Application of Digital Relay Protection on APUA T&D Network

1
Application of Digital Relay Protection on APUA
TD Network
Presented by

• Li Zhengrong Substation Maintenance
  Protection Engineer
• Andre MatthiasDivision Manager
• Electricity/ transmission Distribution Division
• Antigua Public Utilities Authority
• July 23-25, 2002
• 2002 Carilec Engineers Conference
• Montego Bay, Jamaica

2
Application of Digital Relay Protection on APUA
TD Network
KEY WORDS

• Application Digital Relay Protection
  
• Communication Software Workstation
• 69kV Lines 11kV Feeders

3
1.General information
1.1 Introduction of APUA electric power system

• The total installed generation capacity is 64.5MW
  and the present peak load is 34.8MW
• Eight (8) 69kV transmission lines operating in
  close-ring are 59.2kM in length
• Twenty-two (22) 11kV feeders radiating and
  covering entire Island are 539kM in length
• Twelve (12) 69/11kV power transformers at seven
  (7) step-up/-down substations possess a total
  installed capacity of 160.34MVA.

4
1.General Information
1.2 . Requirement for relay upgrade

• 1.2.1 11kv primary feeders
• a. Under-frequency protection feature for
  load-shedding
• b. One-shot re-closing
• c. fuse-saving scheme

5
1.General Information
1.2 . Requirement for relay upgrade (continued)

• 1.2.2 69kv transmission lines
• a. eliminate protection dead zones
• b. reduce duration of faults on power system
• c. prevent equipment damage
• d. differentiate max. load current from min.
  fault current
• e. avoid misoperation of current balance
  protection.

6
1.General Information
1.3 Relay protection upgrade project

• Replacing electromagnetic distance relay
  protections on 69kv transmission lines with 351
  digital relays was done in 2000
• Replacing electronic relays on 11kv feeders with
  DFP-100 and 351/551 digital relays was done in
  2001
• Replacing differential relays on 69/11kv power
  transformers with SEL-587 relays is in progress.
• The entire upgrade project that was from project
  design, settings calculation to relay
  programming, installing and testing, was carried
  out by APUA staff.

7
2. Application of Digital Relays on 11kV Primary
Feeders
2.1 Fundamental Protection Feature

• 2.1.1 Phase-to-phase protection(positive-sequence
  protection 50P)
• Instantaneous over-current with time-delay(50PH )
• Time-definite over-current (50PL)
• 2.1.2 Earth fault protection (zero-sequence
  protection 50N)
• Time-definite zero-sequence over-current (50N)
• 2.1.3 Under-frequency protection for
  load-shedding (81U1,81U1T)
• 2.1.4 re-closing
• One-shot re-closing (SH0) is activated only under
  phase-to-phase fault

8
2. Application of Digital Relay on 11kV Primary
Feeders
2.2 Definition of protection zone

• Phase-to-phase protection(50P)
• Instantaneous over-current with time-delay(50PH),
  protects entire primary feeder and primary side
  of distribution power transformers
• Time-definite over-current (50PL) as backup
  protection of 50PH and fuse links, protects
  entire primary feeder and both sides of
  distribution transformers.
• Protection zone is shown in Figure 1 .

9
2. Application of Digital Relay on 11kV Primary
Feeders
2.2 Definition of protection zone (continued)
Solid link
Relay
Fuse link 1
Fuse link 2
Fuse link 3
50PH
50PL
Figure 1 phase-to-phase over-current protection
10
2. Application of Digital Relays on 11kV Primary
Feeders
2.2 Definition of protection zone (continued)

• B. Earth fault protection(50N)
• Time-definite zero-sequence over-current (50N) as
  backup protection of fuse links, protects entire
  primary feeder and primary sides of distribution
  transformers under earth fault circumstance.
• Protection zone is shown in Figure 2 .

11
2. Application of Digital Relay on 11kV Primary
Feeders
2.2 definition of protection zone (continued)
Relay
Solid link
Fuse link 2
Fuse link 1
50NH
Figure 2 earth-fault protection
12
2. Application of Digital Relay on 11kV Primary
Feeders
2.2 Definition of protection zone (continued)

• C. Fuse link protection
• Fuse link immediately clears faults on both sides
  of protected distribution transformer
• Fuse link clears faults on protected branch of
  primary line.
• Protection zone is shown in Figure 3.

13
2. Application of Digital Relay on 11kV Primary
Feeders
2.2 definition of protection zone (continued)
Fuse link 2
Relay
Solid link
Fuse link 1
Fuse link 3
Figure 3 protection zone of fuse link
14
2. Application of Digital Relay on 11kV Primary
Feeders
2.3. The trip-saving scheme

• Fuse link
• Fuse link blows out first to clear faulted
  branch or distribution transformer
• B. Phase-to-phase protection(50P)
• Instantaneous over-current with time-delay(50PH)
  acts as backup protection for fuse links
• Time-definite over-current (50PL) performs as
  remote backup protection for both 50PH and fuse
  links.

15
2. Application of Digital Relay on 11kV Primary
Feeders
2.3 The trip-saving scheme (continued)

• C. Earth fault protection(50N)
• Time-definite zero-sequence over-current (50N)
  acts as backup protection for fuse links.
• D. One-shot reclosing (SH0)
• One-shot reclosing is activated under
  phase-to-phase faulty condition
• (Notice Consider to avoid a human being or an
  animal to be shocked twice while carelessly
  touching a live conductor one-shot re-closing is
  replaced by manual re-closing under earth fault
  circumstance).

16
2. Application of Digital Relay on 11kV Primary
Feeders
2.4 The fuse-saving scheme

• Phase-to-phase protection(50P)
• Instantaneous over-current without
  time-delay(50PH) will immediately clear fault and
  then be locked by one-shot re-closing after
  circuit-breaker tripping.
• After 5 seconds, the feeder will be closed by
  one-shot re-closing successfully if the temporary
  fault disappears at once
• The permanent fault area will be isolated by
  related fuse link from entire feeder, or
  time-definite over-current (50PL) trips entire
  feeder
• B. Earth fault protection(50N)
• Functions as same as that in the trip-saving
  scheme

17
2. Application of Digital Relay on 11kV Primary
Feeders
2.5 Recorded trips of 11kv feeders

• Date December 13, 2001
• Cause a freak storm
• Total tripped Feeders 11
• Total trip times 19
• Phase-to-ground fault 1 temporary
• Phase-to-phase fault 18 (12 temporary 6
  permanent)

18
2. Application of Digital Relays on 11kV Primary
Feeders
2.6 Under-frequency protection for load-shedding

• a. Under-frequency protection with under-voltage
  supervision
• Use under-frequency trip (81UT) with
  under-voltage supervision(27U) logic to
  eliminate unnecessary trip under phase-to-phase
  fault.
• The trip logic is programmed as
  trip81UT!27U
•  
• b. Circulatory change of trip sequence
• The different under-frequency settings and same
  over-current settings can be preset in each of 6
  groups for circulatory change of trip sequence by
  activating certain settings group.

19
3. Application of Digital Relay on 69KV
Transmission lines
3.1 Protection Feature

• 3.1.1 Phase-to-phase protection
  (positive-sequence protection 50P)
• Directional instantaneous over-current without
  time-delay(Zone one 67P1)
• Directional instantaneous over-current with
  time-delay (Zone two 67P2)
• Directional time-definite over-current protection
  (Zone three 67P3)

20
3. Application of Digital Relay on 69KV
Transmission lines
3.1 Protection Feature (continued)

• 3.1.2 earth fault protection(zero-sequence
  protection 50N)
• Directional instantaneous over-current without
  time-delay(Zone one 67N1)
• Directional instantaneous over-current with
  time-delay (Zone two 67N2)
• Directional time-definite over-current protection
  (Zone three 67N3)
• Directional time-definite over-current protection
  for phase-loss supervision (Zone four 67N4)
• Zero-sequence over-voltage with time-delay (59N)
  as a complement

21
3. Application of Digital Relay on 69KV
Transmission lines
3.1 Protection Feature

• 3.1.3 re-closing
• Synchronize-check (25A) or non-voltage check
  (27S) to initiate re-closing
• One-shot re-closing (SH0) is activated only under
  phase-to-phase fault

22
3. Application of Digital Relay on 69KV
Transmission lines
3.2 Clockwise /Anticlockwise Coordination Route
TmaxOLD2.60Seconds TmaxNOW1.85Seconds
TmaxOLD2.60Seconds TmaxNOW1.85Seconds

13
11
7
8
9
12
14
10
15
Cassada
G
G
G
G
G
G
G
Crabbs
Friars Hill
K3
1
3
2
4
5
6
16
Swetes
Union Road
Lavington
Belmont
Figure 4 Clockwise in blue starts at 1 CB and
ends at 11/13 C.B Anticlockwise in red starts
at 10/12 and ends at 14 C.B
23
3. Application of Digital Relay on 69KV
Transmission lines
3.3 Reduce Duration of Fault Clearing

• The recommended time difference between adjacent
  relays is 0.4-0.6 Seconds for electromagnetic
  relays and 0.25-0.3seconds for digital/
  electronic relays
• The maximum time setting was coordinated as 2.60
  seconds for previous electromagnetic distance
  relays numbered 11,13 and 14, and that for SEL
  digital relay protections at same location is
  1.85seconds.
• The net decrease of time settings between two
  kinds of protections is 0.75seconds.

24
2. Application of Digital Relay on 69KV
Transmission lines
3.4 Eliminate protection dead zone

• 3.4.1 Zero-sequence over-voltage (59N) as a
  complement at some lines while close-ring of
  transmission lines is opened at some certain
  point
• Case A CB 1 opens (see Figure 5)
• Case B CB 9 opens (see Figure 6)
• 3.4.2 distinguish maximum load current ILD from
  minimum fault current IF at 69kV section breaker
  15 by load-encroachment Logic (see Figures
  78)

25
3. Application of Digital Relay on 69KV
Transmission lines
3.4 Eliminate protection dead zone(continued)
Earth fault
K(1.0)
O/V
13
11
7
8
9
12
10
14
15
YO/D
YO/D
Y/YO
Y/YO
Y/YO
Y/YO
YO/D
YO/D
Cassada
G
G
G
G
G
G
G
Crabbs
Friars Hill
1
3
2
4
Opened
5
6
16
Figure 5 Case A circuit-breaker 1 opens
26
3. Application of Digital Relay on 69KV
Transmission lines
3.4 Eliminate protection dead zone(continue)
Opened
8
13
11
7
9
12
10
O/V
Opened
14
15
YO/D
YO/D
Y/YO
Y/YO
Y/YO
Y/YO
YO/D
YO/D
K(1.0)
Cassada
G
G
G
G
G
G
G
K(1.0)
Crabbs
Friars Hill
K(1.0)
K(1.0)
1
3
2
4
5
O/V
O/V
6
16
O/V
Figure 6 Case B circuit-breaker 8 or 9 opens
K(1.0) -----Earth fault
27
3. Application of Digital Relay on 69KV
Transmission lines
3.4 Eliminate protection dead zone(continue)
IF2202A
IF58A
IF158A
K(2)
13
11
7
8
9
12
14
10
15
ILD219A
IF100A
Cassada
G
G
G
G
G
G
G
Crabbs
Friars Hill
1
3
2
4
5
6
16
Figure 7 Distinguishing IFMIN from ILDMAX at
circuit-breaker 15
28
3. Application of Digital Relay on 69KV
Transmission lines
3.4 Eliminate protection dead zone(continue)
X
fault
load
R
Load out
Load in
Figure 8 Distinguishing IFMIN from ILDMAX by
load-encroachment Logic
29
3. Application of Digital Relays on 69KV
Transmission lines
3.5 Prevent equipment damage from abnormal
condition

• 3.5.1 In the previous designs, the closing or
  tripping coils or related relays were frequently
  burned out by overheating when system operator
  switched circuit-breaker by SCADA under following
  abnormal conditions
• a. Substations D.C. low-voltage (less than
  70), or
• b. The stuck output contact of auxiliary relay,
  or
• c. Mechanism jamming of circuit-breaker.
•  

30
3. Application of Digital Relays on 69KV
Transmission lines
3.5 Prevent equipment damage from abnormal
condition(continued)

• 3.5.2 Measures being taken to prevent damage of
  facilities
• a unifying close/open (or trip) commands between
  SCADA and relays
• b. programming new relays and improving wiring
  connection
• c. programming output of close or open commands.
  

31
3. Application of Digital Relays on 69KV
Transmission lines
3.5 Prevent equipment damage from abnormal
condition(continued)
Protection relay
69kV circuit-breaker
SCADA System
Digital Relay
Figure 9 change of control/protection logic
32
3. Application of Digital Relays on 69KV
Transmission lines
3.6 Provide flexible Logic functions

• 3.6.1 Interlocking balance current protection
  on 69kV double lines while single line operates
  (see Figure 10)
• 3.6.2 Speed-up tripping of Zone two (67P2)
  while re-closing onto permanent faulted line
  (see Figure 11)
• 3.6.3 Anti-pump of circuit-breaker (see Figures
  12)

33
3. Application of Digital Relays on 69KV
Transmission lines
3.6 Provide flexible Logic functions (continued)
Close
Close
B/C 351
B/C 351
1
3
G1
G2
2
4
B/C 351
B/C 351
Open
Open
Output 2
Output 1
52A1
52A2
B/C trip
Trip circuit
Output1output contact of 1 351 relay
(67P2) Output2output contact of 2 351 relay
(67P2) 52A1 auxiliary contact of 1
circuit-breaker 52A2 auxiliary contact of 2
circuit-breaker B/C balance current
protection B/C triptrip contact of balance
current protection
Figure 10 Interlocking balance current protection
on 69kV double lines
34
3. Application of Digital Relays on 69KV
Transmission lines
3.6 Provide flexible Logic functions (continues)
67P1
Relay 1
K
Relay 2
G
67P2
67P3
Trip logic Trip 67P1T67P2T67P3T67P2\SH0
Where 67P1Ttimer of zone one (67P1)
67P2Ttimer of zone two (67P2)
67P3Ttimer of zone three (67P3)
\SH0 declining edge of one-shot reclosing
Figure 11 Speed-up tripping of Zone two (67P2)
while re-closing onto permanent faulted line
35
3. Application of Digital Relays on 69KV
Transmission lines
3.6 Provide flexible Logic functions (continued)
SCADA or Manual Closing command
T67P1T
Status of C.B (No logic)
TCL
TOP
Closing command With logic
TLDO
T67P1T
Status of C.B (with logic)
TCL
TOP
TOPinherent open time of circuit-breaker TCLinhe
rent close time of circuit-breaker T67P1Ttimer
of relay zone one (67P1) TLDOdrop-off timer of
logic-controlled contact (TCL T67P1T TOPgt TLDOgt
TCL)

• Figures 12 Anti-pump of circuit-breaker under
  permanent faulty condition

36
3. Application of Digital Relay on 69KV
Transmission lines
3.7 Provide reliable and useful data information
a. The magnitude and phase angle of three-phase
current and voltage b. Dual-directional
single/three-phase active/reactive power and
energy c. Dual-directional load flow d. Power
factor and work frequency e. DC voltage f. 
Pre-fault and fault current and voltage See
downloaded data information
37

  CRB-CAS 1 69KV LINE Date
05/29/02 Time 111355.618 CRABBS
SUBSTATION A B C
N G I MAG (A) 77.534
74.927 78.517 0.387 0.424 I ANG (DEG)
-35.34 -153.68 87.31 134.14 123.30
A B
C S V MAG (KV) 41.222
40.328 40.812 40.583 V ANG (DEG) 0.00
-119.97 117.52 -0.57
A B C 3P MW
2.607 2.514 2.769
7.890 MVAR 1.849 1.677 1.612
5.138 PF 0.816 0.832
0.864 0.838 LAG
LAG LAG LAG I1 3I2
3I0 V1 V2 3V0 MAG
76.978 6.342 0.424 40.779
0.334 2.551 ANG (DEG) -33.90 -105.67
123.30 -0.82 150.90 29.60  FREQ (Hz)
59.92 VDC (V)
114.8     IA IB IC
IN IG 3I2 DEMAND 77.5
74.6 78.4 0.4 0.4
6.7 PEAK 146.4 133.7 150.0
35.2 35.3 35.3  
MWA MWB MWC MW3P MVARA
MVARB MVARC MVAR3P DEMAND IN 0.0
0.0 0.0 0.0
0.0 0.0 0.0
0.0 PEAK IN 0.2 0.2
0.4 0.6 0.2
0.2 1.2 1.2 DEMAND OUT
2.6 2.5 2.8 7.9
1.8 1.7 1.6
5.1 PEAK OUT 4.6 4.3
5.2 14.1 3.8
3.2 3.1 10.1   MWhA MWhB
MWhC MWh3P MVARhA MVARhB MVARhC
MVARh3P IN 0.2
0.2 0.2 0.5 1.0
1.1 1.2
3.3 OUT 28278.4 26797.4
31523.3 86599.1 21038.4 17781.7
17006.4 55826.5

38
3. Application of Digital Relays on 69KV
Transmission lines
3.8 Provide useful supervision

• PT voltage memory polarization unit secures
  reliable operation of relay employed on short
  line while a three-phase fault occurs close to
  busbar.
• b. Directional elements with V2 and V0 voltage
  polarization units secure reliability and
  selectivity of relay under earth fault condition.

39
3. Application of Digital Relays on 69KV
Transmission lines
3.8 Provide useful supervision (continued)

• AC under- and over-voltage
• 69kV PT phase-loss supervision
• 69kV line phase-loss supervision
• Over-/under-frequency
• DC over-/under-voltage
• DC source loss
• Circuit breaker operating and wearing status
• Fault location indication
• k. Relay fault alarm.

40
3. Application of Digital Relays on 69KV
Transmission lines
3.9 other advantages of 351 Digital Relay

• 3.9.1 Two-level access-in password
• First-level available for protection technicians
  to routinely inspect and review.
• Second-level available for protection
  Engineer/senior technicians to program relays and
  operate circuit-breakers.
• 3.9.2 others
• flexible-to-program
• easy-to-install-and-test
• free-to-maintain
• small-in-size
• sealed in metal box to prevent radio interference
  and climate affection
• work under temperature range of 40--85C

41
4. 2030 Communication Relay Software
4.1 2030 Configuration Feature

• A. Configuration
• Being called as Master relay for substation
  communication and integration
• Seventeen(17) 9-pin communication ports
• Programmable relay
• B. Feature
• Data information collection, storage and
  distribution
• Remote or local control, metering and monitoring
• Event alarming/ paging
• Time and date synchronization

42
4. 2030 Communication Relay Software
4.2 Workstation
WORKSTATION REMOTE PC (5040)
2030
MODEM
MODEM
2030
MODEM
PHONE (PAGING)
TELEPHONE BOARD
2030
MODEM
MODEM
LOCAL PC

• 2030 communication relay

2030
MODEM
587
351
551
321
DFP-100
Figure 13 communication configuration
43
4. 2030 Communication Relay Software
4.3 Communication software

• 4.3.1 Human machine interface (HMI)
• Hyper Terminal is a widely used software for
  either local or remote relay communication
• 4.3.2 5010 Setting assistance software
• The most complex work on 351 relay is
  programming due to 512 settings in one of six
  groups.
• This software can
• make relay programming facilitated
• synchronize date and time on relays.

44
4. 2030 Communication Relay Software
4.3 Communication software (continued)

• 4.3.3 5040 Power system report manager
• 5040 software was designed for
  establishment of Workstation.
• It can
• periodically or automatically retrieve the latest
  event reports from designated digital relays
• save event reports in database of workstation for
  viewing in oscillography.

45
5. A Captured Event
IAF1911A IAS1407A 0S
IAF552A
INF2054A INS2016A 0S
INF701A
IAF1642A IAS378A 0.5S
13
11
7
8
9
12
10
14
15
IA(1.0) L1.62KM
INF1589A INS450A 0.5S
Y/ Yo
Yo/Y
Yo/Y
Y/ Yo
Cassada
G
G
G
G
G
G
G
Crabbs
Friars Hill
IAF699A IAS675A 0S
INF700A INS531A 0S
3
2
4
5
6
16
1
1
Y/ Yo
Y/ Yo
Y/ Yo
Y/ Yo
Lavington
Swetes
Belmont
Union Road
Figure 14 fault current distribution situation
on May 05,2002
46
5. A Captured Event( continued)

• CRA-LAV
• DATE TIME EVENT LOCAT CURR
  FREQ GRP SHOT TARGETS
• 05/05/02 062126.909 AG T 1.62 1911 60.06
  1 0 INST 50
• 42 05/05/02 062126.901 67N4
  Asserted
• 41 05/05/02 062126.905 67N3
  Asserted
• 40 05/05/02 062126.905 67P3
  Asserted
• 39 05/05/02 062126.909 67N2
  Asserted
• 38 05/05/02 062126.909 67P2
  Asserted
• 37 05/05/02 062126.917 67N1
  Asserted
• 36 05/05/02 062126.917 67P1
  Asserted
• 35 05/05/02 062126.917 67N1T
  Asserted
• 34 05/05/02 062126.917 67P1T
  Asserted
• 33 05/05/02 062126.917 TRIP
  Asserted
• 32 05/05/02 062126.917 OUT202
  Asserted
• 31 05/05/02 062126.917 OUT201
  Asserted
• 26 05/05/02 062126.963 IN101
  Deasserted
• 21 05/05/02 062126.972 52A
  Deasserted

47
5. A Captured Event( continued)

• LAV-CRA 
• 4 05/05/02 062146.408 AG T 5.71 699
  60.07 1 0 INST 50
•  
• 40 05/05/02 062146.404 67N3
  Asserted
• 39 05/05/02 062146.404 67N2
  Asserted
• 38 05/05/02 062146.404 67P3
  Asserted
• 37 05/05/02 062146.413 67N1
  Asserted
• 36 05/05/02 062146.413 67N1T
  Asserted
• 34 05/05/02 062146.413 TRIP
  Asserted
• 33 05/05/02 062146.413 OUT201
  Asserted
• 32 05/05/02 062146.421 67P1
  Asserted
• 31 05/05/02 062146.421 67P1T
  Asserted
• 20 05/05/02 062146.454 IN101
  Deasserted
• 17 05/05/02 062146.463 52A
  Deasserted

48
6. Conclusion

• About two year operating experience shows that
• a. the digital relay protections secure 69kV
  transmission lines and 11kV primary feeders
  operating under safe, reliable condition
• b. the micro-processed directional over-current
  protection can be applied to the close-ring
  transmission network, especially, to the short
  lines connected to small power system.
•  

49
6. Conclusion

• The established workstation makes daily
  inspection of relays and fault analysis easier.
• All event reports recorded in related relays can
  be immediately downloaded by 5040 software within
  few minutes once an event occurs.
• In accordance with the event reports listed in
  table, the event sequence and cause, conclusion
  can be easily obtained to guide system
  improvement.
•  

50
6. Conclusion

• 3. Based on application of 2030 communication
  relays and 5040 and other related software, the
  established workstation performs functions as
  mini-SCADA system on protection, monitoring,
  metering and control.