1. ANALYSIS OF SUBSTATION
AUTOMATION SYSTEM BASED ON IEC
61850 USING TOPCAL SOFTWARE
A thesis submitted by
UMAIR ABBASI 12EL47
Supervised by:
PROF. DR. ASHFAQUE AHMED HASHMANI

2. CONTENTS
1. Introduction
2. SAS architecture overview
3. SAS HMI commissioning
4. SAS functional configuration
5. SAS availability calculation
6. Conclusion and recommendation

3. INTRODUCTION
• SAS is used for
1) Protection
2) Monitoring
3) Communication
4) Control
• Hardwired control has been used in the past in earlier
versions of SAS utilizing simple communication methods.
• Subsequently IEC61850 has been applied widely in SASs
around the world.

4. OVERVIEW OF SUBSTATION AUTOMATION
SYSTEM (SAS)
Background
• Began in the 1980‘s
• Communications within substations was established between
2003 to 2005
• A major break-through has been achieved with the application of
the Interoperability
• The new standard continues to have a large impact on the design
and implementation of SASs.

5. BASIC FUNCTIONS OF SAS
• Monitoring functions
• Control functions
• Recording functions
• Protection functions

6. COMPONENTS OF IEC-61850 BASED SAS
(a) Operator workstation:
• HMI (Human Machine Interface) is used to perform control
and monitoring operations for the entire substation.
Engineering tasks, such as database maintenance and relay
setting can be equipped in this HMI device.
(b) Station computer:
• The station computer is a substation server device providing
control and monitoring functions, a remote control centre
interface function, data recording function.

7. (c) BCU (Bay Control Unit):
• This is a multifunction control and monitoring unit equipped
with a control and monitoring function at bay level for a
single line.
• BCUs provided for each line.
• The BCU executes control processing in response to
commands from the operator workstation or remote control
centre under normal operational conditions.
SAS ARCHITECTURE OVERVIEW

8. • Ensure communication reliability by adopting a redundant
configuration of Ethernet switches
• Ensure redundant paths by adopting a ring topology.
• Ethernet switches on the IED side are common to several IEDs.
SAS ARCHITECTURE OVERVIEW

9. SAS HMI COMMISSIONING
• The HMI is an important component of substations.
• In most technologies the capabilities of HMI are dependent
not on the technology used but also on the capabilities and
budget allocated to the implementation team.
• The HMI usually starts with a representation of the single line
diagram of the station.

10. GENERAL SCREEN LAYOUT

11. Feeder Function IP address
Grid transformer
Bay control 172.16.3.1
Protection 172.16.3.2
Bus coupler A
Bay control 172.16.130.1
Protection 172.16.130.2
Bus section Bay control 172.16.120.1
Protection 172.16.120.2
Bus coupler B
Bay control 172.16.230.1
Protection 172.16.230.1
Grid Transformer 2
Bay control 172.16.4.1
Protection 172.16.4.2
Grid Transformer 3 Bay control 172.16.8.1
Protection 172.16.8.2
Common Alarm Annunciation Unit 172.16.0.2
SAS EQUIPMENT IPADDRESS

12. SAS FUNCTIONAL CONFIGURATION
• The operator has to execute a sequence of operation in steps to
control a switching device. A non-permissible operational step
will be rejected by system.
• Successful and unsuccessful execution of commands is
accompanied by suitable message in the event list with clear
indication of the switching device & cause.
• No more than one command can be executed in BCU at a time.
• For safety reasons a new command must not be released in the
same BCU before the previous one has been finished

13. SAS FUNCTIONAL CONFIGURATION
Redundancy is implemented to accommodate the
three major failure modes
• Hardware failure
• Communication line
• Data loss.

14. SAS AVAILABILITY CALCULATION
S.# Component Name MTTF(h) Component
1 HMI 87’600 Monitor, Keyboard
and Mouse
2 Station Computer 182’000 Industrial
Computer red
power supply and
with RAID
3 Switch for
IEC61850
474’289 AFS670 Switch
with redundant PS
4 BCU REC670 893’520 Bay Control Unit
for 132kV
5 BCU REF615 893’520 Bay Control Unit
for 13.8kV
6 Industrial Gateway
to NCC
182’000 Industrial
Computer red
Power Supply and
with RAID

15. The General system structure of 132/13.8kV substation

16. CALCULATION
MODEL
132 kV BCUs with
Switch Rings:
132kV BCUs with
switch ring consist of
IED with double
switch ring topology
First of all we make
availability diagram
for switch ring 1A
then switch 2A and
link both switch
rings in a common
reliability diagram
name as “Sum of
132kV”
Ethernet switches (1A) diagram of 132 kV
Ethernet switches (2A) diagram of 132 kV
Sum of 132 kV

17. 13.8kV BCUs have
only single Ethernet
switch ring topology
availability diagram
for 13.8kV switch
ring and link them to
another availability
diagram name as
“Sum of 13.8kV”
13.8kV switch ring
Sum of 13.8kV switch ring
13.8kV BCUs WITH SWITCH
RINGS

18. LOCAL STATION LEVEL
MODEL
GATEWAY(PCS):
Gateways are used
as remote terminal
unit, which has
functions to receive
a command from
central control unit
and also transport
signal from
substation to central
control center

19. COMPLETE SAS
Diagram are shown,
they are with link
station level, gateway
in parallel and sum of
132kV, sum of 13.8kV
diagram in series

20. SYSTEM SIMULATIONS
MTTF CONSIDERING 30
FEATURES
MTTF CONSIDERING 10
FEATURES
MTTF CONSIDERING 5
FEATURES

21. RESULTS
Considering different
numbers of IEDs
feature we get
following results
from above system
simulations model

22. ABOUT
SOFTWARE

23. CONCLUSION AND RECOMMENDATION
• The availability of 99.9850% obtained by repairing a
defective part within 6hours.
• Availability of 99.98% is mainly based on the redundant
parts in the system configuration.
• As we use less number of IED features the availability of
the overall system is increase and in the contra very as we
use large number of features the availability of the system
is decreases.

24. THANK
YOU
QUESTIONS?