3 distance protection

Institut Latihan TNB - ILSAS

Unit Perlindungan, Seksyen Latihan Penghantaran - 2007

KURSUS LATIHAN KEKOMPETENAN

Unit PerlindunganSeksyen Latihan Penghantaran

Institut Latihan Sultan Ahmad Shah (ILSAS)

PERLINDUNGAN PENGHANTARAN(SETAKAT 132kV)



DISTANCE PROTECTION



KLASIFIKASI PERLINDUNGAN TALIAN

1. Perlindungan Unit

2. Perlindungan Bukan Unit



S/Stn = Sub StationCB = Circuit BreakerCT = Current Transformer

S/Stn A S/Stn B

CB ‘A’ CB ‘B’CT ‘A’ CT ’B’

Relay ‘A’ Relay ‘B’

Transmission Line

Zon Operasi

PERLINDUNGAN UNIT



S/Stn = Sub StationCB = Circuit BreakerCT = Current Transformer

S/Stn A S/Stn B

CB ‘A’ CB ‘B’CT ‘A’ CT ’B’

Relay ‘A’ Relay ‘B’

Transmission Line

Zon Operasi

PERLINDUNGAN BUKAN UNIT



Distance Protection

• Operate based on Impedance (Z) measured from fault point.

• Z = V/I (Ω)

• Z directly proportional to line length.



Distance Protection

• Line impedance of 2 x 300mm2 = 0.2742 Ω/km• Line length = 100 km

• Thus total line impedance = 27.42 Ω

• If Zmeasure < Zsetting – No operation • If Zmeasure > Zsetting – operates



Distance Protection• Why use distance:

– Directional– Selective– Fast– Have backup characteristics : (Z2, Z3)– Operates like Unit Protection if communication

channel is provided• Distance Element:

– Zone 1 (Z1) – operates instantaneously (20-40ms) – Zone 2 (Z2) – Timer T2 (300ms)– Zone 3 (Z3) – Timer T3 (3000ms)



Distance Protection

• Relationship of Zpr & Zs

( )

( )

ZprVTratioCTratioZs

VTratioCTratioVs

VprIs

IprZprZs

VprIpr

IsVs

ZprZs

IsVsZs

IprVprZpr

×=

÷=

÷=

×=

÷

=

=

)1()2(

2

1



Distance Protection

• Mho– Directional– For forward fault– Usually for zone 1 or 2 – Eg: YTG, THR, micromho



Distance Protection

• Offset Mho– Can detect reverse fault– Use for zone 3– Z3 Reverse as backup for busbar

• Does not have good coverage for high resistance fault.

• Mostly use for phase to phase fault.



Distance Protection

• Quadrilateral– Have good resistance coverage– Z = R + jXL

– Eg: RAZFE, REL2 100, REL 5.

– Most new relay use combination of these characteristics.

– Quadrilateral to detect earth fault and mho to detect phase to phase fault.



Distance ProtectionPhase to Phase Faults

Zf = V/I = 2ZL

Zf = ZL = V/2I Ω/phase

R ZL

ZfB ZL



Distance ProtectionPhase to Earth Faults

R ZL

ZfE

Zf = V/I = (ZL + ZN) Ω/loop

Where: ZL = Z1 = +ve seq impedance

And ZN = Neutral Impedance

= (Z0 – Z1)/3

R ZL

ZfE ZN

≡



Distance ProtectionPhase to Earth Faults

Zf = V/I = (ZL + ZN) Ω/loop

Where: ZL = Z1 = +ve seq impedance

And ZN = Neutral Impedance

= (Z0 – Z1)/3( )

( )

factoron compensati 13

10

/ 1

1113

1011

3101

IVZf

faultearthZ

ZZkN

phaseZkNaI

VkNZ

ZZZZ

ZZZ

−=

Ω=+

∴

+=

−+=

−

+==



Distance Protection



ZON PERLINDUNGAN JARAK

• Kawasan di mana kerosakan akan dikesan dan diasingkan.

• Mestilah dalam keadaan bertindih.



ZON PERLINDUNGAN JARAK (samb.)

Zon Perlindungan Jarak:

• ZON 1• ZON 2• ZON 3




3 Zon Perlindungan Jarak & Tatahan:

Zon 1

• 80 – 85% daripada nilai galangan talian yang dilindungi(Masa Operasi = Serta-merta)




Zon 2:

• 100% daripada nilai galangan talian yang dilindungi + 50% nilai galangan daripada talian terpendek

Selepasnya

(Masa Operasi = 300 ms)




Zon 3:

100% daripada nilai galangan talian yang dilindungi + 100% nilai galangan talian terpanjang selepasnya

(Masa Operasi = 3 s)

* Zon 3 Reverse

20% daripada nilai galangan talian yang dilindungi (ke belakang) bagi melindungi busbar tempatan




Masa (ms)

3000

300

20ZON 1

ZON 2

ZON 3ZON 3R



Distance Protection

jX

R

Permissive Under-reach Transfer Trip (PUTT) Permissive Over-reach Transfer Trip (POTT) Plain Distance Zone 1 Zone 2 Zone 3 & Zone 3 Reverse Power Swing Blocking

(PSB)

A B

A

B



Distance Protection

• Timer Setting: 132kV (E/F & P/F)

– Z1 : inst.– Z2 : 300ms– Z2+CR : inst– Z3 = Z3R : 3000ms or 3s– SOTF : inst



Distance Protection

• Timer Setting: 275kV (E/F & P/F)

– Z1 : inst.– Z2 : 450ms– Z2+CR : inst– Z3 = Z3R : 3000ms or 3s– SOTF : inst



Distance Protection

• Tripping Logic: 132kV (E/F & P/F)

– Z1 Trip 3 phase– Z2+CR & start A/R

– Z2T– Z3T Trip 3 phase & lock out – Z3RT– SOTF



Distance Protection

• Tripping Logic: 275kV (E/F)





Distance Protection

• Tripping Logic: 275kV (P/F)





Distance Protection

• Power Swing Blocking– Sudden lost of large load.– Isolation of fault– Lost of synchronism between 2 parts of the

system.– Changes of power flow– Can trigger Distance Relay– PSB detect power swing locus and block

distance until the transient condition clears



Distance Protection

Zone 1 = InstantaneousZone 2 = 450msZone 3 = 3000ms

Zone 3

PSBFault’s Impedance Locus

12



• PSB– If time from 1 2 > t, (usually 40ms) it is

assume as power swing and distance relay will be block

– If time from 1 2 < t, it is assume as fault locus and distance relay will operate to clear fault

Distance Protection



Distance Protection

Z <Z<

132 kV

Z = U/I

132 kV



Distance Protection

• Evolving Fault– A phenomena where 2nd fault occur on

different phase (phase to earth) from 1st fault during “dead time”

– Scheme: • Cause 3 phase tripping• Convert A/R from SPDT (750ms) to TPDT

(3.0/3.5s)



Distance Protection

• VTS– To detect fault in VT circuit.– To differentiate VT fault and actual primary

fault.– Block distance if VTS operated.

• Software blocking: detect zero or –ve seq. V• Digital Input: from MCB contacts



Distance Protection• SOTF/Line check

– Scheme use to bypass Z3T for 200ms so that close up or remote fault can be isolated quickly by closing PL.

– DC line check• Use external input from CB discrepancy switch/ CB contact

to trigger SOTF• Manual closing

– AC line check• Detect lost of 3 phase V and I for 200ms before SOTF

trigger.• Auto reclosing



SEKIAN

TERIMA KASIH

3 distance protection

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