Configuration management keeps a single valid, known version of each relay's settings and of the substation SCD file: what is loaded in each device, who changed it, when and why. Without it, settings end up on contractors' laptops, the SCD stops matching the IEDs and every extension starts with weeks of field survey. IEC 61850-6 gives SCL a header with version and history, and IEEE 1686 requires the IED to log changes.
The problem: nobody knows what is loaded
A substation has dozens of live configuration files: each relay’s settings and logic, the SCD with the whole IEC 61850 system, the CID files loaded into each IED, the gateway and SCADA database, and the configuration of switches and firewalls. Every commissioning, settings change from a coordination study, relay replacement or extension changes some of them.
Without a method, the typical story goes like this: the integrator delivers an SCD; a year later, a technician changes a setting on site and saves the file on a laptop; another contractor adds a bay by modifying the IED directly; the original SCD is left out of date. When a fault comes, nobody can say for sure which settings were active. It is the case described in the guide on a relay without documented settings, multiplied across the whole substation.
What configuration management is
It is the discipline that keeps, for each device, a single valid and known version of its configuration. It rests on four ideas:
- Baseline: the approved set of files that describes what is loaded in each device at a given time.
- Change control: no change is loaded without a request, a technical review and an approval; each change produces a new version.
- Single repository: a location owned by the asset owner, with controlled access and backup, where the reference version lives.
- Verification: periodic comparison between what is in the repository and what is loaded in the devices.
- 01RequestReason for the change: study, fault, extension or replacement
- 02ReviewStart from the baseline version and review the change
- 03Load and testLoad it into the device and verify the affected function
- 04RecordThe final file enters the repository as a new version
- 05New baselineWhat is loaded and what is documented match again
What IEC 61850-6 adds to the SCD
The IEC 61850 configuration language (SCL), defined in IEC 61850-6, already includes elements for version control. Each file has a header with its identifier, version and revision, and a history section where each entry records version, date, author, what changed and why. In addition, each control block and each data set has its configuration revision (confRev), which the IED publishes in its messages.
The file types mark the flow: the ICD describes an IED’s capabilities, the SCD describes the whole substation and the CID is the configuration loaded into each IED. Edition 2 added the IID, which returns to the system an IED configuration modified in its own tool, and the SED, for exchanging data between projects. The guide on IEC 61850 SCL files explains each one.
The practical rule that follows is simple: the SCD is the system’s source of truth. A change made in an IED that does not go back into the SCD breaks traceability, and the next person who regenerates the CID files from the SCD will undo that change without knowing it.
What IEEE 1686 adds to the relay
IEEE 1686 sets the cybersecurity capabilities of IEDs, and several of them serve configuration management directly: individual accounts with roles, so that it is known who made the change; an audit trail of logins and of configuration and settings changes; and control of firmware uploads. A relay that logs “group 1 settings changed by user X at such a time” makes it possible to rebuild the history even if someone worked outside the procedure.
IEC 62443-2-1, which covers the asset owner’s security program, lists configuration and change management among its elements. The reason is direct: an unauthorized change is also a security incident.
Why traceability is lost
| Cause | Consequence |
|---|---|
| Final files on the laptop of whoever did the work | The owner does not have the loaded version |
| Changes made in the IED and not in the SCD | The SCD no longer represents the substation |
| Shared accounts on the relays | Nobody knows who changed what |
| Backups without date or identification | The current version cannot be told from earlier ones |
| Extensions with another tool or IEC 61850 edition | The SCD fragments and the projects stop matching |
| No periodic comparison | Differences are discovered during a fault |
What to require in a contract
- Delivery of each device’s final files, the SCD and the CID files, with their version and the complete SCL history.
- That every IED change is reflected in the SCD before the job is closed.
- A record of the differences between the delivered configuration and the previous one.
- Individual accounts enabled on the relays and default credentials changed.
- The tests that verify each change, with their results.
To review what an SCD or CID you received contains, you can use our free IEC 61850 SCL viewer, which shows IEDs, data sets and control blocks.
Comparing what is loaded with what is documented
Periodic verification is the part most often forgotten. In general terms it means reading the active configuration of each device and comparing it with the reference: the relay settings against the repository file, the loaded CID against the one derived from the SCD, and the configuration revision each IED publishes against the one in the SCD. Differences are analyzed one by one: some are legitimate changes that were not recorded and others are errors to be corrected. It is a task done before an extension, after a fault and at each major maintenance.
How we help
Bringing a substation’s settings to a reliable baseline starts with knowing what is loaded. With our remote relay configuration service we read the active configuration of your relays and recloser controls from the main brands, compare it with the documentation, correct what is needed and hand you the files with their history so they stay in your repository. For the SCD and IEC 61850 integration we work through our control, protection and communications configuration and our communications engineering service. Contact us with the brand and model of your equipment.
Related guides
- Relay without documented settings
- IEC 61850 SCL files
- IEC 61850: overview
- Is remote relay configuration secure?
- IEC 62351: cybersecurity for IEC 61850, IEC 104 and DNP3
- Top-down and bottom-up IEC 61850 engineering: SSD to CID
- Migrating from IEC 103, IEC 101 or Modbus to IEC 61850
- Substation communications by voltage level
References
- IEC 61850-6, Configuration description language for communication in power utility automation systems related to IEDs (SCL, header and history).
- IEC 61850-7-2, Abstract communication service interface (ACSI) (configuration revision of control blocks).
- IEEE 1686-2022, Standard for Intelligent Electronic Devices Cyber Security Capabilities.
- IEC 62443-2-1, Security program requirements for IACS asset owners.
Frequently asked questions
What is a configuration baseline in a substation?
It is the approved and verified set of files that describes what is loaded in each device at a given time: each relay's settings, the logic, the SCD and the CID files derived from it, and the configuration of switches and gateway. Each later change starts from that baseline and produces a new one.
How do I know whether my SCD matches what is loaded in the IEDs?
By comparing the configuration revision of each control block and data set in the SCD with the one each IED publishes, and by reading the configuration file loaded in the device to compare it with the one derived from the SCD. A revision mismatch is the quickest sign that someone changed something outside the SCD.
Who should keep the relay settings: the owner or the contractor?
The substation owner. The contractor hands over the verified final files and their history, but the reference copy must stay in a repository of the owner, with controlled access and backup, so that it does not depend on one person or one laptop.