Fundamentals of Teleprotection Systems ABB Automation Utility Communication Systems CHPAU NKT 27.06.2001
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Teleprotection - Contents • • • • • •
Introduction / Protection Systems Protection Schemes / Applications Parameters in Teleprotection Modulation Methods Transmission Principles Transmission Equipment
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Teleprotection - Introduction •
What is it ? -> > Tele-Communication Tele Communication + Protection - Signalling
•
Where is it used ? -> >M Mainly i l att th the hi higher h and d hi highest h t voltage lt llevels l
•
Why is it used ? -> > Cl Clearance off ffaults lt within ithi th the shortest h t t possible ibl titime
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TPS Standards and Publications IEC standards: IEC 60834 60834-1 1 Teleprotection equipment of power systems - Performance and testing Part 1: Narrow-band systems (First edition, 1988) Part 1: Command systems (Second edition, 1999) g of teleprotection equipment of power systems y IEC 60834-2 Performance and testing Part 2: Analogue comparison systems (First Edition 1993)
CIGRE publications: "Teleprotection Guide", Study Committees 34 + 35, Joint Working Group on T l Teleprotection, t ti 1969; 1969 Revised Version "Protection Systems Using Telecommunication", 1985 Revised Version "Protection Using Telecommunications", 2000 (in preparation)
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Protection System Architecture Substation A
Substation B HV-line
Protection Relay
Teleprotection Equipment
Physical Link Telecommunication System Teleprotection System Protection System
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Teleprotection Equipment
Protection Relay
Protection Signal Transmission Type of Information: • Continuous signals • Magnitude and/or phase of power frequency currents • Command type signals (on/off) • Trip / do not trip
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Protection Systems Protection system based on:
Local Information
Information from all points
Signal-transmission not required
Signal-transmission required
Not selective
Selective
with time delayy
No time delayy
conditionally selective ABB Automation Utility Communication Systems CHPAU NKT
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Signal Transmission for Line Protection Quantitative (analogue) Information
Binary (yes / no) Information commands
Amplitude p and/or Phase
command = Blocking of breaker tripping
SIGNAL TRANSMISSION IS ESSENTIAL
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command = Permission of / direct breaker tripping
SIGNAL TRANSMISSION IS SUPPLEMENTARY
Distance Protection Typical stepped distance/time characteristics Operating Time ZONE 3
TA3
ZONE 2
A RA
ZONE 1
TA2
TA1
TB2 C
B RB
TB 1
Distance
A, B, C RA,RB, RC TA1, TA2, TA3 TB1, TB2, TB3
Stations S Protection Relay Operating Times, Relay A Operating Times, Relay B
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RC
Distance Line Protection Permissive Underreach Transferred Tripping (PUTT) B
C
LBC
F
BC1 RBC
RCB
CB1 L
NSD
B,, C LBC RBC,RCB BC1, CB1
Substations Protected line section Protection relay Zone 1 reach, 85% of line section
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NSD
F
Line fault
L
Communication channel (PLC, Microwave, Cable)
Distance Line Protection Permissive Overreach Transferred Tripping (POTT) B
F
LBC
BC1
RBC
CB1
Substations Protected line section Protection relay Zone 1 reach, 130% of line section
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RCB
L
NSD
B,, C LBC RBC,RCB BC1, CB1
C
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NSD
F
Line fault
L
Communication channel (PLC, Microwave, Cable)
Distance Line Protection Direct Transfer Tripping (DTT) B
LBC
F
BC1
RBC
CB1
Substations Protected line section Protection relay Zone 1 reach, 85% of line section
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RCB
L
NSD
B,, C LBC RBC,RCB BC1, CB1
C
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NSD
F
Line fault
L
Communication channel (PLC, Microwave, Cable)
Transformer Protection Example for direct tripping NSD 70C B P
L C
NSD 70C
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P
Pilot cable
L
HV Transmission Line or -Cable
Distance Line Protection Blocking LBC
B
C
F
RBC BCe
BCi CBi RCB L
NSD
B,, C LBC RBC,RCB BCi, CBi BCe, CBe
NSD
Substations F Line fault Protected line section L Communication channel (PLC, Microwave, Cable) Protection relay Zone 1 reach, 130% in direction of the protected line section Range g of p protection relay y in direction of busbars
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CBe
Teleprotection command transmission Command input (local)
Transmission time
Disturbance, Disturbance Impairments
Command output (remote) Genuine Command
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Missing Command
Unwanted Command
Dependability
Security
Telecommunication Channel Impairments ÎImpairments resulting from interference and noise • Isolater I l t / breaker b k operation ti • 50/60 Hz harmonics (pilot cables) • Corona noise (PLC channels) • Fading (microwave channels) • Jitter (digital networks) • Temporary loss of synchronism (digital networks) • Signal interruptions • etc. ÎDisturbed signals may cause protection equipment to maloperate
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Performance Criteria for Teleprotection
Transmission T i i Time
Dependability (Probability of missing command)
S Security it (Probability of unwanted command)
Bandwidth or Data Rate
Optimization / Exchange according to application ABB Automation Utility Communication Systems CHPAU NKT
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Line Protection Possible Signal Connections Between two Distance Relays Designation
1
Short description
5
Permissive underreach transferred tripping Permissive overreach transferred tripping Permissive underreach transferred acceleration g ((direct overreach, Blocking transferred blocking) Blocking
Starting of distance relay permits tripping Directional comparison (signal permits tripping) Carrier acceleration by extension of step (*) Blocking g signals g are transmitted over healthy lines Signal inhibits step extension (*)
6
Unblocking
7
Direct underreach transferred tripping
Loss of guard signal permits tripping pp g for limited time only y Status of relay at receiving end not taken into account
2 3 4
Typical distance relay setting (%) Step 1
Requirements for transmission channel as regards Speed
Security
Dependability
85
M-H
M-H
H
130
H
M
H
85 (130*)
H
L-M
H
130
S
L
H
H-S
L
M
130
H
M
M
85
M-H
S
H
85 (130*)
L = Low M = Medium H = High S = Very severe requirements
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Total Fault-Clearance-Time • Time delay between fault occurrence and line tripping • The fault-clearance time results from: • Relay-time (fault detection) TREL • Command transmission time TAC • Switching delay of line breaker TBR
• Typical values: TTotal =
TREL
+
TAC
+
TBR
75 ms =
20 ms
+
15 ms
+
40 ms
• Target: TTotal = less than 100 ms, Worst Case = 4.5 4 5 tto 5 cycles l max. (50 H Hz))
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Typical requirements for different applications
• Line protection with permissive transfer tripping: • Transmission time • Dependability • Security
T0 = 10 ... 20 ms -2 -3 Plost l t command d ≤ 10 ... 10 Pfalse command ≤ 10-3 ... 10-4
• Line protection with blocking system: • Transmission time • Dependability • Security
T0 = 6 ... 15 ms Plost command ≤ 10-3 Pfalse command ≤ 10-2
• Direct transfer tripping (e.g. transformer protection): • Transmission time • Dependability • Security
T0 = 20 ... 50 ms Plost command ≤ 10-33 ... 10-44 Pfalse command ≤ 10-5 ... 10-6
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Command Systems, Typical Figures Analog systems
Digital systems
Blocking • short transmission time • moderate security • high dependability
Tac Puc Pmc
< 15 ms < 1E 1E-2 2 < 1E-3
< 10 ms < 1E 1E-6 6 < 1E-3
Permissive tripping • moderate transmission time • moderate to high security • moderate to high dependability
Tac Puc Pmc
< 20 ms < 1E-3 ....1E-4 < 1E-2 ....1E-3
< 10 ms < 1E-6 < 1E-3
Direct tripping • moderate transmission time • very high security • very high dependability
Tac Puc Pmc
< 40 ms < 1E 1E-5 5 .... 1E-6 1E 6 < 1E-3
< 10 ms < 1E 1E-9 9 < 1E-3
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Teleprotection Equipment Command Systems NSD S 50 0 / NSD550 S 0 • Plug in unit for multi-purpose Power Line Carrier type ETL HSD 50 • Dedicated protection Power Line Carrier NSD 70 70, NSD 70C • for analog bearers • • •
cables speech channels of analog and digital links power line carrier channels
NSD 70D • for digital g bearers • •
digital multiplexers digital radio, fibre optic links
• with plug-in fibre optic line unit for dedicated fibres ABB Automation Utility Communication Systems CHPAU NKT
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TEBIT: Teleprotection & binary interface TEBIT as teleprotection interface: - 4 commands commands, full full-duplex duplex - addressable
TEBIT as binary interface: - max. 12 binary inputs - max. 12 binary outputs … as „Mini-RTU“
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Digital Networks High capacity = large number of channels Basic channel capacity = 64 kbit/s PDH (Plesiochronous digital hierarchy) • Multiplexing into 2 Mbit/s ( 30 channels) 8 Mbit/s (120 channels) etc. ( ..... channels)
SDH (Synchronous Digital Hierarchy) • Multiplexing of n * 64 kbit/s or n * 2 Mbit/s into 155 Mbit/s Cross-connect functionality Radio or optical fibre links
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etc.
Digital Cross-Connect Networks
Network Management
Network management activities may have a detrimental impact on a protection system, unless adequate precautions are taken
Digital network Digital Cross-Connect Protection terminal
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Incrreasing Securitty
Digital Cross-Connect Precautions Restricted authorisation for re-routing re routing Inhibit auto-rerouting (possibility of excessive delay) U (t Use (tele)protection l ) t ti equipment i t with ith addressing dd i ffacility ilit Use dedicated channels for protection signalling which are non-cross-connectable non cross connectable Use dedicated links for protection signalling
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800 kV redundant Line Protection Breaker
Transducers
HV transmission line
PUTT A B C D
PUTT LINE POTT1 PROT POTT2 I RM91 RE93
ETL PLC 81 I
POTT 1 Permissive overreach tripping NSD 70 indirect POTT 2 P Permissive i i overreach h tripping NSD 50 indirect
BFP
RM 91
Directional comp. prot. NSD 70 indirect
RE 93
Earth fault protection NSD 50 indirect
BFP
Breaker fail protection NSD 50 direct
GSD
Generator protection NSD 50 direct
GSD A B C D
PUTT LINE POTT1 PROT POTT2 II RM91 RE93
NSD 50
A NSD B 70
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Permissive underreach tripping NSD 70 indirect
Coupling
NSD 50
A NSD B 70
from generator
(with NSD 50 and NSD 70)
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ETL PLC 81 II
800 kV redundant Line Protection Breaker
Transducers
HV transmission line
PUTT A B C D
PUTT LINE POTT1 PROT POTT2 I RM91 RE93
PLC
Coupling
NSD 550 ETL 580
A NSD B 70 BFP
from generator
POTT 1 Permissive overreach tripping NSD 70 indirect POTT 2 Permissive overreach tripping NSD 550 indirect RM 91
Directional comp. prot. NSD 70 indirect
RE 93
Earth fault protection NSD 550 indirect
BFP
Breaker fail p protection NSD 550 direct
GSD
Generator protection NSD 550 direct
GSD A B TEBIT C D FOX A 515 B TEBIT C D
PUTT LINE POTT1 PROT POTT2 II RM91 RE93
O ti l fiber Optical fib
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Permissive underreach tripping NSD 70 indirect
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