Sepam Series 60 or 80 DNP 3.0 communication. Why does Sepam return a non-zero value (0x7FFF) for the Frequency and Power Factor when the Circuit Breaker is open and there is no load?

In some cases, a SCADA client may read information from the Sepam to check whether or not there is any load measured by the relay.  In order to determine the status of the circuit breaker, it is recommended to read the Remote Indication bits from the Sepam, or to check the status of the relevant Digital Inputs, rather than trying to check if the Power Factor is zero, for example.

If the SCADA client is using DNP 3.0 communication, Sepam will return an invalid value for the Power Factor and the Frequency measurements if the breaker is open and there is no load.

This is is the value returned for a measurement that cannot be calculated, as explained in the DNP 3.0 manual for Sepam, and this value is 32767 decimal, or 0x7FFF.

This is not a firmware bug with the Sepam.  In fact, this value is returned to indicate that Sepam cannot calculate the requested measurement.  If possible, the Sepam device driver for the SCADA client should be updated in order to interpret this value correctly.

AEDL3

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