Your first end-to-end test can seem to be a daunting task; but the actual test procedure is not very complicated and can be performed more quickly and effectively than traditional relay test techniques…if everything works correctly. That last part is the hard part because you are typically working with a team at a remote location which makes it difficult to determine whether the problem lies with the test plan, relay settings, test-set configuration, or operator error. This article will introduce you to end-to-end testing and answer many of the questions you might have.

1. End-to-End Testing
Chris Werstiuk
Manta Test Systems

2. What is End-to-End Testing?
 Two or more test sets at different
locations
 GPS antennas at both ends
 Fault simulations
 Time-synched start times

3. What is End-to-End Testing?

4. What is End-to-End Testing?
 Test Set Minimums
• 3 Current Channels
• 3 Voltage Channels
• 1 Output
• 1 Input
• GPS/IRIG Clock Synchronization
• Waveform or Fault State Simulations
• Computer?

5. What is End-to-End Testing?
 Computer to Communicate with
Relays
 At least One Operator at Each
Location
 Test Case
• Waveform
• State Simulator
 Understand Expected Results

6. What is End-to-End Testing?
 End-to-End Testing Steps
• Obtain and review test cases
• Isolate High and Low voltage equipment
• Connect I/O
• Connect Analog I/O
• Setup GPS/IRIG
• Communicate and perform meter test
• Choose test plan
• Prepare for test

7. What is End-to-End Testing?
 End-to-End Testing Steps (cont.)
• Choose start time
• Run test
• Review Targets and Event Report
• Repeat for all test cases
• Return equipment to service

8. Why Perform End-to-End Testing?
 Best line protection uses communication
• More reliable
• More Selective
• Faster operation
 Testing one end only finds obvious errors
 End-to-End tests entire scheme
 Most realistic testing possible
 Possible mandated by NERC…

9. How Does it Work?
 System Disturbances occur in 1 ms
 Relays can detect problems within
10us
 Both sides must start within 10us
• Fiber/pilot scheme require installation
• Power system synch in 1 ms
• GPS synch in 2us
• IRIG synch <10us

10. How Does it Work?
 Global Positioning System (GPS)
• US Armed Forces allowed civilian access to
satellite signals
• Antenna receives time signals from 4 satellites
• GPS clock compares difference in time signals
to different satellite positions
 All test sets have same time
 All tests start at same time
 Different test set models have different
start times

11. Where?
 Whenever entire schemes need
confirmation
 Typically communication assisted
protection in substations

12. When?
 Commissioning new installations
 More effective maintenance testing?

13. Detailed Procedures
 Obtain and Review Test Cases
• Understanding typical distance protection
TS TS TS TS
TS TS TS TS
TS TS TS TS
21 21 21 21
Z1 Z1 Z1 Z1
TX 1 TX 1 TX 1 TX 1
21 21 21 21
Z2 Z2 Z2 Z2
RX 1 RX 1 RX 1 RX 1
21 21 21 21
Z3 Z3 Z3 Z3
RLY-3 RLY-1 RLY-2 RLY-4
RLY -1 ZONE 1 RLY -4 ZONE 1
RLY -3 ZONE 1 RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
RLY -3 ZONE 2 RLY -4 ZONE 2
RLY -3 ZONE 3 RLY -4 ZONE 3

14. Detailed Procedures
 Obtain and Review Test Cases
• Fault simulations along and beyond
transmission line
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3

15. Detailed Procedures
 Obtain and Review Test Cases
• Waveform Files
 Comtrade or proprietary Software
 Pros
• Easy to export from modeling
software
• Easy play back
• Add CVT, harmonic, switching
distortions
• Tamperproof
 Cons
• Hard to troubleshoot

16. Detailed Procedures
 Obtain and Review Test Cases
• Waveform Files

17. Detailed Procedures
 Obtain and Review Test Cases
• Data
 Text, Spreadsheet, Database, CSV, Proprietary
 Pros
• Easy to create and understand
• Faster troubleshooting
• On-site corrections possible
• Easy Documentation
 Cons
• Conversion Errors
• Manual data entry

18. Detailed Procedures
 Obtain and Review Test Cases
• Data
RLY-1 Load from Bus to Line (SOURCE BUS for Prefault)
Aspen Output Aspen Output Aspen Output Aspen Output
Pre Fault Fault 1 Fault 2 Post Fault PRE FAULT FAULT 1 Post Fault
Secondary Secondary Secondary Test
Values Angle Values Angle Values Angle Values Angle Test Set Test Set Set
VA 132.79 0 110.9 -1 132.79 0 66.4 0.0 55.5 -1.0 66.4 0.0
VB 132.79 -120 110.9 -121 132.79 -120 66.4 -120.0 55.5 -121.0 66.4 -120.0
VC 132.79 120 110.9 119 132.79 120 66.4 120.0 55.5 119.0 66.4 120.0
IA 200 -10 4452 -81 0 0 0.50 -10.0 11.13 -81.0 0.00 0.0
IB 200 -130 4452 159 0 0 0.50 -130.0 11.13 159.0 0.00 0.0
IC 200 110 4452 39 0 0 0.50 110.0 11.13 39.0 0.00 0.0
RLY-2 Load from Line to Bus (LOAD BUS for Prefault)
Aspen Output Aspen Output Aspen Output Aspen Output
Pre Fault Fault 1 Fault 2 Post Fault PRE FAULT FAULT 1 Post Fault
Secondary Secondary Secondary Test
Values Angle Values Angle Values Angle Values Angle Test Set Test Set Set
VA 132.79 0 119.17 -1 132.79 0 66.4 0.0 59.6 -1.0 66.4 0.0
VB 132.79 -120 119.17 -121 132.79 -120 66.4 -120.0 59.6 -121.0 66.4 -120.0
VC 132.79 120 119.17 119 132.79 120 66.4 120.0 59.6 119.0 66.4 120.0
IA 200 170 4784 -81 0 0 0.33 170.0 7.97 -81.0 0.00 0.0
IB 200 50 4784 159 0 0 0.33 50.0 7.97 159.0 0.00 0.0
IC 200 -70 4784 39 0 0 0.33 -70.0 7.97 39.0 0.00 0.0

19. Detailed Procedures
 Obtain and Review Test Cases
• Phase Relationships – Pre-Fault

20. Detailed Procedures
 Obtain and Review Test Cases
• Phase Relationships – Internal Fault

21. Detailed Procedures
 Obtain and Review Test Cases
• Phase Relationships – External Fault

22. Detailed Procedures
 Obtain and Review Test Cases
• Phase Relationships – Pre-Fault
RLY-1 Ia@ degrees
-20
RLY-2 Ia@160 degrees
RLY-1 Va@0 degrees
RLY-2 Va@0 degrees

23. Detailed Procedures
 Obtain and Review Test Cases
• Phase Relationships – Internal Fault
RLY-1 Ia@ degrees
-85
RLY-2 Ia@-84 degrees
RLY-1 Va@-1degrees
RLY-2 Va@-1degrees

24. Detailed Procedures
 Obtain and Review Test Cases
• Phase Relationships – External Fault
RLY-1 Ia@ degrees
-82
RLY-2 Ia@98 degrees
RLY-1 Va@-4 degrees
RLY-2 Va@-5 degrees

25. Detailed Procedures
 Obtain and Review Test Cases
• Understand scheme under test (DCB, POTT,
etc)
• Make sure all test cases are complete.
• Understand expected results
• Check for obvious errors

26. Detailed Procedures
 Isolate Equipment Under Test
• Offline testing
 Open disconnect switches on outside of Breakers
TS TS TS TS
TS TS TS TS
TS TS TS TS
21 21 21 21
Z1 Z1 Z1 Z1
TX 1 TX 1 TX 1 TX 1
21 21 21 21
Z2 Z2 Z2 Z2
RX 1 RX 1 RX 1 RX 1
21 21 21 21
Z3 Z3 Z3 Z3
RLY-3 RLY-1 RLY-2 RLY-4

27. Detailed Procedures
 Isolate Equipment Under Test
• Relay Input/Output connections
DC+
2
TS-52-5-DC1
1
E2
R1
TRIP
50+51
RELAY TEST SET
F2
3 +
Timer
TS-52-5-DC1 R1
Input
4
TB1-7
G
F
3
C
B
DC-

28. Detailed Procedures
 Isolate Equipment Under Test
• Relay CT/PT Connections
CABLE FROM XFMR-2
VT8
OA OB OC 4200:120V
OA
OB
OC
TS-52-5-AC
16 18 20
ISOLATING DEVICE
15 17 19
1A1
1C0 A
X2 4 2
This
1B1
DWG
X2 8 G5 H5 G6 H6 6
1C1
1A2 1A3
X2 12 8
CT's 123-124-125 3 G7 H7 1
3-3000: MR 1B2 1B3
SET 2000:5
7 G8 H8 5
C200
1C0 1C2 1C3
A
X5 11 G9 H9 9
This
DWG RLY-12
X5
MULTILIN SR-750
X5
RELAY TEST SET
52-5 Magnitude Phase Angle
A Phase Volts Test Volts 0°
B Phase Volts Test Volts -120° (240°)
C Phase Volts Test Volts 120°
N Phase Volts
+
A Phase Amps AØ Test Amps 0°
OA OB OC
+
B Phase Amps BØ Test Amps -120° (240°)
TO 4160V BUS
+
C Phase Amps CØ Test Amps 120°
Alternate Timer Connection
DC Supply -
+
+ Timer Element - Timer
Input Output + Input

29. Detailed Procedures
 Setup GPS Antenna
• Need 4 satellites
• Clear sky – Vehicle roof
• Set test set for GPS input – wait
• Check for error message
• Check with remote ends for same time
• If sky not available – use IRIG

30. Detailed Procedures
 Meter Test
• Warn all ends before test
• Single phase voltage and current to check
connections
• 3 phase tests to check CT/PT ratios and
polarity

31. Detailed Procedures
 Meter Test
• Different relays and test sets have different
phasor references

32. Detailed Procedures
 Choose Test Plan
• All sides agree on test plan
• Different values for different ends

33. Detailed Procedures
 Evaluate Results
• Correct Targets?
• Correct Time Delays?
• Download event records (Optional)

34. Detailed Procedures
 Troubleshooting
• Correct waveform loaded?
• Correct Information loaded?
• Pre-fault duration the same?
• Same phases faulted?
• Same start time?
• Communication active?
• Circuit breaker signals in correct position?
• All leads still attached?

35. Detailed Procedures
 Return Equipment to Service
• Disconnect CT/PT Connections
• Disconnect I/O connections
• Close CT/PT Test Switches
• Check output status
• Close I/O test switches
• Contact switching authority

36. Detailed Procedures
 Prepare Report
• Cover Letter
 Non-electrical
 Summarize activities
 Summarize results
 List problems and action taken
 List outstanding issues
• Test Sheet
 Clear test results
 Relay settings in native and open-source format

37. Common Protection Schemes
 No Communication
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
Test RLY-1 RLY-2
1 Trip Zone-1 in 0 cycles Trip Zone-2 in 20 cycles
2 Trip Zone-2 in 20 cycles Trip Zone-1 in 0 cycles
3 Trip Zone-1 in 0 cycles Trip Zone-1 in 0 cycles
4 Trip Zone-1 in 0 cycles Trip Zone-1 in 0 cycles
5 Trip Zone-1 in 0 cycles Trip Zone-1 in 0 cycles
6 Trip Zone-3 in 60 cycles Trip Zone-2 in 20 cycles
7 Trip Zone-2 in 20 cycles Trip Zone-3 in 60 cycles
8 No trip Trip Zone-3 in 60 cycles
9 Trip Zone-3 in 60 cycles No trip
10 No trip No trip
11 No trip No trip

38. Common Protection Schemes
Press "NEXT" and see if you can guess what the relays will do
 No Communication 1 Press "Next" to move the fault location

39. Common Protection Schemes
 No Communication
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
Test RLY-1 RLY-2
1 Trip Zone-1 in 0 cycles Trip Zone-2 in 20 cycles
2 Trip Zone-2 in 20 cycles Trip Zone-1 in 0 cycles
3 Trip Zone-1 in 0 cycles Trip Zone-1 in 0 cycles
4 Trip Zone-1 in 0 cycles Trip Zone-1 in 0 cycles
5 Trip Zone-1 in 0 cycles Trip Zone-1 in 0 cycles
6 Trip Zone-3 in 60 cycles Trip Zone-2 in 20 cycles
7 Trip Zone-2 in 20 cycles Trip Zone-3 in 60 cycles
8 No trip Trip Zone-3 in 60 cycles
9 Trip Zone-3 in 60 cycles No trip
10 No trip No trip
11 No trip No trip

40. Common Protection Schemes
 Pilot Wire
• Uses traditional differential Theory
• Current in = Current out = No trip
• Slope Characteristic
FAULT CURRENT = 40 00 A FAULT CURRENT = 40 00 A EXTERNAL FAULT CURRENT = 800 0 A
40 0:5 40 0:5 40 0:5 40 0:5
87 = 25 % RESTRAINT SE TTING 87 = 25 % RESTRAINT SE TTING
50 A 50 A Iop 50 A 50 A 10 0 A 10 0 A Iop 10 0 A 10 0 A
RE STRAINT RE STRAINT RE STRAINT RE STRAINT
Iop = 50A + 50A = 100 A Iop = 100 A + -10 0A = 0 A
Iop /Irestrai nt = 100 A / 50 A = 2 Iop / Irestrai nt = 0 A / 100 A = 0
Iop /Irestrai nt = 200 % > 25% settin g = TRIP Iop /Irestrai nt = 0% < 25 % se tti ng = NO TRIP
Differential Protection 25% Characterisic Curve
14
Operating Current (Iop)
12
10
8 Trip Area
6
Restraint Area
4
2
0
0 1 2 3 4 5 6 7 8 9 10 11
Restrain Current (Ir)

41. Common Protection Schemes
 Pilot Wire
• 3 phase current passes through relay filters to create single
phase signal that can be sent over two pilot wires
• Pilot Signal can be current or voltage
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2 Test RLY-1 RLY-2
1
RLY -1 ZONE 3
Trip 87 in 0 cycles Trip 87RLY -20ZONE 3 RLY -2 ZONE 2
in cycles
2 Trip 87 in 0 cycles Trip 87 in 0 cycles
3 Trip 87 in 0 cycles Trip 87 in 0 cycles
4 Trip 87 in 0 cycles Trip 87 in 0 cycles
5 Trip 87 in 0 cycles Trip 87 in 0 cycles
6 No trip No trip
7 No trip No trip
8 No trip No trip
9 No trip No trip
10 No trip No trip
11 No trip No trip

42. Common Protection Schemes
 Phase/Charge Comparison
• Current greater than pickup starts communication
• Ignores current magnitude
• Trip signal sent with every negative half-cycle
• Block signal sent every positive half-cycle
• External fault = current 180 degrees out of phase
• Trip and block signals cancel
EXTERNAL FAULT CURRENT = 8 000 A
40 0:5 40 0:5
TX 1 TX 1
$ # $ #
* @ RX 1 RX 1 * @
$ = RLY-1 BLOCK $ = RLY-1 BLOCK
* = RLY-2 ATTEMPTS TRIP * = RLY-2 ATTEMPTS TRIP
# = RLY-2 BLOCK # = RLY-2 BLOCK
@ = RLY-1 ATTEMPTS TRIP @ = RLY-1 ATTEMPTS TRIP
TRIP BLOCKED TRIP BLOCKED

43. Common Protection Schemes Press "NEXT" and see if you can guess what the relays will do
 Phase/Charge Comparison 1 Press "Next" to move the fault location

44. Common Protection Schemes
 Phase/Charge Comparison
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2 Test RLY-1 RLY-2
1
RLY -1 ZONE 3
Trip 87 in 0 cycles Trip 87RLY -20ZONE 3 RLY -2 ZONE 2
in cycles
2 Trip 87 in 0 cycles Trip 87 in 0 cycles
3 Trip 87 in 0 cycles Trip 87 in 0 cycles
4 Trip 87 in 0 cycles Trip 87 in 0 cycles
5 Trip 87 in 0 cycles Trip 87 in 0 cycles
6 No trip No trip
7 No trip No trip
8 No trip No trip
9 No trip No trip
10 No trip No trip
11 No trip No trip

45. Common Protection Schemes
Direct Transfer Trip Scheme (DTT)
• A designated trip signal at one relay trips all relays
Direct Under-reaching Transfer Trip
(DUTT)
• Same as DTT except Zone 1 is trip signal
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
Test RLY-1 RLY-2 Test RLY-1 RLY-2
1 Trip Zone-1 in 0 cycles Trip Zone-2 in 20 cycles 1 Trip Zone-1 in 0 cycles DUTT Trip <3 cycles
2 Trip Zone-2 in 20 cycles Trip Zone-1 in 0 cycles 2 DUTT Trip <3 cycles Trip Zone-1 in 0 cycles

46. Common Protection Schemes
Direct Under-reaching Transfer Trip 1
Press "NEXT" and see if you can guess what the relays will do
(DUTT) Press "Next" to move the fault location
• Same as DTT except Zone 1 is trip signal

47. Common Protection Schemes
Permissive Over-Reaching Transfer Trip
(POTT)
• Zone 2 Pickup on both relays = COMM Trip
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
Test RLY-1 RLY-2 Test RLY-1 RLY-2
1 Trip Zone-1 in 0 cycles Trip Zone-2 in 20 cycles 1 Trip Zone-1 in 0 cycles POTT Trip <3 cycles
2 Trip Zone-2 in 20 cycles Trip Zone-1 in 0 cycles 2 POTT Trip <3 cycles Trip Zone-1 in 0 cycles

48. Press "NEXT" and see if you can guess what the relays will do
Press "Next" to move the fault location
Common Protection Schemes
Permissive Over-Reaching Transfer Trip (POTT) 1
• Zone 2 Pickup on both relays = COMM Trip

49. Common Protection Schemes
POTT Scheme
• Sudden Reversals can cause nuisance trips
• RLY-4 Detects Z2 and send PT to RLY-3
• RLY-1 Trips and RLY-3 Detects Z2
• Will RLY-4 PT stop before RLY-3 Z@ Pickup
RLY - 1 - Z o ne 1 RLY - 2 - Z o ne 2 RLY - 2 - Z o ne 2
1 1
RLY RLY RLY RLY
-1 -2 -1 -2
RLY - 3 - Z o ne 3 RLY - 4 - Z o ne 2 RLY - 3 - Z o ne 2 RLY - 4 - Z o ne 3
RLY RLY RLY RLY
-3 -4 -3 -4

50. Common Protection Schemes
Press "NEXT" to see what can happen in POTT is incorrectly
POTT Scheme 3 applied.

51. Common Protection Schemes
Permissive Over-Reaching Transfer Trip
(POTT)
• Zone 2 Pickup on both relays = COMM Trip
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
Test RLY-1 RLY-2 Test RLY-1 RLY-2
1 Trip Zone-1 in 0 cycles Trip Zone-2 in 20 cycles 1 Trip Zone-1 in 0 cycles POTT Trip <3 cycles
2 Trip Zone-2 in 20 cycles Trip Zone-1 in 0 cycles 2 POTT Trip <3 cycles Trip Zone-1 in 0 cycles

52. Common Protection Schemes
Directional Comparison Unblocking
(DCUB)
• Same as POTT except uses Power Line Carrier
• Guard signal present until permissive sent
• Relay must detect loss of guard AND PT for
COMM trip
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
Test RLY-1 RLY-2 Test RLY-1 RLY-2
1 Trip Zone-1 in 0 cycles Trip Zone-2 in 20 cycles 1 Trip Zone-1 in 0 cycles DCUB Trip <3 cycles
2 Trip Zone-2 in 20 cycles Trip Zone-1 in 0 cycles 2 DCUB Trip <3 cycles Trip Zone-1 in 0 cycles

53. Common Protection Schemes
Directional Comparison Unblocking
(DCUB) 1
Press "NEXT" and see if you can guess what the relays will do
Press "Next" to move the fault location

54. Common Protection Schemes
Directional Comparison Unblocking
(DCUB)
• Same as POTT except uses Power Line Carrier
• Guard signal present until permissive sent
• Relay must detect loss of guard AND PT for
COMM trip
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
Test RLY-1 RLY-2 Test RLY-1 RLY-2
1 Trip Zone-1 in 0 cycles Trip Zone-2 in 20 cycles 1 Trip Zone-1 in 0 cycles DCUB Trip <3 cycles
2 Trip Zone-2 in 20 cycles Trip Zone-1 in 0 cycles 2 DCUB Trip <3 cycles Trip Zone-1 in 0 cycles

55. Common Protection Schemes
Permissive Under-reaching Transfer Trip
(PUTT)
• Zone 1 Pickup on one relay and Zone 2 Pickup on second
relay = COMM Trip
• No sudden reversal problem because Zone 1 doesn’t over-
reach
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
Test RLY-1 RLY-2 Test RLY-1 RLY-2
1 Trip Zone-1 in 0 cycles Trip Zone-2 in 20 cycles 1 Trip Zone-1 in 0 cycles PUTT Trip <3 cycles
2 Trip Zone-2 in 20 cycles Trip Zone-1 in 0 cycles 2 PUTT Trip <3 cycles Trip Zone-1 in 0 cycles

56. Press "NEXT" and see if you can guess what the relays will do
Press "Next" to move the fault location
Common Protection Schemes
Permissive Under-reaching Transfer Trip
(PUTT) 1

57. Common Protection Schemes
Permissive Under-reaching Transfer Trip
(PUTT)
• Zone 1 Pickup on one relay and Zone 2 Pickup on second
relay = COMM Trip
• No sudden reversal problem because Zone 1 doesn’t over-
reach
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
Test RLY-1 RLY-2 Test RLY-1 RLY-2
1 Trip Zone-1 in 0 cycles Trip Zone-2 in 20 cycles 1 Trip Zone-1 in 0 cycles PUTT Trip <3 cycles
2 Trip Zone-2 in 20 cycles Trip Zone-1 in 0 cycles 2 PUTT Trip <3 cycles Trip Zone-1 in 0 cycles

58. Common Protection Schemes
Directional Comparison Blocking (DCB)
• Zone 2 Pickup on one relay with Zone 3
detected on other relay = COMM Trip blocked
• Zone 2 with no blocking signal = COMM trip
• Sudden reversal nuisance tripping possible
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
Test RLY-1 RLY-2 Test RLY-1 RLY-2
1 Trip Zone-1 in 0 cycles Trip Zone-2 in 20 cycles 1 Trip Zone-1 in 0 cycles DCB Trip <3 cycles
2 Trip Zone-2 in 20 cycles Trip Zone-1 in 0 cycles 2 DCB Trip <3 cycles Trip Zone-1 in 0 cycles

59. Common Protection Schemes
Press "NEXT" and see if you can guess what the relays will do
Press "Next" to move the fault location
Directional Comparison Blocking (DCB) 1

60. Common Protection Schemes
Directional Comparison Blocking (DCB)
• Zone 2 Pickup on one relay with Zone 3
detected on other relay = COMM Trip blocked
• Zone 2 with no blocking signal = COMM trip
• Sudden reversal nuisance tripping possible
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2
RLY -2 ZONE 2
RLY -1 ZONE 3 RLY -2 ZONE 3
Test RLY-1 RLY-2 Test RLY-1 RLY-2
1 Trip Zone-1 in 0 cycles Trip Zone-2 in 20 cycles 1 Trip Zone-1 in 0 cycles DCB Trip <3 cycles
2 Trip Zone-2 in 20 cycles Trip Zone-1 in 0 cycles 2 DCB Trip <3 cycles Trip Zone-1 in 0 cycles

61. Common Protection Schemes
 Line Differential
• Not your typical slope
• A, B, C, I2, and I0 current
• Alpha Plane = Vector Math
• Remote amps @ x degrees / Local amps @ y degrees
I RLY 2 0.33 @170
• Prefault = IA    0.67 @180
I RLY 1 0.50 @ 10 
I RLY 2 8.0 @ 81
• 3 Phase Fault1 = IA    0.72 @ 0
I RLY 1 11.1@ 81 
• 1 Phase Fault2 = IA 
I RLY 2

2.76 @ 80 
 0.072 @ 3 I 0 ALPHA 
I RLY 2 0.66 @ 78.4 
  0.05 @ 4.6 
I RLY 1 37.99 @ 83 
I RLY 1 13.06 @ 83 
I RLY 2 0.39 @ 91 I RLY 2 1.07 @ 80.6 
IB    0.661@180  I 2 ALPHA    0.09 @ 2.4 
I RLY 1 0.59 @ 89 
I RLY 1 12.44 @ 83.0 
I RLY 2 0.39 @101
IC ALPHA    0.661@180 
I RLY 1 0.59 @ 79 

62. Common Protection Schemes
 Line Differential IMAG (Iremote/Ilocal)
• Alpha Plane
TRIP
REGION
RESTRAINT IAfault 2
REGION I0fault 2
I2fault 2
Iprefault
REAL (Iremote/Ilocal)
IBfault 2 Ifault 1
ICfault 2

63. Common Protection Schemes
 Line Differential
10 9 6 1 3 5 4 2 7 8 11
RLY RLY
-1 -2
RLY -1 ZONE 1
RLY -2 ZONE 1
RLY -1 ZONE 2 Test RLY-1 RLY-2
1
RLY -1 ZONE 3
Trip 87 in 0 cycles Trip 87RLY -20ZONE 3 RLY -2 ZONE 2
in cycles
2 Trip 87 in 0 cycles Trip 87 in 0 cycles
3 Trip 87 in 0 cycles Trip 87 in 0 cycles
4 Trip 87 in 0 cycles Trip 87 in 0 cycles
5 Trip 87 in 0 cycles Trip 87 in 0 cycles
6 No trip No trip
7 No trip No trip
8 No trip No trip
9 No trip No trip
10 No trip No trip
11 No trip No trip

64. Conclusion
POTT PUTT DCB Pilot Wire Phase Comparison Line Differential
Trip 87 in 0 Trip 87 in 0
RLY-1 RLY-2 RLY-1 RLY-2 RLY-1 RLY-2 cycles cycles RLY-1 RLY-2 RLY-1 RLY-2
Trip Zone-1 Trip Zone-2 Trip Zone-1 Trip Zone-2 Trip Zone-1 Trip Zone-2 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0
1
in 0 cycles in <3 cycles in 0 cycles in <3 cycles in 0 cycles in <6 cycles cycles cycles cycles cycles cycles cycles
Trip Zone-2 Trip Zone-1 Trip Zone-2 Trip Zone-1 Trip Zone-2 Trip Zone-1 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0
2
in <3 cycles in 0 cycles in < 3 cycles in 0 cycles in <6 cycles in 0 cycles cycles cycles cycles cycles cycles cycles
Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0
3
in 0 cycles in 0 cycles in 0 cycles in 0 cycles in 0 cycles in 0 cycles cycles cycles cycles cycles cycles cycles
Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0
4
in 0 cycles in 0 cycles in 0 cycles in 0 cycles in 0 cycles in 0 cycles cycles cycles cycles cycles cycles cycles
Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip Zone-1 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0 Trip 87 in 0
5
in 0 cycles in 0 cycles in 0 cycles in 0 cycles in 0 cycles in 0 cycles cycles cycles cycles cycles cycles cycles
Trip Zone-3 Trip Zone-2 Trip Zone-3 Trip Zone-2 Trip Zone-3 Trip Zone-2
6 No trip No trip No trip No trip No trip No trip
in 60 cycles in 20 cycles in 60 cycles in 20 cycles in 60 cycles in 20 cycles
Trip Zone-2 Trip Zone-3 Trip Zone-2 Trip Zone-3 Trip Zone-2 Trip Zone-3
7 No trip No trip No trip No trip No trip No trip
in 20 cycles in 60 cycles in 20 cycles in 60 cycles in 20 cycles in 60 cycles
Trip Zone-3 Trip Zone-3 Trip Zone-3
8 No trip No trip No trip No trip No trip No trip No trip No trip No trip
in 60 cycles in 60 cycles in 60 cycles
Trip Zone-3 Trip Zone-3 Trip Zone-3
9 No trip No trip No trip No trip No trip No trip No trip No trip No trip
in 60 cycles in 60 cycles in 60 cycles
10 No trip No trip No trip No trip No trip No trip No trip No trip No trip No trip No trip No trip
11 No trip No trip No trip No trip No trip No trip No trip No trip No trip No trip No trip No trip

65. Questions???