1. Distance and Differential Teleprotection
Complete guide to setup, demonstrate, test and troubleshoot
Focus on Distance Teleprotection

2. Introduction
Overview of the Application
Bill of Materials
Diagram of setup
Detailed instructions
Test Procedure & Success Criteria
Appendix A: Scripts
Appendix B: Overview of Teleprotection
Appendix C: The Megaplex TP module

3. Distance and Differential Teleprotection
This guide is designed to allow you to setup, demonstrate, test and troubleshoot Distance Teleprotection
The application is based on ERP and uses MP-4100
It is aimed at Electric Utilities
The main benefits to the user are:
Easy connection to legacy equipment
Smooth migration from TDM backbone to PSN
Fast implementation
Powerful Management

4. Application Overview
The diagram shows Distance and Differential Teleprotection with the MP-4100 in both sites
We will focus on Distance Teleprotection

5. Review of the Application
Distance Teleprotection is a function of Electric Utility networks that checks for failures in long-distance high tension power cables
Reporting is by specialized (3rd party) boxes that report to the MP-TP card in DC voltages

6. Bill of Materials Product Catalog Name and Number S/W version Quantity
MP-4100
MP-4100-MN
N/A 2
Power supply
MP-4100M-PS/230
Common logic
MP-4100M-CL.2/622GBEAUTP 4
TP module
MP-4100M-TP/220/SSR
2.50.7
ETX-220A
ETX220A/AC/3XFP/10U/SYE/BSK
5.9.0(0.15) 1
Non-RAD
Name
Description
Quantity
Notes
ETH cables
Copper – gigabit cables 5
Connecting the ring and the laptops to the ring
USB-Serial converter 1

7. TP with RADview over ERP
RADview NMS
0/101
ETX-220A
1 GbE
ERP
1/1
1/2
Megaplex-4
“A”
Megaplex-4
“B”
East
East
CL-A/1
CL-A/1
M-TP/220/SSR
M-TP/220/SSR
TP Alarm-relay
CL-B/1
CL-B/1
TP Alarm-relay
3/1
3/1
Neighbor
West
RPL
West
TP Unit
TP Unit
In our case we will use the LED output without the TP unit
The TP module is in slot 3
The RADview will be shown using Shelf View

8. Services Description TP signals between 2 TP cards over ERPS
This service will use VLAN 400
In each MP we will use Bridge #1 and ports 1, 2 & 6
Ports 1 & 2 for the CL-A/1 and CL-B/1
Port 6 to SVI 3 which is bound to Bridge #2 port #2 (PW)
The PW will be between and (called peer 2)
The internal cmd port 3/1/1 is activated
The cmd-channel 3/1 is allocated TX 101/102 and RX 102/101

9. Let’s build it!

10. What are the steps…? Build the infrastructure Define the modules
Configure the bridge
Setup the flows
Configure the PW router
CMD-IN and CMD-OUT
Cross-connect

11. 1. Build the Infrastructure
We’re going to use the existing ERP ring
See appendix for CLI scripts to build the ERP ring
The TP module will work with any infrastructure, here we are using it with a PSN based network

12. 2. Define the modules We will use one TP module in slot 3
Enter the following command in both MP-4100 units
configure slot 3 card-type alarm-relay tp
Give a few moments for this card to be recognized

13. Table of ERP ring VLAN numbers and Bridge ports (existing)
VLAN & Profile Name
Bridge Ports
Flow Name
Ingress
Egress 54
1, 2 & 3
MNG_in_A
CL-A/1
BP#1
MNG
MNG_in_B
CL-B/1
BP#2
MNG_router_in MNG_router_out
SVI 1 (to Router 1)
BP#3
100
1, 2 & 4
DATA_METH_A
DATA_METH
DATA_METH_B
DATA_METH_IO_1_1
ETH 1/1
BP#4
1000
1, 2
OAM_SF_TRIGGER_A
OAM_SF_TRIGGER
OAM_SF_TRIGGER_B

14. 3. Configure the bridge We’ll use Bridge #1 ports 1, 2 & 6, VLAN 400
configure bridge 1
port 6
no shutdown
exit
vlan 400
tagged-egress 1,2,6
exit all
configure port svi 3 no shutdown

15. 4. Set up the Flows Setup the Classifier Profile TP_PW
configure flows classifier-profile TP_PW match-any match vlan 400
Your task: Setup the following flows (use reverse-direction for Physical ports)
VLAN & ClassifierProfile Name
Bridge Ports
Flow Name
Ingress
Egress
400
1, 2 & 6
TP_PW
CL-A/1
BP#1
TP_PW_B
CL-B/1
BP#2
TP_PW_router_in
TP_PW_router_out
SVI 3
BP#6

16. 5. Set up the PW Router MP-A MP-B
configure router 2 interface 2 address /24
configure router 2 interface 2 bind svi 3
configure router 2 static-route /24 address
configure peer 2 ip
MP-B
configure router 2 interface 2 address /24
configure peer 2 ip

17. 6. CMD-IN and CMD-OUT – ODD Groups
We’ll use MP-A as the ‘source’ of the signal
MP-A:
configure port cmd-in 3/1 no shutdown
configure port cmd-in-i 3/1/1 trigger-bind 1 cmd-in 3/1
configure port cmd-in-i 3/1/1 no shutdown
configure port cmd-channel 3/1 trigger-mode security-optimized
configure port cmd-channel 3/1 tx-address 101
configure port cmd-channel 3/1 rx-address 102
configure port cmd-channel 3/1 rate 64
configure port cmd-channel 3/1 no shutdown
configure port ds1 3/1 no shutdown

18. 6. MP-B is the ‘receiver’- EVEN groups
configure port cmd-out-i 3/1/1 no shutdown
configure port cmd-out 3/1 trigger-bind 1 cmd-out-i 3/1/1
configure port cmd-out 3/1 no shutdown
configure port cmd-channel 3/1 trigger-mode security-optimized
configure port cmd-channel 3/1 tx-address 102
configure port cmd-channel 3/1 rx-address 101
configure port cmd-channel 3/1 rate 64
configure port cmd-channel 3/1 no shutdown
configure port ds1 3/1 no shutdown

19. 7. Configure the PWE and complete the X-Connect
configure pwe pw 2 type ces-psn-data psn udp-over-ip
peer 2
label in 2 out 2
no oam
tdm-payload size 1
jitter-buffer 2500
exit all
############################################################
######## Cross connect ########
configure cross-connect ds0 ds1 3/1 ts 1 cmd-channel 3/1
configure cross-connect pw-tdm pw 2 ds1 3/1 time-slots 1
And finally:
commit
save

20. Review of the steps Build the infrastructure Define the modules
Configure the bridge
Setup the flows
Configure the PW router
CMD-IN and CMD-OUT
Cross-connect

21. Testing the setup and Success Criteria

22. Test Procedure Checking the Distance Teleprotection functionality
Action
Expected Result
Pass/Fail
Open the shelf-view
On the Agent: open the TP card (TP>Configuration>Zoom)
On both MP-A & MP-B:
Check status of the LED CMD IN 1, IN-i 1/1, Channel 01 and DS1-1
EVEN groups look for CMD OUT 1, OUT-I 1/1, Channel 01 and DS1-1
LED should be Green
PASS
On MP-A:
Force Active on cmd-in 3/1
On MP-B CMD OUT 1 LED turns to RED
On MP-B:
On MP-A CMD OUT 1 LED turns to RED

23. Let’s test it Open the shelf-view
On the Agent: open the TP card (TP>Configuration>Zoom)

24. Testing – MP-A Here’s the open module:
Verify that CMD IN 1, IN-i 1/1, Channel 01 and DS1-1 are GREEN
EVEN groups look for CMD OUT 1, OUT-I 1/1, Channel 01 and DS1-1

25. Testing – MP-B Here’s the open module:
Verify that CMD OUT 1, OUT-i 1/1, Channel 01 and DS1-1 are GREEN
EVEN groups look for CMD OUT 1, OUT-I 1/1, Channel 01 and DS1-1

26. MP-A test – result on MP-B
Force Active on cmd-in 3/1 and verify that CMD OUT 1 LED on MP-B turns to red:

27. Verify that Fault>Port Alarms on MP-B reports Major Alarm

28. Event Browser
EMS>Event Browser and check that events are shown as Active Alarms
Go to MP-A and disable the force-active command on CMD IN 3/1
Verify that CMD OUT 1 LED on MP-B turns green
Verify that events are cleared from Active alarms and shows as cleared in History Alarms

29. Challenge
Force an alarm from MP-B to MP-A

30. Appendix A Setup Script

31. CLI scripts for ERP setup
Setup the ETX-220
Setup the first MP
Setup the second MP

32. MP-A – script
exit all
################ MP-A #######
######## Teleprotection #######
######## ########
################################################################
configure slot 3 card-type alarm-relay tp
configure bridge 1
port 6
no shutdown
exit
vlan 400
tagged-egress 1,2,6
#################################################################
######## Flows ########
configure flows classifier-profile TP_PW match-any match vlan 400
############################# TP_PW FLOW_ERP ######################
configure flows flow TP_PW classifier TP_PW
configure flows flow TP_PW no policer
configure flows flow TP_PW ingress-port ethernet cl-a/1
configure flows flow TP_PW egress-port bridge-port 1 1
configure flows flow TP_PW reverse-direction queue 0 block 0/1
configure flows flow TP_PW no shutdown
configure flows flow TP_PW_B classifier TP_PW
configure flows flow TP_PW_B no policer
configure flows flow TP_PW_B ingress-port ethernet cl-b/1
configure flows flow TP_PW_B egress-port bridge-port 1 2
configure flows flow TP_PW_B reverse-direction queue 0 block 0/1
configure flows flow TP_PW_B no shutdown
SVI ports ######################
configure port svi 3 no shutdown
################## ROUTER FLOW ###########################
configure flows flow TP_PW_router_in classifier unaware
configure flows flow TP_PW_router_in no policer
configure flows flow TP_PW_router_in vlan-tag push vlan 400 p-bit fixed 7
configure flows flow TP_PW_router_in ingress-port svi 3
configure flows flow TP_PW_router_in egress-port bridge 1 6
configure flows flow TP_PW_router_in no shutdown
configure flows flow TP_PW_router_out classifier TP_PW
configure flows flow TP_PW_router_out no policer
configure flows flow TP_PW_router_out vlan-tag pop vlan
configure flows flow TP_PW_router_out ingress-port bridge 1 6
configure flows flow TP_PW_router_out egress-port svi 3
configure flows flow TP_PW_router_out no shutdown
#################### END FLOW ###########################
########################################################
######## Router CONFIGURATION ########
configure router 2 interface 2 address /24
configure router 2 interface 2 bind svi 3
configure router 2 static-route /24 address
configure peer 2 ip

33. MP-A – script part 2
######### CMD-in and DS1 on TP #######################
configure port cmd-in 3/1 no shutdown
configure port cmd-in-i 3/1/1 trigger-bind 1 cmd-in 3/1
configure port cmd-in-i 3/1/1 no shutdown
configure port cmd-channel 3/1 trigger-mode security-optimized
configure port cmd-channel 3/1 tx-address 101
configure port cmd-channel 3/1 rx-address 102
configure port cmd-channel 3/1 rate 64
configure port cmd-channel 3/1 no shutdown
configure port ds1 3/1 no shutdown
#####################################################
##### TP_PW ces-psn-data psn udp-over-ip ########
#######################################################
configure pwe pw 2 type ces-psn-data psn udp-over-ip
peer 2
label in 2 out 2
no oam
tdm-payload size 1
jitter-buffer 2500
exit all
##### Cross connect ########
configure cross-connect ds0 ds1 3/1 ts 1 cmd-channel 3/1
configure cross-connect pw-tdm pw 2 ds1 3/1 time-slots 1
commit
save

34. MP-B – script part 1 exit all ########### MP-B ########
####### Teleprotection ########
#############################################
configure slot 3 card-type alarm-relay tp
configure bridge 1
port 6
no shutdown
exit
vlan 400
tagged-egress 1,2,6
####################################################
######## Flows ########
configure flows classifier-profile TP_PW match-any match vlan 400
########### TP_PW FLOW_ERP ###########################
configure flows flow TP_PW classifier TP_PW
configure flows flow TP_PW no policer
configure flows flow TP_PW ingress-port ethernet cl-a/1
configure flows flow TP_PW egress-port bridge-port 1 1
configure flows flow TP_PW reverse-direction queue 0 block 0/1
configure flows flow TP_PW no shutdown
configure flows flow TP_PW_B classifier TP_PW
configure flows flow TP_PW_B no policer
configure flows flow TP_PW_B ingress-port ethernet cl-b/1
configure flows flow TP_PW_B egress-port bridge-port 1 2
configure flows flow TP_PW_B reverse-direction queue 0 block 0/1
configure flows flow TP_PW_B no shutdown

35. MP-B – script part 2 ####### SVI ports ########################
configure port svi 3 no shutdown
########## ROUTER FLOW ###################
configure flows flow TP_PW_router_in classifier unaware
configure flows flow TP_PW_router_in no policer
configure flows flow TP_PW_router_in vlan-tag push vlan 400 p-bit fixed 7
configure flows flow TP_PW_router_in ingress-port svi 3
configure flows flow TP_PW_router_in egress-port bridge 1 6
configure flows flow TP_PW_router_in no shutdown
configure flows flow TP_PW_router_out classifier TP_PW
configure flows flow TP_PW_router_out no policer
configure flows flow TP_PW_router_out vlan-tag pop vlan
configure flows flow TP_PW_router_out ingress-port bridge 1 6
configure flows flow TP_PW_router_out egress-port svi 3
configure flows flow TP_PW_router_out no shutdown
############ END FLOW ###############
#########################################
####### Router CONFIGURATION ########
######################################
configure router 2 interface 2 address /24
configure router 2 interface 2 bind svi 3
configure router 2 static-route /24 address
configure peer 2 ip

36. MP-B – script part 3 ##### CMD-out and DS1 on TP #################
configure port cmd-out-i 3/1/1 no shutdown
configure port cmd-out 3/1 trigger-bind 1 cmd-out-i 3/1/1
configure port cmd-out 3/1 no shutdown
configure port cmd-channel 3/1 trigger-mode security-optimized
configure port cmd-channel 3/1 tx-address 102
configure port cmd-channel 3/1 rx-address 101
configure port cmd-channel 3/1 rate 64
configure port cmd-channel 3/1 no shutdown
configure port ds1 3/1 no shutdown
##################################################
#### TP_PW ces-psn-data psn udp-over-ip ########
###################################################
configure pwe pw 2 type ces-psn-data psn udp-over-ip
peer 2
label in 2 out 2
no oam
tdm-payload size 1
jitter-buffer 2500
exit all
###########################################
####### Cross connect ########
#############################################
configure cross-connect ds0 ds1 3/1 ts 1 cmd-channel 3/1
configure cross-connect pw-tdm pw 2 ds1 3/1 time-slots 1
commit
save

37. Appendix B Overview of Teleprotection

38. Purpose of Teleprotection
The idea of teleprotection is - when a failure in a high voltage line happens (Shortage, overload, interruption …):
First: to isolate the relevant segment as quickly as possible from the network to prevent a domino affect
Then: to adjust relevant components in the network to work under the new status (without the disconnected circuit) as soon as possible

39. Teleprotection Process
The measuring transformers take samples of the 50 Hz signal and deliver them using “Sampled Values” messages to the protection relay
The protection relay analyses this information and makes decisions on whether to trip the line or not
The Trip decision is translated to 250VDC signal
0 - the line is OK
1 - there is a fault, trip the line

40. Distance Protection
A non-circuit protection whose operation and selectivity depend on local measurement of electrical quantities from which the equivalent distance to the fault is evaluated by comparing with zone settings
This signal is generated externally to the MP
As soon as the signal is received the local TP module acts
Passes signal to CMD channel (where configured)
Shows LED activity
Stores and records history via management network

41. Teleprotection Types Distance Relay protection
Measures the impedance on the line – RTU signals in DC voltage
Differential Teleprotection
Analyses the current on an HT line and trips if there is a change
Signals are carried in IEEE C37.94 (on fiber)

42. Automation – second stage
Allows remote control of the devices
Redirect the power to allow continuance of supply

43. Distance TP and the Relays
Referring to the diagram below, and assuming TP alarm relays at each location with 2 relays at location B & C (one for each direction)
A break between B & C shows on the relay at B pointing towards C and on the C relay pointing towards B
BUT it also shows on the relay at A – as the HT line is a continuous line
The relay at B pointing towards A tells the A relay that no action is required – as it has not sensed the alarm in the direction of A
Location A
Location B
Location C
Location D

44. Substation Typical Application
Telecom Control Center
Substation C
Substation B
NMS
Substation A
Communication House
E1/SDH/PSN
Network
Megaplex-4100/4
Controlling
Station
SDH/E1/ETH
GPS
Control Center
SCADA Controller
HSF OP
IEEE C37.94 FO
LAN (IEC ) TP OP OP TP
MP-4100/4
MP-4100/4
RTU TP
RTU TP
OP – OP-108C, Megaplex Module with Optical Link, 4 x E1 + FE
HSF – Megaplex Module with 2 x C37.94 Ports
TP – Megaplex Teleprotection Module
RTU
RTU
RTU
Relay/Control Enclosure

45. What are the Challenges in TP
Missed Commands & Unwanted Commands
A Missed Command is a signal that does not get noticed
An Unwanted Command is a command that does not originate in the high tension network
Causes could be:
Noisy input
Noisy communications link
Results are loss of electrical supply when this was not required
Teleprotection reaction times

46. Unwanted Commands and Security
An Unwanted Command is a command that is not generated by a signal – but by noise
The Probability of an Unwanted Command is called Puc
The Security of the teleprotection system is defined as 1- Puc
Puc is tested using burst of random errors as defined by the standard IEC
“for a digital system, the theoretical value of Puc is normally very low…..acceptable to make an analytic proof of Puc…”

47. Analytic Proof of Puc Taken from IEC 60834-1 Annex C
If n=number of bits in guard/trip word
If x=no of bits different between guard word & trip word
If p=Bit Error Rate (BER) (can be between 0 and 1)
If q=probability that a bit will be received correctly (q=1-p)
Probability of x bits being corrupted=p^x
Probability that only these bits are corrupted and the rest arrive ok=p^x.q^n-x)
If the trip/guard word needs to be received r times
Then Puc = [p^x.q^(n-x)]^r
Substituting p for q (recall that q=1-p) we get Puc = [p^x.(1-p)^(n-x)]^r

48. Using real numbers in the Puc
If n=number of bits in guard/trip word = 32 (8 bits x 4 )
If x=no of bits different between guard word & trip word
= 8 bits (1 per CMD channel port plus 1 redundant checkbit)
If p=Bit Error Rate (BER)
= 0.01 (10% = 10^-2)
If the trip/guard word needs to be received r times
In the MP, r = 3
Remember: Puc = [p^x.(1-p)^(n-x)]^r
So Puc = [0.01^8.(1-0.01)^(32-8)]^3
= [0.01^8.(0.99)^(16)]^3
= e-49 - extremely small!!
So the Security (=1-P) is very nearly 1 !!

49. BER – Bit Error Rate Assuming data rate of 2000 frames/second
BER = E-3 : Expected time until DETECTION MODE passes an error (4 errors in one byte) E6 seconds = 82.7 days
BER = E-4: Expected time until DETECTION MODE passes an error (4 errors in one byte) E10 seconds = 567 years
BER = E-6: Expected time until DETECTION MODE passes an error (4 errors in one byte) 1.79E18 seconds > 56 million years

50. Missed Commands and Dependability
A Missed Command is a command that should have been transmitted but was not (due to the teleprotection system failure)
The Probability of a Missed Command is called Pmc (where P varies between 0 – no missed commands and 1 (all commands are missed)
The Dependability is defined as 1 – Pmc (the inverse of the Probability)

51. Missed Commands PMC– test at RADTP Tx
MP-4100 #1 Rx
MP-4100 #2
ML-8E1
System under test E1
Binary Symmetric Channel with BER Control
ABB AES TEST BOX
Emulation of Commands
BER Generator
Counter of Lost
Commands Q-ty
In tests at RAD, the option selected was Security Optimized
Each test was run 4 times for each signal (so N was 4 x 4 = 16)
The following results table was created:
Bit Error Rate
Commands transmitted (CTX)
Commands received (CRX)
Percentage of loss (CTX-CTR/CTX)%
Pass or fail
10-E3
N x 65530
N x 65528 %
Pass
10-E4
0.0%
10-E5

52. Fault clearance times

53. Appendix C The Megaplex TP module

54. Teleprotection Module
4 input commands
4 primary output commands
4 secondary output commands
For each secondary command one primary command can be selected.
More than one secondary command can be bounded to one primary command
The RX/TX processing for each of the commands is independent, no mutual influence between commands
MP-4100
MP-4104
# of modules 10 4
# of input commands 40 16
# of output commands 80 32

55. Command Input/Output Electrical Characteristics
Input – DC Voltage
Output Relays - The output circuit will sustain at least 250V, 0.25A on an inductive load.
Connector (fits on the front of the card) - The terminal output allows connecting wires up to 2.5 sq. mm
Taken from the IEC standard
Nominal Input Control voltage (Jumper controlled)
+/-220VDC or +/- 110VDC  .
Input control voltage point for 220VDC
Below 160VDC = OFF
Above 176VDC = ON
Input control voltage point for 110VDC
Below 80VDC = OFF
Above 88VDC = ON
Input control voltage preset duration time (filter) adjustable
0-100ms in steps of 0.5ms.

56. CLI and the TP module
All ports (including physical and command channels) need to be made active
Use the no shutdown CLI command for this
Failure to perform this command leaves the channel in the inactive state
Useful if you don’t want to generate certain alarms
Part of all CLI scripts

57. Command Input Parameters – digital output pulse
Value Range
preset duration
0-100 msec
bounce override
0 to msec
input-active 
High/Low
force-active
Bounce Override: If a signal is sensed for 90% (or more) of this preset time – then the TP card will accept this as a true signal
Preset Duration: having accepted this as a true signal, this is the minimum length of the output signal from the TP card. If the input pulse is shorter than the preset duration, the command will be extended to the preset duration time. If the input pulse is longer than the preset duration, the command length will be the length of the input pulse

58. Input-active
Force-active – allows the user to force the output to high
Input-active – defines how the TP card reacts to an input
If the input is high –then the default output is high
If we set input-active to low – then when the signal STOPS the output will go HIGH
Can be used to check the comms link:
On one signal line set input active to LOW (no signal needed)
This means that the Input to the network (the CMD-IN-I) will be set HIGH
If the line fails, the remote received input will drop, the output becomes active (=HIGH) and an alarm is generated

59. Command Output parameters front panel relays
Value
prolongation
0 to 100msec
alarm-state-energized
yes/no
Prolongation - defines the length of the output pulse
If the input pulse is shorter than the prolongation, the command will be extended to the prolongation time. If the input pulse is longer than the prolongation, the command length will be the length of the input pulse

60. CMD-Channel Parameter Value trigger-mode speed-optimized
security-optimized
rate
64kbps/128kbps
Tx/Rx-address
1-254
Trigger-mode – speed-optimized = faster response
Security optimized = check 3 frames before sending the command
Rate – normally we use 64kbps
Tx/Rx address – this is the address of this TP card in the network. Ensures that TP CMDs go to correct destination

61. Security and speed optimized
Speed optimized – first correct frame with new trip value will be forwarded to trip cross connect
Security optimized - The new trip value shall be stable for at least 3 frames
Security optimized adds additional 1.5 msec latency

62. LED functionality Command IN/OUT:
No Alarm State Green
Alarm State Red
Shutdown OFF
LED is “ON” as result of event and “OFF” automatically or cleared by user (can be latched by the event)
CMD Channel:
Sync Green
RAI/LOS/Address mismatch Red
Shutdown OFF
RAI – Remote Alarm Indication
LOS – Loss of Sync

63. Communication Channel Frame
TS#1 Frame# n
TS#1 Frame# n+1
TS#1 Frame# n+2
TS#1 Frame# n+3 1 2 3 4 5 6 7 8 …
TDM Frame alignment
Address field to prevent wrong switching of the timeslot. Rx Address compared to expected Tx
Command bits
CRC for the Commands
Time stamp for latency check **
CPU communication channel (SCC in CPU with HDLC)
FP, Fault propagation – used to indicate network failure. Shall be “0”
RAI – Remote alarm Indication. RX Sync loss or continuous Address mismatch
ACT, Active – “1”, Non active – “0”. This bit indicates if this bundle is Active/Standby
Spare Bits
** The Time Stamp provides continuous monitoring of the channel latency – recorded on the status fields

64. Communication Channel fields
Frame alignment- The frame alignment is based on TDM sync machine. One bit used for byte synchronization.
All 4 Command bits are protected with 4 CRC bits
Address Authentication, upon mismatch on Address field:
Frame is discarded.
Alarm is raised and counted
Command outputs maintain previous value.
CPU Communication channel synchronization is separate from TDM sync, allows additional channel monitoring tool

65. Communication channel
Two independent channels (cmd-channel) per module.
The rate of each channel can be selected (either 64kbps or 128kbps)
Each channel can be configured with redundancy
Redundancy of each channel can be configured to revertive or non revertive mode

66. Command Channel
Criteria for bringing up the Command Channel – Ready for service:
Sync, Remote Sync, Address, CRC
Command Channel Monitoring
Error frame:
Sync bit error
Address Mismatch
CRC Error
Out Of Service Command Out-i (single signal)
On (continuous ON)
Off (continuous OFF)
Last Valid State
Serial bundle rate
Loss Discovery Time
64kbps
1.5 msec
128kbps
0.75 msec

67. Command Channel Protection
Protection switching is based on following indications:
H/W detection of Sync Loss (High BER)
S/W decision (Low BER)
Protection switch over from Active to Standby CMD channel in less than 10 msec (effected by HW in the module)
Remote Sync Loss (This indication for protection switch over ensures symmetrical communication between nodes)

68. Latency over PDH
The E2E latency over PDH (E1/SDH) line is under 2.5 msec
The latency does not include:
Input trip filters:
bounce override
preset
Output Latch
command prolongation
Round trip latency is shown in ‘show status’ in cmd-channel
Round trip starts from lower Tx address
Status is only shown from the one side
The other side will show round trip of 0 msec

69. Continuous Latency Measurement
Latency measurement is done per working and protection Command Channel (total four engines)
Latency check is done in HW based on dedicated bits in the TP frame
One side is originator and opposite side echoes the bits back
The difference between Rx and Tx values is the actual channel latency calculated by originator

70. Network Topology
No matter what the infrastructure (SDH, PSN, PDH) the MP TP card provides a solution

71. Trip cross connect block

72. Explanation of the Trip x-connect block
The card accepts up to 4 local signals, and can output up to 8 local signals (4 primary and 4 secondary)
There are 6 command channels each supporting 4 signals
These are used for remote comms
A channel can be routed to another TP card (using the Tx/Rx address field)
Each command channel has an assigned back-up channel
Channel 1 is backed up by channel 2
Channel 3 is backed up by channel 4
The last two channels are used for input to the TP card
There are always more inputs than outputs

73. Why do we need all this connectivity?
We need to have more inputs than outputs
Automation function may generate commands
Commands may need to go to more than one destination
For example – a T junction effect
A signal from a network port, arrives at the local port and has to exit there while also continuing to the next node

74. What happens to the signal
Referring to the diagram, an input signal (from an RTU) can be routed to any other location where the junction is shown as an ‘o’.
Input signals can only be routed to command channels (not to local outputs), while command channel input signals can be routed to both local output and other command channel output
Any input signal can control up to 5 output signals

75. Trip cross-connect in the TP module
Output from the network
Input from the RTU
Secondary local output
Input to the network
Primary local output (to RTU) and LEDs

76. Event Reporting
The event recording is done in the module including time stamping to allow accuracy of 1 msec
The MP accepts the GPS time via IEC or SNTP
SNTP = Simple Network Timing Protocol