CIGRE Study Committee B5
Preferential Subject 2
Specification and Evaluation of Substation
Automation Systems
Session Summary
Steven A. Kunsman
Special Reporter
Calgary, Canada (15-Sept-2005)
Steven A. Kunsman (USA)
CIGRE Study Committee B5
Session Summary
Preferential Subject 2 addresses Substation Automation
(SA) Systems specification and bid evaluation process
Fourteen questions related to five main categories:
Process and experience of SA Systems Specifications
Privatization impacts on infrastructure and specifications
First experiences with IEC 61850 based specifications
Applications and test methods of SA Systems
Trends in SA Systems (functional consolidation)
Steven A. Kunsman (USA)
CIGRE Study Committee B5
Process and experience of SA Systems Specifications
Question 2-1: The specification process depends on input from many users of the SA
System. How does the specification team value this user input and rank prioritization
of the requirements? How should lower priority requirements be stated in the
specification since these requirements may easily be fulfilled by the technical solution
at minimal cost?
Identification of essential requirements
Functionality, architecture, performance and given constraints
Definition of functional requirements to identify basic
requirements (“what” and not “how”)
Hard requirements for Factory Acceptance Test (FAT)
Use of internal knowledge and experience to set priorities
Mentorship of human knowledge
Common sense to keep simple
Decomposition of existing “how” to develop new “what”
Develop weighting factors to divergent requirements
Recommendation that weighting factors should be pre-defined in
Steven A. Kunsman (USA)
CIGRE Study Committee B5
Process and experience of SA Systems Specifications
Question 2-2: As mentioned earlier, the bid tender evaluation process
recommendations have been made in the B5-201 paper and guideline. What are the
experiences in the utilities with the tender evaluation process? Are structured and
formalized processes used?
Tender evaluation structured
Some utilities process regulated (EU directive, Official Journal)
Prequalification of vendors
Examination of the proposal for
Technical content to requirements, supplier service capability
Post-tender clarification essential to resolve uncertainties
Comparison done by valuing the solution/cost for each proposal
Examination of bid for optional requirement fulfilment to make
Penalty for requirement exclusions/exceptions
Homologation of IEDs to simple the evaluation process
Evaluation of vendor solutions may be difficult since multiple technical
solutions can fulfil requirements – tool automation of process possible
Steven A. Kunsman (USA)
CIGRE Study Committee B5
Process and experience of SA Systems Specifications
Question 2-3: Along with the capability of new technologies, specification and
engineering of substation automation systems will also be influenced by new standards
like IEC 61850. How does the introduction of IEC 61850 logical nodes and devices
impact the specification and engineering process? Will utilities allow for the free
allocation of functional elements in different logical devices to maximize component
costs savings?
No impact on functionality and constraints (NCC connection)
Impacts from IEC 61850 based
Free allocation of function (could require utility philosophy
Use of self-description and Substation Config. Language
Process interface (“hard”wire to “soft”wire)
Reliability and availability instead of system architecture
Specification remaining on a functional level permits high level of
freedom in the technical solution
IEC 61850 functions and architecture can be transparent to users
Use of the self description required by the standard can permit
Steven A. Kunsman
evaluation of solutions
CIGRE Study Committee B5
Privatization impacts on infrastructure and specifications
Question 2-4: The demand on the communication infrastructure will continue to
increase as the accessibility ease and additional valued information from the modern
SA System is consumed by the various utility departments demand. How should future
communication infrastructure utilization/expansion be included in the SA System
specifications? How can these additional costs justified?
Choice of Ethernet for SA LANs provides a high degree of flexibility and
Ethernet technology already at 1 GB
Switches preserve infrastructure via backward compatibility
Enables additional cost when additional capabilities are requested
WAN scalability more difficult and investment decisions should be based
on life cycle and future demands of the physical infrastructure
Possible separation of data users (operations, engineering, and SCADA)
Requires physical separation of the communication infrastructure
and cost are accepted to assure reliability and security
Steven A. Kunsman (USA)
CIGRE Study Committee B5
Privatization impacts on infrastructure and specifications
Question 2-5: One of the recommendations in the DE01-204 paper is the use of
commercial software for an open tool and especially web browser to review and change
IED parameters. Utility security is a major issue for systems as well as tools. As soon
as systems are connected the corporate Intranet or network, the security vulnerability
and threat potential increases. How should the security aspects of the SCS and SA
Systems be specified to provide the flexibility in use of commercial software (e.g. web
Commercial software can provide easy to use interface
Security aspects of such software utilization need to be considered
For example, Banking application are easy to use but major
infrastructure and costs to assure security are transparent to users
Security aspects are being addressed
IEC TC57 working on guidelines for web services applications
Communication network topology must account for different
access levels of the various users
IEC TC57 WG 15 work ongoing for security measures in all TC57
TASE.2, IEC 61850, etc
browser very prone to viruses unless not connected to “www’
Steven A.Web
Kunsman (USA)
CIGRE Study Committee B5
First experiences with IEC 61850 based specifications
Question 2-6: The CH01-203 paper states the key point for SA System Specification is
the requested functionality of the substation application and the utility operational
philosophies. This implies that the IEC 61850 “standard” does not mean a single or
standard solution is required to meet different utility requirements and operation
philosophies. How do the first IEC 61850-based technical solutions differ from utility to
First IEC 61850 system are upgrades of existing stations
Same functionality with new station bus (IEC 61850-8)
Turnkey systems controls the interoperability risk
Only scratching the surface of the IEC 61850 capabilities
Utility philosophy drives the differences like:
Interlocking over “hard”wire or “soft”wire (peer-to-peer
Station level or device level redundancy
System architect (utility or integrator)
IEC 61850 does not define standardized solution but only means to
fulfil a set of functional requirements
Steven A. Kunsman (USA)
CIGRE Study Committee B5
First experiences with IEC 61850 based specifications
Question 2-7: One of the IEC 61850 goals is vendor interoperability. The key point
referenced in Question 2-6 makes a strong statement that the standard’s goal on
interoperability means different vendor devices can be used to satisfy a utility’s
philosophy or solution. It does not imply that the possibility to interchange different
vendor devices into an already engineered solution. How do the first experiences
reflect on the interoperability goal? What are the key factors required in the SA System
specification to assure interoperability without losing post-engineered SA system
possibility to change vendor A to vendor B?
Minimal system re-engineering possible if:
Data available to support all SA applications
Continued standardization of object model extensions
Like functionality in device A and B
Only IED re-engineering required and system level okay
Use of smart tools using SCL files to automate process
Application performance is also important criteria
Preservation of the SCD (station SCL file) defining SAS functionality
IEC 61850 in 1st year – extensions and clarifications are being made
but released parts are stable
Steven A. Kunsman (USA)
CIGRE Study Committee B5
First experiences with IEC 61850 based specifications
Question 2-8: It is clear that the long desired benefits of an IEC 61850 SA System are
staring to be realized. For greenfield (new) substations, the specification based on IEC
61850 has and will demonstrate value. Reality is that the majority of the infrastructure
upgrades and expansions may involve operating a legacy SAS and a modern SAS in the
same substation for some transition period. As the AU01-201 paper points out, the
operation in co-existence is difficult and has additional costs. How shall the “hybrid”
or substation expansion project be specified to take advantage of the benefits of the
IEC 61850 while preserving the installed SAS functionality?
Possible to extend the legacy SAS or upgrade to new SAS
Hybrid system connected through proxy or protocol converter
Issues with “soft”wire interlocking (reaction time of conversion)
Legacy devices can be represented as virtual IEC 61850 device
Migration projects upgraded bay by bay to keep station operational
Migration of IEC 61850 based system in future shall be easier since
being based on a standard that was developed for future migration
Hybrid substations must consider operational issues & additional
costs of operating the mixed system
Steven A. Kunsman (USA)
CIGRE Study Committee B5
First experiences with IEC 61850 based specifications
Question 2-9: On similar thoughts, how can those utilities that will wait for proven
experience in IEC 61850 based system take advantage of the IEC 61850 concepts in
SAS specification as well as make sure their legacy system can be migrated to an IEC
61850 in the future?
RTE specification does not require IEC 61850 but welcome this
technical solution
Requirement defined on the functional level
Responsibility of the turnkey supplier to assure compliance to the
specification which addresses medium and long term maintenance
and future migration
Japanese market will wait until technology is proven before any
Functional specification can be presented as an SCL file
Represent legacy device in SCL files to future usage
IED selection made carefully to assure the device supports the legacy
protocol as well as ethernet based protocols
of protocol in IED
Steven A. Kunsman
CIGRE Study Committee B5
Applications and test methods of SA Systems
Question 2-10: In some of the papers, migration to functional specification and the
advancements in technology lead to complexity in the system making it very difficult to
test. The utility stated that they need to trust and will rely on the vendor to assure
functionality compliance in the devices and systems. It is also fact that IEC 61850-10
conformance does not include application or system level testing. How can the
features (e.g. Substation Configuration Language) be utilized to assure the maximum
test coverage and the SA Systems compliance to the functional specification?
Use of SCL is only a start to assuring maximum test coverage
IEC 61850-10 defines the requirements for device conformance
Use of SCL in the engineering process minimizes risk
Application to Application testing is required
Automated Test Systems (ATS)
System Verification Centers (SVC)
IEEE C37.115 can be utilized to assure maximum test coverage
Use of scenario test scripts and transaction sequences
SCL, ATS, SVC and IEEE C37.115 make it A-A OK!
Steven A. Kunsman (USA)
CIGRE Study Committee B5
Applications and test methods of SA Systems
Question 2-11: Can the application test scenarios defined in C37.115 be used to assure
maximum test coverage and provide validation of the SA System to the SAS
specification? If the SAS specification has different application requirements from
those defined in the C37.115 standard, how can the standard be used to accommodate
application variations?
Any approach requires a comprehensive description of
Components (or functions) under test
Test drivers and stimulus mechanisms
Operational scenarios
C37.115 recommends the following procedure for each test scenario
A power system control and protection functional description and
evaluation criteria
An object model of the participating IEDs
Transaction sequence representing operational situations
Issue: How to map to specific protocols – DNP, IEC 61850, etc.
Source: Holstein
Steven A. Kunsman (USA)
CIGRE Study Committee B5
Trends in SA Systems (functional consolidation)
Question 2-12: In many of the papers, the existing substation equipment is based on a
collage of technologies from discrete devices (electromechanical) and control systems
to proprietary SAS. How does one assure that SAS specification developed in 2005
allows for future solutions taking advantage of the continued SAS evolution and
functional consolidation?
Policy to upgrade complete station or single voltage level
Supplier’s choice in SAS architecture and interfaces
Introduction of IEC 61850 may facilitate this process
Expect vendors to maintain system for > 15 years
Hard to assure future advantage with 2005 specification
Changes in specification required as technology advances are
realizable (hardwire to cable-less substation)
Utility specify what level of technology (station bus, process bus, soft
protection and control) is accepted an in what time
Highly dependant on utility philosophy and risk adverseness
Steven A. Kunsman (USA)
CIGRE Study Committee B5
Trends in SA Systems (functional consolidation)
Question 2-13: How does the free allocation of functions according to IEC 61850
change the physical configuration of the SAS and its components?
Question 2-14: How does the continued trend in functional consolidation influence the
SA system engineering or re-engineering?
Continued technology advances will allow greater performance with
less hardware components
IEC 61850 free allocation of functions supports the advances in
technology like Soft Protection and Control
Economical factors will drive when such solution have
manageable risk versus reward
Issue with centralized system is the clear demarcation of the
functionality to provide isolation between the different utility entities
Communication barriers removal will promote further consolidation
Introduction of the process bus IEC 61850-9-2 will be an enabler
Steps towards global view are compatibility of IEC 61850 data
models and IEC 61968/1970 CIM model
Steven A. Kunsman (USA)
CIGRE Study Committee B5
Key Factors/Summary
Research and investigate the SA System requirements and
understand what is trying to be solved. Specify the “what” and not
the “how”.
Define requirements on functional level and try not specify
technical solutions. Technical solution can be compared and
evaluated during bid evaluation process.
Evaluation criteria needed for comparing different solutions
satisfying the same functional specification
IEC 61850 is a new standard for SA Communication
Architectures but also provides significant value in the SA System
project specification, design and validation phases
Use experiences provided by both utilities and vendors as
reference for future specification activities
Steven A. Kunsman (USA)
CIGRE Study Committee B5
Thank you
Congratulations for making it
through 1st Day of Sessions
Steven A. Kunsman (USA)

SC34 Status Report 1999