Clause 5 of IEC 61850-4 describes the engineering of a substation automation system (SAS) as three chained tasks: project design, parameterization and documentation. It classifies parameters by treatment into configuration parameters (changed offline) and operating parameters (changeable online), and by origin into system, process and functional parameters. It calls for three tools, for project design, parameterization and documentation, with flexibility, expandability and scalability, and for automatic documentation with unique signal identifiers.
What SAS engineering means
Part 4 of IEC 61850, in its 2002 edition 1, deals with system and project management. Its clause 5 defines the engineering of a substation automation system (SAS) as three tasks:
- Define the equipment configuration: which IEDs exist and how they relate to each other and to their environment.
- Adapt the functionality and signals to the customer’s operating requirements by means of parameters.
- Document all specific definitions: parameter set, terminal connections and so on.
The SAS consists of several IEDs that communicate with each other and interact with three environments: the telecommunication environment (control centers, subordinate systems, teleprotection), the local operator, and the process environment (switchgear, instrument transformers, auxiliaries). Teleprotection is outside the scope of the series. Typical IEDs are, for the telecommunication environment, gateways, converters, RTUs and relays; for the HMI, gateways, computers, workstations and IEDs with built-in HMI; and for the process, bay control units, relays, RTUs, meters, stand-alone controllers, transducers and digital instrument transformers.
How parameters are classified
Parameters are data that control and support the operation of the equipment configuration, the IED software, the process environment, the HMI and the telecommunication environment. The set of all SAS parameters is the SAS parameter set, made up of the used parts of each IED’s parameter set.
The standard classifies them in two independent ways:
| By treatment (category) | What they are |
|---|---|
| Configuration parameters | Define the overall behavior of the SAS and its IEDs. They are usually assigned during the initial parameterization and must be updated on an extension or functional change. They are generated and modified offline; the SAS may run in a restricted, temporary way while they are entered |
| Operating parameters | Define the behavior of partial functions. They must be changeable online, without restricting operation, within defined ranges. Protection functions combined with other functions in an IED must not be affected during that parameterization. They are loaded through the telecommunication interface, the HMI or the IED’s service interface |
| By origin (type) | What they describe |
|---|---|
| System parameters | The cooperation between IEDs: component configuration, communication procedure (protocol, speed), scope of the functions at station level, relations between data of different IEDs such as station interlocking or display on the single-line diagram, event texts and data flows to the HMI, printer, archive and telecontrol. They must be consistent throughout the SAS and validated with a general parameterization tool |
| Process parameters | All the information exchanged between the process and the SAS: double-point events, double commands, the relation between an event input and a command output, command transmission times, suppression of transient events (filter time) and damping of measured values (threshold) |
| Functional parameters | The qualitative and quantitative characteristics of the functionality the customer uses: regulator target values, protection pickup and trip conditions, automatic sequences, IED-level interlocking, and automatic control, protection and adjustment algorithms. They are normally changeable online |
Functional parameters are divided into switchable and non-switchable groups. Several groups of values can coexist in an IED, with only one active at a time; it must be possible to switch between them online. In practice this is what is known as setting groups.
Categories and types cross over: configuration parameters include system and process parameters; operating parameters include process and functional parameters, such as limit values, target values, command output times and switching sequence delays.
The engineering process
The standard describes it as a chain of three tasks, with process-signal and functionality checklists as input:
- Project design. The technology concept is defined: structure, IED configuration and interfaces to the process
- Parameterization. The source parameter set and the process data lists loaded into the SAS are generated
- Documentation. The equipment and parameter documentation of the project is produced
- Automation system. The IEDs end up with their configuration and parameters loaded
The three tools
The standard recognizes that, in practice, engineering tools make this work efficient, and that they may be designed according to the manufacturer’s philosophy.
Project design tool. It proposes the selection of components with their functions at the planning stage. It is normally database-driven and requires the needed process signals and functions to be entered; it answers with checklists that the integrator and the customer must agree on. The result defines the structure and configuration of the SAS, with its process interfaces.
Parameterization tool. It supports the creation of a consistent source parameter set for all IEDs. It may be split into a general tool, which manages system parameters at SAS level, and tools specific to each IED. Its main tasks are to generate the process data lists from the source set and manage them securely; it must be able to read the actual parameter values. It also supports management, archiving and documentation of the source set. Its input module must be structured according to the substation architecture: substation, voltage level, bay, equipment and information. The source set carries a unique identification that includes the substation, the parameterization status (initial or modification), the operator, the access authorization, the date and the software versions of the IEDs and of the tool.
Responsibilities in parameterization, according to the figure in the standard: the customer is responsible for the process, functional and operating parameters; the integrator, for the requirements and the system parameters.
Documentation tool. It generates uniform, project-specific documentation in line with the required standards (IEC 61175, 60848, 61346 and 61082). It includes equipment documentation, which shows the external connections between the SAS components and the process, and parameter documentation, which shows the internal relations agreed during parameterization. It should be able to generate a difference list with the changes it knows about.
Flexibility, expandability and scalability
- Flexibility and expandability: they require being able to extend the equipment configuration with more IEDs or IEDs of different functionality, and depend on the tools, above all the parameterization tool.
- Scalability: the parameterization tool should serve all applications of a product family: transmission or distribution networks, voltage range (medium, high, extra high), level of integration (from a simple telecontrol unit to an integrated control, monitoring and protection system with distributed intelligence), complexity of functions and telecommunication functions. It must be extendable in steps so that the work at each level uses minimum resources and cost. It should also support rationalization with macros and copy functions.
Automatic project documentation
The documentation has two components: equipment documentation (circuit diagrams, signal list, functional diagrams of external schemes) and parameter documentation (configuration list, signal list, parameter lists, graphic representation of screens and menus, and functional diagrams of internal functions). The link between the two is the signal list, which must have unique, uniform identifiers in both documents. Automatic generation must ensure consistency between the documentation, the project checklists, the source set and the process data lists.
The configuration list is the starting point of the parameter documentation, together with the single-line diagram: it gathers the IEDs and components with their hardware and software versions, the parameterization tool version and the identification of the parameter set. For process parameters the standard lists typical documents: signal lists, telecontrol mapping lists (signal to protocol address), message text lists, characteristic curve lists, HMI lists, archive lists and acquisition lists, with attributes such as binary-input filter times or command times. Functional parameters are documented in lists and in function block diagrams.
What to do with this in a project
- Distinguish which parameters the customer changes in operation and which are configuration parameters that require offline intervention.
- Keep a single signal list with unique identifiers, from which the drawings, the parameterization and the tests are derived.
- Record the version of the parameter set, the programs and the devices at every change. See SCL files.
- Know the engineering workflow your integrator uses: top-down and bottom-up engineering and the system configurator.
Secondary engineering with Tiza Group
Need to organize the signal list, parameters and documentation of your IEC 61850 project? At Tiza Group we do it as part of our secondary engineering, at medium, high and extra-high voltage, in substations and industry, delivered remotely.
Related guides
- SCL files in IEC 61850
- IEC 61850 engineering: top-down and bottom-up
- IEC 61850 system configurator
- IEC 61850: what it is, parts of the standard and data model
- IEC 61850-4 system life cycle and quality
- IEC 61850 glossary: acronyms and terms of the standard
References
- IEC 61850-4 (edition 1, 2002): system and project management, clause 5.
Frequently asked questions
What is the difference between a configuration parameter and an operating parameter?
Configuration parameters define the overall behavior of the system and its IEDs, are assigned during the initial parameterization and are generated or modified offline, that is, without normal system operation. Operating parameters define the behavior of partial functions and must be changeable online, without restricting operation and within defined value ranges.
What is the source parameter set and what is it for?
It is the consistent set of parameters for all IEDs that the parameterization tool generates. It is the basis for producing the process data lists loaded into the system, for archiving and controlling changes, and for generating the documentation. It carries a unique identification with the substation name, parameterization status, operator, authorization, date and software versions.
Does the standard require a particular manufacturer's tool?
No. Part 4 says engineering tools may be designed according to the manufacturer's philosophy. What it requires is their functions: selecting components and functions, generating and managing parameters securely, and producing uniform project documentation. Exchange between tools from different manufacturers is handled by the configuration language of Part 6.