IEC 61850 – Types of SCL files

In order to work with SCL files, IEC 61850-6 defines 6 types of files: SSD, ICD, SCD, CID, IID, and SED.

SSD – System Specification Description: This file describes the topology of the electrical system to automate and the required functions (logical nodes) without including the specific IED models that implement these functions. This will have Substation part, Data type templates and logical node type definitions but need not have IED section.
ICD – IED Capabilities Description: Template file provided by the vendor describing the device information model and capabilities. It is the base for automate the IEC 61850 system. The file contains a single IED section, an optional communication section and an optional substation part which denotes the physical entities corresponding to the IED.
SCD- Substation Configuration Description: File with the complete configuration of the system including the information model of the real equipment selected, the network parameters, the data flows and even the relationship with the electrical topology. It contains substation, communication, IED and Data type template sections. An *.SSD file and different *.ICD files contribute in making an SCD file.
CID – Configured IED Description: File only one configured IED including the information published in GOOSE messages and the information available for the different clients. It can be considered as an SCD file stripped down to what the concerned IED need to know and contains a mandatory communication section of the addressed IED.
IID – Instantiated IED Description: Configuration file generated with the IED engineering tool generated after the configuration of GOOSE subscriptions and the assignation of these signals to the internal logics. This file contains only the data for the IED being configured: one IED section, the communication section with the IED’s communication parameters, the IED’s data type templates, and, optionally, a substation section with the binding of functions (LNodes) to the single line diagram.
SED – System Exchange Description: File format used to exchange configuration information between two different projects that need to configure any data exchange between IED located at different locations. It is a subset of an SCD file with additional engineering rights for each IED as well as the ownership (project) of SCL data.
The IID and SED types were introduced with IEC 61850 Edition 2.

IEC 61850-4 and IEC 61850-6 also define 61850 tooling requirements and functionality that allow the Substation Automation System workflow to be achieved. The specific tools are:
System Specification Tool (SST): This tool allows for the specification of process signal exchange, required automation and communication information exchange, and power system network topology.
IED Configuration Tool (ICT): This tool produces a template of the capabilities of a specific IED, accepts a parameterized system file to configure an IED, and produces an image of the parameterized IED.
System Configuration Tool (SCT): This tool accepts the specification information provided by the SST and is used by a system engineer to provide concrete functions, IEDs, network topology, and communication information needed to create a parameterized automation system. Additionally, the tool accepts the capability templates produced by the ICT and these templates are used to fulfill the specification requirements.

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