CDV61850-6©1EC:2002 -11- 57WG10 By access services to parameter and configuration data defined according to this stan- dard.In this case the standardised methods according to part 7 shall be used. Version 8CDV,August 2002
CDV 61850-6 © IEC:2002 – 11 – 57/WG10 Version 8CDV, August 2002 • By access services to parameter and configuration data defined according to this standard. In this case the standardised methods according to part 7 shall be used
CDV61850-6©1EC:2002 -12- 57WG10 6 The SCL object model The SCL in its full scope describes a model of The primary system structure:which primary apparatus functions are used,and how the apparatuses are connected.This results in a designation of all covered switchgear as substation automation functions,structured according to IEC 61346-1. The communication system:how IEDs are connected to subnetworks and networks,and at which of their communication access points (communication ports). The application level communication:How data is grouped into data sets for sending,how IEDs trigger the sending and which service they choose,which input data from other IEDs is needed Each IED:which logical devices are configured on each IED,which logical nodes of which class and type belong to each logical device,and which reports with which data and which(pre-configured)associations are available;which data shall be logged. Instantiable logical node(LN)type definitions.The logical nodes as defined in part 7 have mandatory,optional and user defined (external)data(DO)as well as optional services, and are therefore not instantiable.In this document instantiable LNTypes are defined. which contain as template the really available DOs and services. The relations between instantiated logical nodes and their hosting IEDs on one side and the switchyard (function)parts on the other side. Note:SCL allows the specification of user defined DOs as extension of standard LN classes as well as completely user defined LNs according to the rules of parts 7-4.This means,that the appropriate name space attributes shall be defined in the logical node types. An SCL file describes an instance of the model in a special way.However its semantic can only be fully understood by reference to the model itself.This clause therefore describes the model by using UML notation.The next clauses then define how an instance of the model is formally described in SCL. The UML object model is contained in figure 3.Note that it is not complete from the modelling sense,i.e.it does not show any superclasses from which the used classes may be derived.It restricts to those concrete object types that are used within SCL,in case of the substation structure mainly for the purpose of functional designation.Further it does not contain the lev- els below Data(DOs),which are defined e.g.in 7-2. The object model has three basic object levels: Substation:the switchyard devices(process devices),their connection on single line level (topology),and the designation of devices and functions are described.The designations are constructed according to the functional structure of IEC 61346. Product:this stands for all SAS product-related objects like IEDs and logical nodes. Communication:this contains communication related object types like subnetworks and communication access points,and describes the communication connections between IEDs respective indirectly between logical nodes as clients and servers. Version 8CDV,August 2002
CDV 61850-6 © IEC:2002 – 12 – 57/WG10 Version 8CDV, August 2002 6 The SCL object model The SCL in its full scope describes a model of • The primary system structure: which primary apparatus functions are used, and how the apparatuses are connected. This results in a designation of all covered switchgear as substation automation functions, structured according to IEC 61346-1. • The communication system: how IEDs are connected to subnetworks and networks, and at which of their communication access points (communication ports). • The application level communication: How data is grouped into data sets for sending, how IEDs trigger the sending and which service they choose, which input data from other IEDs is needed. • Each IED: which logical devices are configured on each IED, which logical nodes of which class and type belong to each logical device, and which reports with which data and which (pre-configured) associations are available; which data shall be logged. • Instantiable logical node (LN) type definitions. The logical nodes as defined in part 7 have mandatory, optional and user defined (external) data (DO) as well as optional services, and are therefore not instantiable. In this document instantiable LNTypes are defined, which contain as template the really available DOs and services. • The relations between instantiated logical nodes and their hosting IEDs on one side and the switchyard (function) parts on the other side. Note: SCL allows the specification of user defined DOs as extension of standard LN classes as well as completely user defined LNs according to the rules of parts 7-4. This means, that the appropriate name space attributes shall be defined in the logical node types. An SCL file describes an instance of the model in a special way. However its semantic can only be fully understood by reference to the model itself. This clause therefore describes the model by using UML notation. The next clauses then define how an instance of the model is formally described in SCL. The UML object model is contained in figure 3. Note that it is not complete from the modelling sense, i.e. it does not show any superclasses from which the used classes may be derived. It restricts to those concrete object types that are used within SCL, in case of the substation structure mainly for the purpose of functional designation. Further it does not contain the levels below Data (DOs), which are defined e.g. in 7-2. The object model has three basic object levels: • Substation: the switchyard devices (process devices), their connection on single line level (topology), and the designation of devices and functions are described. The designations are constructed according to the functional structure of IEC 61346. • Product: this stands for all SAS product-related objects like IEDs and logical nodes. • Communication: this contains communication related object types like subnetworks and communication access points, and describes the communication connections between IEDs respective indirectly between logical nodes as clients and servers
CDV61850-6©IEC:2002 -13- 57WG10 Additionally the logical node type section allows specifying in a type oriented(i.e.reusable) way which data and attributes are really existing on an IED.A logical node type is an instan- tiable template of the data of a logical node More model details contained in SCL,e.g.the structure within the logical nodes,are de- scribed in parts 7-x. The substation object level and the product object level in itself form hierarchies,which are used for naming and can be mapped to the functional and product structures according to IEC 61346.The communication object level model just contains the communication connec- tion relations of devices to subnetworks,between subnetworks by means of routers,and the placement of master clocks at the subnetworks for time synchronisation.The modelling of gateways is not considered here-it is a local issue of the appropriate gateway logical node. Nevertheless,it is recommended that a gateway from another protocol to IEC61850 models all IEDs below as IEC61850 logical devices. As can be easily seen from Figure 3,the logical node (abbreviated as LN or LNode)is the transition object,which is used to connect the different structures.This means that the LN as a product also has a functional aspect within the switchyard functionality and a communica- tion aspect within the substation automation system. The substation functional objects as well as the product related objects are hierarchically structured.Each higher level object consists of lower level objects.This hierarchy is reflected in the designation structure of the objects according to IEC 61346-1.The function structure of IEC 61346-1 shall be used for the substation objects,while its product structure should be used for IED designation and structure. In SCL it is foreseen that within each structure two kinds of designation are possible: A name is used as (hierarchical part of)a technical key to designate the object.Each object within a hierarchy has an attribute Nam,which contains its reference part within the hierarchy.Technical keys are used in technical documentation for building and main- taining the system,or for automatic processing of engineering related information.This designation is also used in SCL to describe links between different model objects.In this case,as far as possible the attribute containing the link gets a name of the form <Tar- gettype>Nam,e.g.DONam for a link to a Data object.This Nam relates to and mostly is identical to what is called Name in part 7-2. A description part is used as (hierarchical part of)an operator related object identifica- tion.An object within a hierarchy has an attribute Desc,which contains its textual de- scription part within the hierarchy.Textual identifications are for example used in operator interfaces and operator manuals A reference(Ref)within SCL is,as defined in 7-2,a unique identification of an object,con- taining as a path the concatenation of all names in the hierarchy levels above until the level of the object.For forming names,also the term Instance with abbreviation Inst is used.It is a part of a name,making it unique within this level (see examples later on). The following clauses describe the different parts of the model,their meaning and respective usage.Object attributes are mentioned here only if necessary for the understanding of the model.Further object attributes are described later in the SCL definition.Further model de- tails belonging to parts 7-x and especially explained in 7-1 and 7-2 are purposely not shown here.The name model of the switch yard functionality however is only found in this part,and therefore shown as far as used within this part. Version 8CDV,August 2002
CDV 61850-6 © IEC:2002 – 13 – 57/WG10 Version 8CDV, August 2002 Additionally the logical node type section allows specifying in a type oriented (i.e. reusable) way which data and attributes are really existing on an IED. A logical node type is an instantiable template of the data of a logical node. More model details contained in SCL, e.g. the structure within the logical nodes, are described in parts 7-x. The substation object level and the product object level in itself form hierarchies, which are used for naming and can be mapped to the functional and product structures according to IEC 61346. The communication object level model just contains the communication connection relations of devices to subnetworks, between subnetworks by means of routers, and the placement of master clocks at the subnetworks for time synchronisation. The modelling of gateways is not considered here – it is a local issue of the appropriate gateway logical node. Nevertheless, it is recommended that a gateway from another protocol to IEC61850 models all IEDs below as IEC61850 logical devices. As can be easily seen from Figure 3, the logical node (abbreviated as LN or LNode) is the transition object, which is used to connect the different structures. This means that the LN as a product also has a functional aspect within the switchyard functionality and a communication aspect within the substation automation system. The substation functional objects as well as the product related objects are hierarchically structured. Each higher level object consists of lower level objects. This hierarchy is reflected in the designation structure of the objects according to IEC 61346-1. The function structure of IEC 61346-1 shall be used for the substation objects, while its product structure should be used for IED designation and structure. In SCL it is foreseen that within each structure two kinds of designation are possible: • A name is used as (hierarchical part of) a technical key to designate the object. Each object within a hierarchy has an attribute Nam, which contains its reference part within the hierarchy. Technical keys are used in technical documentation for building and maintaining the system, or for automatic processing of engineering related information. This designation is also used in SCL to describe links between different model objects. In this case, as far as possible the attribute containing the link gets a name of the form <Targettype>Nam, e.g. DONam for a link to a Data object. This Nam relates to and mostly is identical to what is called Name in part 7-2. • A description part is used as (hierarchical part of) an operator related object identification. An object within a hierarchy has an attribute Desc, which contains its textual description part within the hierarchy. Textual identifications are for example used in operator interfaces and operator manuals. A reference (Ref) within SCL is, as defined in 7-2, a unique identification of an object, containing as a path the concatenation of all names in the hierarchy levels above until the level of the object. For forming names, also the term Instance with abbreviation Inst is used. It is a part of a name, making it unique within this level (see examples later on). The following clauses describe the different parts of the model, their meaning and respective usage. Object attributes are mentioned here only if necessary for the understanding of the model. Further object attributes are described later in the SCL definition. Further model details belonging to parts 7-x and especially explained in 7-1 and 7-2 are purposely not shown here. The name model of the switch yard functionality however is only found in this part, and therefore shown as far as used within this part
CDV61850-6©1EC:2002 -14- 57WG10 Substation Voltage 1 Bay Primary Device◇ Subdevice level 1 Phase 1 10.5 Terminal CBR 1 DIS ConNode VTR 0.* LNode Data 1* associatrons 1 1.* ◇1 IED AccessPoin Server LDevice 1.* 0,1 Router 0,1 Functional substation structure Subnetwork Product/IED structure 0,1 Clock Communication structure Figure 3-SCL object model The following Figure 4 shows an instance of this model:a simple example of a SA system used for a switchyard.The naming is performed according to IEC 61346.The switchyard has a 110kV voltage level E1.It is a double bus bar system with two line bays =E1Q1 and =E1Q3, and a bus coupler =E1Q2.The IEDs are already assigned to switchyard functionality (e.g.the bay controller-E1Q1SB1 as a product is assigned to bay =E1Q1,and its LN CSWI1 controls the circuit breaker =E1Q1QA1 via the LN XCBR1 on the IED -E1Q1QA1B1).Observe that in IEC 61346 terms here the bay is a transition object,i.e.it has a function(=sign,at switch- yard level),and it is considered to be as product a part of the switch yard.Figure 4 shows with the sign only the product-related designation.The functional name (at switchyard level)is not repeated.The station level communication subnetwork is named W1.There are additional three subnetworks at process level(W2,W3,W4).Access points are seen in the picture,but their designations are not shown.Also logical devices and servers are not shown in the picture.This means especially that dynamic connections like associations are not shown. Version 8CDV,August 2002
CDV 61850-6 © IEC:2002 – 14 – 57/WG10 Version 8CDV, August 2002 Voltage level Bay PrimaryDevice CBR ConNode DIS VTR IED AccessPoint Server LDevice LNode Subnetwork 1..* 1 1..* 1..* 1 1 1 1 1 1 1 1 Data 1 1 1 1..* 1..* associations 0,1 0,1 Functional / substation structure Product / IED structure Communication structure 0..* Substation 1 1 Terminal 1 1 0..5 Subdevice Phase 1 Router 1 Clock 0,1 Figure 3 - SCL object model The following Figure 4 shows an instance of this model: a simple example of a SA system used for a switchyard. The naming is performed according to IEC 61346. The switchyard has a 110kV voltage level E1. It is a double bus bar system with two line bays =E1Q1 and =E1Q3, and a bus coupler =E1Q2. The IEDs are already assigned to switchyard functionality (e.g. the bay controller -E1Q1SB1 as a product is assigned to bay =E1Q1, and its LN CSWI1 controls the circuit breaker =E1Q1QA1 via the LN XCBR1 on the IED -E1Q1QA1B1). Observe that in IEC 61346 terms here the bay is a transition object, i.e. it has a function (= sign, at switchyard level), and it is considered to be as product a part of the switch yard. Figure 4 shows with the – sign only the product-related designation. The functional name (at switchyard level) is not repeated. The station level communication subnetwork is named W1. There are additional three subnetworks at process level (W2, W3, W4). Access points are seen in the picture, but their designations are not shown. Also logical devices and servers are not shown in the picture. This means especially that dynamic connections like associations are not shown
CDV61850-6©1EC:2002 -15- 57WG10 AA -P1 WI logical bus -E101 -E1Q2 -E103 -SB1 -BPI -SB1 -SB1 -BP1 Control Protection Control Control Protection IED IED IED IED IED CSWIl -PIOCI -CSWII -CSWIl -PIOCI -W2process bus -W3 process pus -W4 process bus -BI -B1 -OF PISA -OB -9A1 B2 PISA -XCBRI -BI PISA -XCBRI -QAL ① --QE1 -XMEAI -XCBRI ① -QE1 L-XMEAI -XMEAL.2 Figure 4-Example configuration 6.1 The substation model The substation model(upper part of Figure 3)is an object hierarchy based on the functional structure of the substation.Although each object is self-contained,its reference designation is derived from its place in the hierarchy.Because LNs perform functions within the complete context of the substation,they can be attached as lower level functional objects on each sub- station function level.Typically a switch controller LN is attached to a switching device,while a measuring LN is attached to the bay which delivers the measurands. The purpose of the substation model is To relate a logical node to a substation function (substation part or primary device or subdevice) To derive a functional designation for the logical node from the substation structure The following substation objects of the functional structure (in hierarchical order)are used in the SCL model.More background information on these words can be found in the glossary [IEC61850-2]: Substation: the object identifying a whole substation. Voltage level: an identifiable substation part having an identical voltage.If this name structure part is not needed (e.g.for a transformer,or a non electrical part of the substation),then an empty designation string (name)for this level is used,and no voltage value specified. Bay: an identifiable part or subfunction of the switchyard(substation)within one voltage level.Especially the transformer is a bay,which may either be Version 8CDV,August 2002
CDV 61850-6 © IEC:2002 – 15 – 57/WG10 Version 8CDV, August 2002 Control IED -CSWI1 =QB2 =QE1 =QC1 =QA1 Protection IED -PIOC1 PISA -XCBR1 -XMEA1 -E1Q1 -SB1 -BP1 -B1 -AA1 -SA1 -P1 Control IED -CSWI1 =QB2 =QE1 =QC1 =QA1 Protection IED -PIOC1 PISA -XCBR1 -XMEA1 -E1Q3 -SB1 -BP1 -B1 -E1Q2 Control IED -CSWI1 -SB1 PISA -XCBR1 -XMEA1, 2 -B1 -W2 process bus -W3 process bus -W4 process bus -W1 logical bus =QB1 =QA1 =QB2 Figure 4 - Example configuration 6.1 The substation model The substation model (upper part of Figure 3) is an object hierarchy based on the functional structure of the substation. Although each object is self-contained, its reference designation is derived from its place in the hierarchy. Because LNs perform functions within the complete context of the substation, they can be attached as lower level functional objects on each substation function level. Typically a switch controller LN is attached to a switching device, while a measuring LN is attached to the bay which delivers the measurands. The purpose of the substation model is • To relate a logical node to a substation function (substation part or primary device or subdevice) • To derive a functional designation for the logical node from the substation structure The following substation objects of the functional structure (in hierarchical order) are used in the SCL model. More background information on these words can be found in the glossary [IEC 61850-2]: Substation: the object identifying a whole substation. Voltage level: an identifiable substation part having an identical voltage. If this name structure part is not needed (e.g. for a transformer, or a non electrical part of the substation), then an empty designation string (name) for this level is used, and no voltage value specified. Bay: an identifiable part or subfunction of the switchyard (substation) within one voltage level. Especially the transformer is a bay, which may either be