Line differential relay 7SD52

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Line differential relay 7SD52
Line differential relay for HV and UHV
lines/cables with a serial communication
interface 7SD52
2
Protection and communication join togetherThree
benefits of the 7SD52

• Differential protection for the universal
  use with easy to handle settings Two up
  to six line ends , for serial and parallel
  compensated lines, handles transformers and
  compensation coils within the protection zone,
  tripping time approx. 15 ms with fast high
  set element
• Additional functions for very long overhead
  lines and cables Considation of local CT
  errors, charge current compensation (step
  2), increased setpoint during switching-on
  conditions
• Direct and modular connection to fibre optic
  and digital communication networks

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Application for a three terminal configuration
Monomode fibre optic cable up to 35 km with 1300
nm interface
Monomode fibre optic cable up to 10 km (1300 nm
modul)
Distance relay 7SA52
X21 G703.1
SDH comms-network
o
e
820 nm max. 3 km
e
o
OptionI-REGB
Comms- converter G703.1 64 kBitX21 N64
kBit (1?N?8)
time synchronisation
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Scope of functions / Hardware options
Options for the Protection Interface
Scope of functions - Fast high set element
with charge comparision- Sensitive normal trip
stage with vector summation principle -
Autoreclosure 1/3 pole - Communication features -
Commissioning aid - Overload protection -
Backup-/emergency overcurrent - Multiterminal
extention- Switch on to fault protection- 4
remote commands 24 remote signals
Relay Hardware
820 nm1,5 / 3 km multimode
ST- connector
3Iph, and IE 4 U 8 binary inputs 16 contacts
1 - 2 protection interfaces System
interface PC-interface Time synchronisation
internal
1300 nm10 kmmonomode
ST- connector
internal
½19
16 binary inputs 24 contacts 24 binary inputs 32
contacts Option 5 fast trip contacts
O
1300 nm35 kmmonomode
FC- connector
internal
ElectricalX21 G703.1interface
820 nm1,5 kmST-connectors
119
External converter
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Hardware option of the comms interfaces
Remote line end 2
Plug in modules
Remote line end 1
Protection interface 1Port D
Synchronous N x 64kB/sec
Subst. control interface
Substation control
communication modules
Interfacemodul 2
FO (Fibre optic) or RS485or RS232 Available
ProtocolsIEC - standard
RS485 or FO
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Main board of the relay with its Communication
- Interfaces
Main processor board of the relay Sockets for
the communicationmodules
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Main protection functionFeatures of the
differential function

• Phase selective multiend differential
  protection(2 - 6 ends). Tripping time 15 ms with
  fast charge comparison protection.
• Fundamental vector comparison for the sensitive
  trip stage.
• Dynamic increase of differential setpoint during
  switch-on of long lines / cables (settable time)
• CT saturation detector (only 5 ms saturation free
  time due to external faults necessary)
• Phase selective intertrip within 15 ms
• Settable delay time for single phasefaults
  (feature for inductive compensated networks)
• Option Inrush 2nd harmonic restraint with
  vector group adaption. Undelayed trip for high
  fault currents
• Optional Lockout function

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Adaptive differential relayingConsideration of
CT- errors and comms-errors
I1
I2
IDiffIN
Tripping area
I2
I3
I3
Restraint area
I1
IDiffgt
I1
I IN
IDiff I1 I2 I3
Phasor summation Error summation
I IDiffgt Linear CT-error (
Syncronization error
IK)
Trip, if diff.current exceeds the max.
permissible error
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To complete the 7SD52Additional functions

• 3 stage backup- or emergency O/C protection(Can
  be activated automatically if the communication
  with the remote end is gt50 ms interrupted)
• Overload function (Thermal replica with
  IOperation)
• User definable logic and control functions(AND,
  OR, NOT, Timer, Flip-Flop)
• 4 remote commands via binary input or logic
  inputs (destination is adressable), 24 remote
  signals
• Operational values currents, voltages,
  power,delay time, differential current - remote
  end refresh 2 s
• Fault recorder with voltages, currents, binary
  traces and differential and restraint current per
  phase
• Fast monitoring functions(Fast broken wire
  supervision, Current symmetry)
• Switch On to Fault protection
• Option Three pole and single pole AR (Single
  pole AR during 2pole fault without earth
  possible, adaptive AR)

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Familiar with digital communication networks
Features of the relay to relay communication

• Synchronous data transmission by HDLC- protocol
  
• Permanent supervision of the data transmission
• Measurement and compensation of signal
  transmission time (max. 20 ms)
• Counts number of invalid telegrams
  Blocking the diff.protection if transmission
  failure rate is too high
• Settings for the data transmission (N64
  kBit/s, N settable from 1 - 8, synchronous
  HDLC-protocol)
• Communication device addresses (Protection
  devices are clearly assigned to a defined
  protection section)
• Detection of reflected data in the loops in
  comms- network
• Step 2 Microsecond exact time synchronisation
  via satellite (civil - IRIG-B) (If
  signal transmission time depends on the
  transmission direction, Online high
  resolution fault recorder)

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Ring and Chain topologie
Automatic change fromclosed ring to chain, if
one connection is lost or not available
side 2
side 3
I2
Connection to other diff. relays
I3
I3I1
I2
I1I2
I3
I1
I3I1
I1I2
side 1
Closed ring
Partial current summation
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Topologies Chain topology for max. 6 line ends
1
3
2
PI1
PI1
PI2
PI1
PI2
PI - Protection Interface
PI1
4
6
5
PI2
PI1
PI2
PI1
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Topologies Ring topology, 6 line ends
3
1
2
PI1
PI2
PI1
PI2
PI2
PI1
PI1
PI2
4
6
5
PI2
PI1
PI2
PI1
PI - Protection Interface
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Plug and Protect Commissiong helps and test
features

• Signal transmission timeMean value of transmit
  and receive direction
• Generation of signals for switching test
  loopsSending of defined telegram patterns looped
  back to the receive input of the transmitting
  relay
• Absolute value and phase measurement of
  currentsLocal measurement of angle between IL1,
  IL2, IL3,Angle between currents of each phase
  from remote
• CB test trip
• Counting of faulty telegrams in per minute and
  hour
• Activation of binary inputs and outputs by
  operating software DIGSI 4.
• Display of the status of binary inputs
• Test telegrams to the substation control system
• Automatic Switchover from 3 line to 2 line end
  configuration (while commissioning 3rd line end)
• Complete commissioning support with DIGSI 4
  andbrowser based PC-software

IL1_2
Phi1-gt2
IL1_1
IL2_1
IL2_2
IL3_2
IL3_1
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Browser based commissioning aid
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Comprehensive fault analysis with DIGRA 4
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Prefault and fault conditions in the vector
diagram