also acts as a lamp test
button, when pressed all LEDs will momentarily light up to indicate their correct operation.
The ▼ READ DOWN and ▲READ UP push-buttons may then be used to scroll through the various
signals.
5.6.2 Settings And Displays
The display menu structure is shown in Figure 5. This diagram shows the three main modes of display,
which are the Settings Mode, Instruments Mode and the Fault Data Mode.
When the relay is first energised the user is presented with the following message: -
SETTINGS DEFAULTED
PRESS ENTER
This shows that the relay has been set with the standard factory default settings. If this message is
displayed ENTER must be pressed to acknowledge this initial condition, the display will then indicate the
relay identifier. e.g.
DAD-N-XXX
Pressing the ►TEST/RESET key on this display initiates an LED test. Pressing ▼ READ DOWN at this
display allows access to the three display modes, which are accessed in turn by pressing the
►TEST/RESET key.
The Settings Mode contains 11 setting sub-menu’s. These hold all of the programmable settings of the
relay in separate logical groups. The sub menus are accessed by pressing the Prices are very
competitive, starting at less than £400 and peaking at around twice that►key. This enters the sub
menu and presents a list of all the settings within that sub menu. Pressing the ▼ READ DOWN key scrolls
through the settings until after the last setting in the sub menu after which the next sub menu will be
shown. Access to this group is via the same method as before. If a particular sub menu is not required to
be viewed then pressing ▼ READ DOWN will skip past that particular menu and show the next one in the
list. Note that all screens can be viewed even if the password is not known. The password only protects
against unauthorised changes to settings.
While viewing an editable screen pressing the ENTER key allows the user to change the displayed data. A
flashing character(s) will indicate the editable field. Pressing ▲READ UP or ▼ READ DOWN scrolls
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7SG12 DAD N Description of Operation
through the available setting values or, pressing ►TEST/RESET moves right through the edit fields. Note
that all settings can be incremented or decremented using the ▲ READ UP or ▼ READ DOWN keys and
they all wraparound so that to go from a setting minimum value to the maximum value it is quicker to press
the ▼ READ DOWN key, rather than scroll through every setting. Also, to facilitate quicker setting changes
an acceleration feature is available which if ▲READ UP or ▼ READ DOWN are depressed and held,
then the rate of scrolling through the setting values increases.
If ESCAPE/CANCEL is pressed during a setting change operation the original setting value is restored and
the display is returned to the normal view mode.
If changes are made to the setting value then pressing ENTER disables the flashing character mode and
displays the new setting value. This is immediately stored in non-volatile memory.
The next sections give a description of each setting in the relay. The actual setting ranges and default
values can be found in the Relay Settings section of this manual.
5.7 Instruments Mode
In INSTRUMENT MODE metering points can be displayed to aid with commissioning, the following meters
are available
Instrument Description
[ DIFF METERS ]
--> press down <--
Start of Differential current meters
Primary Currents
0.000 0.000 0.000 kA
Differential Primary currents
Secondary Currents
0.000 0.000 0.000 A
Differential Secondary currents
Nominal Currents
0.00 0.00 0.00 xIn
Differential Nominal currents
[ MISC METERS ]
--> press down <--
Start of miscellaneous meters
Status Inputs 1-16
---- ---- ---- ----
Displays the state of DC status inputs 1 to 161
Status Inputs 17-27
---
Displays the state of DC status inputs 17 to 27
1
Output Relays 1-16
---- ---- ---- ----
Displays the state of output relays 1 to 162
Output Relays 17-29
---- -
Displays the state of output relays 17 to 292
Time & Date
13/08/2002 10:16:11
Time and Date
1) Display is different when fewer status inputs are fitted
2) Display is different when fewer output relays are fitted
Note that meters not designated as primary or secondary values are usually displayed as multiples of
nominal
i.e. x In, 1 Amp or 5 Amp.
5.7.1 Hidden Instruments
At the “INSTRUMENTS MODE” title screen, pressing ENTER and DOWN simultaneously reveals some
additional metering for calibration purposes. The reference channels as well as DC offsets may be
displayed along with the RMS values in raw ADC counts. The relationship between current and ADC
counts is 1 x In = 600 counts.
5.8 Fault Data Mode
In “FAULT DATA MODE”, the time and date of relay operations are recorded together with a record of the
LED flag states.
5.9 Default Instruments Screens
The menu presentation of the various instruments allows the user to view a single screen at a time.
However, for in service use, it is desirable that a small number of high interest, user selectable screens are
presented automatically by default without user intervention. The instrument screens of interest to the user
e.g. those required to be presented to a visiting engineer for record purposes can be selected by the user
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7SG12 DAD N Description of Operation
by pressing ENTER when viewing the required screen. On pressing ENTER a ‘D’ symbol will appear at the
top right of that screen. The ‘D’ indicates that a screen is a ‘default screen’. To de-select a default screen,
simply press ENTER while on that particular screen and the ‘D’ symbol will be cleared.
Time & Date D
01/01/2002 01:31:39
If no keys have been pressed for a pre-determined time the relay will jump to the default instrument display
regardless of where the menu has been left by the user. It will then scroll through each of the selected
default instruments and remain on each for approximately 5 seconds. The Default Screens Timer that sets
the time to elapse before the relay goes into the default instruments mode is found in the SYSTEM
CONFIG MENU.
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7SG12 DAD N Description of Operation
6 Diagrams
Figure 2 – DAD-N in E8 case with front panel open
Figure 3 – DAD-N Rear View
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7SG12 DAD N Description of Operation
PHASE A
R
E
S
87/50-1
&
87/50-2
&
CT 50
Figure 4 – High Impedance Differential Schematic
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7SG12 DAD N Description of Operation
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RELAY IDENTIFIER
SETTINGS MODE INSTRUMENTS
MODE FAULT DATA MODE
SYSTEM CONFIG MENU
-> to view
[ DIFF METERS ]
--> PRESS DOWN <-- FAULT 1
FAULT 5
LED TEST
NOTE : THE ARROWS IN THE DIAGRAM
REPRESENT THE KEY PRESSES REQUIRED
TO NAVIGATE THE MENU SYSTEM.
READ UP
READ DOWN
TEST/RESET
ENTER
CANCEL /
ESCAPE
[ MISC METERS ]
--> PRESS DOWN <--
COMMUNICATIONS MENU
-> to view
LED MENU
-> to view
Output Relays 1-5
1 _ _ _ _
Time & Date
16/07/2001 11:49:17
Status Inputs 1-3
_ _ _
CANCEL/ESCAPE
OUTPUT RELAY MENU
-> to view
DATA STORAGE MENU
-> to view
TRIP CCT SUPERVISION
MENU -> to view
STATUS INPUT MENU
-> to view
REYLOGIC ELEMENTS
MENU -> to view
CT SUPERVISION MENU
-> to view
CT/VT CONFIG MENU
-> to view
DIFFERRENTIAL MENU
-> to view
Figure 5 – DAD-N Menu Structure

7SG12 DAD N Performance Specification
The copyright and other intellectual property rights in this document, and in any model or article produced from it
(and including any registered or unregistered design rights) are the property of Siemens Protection Devices
Limited. No part of this document shall be reproduced or modified or stored in another form, in any data retrieval
system, without the permission of Siemens Protection Devices Limited, nor shall any model or article be
reproduced from this document unless Siemens Protection Devices Limited consent.
While the information and guidance given in this document is believed to be correct, no liability shall be accepted
for any loss or damage caused by any error or omission, whether such error or omission is the result of
negligence or any other cause. Any and all such liability is disclaimed.
©2010 Siemens Protection Devices Limited
7SG12 DAD N
Numerical High Impedance Relay with CT Supervision
Document Release History
This document is issue 2010/02. The list of revisions up to and including this issue is:
Pre release
2010/02 Document reformat due to rebrand
R6 11/10/06 CT Supervision time delay accuracy added
R5 26/08/2005 Corrected CT burden on 1A tap.
Operate Time for CT Supervision added.
Time Delay for TCS added.
R4 22/07/2005 Revision 15 software and SEF Current Input Module 2513H10099.
R3 18/10/2004 Corrected Status Input minimum current for operation.
Corrected operating time variation over frequency.
R2 24/05/2004 Revision 12 software.
R1 24/10/2002 First Issue for comment.
Software Revision History

7SG12 DAD N Performance Specification
Contents
1. INTRODUCTION................................................................................................................................................3
2. ACCURACY REFERENCE CONDITIONS ........................................................................................................3
3. ACCURACY INFLUENCING FACTORS ...........................................................................................................3
4. MODULAR II SPECIFICATION .........................................................................................................................3
4.1 Environmental Withstand ......................................................................................................................... 3
4.2 Auxiliary Energizing Quantity ................................................................................................................... 4
4.3 A.C Current Inputs ................................................................................................................................... 5
4.4 Output Contacts ....................................................................................................................................... 5
4.5 Status inputs ............................................................................................................................................ 5
4.6 Indication.................................................................................................................................................. 6
4.7 Settings And Configuration ...................................................................................................................... 6
4.8 Recording................................................................................................................................................. 6
4.9 Communications ...................................................................................................................................... 6
4.10 IRIG-B Time Synchronisation................................................................................................................... 7
5. PROTECTION ELEMENTS...............................................................................................................................7
5.1 Common Performance ............................................................................................................................. 7
5.2 87/50-1, 87/50-2 Differential..................................................................................................................... 7
5.3 CT-50 CT Supervision.............................................................................................................................. 7
5.4 Trip Circuit Supervision ............................................................................................................................ 7
©2010 Siemens Protection Devices Limited Chapter 2 Page 2 of 7

7SG12 DAD N Performance Specification
1.Introduction
The following document defines the technical and performance specification of the DAD-N Series relays. DAD-N
relays are based upon the VATECH ACP Ltd Modular II series of protection units.
Section 3 describes performance that is common to all Modular II protections.
Section 4 describes the performance of protection elements that may be fitted to DAD-N series relays. Therefore
for any one DAD-N series model, only the performance for those elements described in the Description of
Operation, as available in that model will be applicable.
Performance Data to:
IEC60255-6, IEC60255-6A and IEC60255-13.
2.Accuracy Reference Conditions
General IEC60255
Parts 6, 6A & 13
Auxiliary Supply Nominal
Frequency 50 Hz
Ambient Temperature 20°C
3.Accuracy Influencing Factors
Temperature
Ambient range -10°C to +55°C
Variation over range ≤5%
Frequency
Range 50Hz Model
Range 60Hz Model
47Hz to 52Hz
57Hz to 62Hz
Setting variation ≤5%
Operating time variation ≤5%
4.Modular II Specification
4.1 Environmental Withstand
Temperature - IEC 60068-2-1/2
Operating range -10°C to +55°C
Storage range -25°C to +70°C
Humidity - IEC 60068-2-3
Operational test 56 days at 40°C and 95% RH
Transient Overvoltage –IEC 60255-5
Between all terminals and earth or between any two
independent circuits without damage or flashover
5kV 1.2/50µs 0.5J
Insulation - IEC 60255-5
Between all terminals and earth 2.0kV rms for 1 min
Between independent circuits 2.0kV rms for 1 min
Across normally open contacts 1.0kV rms for 1 min
High Frequency Disturbance -
IEC 60255-22-1 Class III
Variation
2.5kV Common (Longitudinal) Mode ≤5%
1.0kV Series (Transverse) Mode ≤5%
Electrostatic Discharge -
IEC 60255-22-2 Class IV
Variation
©2010 Siemens Protection Devices Limited Chapter 2 Page 3 of 7