1. Cigre SCB5 Colloquium
2005 September, Calgary Preferential Subject 2
Question 13
Stig Holst ABB Sweden

2. SC B5: PS2, Q 13 Allocation of functions
How does the free allocation of functions according to IEC change the physical configuration of the SAS and its components?
The functional integration will continue to increase:
Economical requirements are the main driving force
Technical development and improved performance of microprocessors makes it possible
The free allocation according to IEC supports it

3. Conventional protection and control system
Old conventional protection
Object level
Modern conventional protection
Object level
Often accepted today
One IED for one object
Large number of functions in each IED
All P&C functions for one object in one IED possible
Lower price/function
Some utilities still require separate IEDs for protection and control
Large number of protection equipments
One relay for each function
P&C P C

4. Increased functional integration
P&C functions for several objects in one IED
Different allocation of functions
Supported by IEC 61850
P&C 1
2 Z< E C
P&C 2
MAIN 1
MAIN 2
Protection and Control for 2 Lines in one IED
Protection for 2 lines + Control for 1 diameter in one IED

5. Soft P&C - Total functional integration
A Soft P&C is a system where all or most P&C functions in a station are integrated in one main computer – Requires a process bus
Standardized process bus – User requirement for acceptance of a Soft P&C system
IEC should be used
The Soft P&C system must fulfill all basic power system requirements
Dependability
Security
Availability
Duplication of the main computer and other components will often be necessary

6. Future P&C system
Totally integrated P&C system with centralized allocation of functions
Process bus
IEC
Soft P&C
Main comp
(AFL)
I/O
Control center
Control
building
P&C Application SW

7. Future P&C system - conventional design
P&C system with decentralized allocation of the same functions
P&C
Application SW
Control center
I/O
Station bus
IEC
AFL
Control
building

8. SC B5: PS2, Q 13 Allocation of functions
Conclusions
Future P&C product platforms will support both:
Totally integrated P&C system with centralized allocation of functions
Conventional P&C system with decentralized allocation of functions
The free allocation of functions according to IEC supports development of these P&C platforms