- Remote IEC 61850 testing for digital substations
In digital substations, protection and automation functions increasingly depend on the correct behaviour of Ethernet–based communication equipments. GOOSE, Sampled Values and MMS are no longer isolated engineering concepts, they are part of the operational chain that protects real electrical assets.
This creates a clear challenge for utilities, OEMs and system integrators: how can they verify that critical IEC 61850 equipments still behave as expected after a firmware update, a bay extension, a configuration change, or a maintenance intervention, without sending an expert team to every substation?
RELY-TEST addresses this challenge by enabling remote, automated testing of IEC 61850 communications at station bus and process bus level. There are several possibilities to test based on IEC 61850-10, please, find below an use case example how the device is used for.
- RELY-TEST One Application Case: Remote Validation of Protection Response
Consider a utility operating several digital substations. After a protection IED software update, the engineering team needs to confirm that the device still reacts correctly to process bus events and publishes the expected GOOSE response within the required time.
Instead of moving a specialised test team to the substation, RELY-TEST can remain connected to the substation network and be accessed remotely by the expert team. The engineer uploads or selects the corresponding SCD configuration, prepares the test scenario, customises the test template and runs the validation from a remote location.
In this use case, RELY-TEST emulates the process bus stimulus by publishing Sampled Values towards the IED under test. For example, it can reproduce an abnormal current condition or a controlled signal variation. The IED processes this simulated condition and, if its protection logic behaves correctly, publishes the corresponding GOOSE message.
RELY-TEST then subscribes to and monitors the GOOSE response. By using hardware timestamping, the system can measure the time between the injected event and the received response, providing accurate visibility into the real behaviour of the communication and protection chain.
This is especially valuable because the test does not require the device to read incoming Sampled Values from the network. The validation is built around SV generation, GOOSE response monitoring and latency measurement, making it a practical and realistic test case for remote IEC 61850 verification.
- RELY-TEST Configuration
The process starts by connecting the device to the relevant station bus or process bus architecture, including PRP or HSR when required.If the test needs a common time reference, PTP synchronisation can be enabled before starting the validation.
The engineer then uploads the substation SCL file, either an SCD or CID, so RELY-TEST can automatically identify the IEDs, communication parameters, datasets, GOOSE messages and SV streams available in the system. Based on this information, a test scenario is created and reviewed remotely.
In a typical protection validation case, RELY-TEST generates a simulated Sampled Values stream towards the IED under test. This emulated process bus condition can reproduce a controlled current or voltage event without requiring the device to read incoming SV traffic from the network. The IED processes the simulated condition and publishes the corresponding GOOSE response.
RELY-TEST subscribes to that GOOSE message, monitors the received values and validates whether the expected protection or automation response has been triggered. By using hardware timestamping, the system can also measure the latency between the injected event and the received response.
The test is created by linking a reusable template to the selected scenario. Once configured, it can be executed remotely in step-by-step or continuous mode. After execution, the engineer can validate the result, add comments and generate a report.
This workflow allows utilities, OEMs and system integrators to run repeatable IEC 61850 tests without sending expert teams to every substation, reducing field effort while improving confidence in critical protection and automation communications.
If you need further details about RELY-TEST: please contact info@soc-e.com