65th AMEU Convention2016 54 65th AMEU Convention 2016 The engineering and maintenance of a substation automation system has always been a complex process. Maintenance problems and cost are the most important points to take into account to evaluate a substation automation system. If the utilities are expected to invest in new technologies for the control of their substations based on the IEC 61850 standard the engineering must be easier and the operation and maintenance costs must be lower. But now with the amount of data in the IEC 61850 data models for the IEDs, the availability of powerful tools to manage all this information and configuration options is crucial. One of the IEC 61850 objectives is to reduce all the engineering process, including system specification, IEDs configuration, factory acceptance test and on-site installation. Another objective which must be taken into account is to facilitate the maintenance of these systems. To achieve those objectives a set of tools specifically designed for the IEC 61850 standard and data models becomes decisive to get the most out of the standard. Utilities have different strategies as far as maintenance is concern. Some utilities subcontract the maintenance and others assume it. In any case, one of the problems that the SAS maintenance responsible must face is the different tools that need to access to and configure the SAS. It’s a fact that each vendor supplies his own configuration tools but even in some cases there are different tools from the same vendor for different device families. Now that the IEC 61850 has standardised more aspects not only in the communication protocol but also in the definition of the configuration of a device, the objective of reducing the number of tools needed in the configuration and maintenance of a SAS should be kept in mind. If this reduction is achieved it will be mainly related with the use of the standard configuration file based in the XML that the IEC 61850 defines. IEC 61850 standard defines a hierarchical information model with a data naming that need to be understood in order to accomplish the engineering process. Besides, the data exchange among the different IEDs in the system may be done either using a point to point client-server communication profile or a point to multipoint publisher-subscriber profile. These data exchanges are configured during the engineering stage providing the data needed by the different IEDs: protective relays, HMI (human machine interfaces) or RTU (remote terminal units). Not all the users need to understand the details of the information model, any substation engineer will recognise immediately the concepts of a breaker, recloser or the ANSI codes as 51N, but the IEC 61850 standardised names as XCBR (breaker), RREC (recloser) or PIOC (over-current protection function) will only be understood after some practice working with the IEC 61850 standard. The use of engineering tools should try to join the concepts and terms with the IEC 61850 dictionary. The use of the descriptive information in the standard file format SCL (system description configuration language) can be used to perform this task. IEC 61850 engineering tools The engineering and maintenance of substation automation systems have always been complex processes, mainly in multi-vendor solutions. The goal of the IEC 61850 series is to provide interoperability between the IEDs from different suppliers or, more precisely, between functions to be performed by systems for power utility automation but residing in equipment (physical devices) from different suppliers. This also affects to the engineering tools that should be able to handle the configuration files of any IEC 61850 device. In a complete implementation of the standard all the device information should be modeled and available in the configuration files and with the IEC 61850 communication services. This includes the device settings, one feature than usually has been limited to the manufacturer’s software tool. This means that even though the usual practice for protections setting configuration is to use the manufacturer’s software, with IEC 61850 the configuration settings would be possible from any IEC 61850 client. Another characteristic that must be taken into account is the amount of data included in the IED’s data models. The IEC 61850 data model definition is based on hierarchical information models with logical devices, logical nodes, data objects and data attributes. Each data object may contain several attributes with value, quality, timestamp and description information. For protection devices with all the information modeled and available with the IEC 61850 protocol, the number of attributes in the data model may be the order of thousands and the size of the ICD/CID file may be the order of MB. Due to this requirement the engineering software tools must be designed to be able to handle this amount of information. Some of the characteristics that are desirable in an IEC 61850 engineering software tool are: l Import and export of normative configuration files (ICD files). l Graphical display of the information model either as a tree or a list of items with filter functionality. l Easy creation of complex information models with modeling based on drag and drop actions. l Internal repository of all the IEDs modeled. l Reusability of created types available. l Dictionary with the definitions included in the standard to improve the comprehension of the models. l Creation and modification of datasets and control blocks. l Quick assignments of initial values and descriptions. l Modular design. The document IEC 61850-6 describes the XML structure used for a common interchange among different tools. The XML information structure is divided into four sections identifying the substation topology, the communication networks, the IED information models and the data type templates used to build the information models. IEC 61850-6 identifies the different file formats that can be exchanged among the different tools. The following formats are described: l SSD: System specification description. This file describes the single line diagram and functions of the substation and the required logical nodes. l ICD: IED capability description. This file describes the functional and engineering capabilities of an IED type. Minimising the impact of IEC 61850 in new automation projects by Rodolfo Pereda and Aitz Amezaga, Ingeteam Power Technology This article describes the challenges that the use of IEC 61850 imposes on the different actors that which part in the various stages of the development of substation automation projects and how some of these challenges can be minimised using the appropriate tools.
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54 65th AMEU Convention 2016
The engineering and maintenance of a substation automation system has always been a complex process. Maintenance problems and cost are the most important points to take into account to evaluate a substation automation system. If the utilities are expected to invest in new technologies for the control of their substations based on the IEC 61850 standard the engineering must be easier and the operation and maintenance costs must be lower.
But now with the amount of data in the IEC 61850 data models for the IEDs, the availability of powerful tools to manage all this information and configuration options is crucial. One of the IEC 61850 objectives is to reduce all the engineering process, including system specification, IEDs configuration, factory acceptance test and on-site installation.
Another objective which must be taken into account is to facilitate the maintenance of these systems. To achieve those objectives a set of tools specifically designed for the IEC 61850 standard and data models becomes decisive to get the most out of the standard.
Utilities have different strategies as far as maintenance is concern. Some utilities subcontract the maintenance and others assume it. In any case, one of the problems that the SAS maintenance responsible must face is the different tools that need to access to and configure the SAS. It’s a fact that each vendor supplies his own configuration tools but even in some cases there are different tools from the same vendor for different device families.
Now that the IEC 61850 has standardised more aspects not only in the communication protocol but also in the definition of the configuration of a device, the objective of reducing the number of tools needed in the configuration and maintenance of a SAS should be kept in mind. If this reduction is achieved it will be mainly related with the use of the standard configuration file based in the XML that the IEC 61850 defines.
IEC 61850 standard defines a hierarchical information model with a data naming that need to be understood in order to accomplish the engineering process. Besides, the data exchange among the different IEDs in the system may be done either using a point to
point client-server communication profile or a point to multipoint publisher-subscriber profile. These data exchanges are configured during the engineering stage providing the data needed by the different IEDs: protective relays, HMI (human machine interfaces) or RTU (remote terminal units).
Not all the users need to understand the details of the information model, any substation engineer will recognise immediately the concepts of a breaker, recloser or the ANSI codes as 51N, but the IEC 61850 standardised names as XCBR (breaker), RREC (recloser) or PIOC (over-current protection function) will only be understood after some practice working with the IEC 61850 standard. The use of engineering tools should try to join the concepts and terms with the IEC 61850 dictionary. The use of the descriptive information in the standard file format SCL (system description configuration language) can be used to perform this task.
IEC 61850 engineering tools
The engineering and maintenance of substation automation systems have always been complex processes, mainly in multi-vendor solutions. The goal of the IEC 61850 series is to provide interoperability between the IEDs from different suppliers or, more precisely, between functions to be performed by systems for power utility automation but residing in equipment (physical devices) from different suppliers. This also affects to the engineering tools that should be able to handle the configuration files of any IEC 61850 device.
In a complete implementation of the standard all the device information should be modeled and available in the configuration files and with the IEC 61850 communication services. This includes the device settings, one feature than usually has been limited to the manufacturer’s software tool. This means that even though the usual practice for protections setting configuration is to use the manufacturer’s software, with IEC 61850 the configuration settings would be possible from any IEC 61850 client.
Another characteristic that must be taken into account is the amount of data included in the IED’s data models. The IEC 61850 data model definition is based on hierarchical information
models with logical devices, logical nodes, data objects and data attributes. Each data object may contain several attributes with value, quality, timestamp and description information. For protection devices with all the information modeled and available with the IEC 61850 protocol, the number of attributes in the data model may be the order of thousands and the size of the ICD/CID file may be the order of MB. Due to this requirement the engineering software tools must be designed to be able to handle this amount of information.
Some of the characteristics that are desirable in an IEC 61850 engineering software tool are:
l Impor t and expor t o f normat ive configuration files (ICD files).
l Graphical display of the information model either as a tree or a list of items with filter functionality.
l Easy creation of complex information models with modeling based on drag and drop actions.
l Internal repository of all the IEDs modeled.
l Reusability of created types available.
l Dictionary with the definitions included in the s tandard to improve the comprehension of the models.
l Creation and modification of datasets and control blocks.
l Quick assignments of initial values and descriptions.
l Modular design.
The document IEC 61850-6 describes the XML structure used for a common interchange among different tools. The XML information structure is divided into four sections identifying the substation topology, the communication networks, the IED information models and the data type templates used to build the information models.
IEC 61850-6 identifies the different file formats that can be exchanged among the different tools. The following formats are described:
l SSD: System specification description. This file describes the single line diagram and functions of the substation and the required logical nodes.
l ICD: IED capability description. This file describes the functional and engineering capabilities of an IED type.
Minimising the impact of IEC 61850 in new automation projects by Rodolfo Pereda and Aitz Amezaga, Ingeteam Power Technology
This article describes the challenges that the use of IEC 61850 imposes on the different actors that which part in the various stages of the development of substation automation projects and how some of these challenges can be minimised using the appropriate tools.
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l IID: Instantiated IED description. This file is similar to the ICD file but with preconfigured data.
l CID: Configured IED description. It describes the communication related part of an instantiated IED within a project.
l SCD: System configuration description. This file contains all IEDs including the configured data flow and needed DataTypeTemplates, a communication configuration section and a substation description section.
l SED: System exchange description. This file describes the interfaces of one project to be used by the other project, and at re-import the additionally engineered interface connections between the projects.
Fig. 1 (from IEC 61850-6 standard) explains the usage of SCL data exchange in the engineering process.
IEC 61850-6 introduces the concept of two different tools: the IED configuration tool and the system configuration tool. The functionality of these tools can be divided in different pieces of software depending on the end user of the tool and the device that is being configured.
According to this, the following engineering tools are identified:
l Protective relay IED engineering tool
l Protective relay IED configuration tool
l System configuration tool
l SCADA and HMI configuration tool
l RTU configuration tool
Protective relay engineering tool
This tool, that may be also called IED model tool, allows the definition of the data models of any device according to the IEC 61850 communication standard. The main task of this tool is the definition of an ICD file, the template of IED that is provided by the manufacturer to the system integrator. It is mainly used by the IED manufacturer and usually it is not exposed to the end user or system integrator in the different projects as the IED information model is linked to the data available in the relay and it may not be extended.
This tool should allow the definition of a data model from scratch or should allow importing any standard configuration file (ICD/CID) to create and modify the system data base.
The easy creation and management of complex information models for example drag and drop and copy/paste based actions in a graphical environment make the tool more intuitive. The reusability of all the types or data models created with some kind of repository of all the IEDs modelled or with the definitions included in the standard to improve the comprehension of the models will reduce further engineering. This tool should allow to import and export any standard configuration file regardless of the manufacturer.
Protective relay engineering tool features:
l Selection of the logical nodes and the available data points from the standard.
l Extension of logical nodes according to the device functionality or project requirements.
l Connection of the IEC 61850 information model to the internal data base of the IED. This can be done using the SCL extension mechanisms using the XML Private tag or with the “sAddress” (short address) attribute in the SCL files. Some devices may have this connection pre-established internally so there is no need to include any data in the ICD file.
l Configuration of the predefined datasets, report control blocks, goose control blocks, default settings and control models.
Protective relay configuration tool
This tool, that may be also called IED configuration tool is usually provided by the IED manufacturer and it is in charge of the configuration of the specific IEDs using the predefined files provided by the manufacturer or internal templates of the different IED models.
One of the main objectives of this tool should be to hide to the user the complexity of the IEC 61850 so that the user does not need to be an expert in the standard. Nowadays each vendor provides its own relay configuration tool but with a full IEC 61850 compatible IED it should be possible to configure the device with a standard configuration tool. This of course depends on each vendor implementation and if all the relay settings are available with IEC 61850 communication services.
Protective relay configuration tool features:
l Modification of settings of the relay.
l Modification of dataset, report and
goose control blocks (depending on IED capabilities).
l Generate a CID file with the configuration of an IED.
l Sending the configuration to the IED either sending the SCL file to the IED, with IEC 61850 communication services or with any other proprietary communication mean and format.
System configuration tool
The system configuration tool is an IED independent system level tool that shall be able to import configuration files from several IEDs, and configure each device with the project specific information. The result of this process should be an SCD file with the complete information model of all the IEDs configured in the system. This SCD file can be divided into a set of CID files, each one with the specific configuration of an IED.
System configuration tool features:
l The IED naming on the specific system.
l The network topology configuration identifying the different sub-networks and the access points.
l The data exchange definitions. It includes the configuration of datasets, report control blocks or/and GOOSE messages. This task is based on the IED capabilities that are described within the ICD file provided by the manufacturer and the data required by the different IEDs to accomplish their tasks.
l It may be used to modify the different settings of the specific relays depending on their location in the substation.
Local SCADA and HMI configuration tool
The HMI shows the relevant data on the system and gives the operator the possibility
Fig. 1: Reference model for information flow in the configuration process.
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of sending commands and modifying settings on specific devices. The HMI configuration tool may be able to understand the SCD or CID files in order to know the data naming structure and the references available in the system. This data references shall be linked to the graphical components that represent the status and measurements of the system.
The relevant data that shall be linked to the alarms and events screens and shall be kept in a historical record. Also some measurements may be represented in flow charts and stored in order to save the history of the substation.
RTU configuration tool
The control centre requires a subset of the information provided by the IEDs of the system data points. Traditionally, the control centres use the telecontrol protocols as IEC 60870-5-101, IEC 60870-5-104 or DNP3. The utility may define the list of points needed using different file formats and ways of identifying the data needed. In some cases the addressing of the data points may be defined by the utility or the system integrator.
System commissioning tools
Once an IEC 61850 system is deployed, the local HMI and the control center collect the information needed showing it with the appropriate format to the end user. During the commissioning and the integration of the different components of the substation there may be a need of different tools to validate the appropriate behavior of the system:
l IEC 61850 client software
l IEC 61850 server software
l Control centre emulator
l Traffic analyser or sniffer
IEC 61850 client software
IEC 61850 client software is the tool that emulates the behaviour or any of the IEC 61850 clients in the system, like the human machine interfaces or the RTU gateway to communicate with the SCADA. Some of the functions of a client emulation tool must be SCL file loading, data polling, dataset polling, setting and set-point modification, event retrieval and configuration (report or log), control services or file access.
It is used to check that a device is responding to the IEC 61850 configured parameters and it is essential in case of troubleshooting or during the HMI and RTU configuration and engineering.
Its main features should cover:
l C a p a b i l i t y t o c o n n e c t t o a n y IEC 61850 server
l CID file management
l Recovering of the IED information model by the use of the self-description interface
l Data access
l Set-points and settings edition and modification
l Commands handling with different control models
l Reception of spontaneous notifications by report or GOOSE messages
l File transfer
IEC 61850 server software
IEC 61850 server software is the tool that emulates the behaviour of a real device loading its CID file. Some of the functions of a server emulation tool must be the graphical display of the information sent to the clients, server information model easy navigation, configurable data change sequences and
events generation or configurable response of control services to emulate different behaviours.
The main use of this tool is the reduction of the engineering and validation time for the HMI, SCADA and RTU development. With the server emulator software there is no need to have physically connected all the IEDs during the HMI or RTU engineering and can be used to check that the IEC 61850 client’s configuration is according the IEDs data models testing of all the data configured in the reports or periodic readings that the clients are using.
The main features of this tool are:
l Data point modification on demand or by specific pattern.
l Quality flag modification.
l Internal logics to simulate the IED behaviour.
l Implementation of different control models.
l Capability of accepting and rejecting control orders.
l Reporting and GOOSE functionality.
Control centre emulator
This tool emulates the protocol used in the control centre. Before the site acceptance test, the system integrator shall guarantee that the status, measurements commands and counter are sent to the control centre using its specific format and information types. The main features of this tool are:
l Possibility of receiving, transmitting and analysing all the ASDU (application Service Data Units) of the control centre protocol.
l User interface to send the commands requested by the user simulating the commands sent from the control centre.
With this tool the integration of the system in the control centre of the utility should be guaranteed and the data interchange from end to end is validated.
Traffic analyser and switch with port mirroring
This piece of software monitors the traffic exchange among the IEDs in the substation. In order to analysed the traffic generated by different IEDs the use of a switch with port mirroring features is a must. It is not usual but in some cases it is needed to analyse the network traffic to check if there is any problem.
One of the examples where the use of this tool may be recommended is to analyse the GOOSE messages in the peer-to-peer communications in the network. Especially when measurements are used because a
UserRequired IEC 61850 knowledge
Toolswithout appropriate tools
with optimised tools
Protection relay manufacturer
High Medium
Text editor, Xml editor
SCL graphical editor
IED engineering specific tool
Protection engineer High LowText editor
SCL graphical editor
SCADA engineer Medium Low
System configuration tool
SCADA programming software
IEC 61850 commissioning tools
RTU engineer Medium Low
System configuration tool
RTU configuration software
IEC 61850 commissioning tools
Control center emulator software
System integrator High MediumIED configuration tool
System configuration tool.
System operator Low Low No need of IEC 61850 specific tools
Table 1: Levels of IEC 61850 knowledge needed by the user.
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wrong dead band configuration (the value that the measure must vary to be sent as a change in a new GOOSE message) may cause an excessive multicast network traffic that can affect to the other IEDs.
User identifi cation and the tools needed by each user
Most of the tools described in this paper use the same information model described in the SCL syntax but the features exposed to each user role should be controlled so the user cannot modify the aspects that it is not intended to. For instance, the user who configure the settings of a protective function may not be the one that select which data is sent to another relay by the GOOSE messaging feature.
The different users that are involved in substation automation projects can be protection relay manufacturer (R&D engineer), protection engineer, SCADA engineer, RTU engineer, system integrator and system operator. The following paragraphs identify the activities performed by each user and the tools needed to accomplish these tasks.
Protection relay manufacturer R&D engineer
l Its goal it to describe the functionality of the protective relay using the logical nodes and data objects described in the IEC 61850 standard.
l Its knowledge in the protective relay internal parameters is used to link the internal data location and format with the different protocol interfaces, as the IEC 61850 interface.
l Tools needed: IED engineering tool, IED configuration tool.
Protection engineer
l It configures the different settings of the protective relays based on the system specification. Depending on the protective relay capabilities, this information shall be uploaded to the IED using a proprietary interface or using open interfaces as the File Transfer Protocol or the MMS file transfer mechanism described in the standard.
l If some of the protective relays settings are configured in the SCL file, the user will need to understand the IEC 61850 information model structure and semantics.
lTools needed: IED manufacturer specific tools, SCL editor.
SCADA engineer
l Configures the HMI according to the system specification.
l May program some logics in the HMI for interlocking.
l Configures the data access from the different IEDs and validates the SCADA.
lTools needed: System configuration tool, SCADA editor, IEC 61850 commissioning tools
RTU engineer
l Configures the communication parameters of the control centre protocol.
l Configures the protocol translation between IEC 61850 references and the utility addressing specifications.
lTools needed: System configuration tools, RTU configuration tool, Communication centre emulator software, IEC 61850 commissioning tools
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System integrator
l It configures the network parameters of the different IEDs.
l It configures specific logics among different IEDs.
l Horizontal communication using GOOSE may reduce cabling.
lTools needed: System configuration tool, IED specific configuration tools (depending on the IED capabilities)
System operator
l Monitor or control the system using the HMI or local SCADA system and the control centre.
l Modify settings of the relays with or without the help of the IED manufacturer or system integrator.
l Tools needed: By default there is no need for additional tools.
The use of IEC 61850 in the system may imply new opportunities to modify set-points remotely or to retrieve COMTRADE files using new access points in the substation with the appropriate security measurements. These new functionalities may imply the use of new tools.
The degree of knowledge in IEC 61850 depends on the IED capabilities and the optimisation of the tools. As a summary the following table defines the different levels of
IEC 61850 knowledge needed, depending on the user and the tools.
Conclusions
This paper proposes a point of view about the guidelines that an IEC 61850 toolkit should cover, from the IED model tool that should allow the easy creation and management of complex information models, for example based on drag and drop actions in a graphical environment, to the system configuration tool that should use the IED models created previously to instantiate the real devices in each substation, configuring initial values, descriptions, information reports, etc.
The IEC 61850 promises real benefits in the integration of devices from different vendors and the reduction in the engineering of the system that will only be achieved if a new set of powerful tools, designed to fulfil the standard requirements, are available.
A good approach should be to maintain a system data base based on the IEC 61850 data model objects and structure. This data base should be automatically created importing the normative configuration files of each device and there should be only one data base in the system not only for the bay level
devices but also for the station level devices like the HMI or the RTU to communicate with central control rooms.
The degree of knowledge in IEC 61850 needed by each user depends on the IED capabilities and the optimisation of the tools. Not all the users will have the same knowledge about the standard and of course not all the users need the same degree of knowledge.
To help each different user, tools with different levels of detail in the standard are needed. The different tools involved in the engineering and maintenance process of IEC 61850 systems have been identified and described. Due to the complexity of the standard, tools become even more important that in former systems. In some cases, tools must provide the maximum level of information, for example with the IEC 61850 data references. But in other cases, tools must hide the user the detailed information of the IEC 61850 data models and only present the application view that the user is used to.
Now that the IEC 61850 has standardised more aspects not only in the communication protocol but also in the definition of the configuration of a device, the objective of reducing the number of tools needed in the configuration and maintenance of a SAS should be kept in mind.
In conclus ion, the more complex a communication protocol or a data model are, the more important the software tools become. And without questioning the benefits of the IEC 61850 standard, which are many and important, it must be taken into account that to manage the IEC 61850 requirements the appropriate tools must be available.
References[1] IEC 61850-6: Communication networks and
systems for power utility automation – Part 6: Configuration description language for communication in electrical substations related to IEDs.
[2] IEC 61850-7-4: Communication networks and systems for power utility automation – Part 7-4: Basic communication structure for substation and feeder equipment – Compatible logical node classes and data classes.
[3] IEC 61850-10: Communication networks and systems for power utility automation – Part 10: Conformance Testing.
[4] A new generation toolkit for the engineering and maintenance of IEC 61850 based SAS. R Pereda (Ingeteam, Spain), A Amezaga (Ingeteam, Spain). Cigré paper, no. 108, October 19-24, 2009 Korea.
[5] E San Telmo and R Pereda, Ingeteam Technology: "Minimising the impact of IEC 61850 in the new automation projects", Cigre SCB5 Collogquium, Switzerland, 2011.
[6] Cigré B5.12 TB 466, 2011 “Engineering Guidelines for IEC 61850 Based Digital SAS”.
Contact Rodolfo Pereda, Ingeteam Power Technology SA, [email protected]
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