Communication networks are an integral part of utility automation systems. With the increased usage of non-conventional instrument transformers and IEC 61850 protection devices, more and more critical information, like sampled values streams and GOOSE messages, are transmitted on these networks.
All protection, automation, and control devices have to be online and communicating appropriately. Testing tools and techniques are needed to verify and supervise the operation of protection, automation, and control (PAC) systems.
This already starts in the commissioning phase, where communication problems are ruled out and the correct transmission of all signals is verified. Later on, during the operation of a digital substation, it is crucial that problems are detected immediately, so staff can react on it.
The correct functioning of the communication network is an essential precondition for the optimal performance of a PAC system. Consequently, the performance of the communication network needs to be measured and assessed on its own. Depending on the communication architecture and technologies deployed, different approaches are applicable.
Verification of the IEC 61850 communication
In the standardised IEC 61850 substation configuration language (SCL) format, it is verified that the IEC 61850 servers of all intelligent electronic devices (IED) are available and reachable over client/server (C/S) connection and the substation real-time network traffic (GOOSE and sampled values) is actually present on the communication network as defined in the configuration files.
A network analyser tool can verify, proof, and document that all protection and control devices are communicating properly. Such verifications are mainly done in factory and site acceptance tests (FAT, SAT), and during the commissioning. In case of a malfunction, the network analyser tool has to provide detailed information for debugging.
If an IED is “checked green”, the complete IEC 61850 communication has been found as defined in the configuration files. A warning means there is an issue, which can be related to the server in the IED, or that not all sampled values streams or GOOSE messages are found on the network as expected.
An error is shown if an IED or one of its services is not found during the verification process. Differences in found sampled values streams or GOOSE messages are visualised by showing the found values next to the defined ones. If the values found on the network are the correct ones, the IED configuration file has to be updated, otherwise the device need to be reconfigured.
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