IEC 61850 reports: where telemetry transfer most often breaks on a digital substation
In digital-substation projects most attention goes to GOOSE, SV, PTP and the network. But there is another important layer — MMS exchange and IEC 61850 reports, through which SCADA, HMI, gateways and monitoring systems receive telemetry from IEDs. In practice the problems here are deceptively simple: the MMS connection is up, the device is reachable, the client «sees» the server — yet data does not update, some signals disappear, events are duplicated, or the report control block does not activate at all. This article covers the sharpest problems with report control blocks (RptEna, ConfRev, a block already taken by another client, TrgOps, a DataSet mismatch, duplication from the buffer via entryID and too much faith in the SCL file) and a practical principle: cross-check the SCL file, the device's actual MMS model and a PCAP capture together.