technicalpresentation_7sd52_en_ (1).ppt

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Protection and Substation Control EV S 1

Numerical Pilot Protection 7SD52

using digital wide-band communication

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Numerical pilot protection relay 7SD52

Universally applicable to power systemconfigurations up to six ends ,containing :OH-LinesCablesTransformers

For digital data transmissenVia dedicated optical fibresVia Communication networks

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Numerical Pilot Differential Protection Principle

Operate : ID = IA +IB

Bias: IB = IA + IB

Operating Criterium: ID K1 + K2 . IS

operate

stabilize

ID

IB

I

IA IB

IIAS , IAC

IBS , IBC

+j

IAC

IA

ID

IB IBC

IBS

IAS +

IA = IAS + j IAC

IB = IBS + j IBC

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Definition of Synchronous Phasor:measured at different locations based on a common time reference

Time reference

Location : B

Location : A

Relay A

RE

iA

iB B

IB

IB

IM

Relay B

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ni2sin

ni2cos

C(k)S(k)(k) j III

S(k)I

C(k)Ij

)(kI

)( inki

k-n

0 1 2 . . . n

i

C(k)I

S(k)I

k

Numerical pilot protection: Advanced Fourier analysis of the currents - Supress DC components, harmonics

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Advanced Fourier Transformation - Optimized filtering coeffizients for 7SD52 -> Suppress DC 4 times better thanconventional Fourier-filters -> Archieve high sensitivity

1N

1nnS iΔnωsin2 tNI

1N

1nn

NOC iΔtnωcos

2i

2i2

NI

t

i0 i1 i2 iN

n

0 1 2 N

0 1 2 N

3 . . . .

3 . . .

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Advanced Full Cycle Fourier analysis: Filter characteristic

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Orthogonal Current Components (Advanced Fourier Filter)

t

I(t)

= 0

dt t sin t)( 21

360 - Ø

Ø

S

II

dt t cos t)( 1 360 - Ø

Ø

II2C0 j 1

j

0

CS(Ø)

II

III

21 j

23 30

II

23 j

21 60

II

1 j 0 90 I

I

j IC I

IS

t = 0

t

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tL2

tL1

tV

tA1

tA2

tA3

tA4

tA5

tB1

tB2

tB3

tB4

I

A B

Propagation time: tL1= tL2= 1/2 x (tA-reception - tA1- tV)

Corrected sampling instant: tB3= tA-reception -tL2 IB(tB3)

IB(tA3)

= (tB3 - tL2) x (360O/Tperiod)

...IS(A), IC(A)

tA1

tB3tA1

tV

IS(B), IC(B)....

I

Numerical Pilot Differential Relay Propagation Time Measurement and Phasor Angle Correction

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Example for the delay time calculationFlight from Berlin <-> New York Flight from Berlin <-> New York You can not calculate the duration of a flight if you look at the clock in Berlin on departure and You can not calculate the duration of a flight if you look at the clock in Berlin on departure and

later note the local New York time on arrival. The reason are the different time zones.later note the local New York time on arrival. The reason are the different time zones.

The relays are also in two time zones.. Each relay has it´s own 1 us resolution timer.The relays are also in two time zones.. Each relay has it´s own 1 us resolution timer.

Tdepart / B->NY (6:00) --------------------> Tarrival / B->NY (8:00)Tdepart / B->NY (6:00) --------------------> Tarrival / B->NY (8:00) From the flight back from New York to Berlin the local departure time in NY and the arrival time in Berlin is:From the flight back from New York to Berlin the local departure time in NY and the arrival time in Berlin is:

T arrival / NY->B (23:00)T arrival / NY->B (23:00) <--------------- <--------------- T depart / NY->B (9:00)T depart / NY->B (9:00)Under the assumption, that the flight to New York and the flight back from NY have the same durationUnder the assumption, that the flight to New York and the flight back from NY have the same duration

the relevant time results can be calculated. the relevant time results can be calculated.

The time difference between The time difference between NYNY and and BB and the duration of the flight (transmission time) and the duration of the flight (transmission time)

Duration =Duration = (( T arrival / B->NYT arrival / B->NY -- T depart / B->NY+ T arrival / NY->BT depart / B->NY+ T arrival / NY->B - Tdepart / NY->B ) / 2- Tdepart / NY->B ) / 2Time difference = Time difference = (Tdepart / B->NY - Tarrival / B->NY(Tdepart / B->NY - Tarrival / B->NY + Tarrival / NY->B+ Tarrival / NY->B - Tdepart / NY->B ) / 2- Tdepart / NY->B ) / 2

Duration = (8:00 - 6:00 + 23:00 - 9:00) / 2 = 8 hours (-> delay time)Duration = (8:00 - 6:00 + 23:00 - 9:00) / 2 = 8 hours (-> delay time)

Time diff. = (6 Uhr - 8 Uhr + 23 Uhr - 9 Uhr)/2 = 6 hours (-> difference between the time zones)Time diff. = (6 Uhr - 8 Uhr + 23 Uhr - 9 Uhr)/2 = 6 hours (-> difference between the time zones)

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HDLC FRAME FORMAT

01111110 16 bitsrelays

address

8 or 16bits

any length0 - N bits

32 bits 01111110

OpeningFlag

AddressField (A)

ControlField (C)

InformationField (I)

FrameCheck

Seqence(FCS)

ClosingFlag

time data

status + commandCurrent vectors

message validation

Synchronizing

Coded message of current differential protection 7SD52

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I I

Monomode fibre1300 ober 1550 nm

a) Dedicated optic fibre

I I

PCMMUX

PCMMUX

Optic fibre or microwave Wire G.703

O.F.

G.703

O.F.

G.703

Multimode optic fibres850 nm

Multimode optic fibres850 nm

b) Channel of a data transmission system or of a data transmission network (Protection and PCM-device in the same room)

Further services: Telefon, Data transmission,etc.

I I

PCMMUX

PCMMUX

Optic fibre or Microwave Wire, G.703



Further services: Telefon, Data transmission,etc.b) Channel of a data transmission system, or of a data transmission network

(Protection and PCM-device not in the same room)

Numerical pilot differential protection: Communication options

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Application for a three terminal configuration

SDHcomms-network

X21G703.1

820 nm

max.3 km

eoPCM

multi-plexer

Monomode fibre optic cable up to 35 km with 1300 nm interface

Distance relay7SA52

Mon

omod

e fib

re o

ptic

cab

le u

p to

10

km

(130

0 nm

mod

ul)

PCMmulti-plexero

eoe

Comms-converterG703.1: 64 kBitX21: N*64 kBit (1N8)

Option:

I-REGBtimesynchronisation

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Scope of functions / Hardware options

- For system configurations with up to 6 terminals

- Fast high set charge comparision (subcycle trip)

- Sensitive current phasor differential

- Inrush restraint (2nd harmonic) and vector group adaption

- CT saturation detector

- Autoreclosure 1/3 pole

- Overload protection

- Switch on to fault protection

- 4 remote commands, 24 remote signals

½*19´´

1*19´´

16 binary inputs24 contacts

24 binary inputs32 contacts

Option: 5 fast trip contacts

3Iph, and IE 4 U 8 binary inputs16 contacts 1 - 2 protection interfaces System interfacePC-interfaceTime synchronisation

Numerical line differential protection 7SD52

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Communication OptionsCommunication Options

FO5: distance 1,5 km (with clock feed-back)FO5: distance 1,5 km (with clock feed-back)FO6 : distance 3kmFO6 : distance 3km

O

O 1300 nm1300 nm

10 km10 km

O 1300 nm1300 nm35 km35 km

OE X21X21

G703G703

internal

internal

internal

external

820 nm820 nm1,5 km / 3 km 1,5 km / 3 km

FO7 : distance 10kmFO7 : distance 10km

FO8: distance 35kmFO8: distance 35km

KU : hook-up to communication networkKU : hook-up to communication network

Km data for worst-case conditionsKm data for worst-case conditions

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Hardware option of the comms interfaces

Protection interface 2Port E

Synchronous N x 64kB/sec7SD52

Protection interface 1Port D

Synchronous N x 64kB/sec

Serial time sync. input

GPS-receiver

Interfacemodul 1RS485 or FOor RS232

service-interfaceDIGSI 4; also for

modem connectionand Browser

local-PCinterface

DIGSIlocal

Browser

Substation controlcommunication modulesFO (Fibre optic) or RS485or RS232Available ProtocolsIEC - standard

Interfacemodul 2RS485 or FO

Subst. control interface

Plug in modules

Remote line end 2

Remote line end 1

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Main processor board of the relay

Sockets for the communicationmodules

Main board of the relay with it´s Communication - Interfaces

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87L

87L

dti5

0

1 cycle Phasor,fundamental frequency

Every 5ms (128-512 bBit), 10 ms (64 kBit)

Adaptive Algorithm: Fast Charge comparison and very sensitive Phasor differential

Charge comparison Fast normal trip stage IDiff>> Setting: 0,67*ILoadmax/INFast, <1cycle

dti5

0Phasor differentialFor high resistive faultsIDiff> Setting: 0,1-0,2 IN

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IDiff = I1 + I2 + I3Calculated Phasor sum:

IRestrain = c.t. tolerance + Syncronising tolerance

trip condition:trip condition: IDiff >Ilow set and IDiff > IRestraint

Restrain:

IDiffIN,load.

Irestr IN,Betr.

I1 I2

I3IDiff> I1

I2 I3

I1

0.5

restrain

trip

0,15

loadThrough fault

Adaptive differential relayingConsideration of CT- and communication-errors

Minimum pick-up: IDiff = Ilow set

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Spill Current through Line Charging Capacitances

Source V1

Kichhoff equation: I1 + I2 - IDiff - IC = 0

Service conditions: IDiff = 0, IC = I1 + I2 Difference equals charging current

Pick-up value: IDiff> >2,5.. 4 • IC sensitive set point at short lines,

minimum 0,1 IN

I1

I2

C.t.2

IDiff

C.t. 1

Protected Zone defined by c.t.1 and c.t.2

IC

I1

Source V2

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Setting above spill currents: c.t. error and line charging

IDiff = |- I1´ + I2´| = f1• I1 + f2 • I2

Load: I1 = IN

IDiff=0,1 • I1 = 0,1• IN

Through Fault: I1 = 10 • IN

IDiff = 10,5 • IN - 9,5 • IN = IN

• IDiff> set point > line charging current

• Percentage bias > Sum of c.t. errors

I1´=0,95•I1 I2´=1,05•I1

IDiff=0,1 • I1

-I1I1

IDiff

Minimum pick-up related to line charging current

I1

Percentage bias related to c.t. errors

Resultingset point

IDiff>

Set points:

1I CIII 12

LCLUjCI

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Approximated c.t. Tolerance

Basis for the restraint current calculation

ALFe / ALFN • IN,c.t

: parameter 7SD52

IDiff

I1

I1

Example: 10P10, fB < 3%, fK at ALFN = 10%

Fault current tolerance

Load current toleranceTolerance ofa real CT

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Current transformer data

c.t. e.g. 5P20, 10VA

% tolerance at ALFN

Thumb rule:Ri 0,1...0,2 * RN

RN at 10 VA 10

=> Ri 2

ALFe = ALFN Pi + PN

Pi + PB

With PB = Pleads + Prelay (0,1 VA)

= 2 VA + 10 VA

2 VA + 1 VA

= 4

Resulting Relay Parameter:

• effective ALF / nominal ALF = 4 (calculation as per above)• IEC 44 -1: tolerance in load area up to ALFe / ALFN : 1% with 5P, 3% with 10P c.t.s total error at accuracy limit nN = 5% with class, 5P and 10% 10 P

ALFe

ALFN

C.t. ParameterC.t. Parameter

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Internal restraint current calculation due to CT-errors

10P10 10 VA400:1ALFe/ALFN = 1fLoad 3 = 3% (0,03)fSC 3 = 10% (0,1)



IC = 100 A

800 A4800 A

400 A800 A

1200 A5600 A

IStab = 2.5 • line charge currents (basic restraint value) + c.t. error currentsIDiff = actual deviation of vector summation and charge summation

Case 1 (Through load)IRest = 2,5 • 100 A + 800 A • 0,01 + 1200 A • 0,01 + 400 A • 0,03 = 282 A I restr / IN,load = 0,176Idiff = 100 A I Diff / IN,load = 0,063

Case 2 (Through fault)IRest = 2,5 • 100 A + 4800 A • 0,01 + 5600 A • 0,05 + 800 A • 0,1 = 658 A I restrain / IN,load = 0,41IDiff = 40 A I Diff / IN,load = 0,025

IN,load = 1600 A

The restraint current is the sum of the maximal expected CT-errors

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Harmonic order

Harmonic content of the differential current

0

2

10

|fn|

|f1|

0

0

t

t

ct I2 ct I1

Id = I1 - I2

CT Saturation detector based on harmonic analysis

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Charge comparison: Charge comparison: Operating PrincipleOperating Principle

protected Line configuration

7SD52 7SD52

I1

I2

I3

7SD52

Qpart2=Q2+Q3+Q4

I4

Qpart3=Q3+Q4 Qpart

4=Q4

Qpart3=Q1+Q2+Q3Qpart

2=Q1+Q2Qpart1=Q1

1 2 3 4

Qdiff =Q1+Q2+Q3+Q4

Qdiff

Q2Q1 Q3 Q4

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Charge Comparison:Charge Comparison: Charge calculation, Operating characteristic, Tripping timesCharge calculation, Operating characteristic, Tripping times

Charge calculation by numerical integration

Current Measuring window

1 Qt0 t1 t2 t3 t4 t5 t6

|Q diff|

Operate(internal fault)

Q DIFF> Settable pick-up value

qdiff12.dsf

slope depending on Q diff

speed 2 relays 3 relays 6 relays64 kbit/s 21 ms 21 ms 41 ms128 kbit/s 16 ms 16 ms 24 ms512 kbit/s (FO) 14 ms 14 ms 17 ms

5 ms (50 Hz)

Corrected time instantsafter end-to-end time synchronisation

Relay calculates the charge. Setting as current value IDiff>>

Calculated charge restraint valuefrom CT-errors , synch. errors

QRest

=IDiff>>Restraint Area

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7SD52 Pilot Protection: Sliding data windows

current,voltage

fault-inception

time

voltagecurrent

5 ms charge and20 ms phasor data windows

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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 (N*64 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)

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

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Ring and Chain topologie

Closed ring Partial current summation

I3

I2

I1

side 1

side 2

side 3

I3

I2

I1

side 1

side 2

side 3

I3+I1 I2

I1+I2 I3

I3+I1

I1+I2

Connection to

other diff. relays

Automatic change fromclosed ring to chain, if one connection is lostor not available

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Breaker-and-a-half Scheme, Through Fault Stabilisation

busbar 2

busbar 1

I f =

thro

ugh

faul

t cur

rent

87LTo remote end

busbar 2

busbar 1

I f =

thro

ugh

faul

t cur

rent 87L

To remote end

87L

Partial differential Full differential

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Topologies: Chain topology for max. 6 line ends

1 32

46 5

PI - Protection Interface

PI1 PI1 PI2 PI1

PI2

PI1

PI2PI1PI2PI1

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Topologies: Ring topology, 6 line ends

31 2

46 5

PI1

PI2

PI1

PI2PI1PI2PI1

PI2

PI1

PI2 PI1 PI2

PI - Protection Interface

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Web-Browser based commissioning tool

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7SD52: Commisioning and Monitoring using Web-Browser

technicalpresentation_7sd52_en_ (1).ppt

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