Deadband Value Configuration

In IEC 61850 communication standard, certain parameters have an instantaneous values which begins with inst and a deadband value. The instantaneous value is updated every second. The deadband value is set to the new instantaneous value when the difference between the new instantaneous value, and the deadband value exceeds the deadband value configured for that parameter.

The CET850 configuration software is used to configure the deadband value of a data point in the CID file. In IEC 61850-7-3, the deadband values are expressed as percentage, whereas in MasterPacT MTZ IED devices, the deadband values are expressed as integer values. These values are usually in different units than the dead banded value. This value is stored in the db parameter associated with that data point. For example, a value with units of Amperes may have a deadband value with units of Milliamperes. These values are usually in different units than the dead banded value.

Example:

Configure the power report for client connection to be triggered (sent) when phase A current changes by 5 A or more from one reading to the next. The phase A current is in units of 1 A and the deadband parameter (db) is in units of 0.1 A.

The CET850 configuration software can be used to build a CID file that includes the following settings:

Set the db parameter of phase A (MMXU > A > phsA) to 50 which specifies a deadband range of 5 A 50 x 0.1 A = 5 A.
Set the dchg option to True to get the reports for client connection.

NOTE: Reports are only sent if this option is enabled by the client.

Refer to the figure below to understand the deadband operation:

Initially, the phase A current has an instantaneous magnitude and a deadbanded magnitude of 5 A. The deadband quantity set through the CET850 configuration software is 5 A.

Marker position	Instantaneous magnitude of Phase A current	Operation analysis
1	12A	The difference between the instantaneous magnitude and deadbanded magnitude is greater than 5 A (the deadband range). The dchg trigger is set, which sends report on data change to the client. The deadbanded magnitude is set to the instantaneous magnitude (12 A).
2	4A	The difference between the instantaneous magnitude and deadbanded magnitude is greater than 5 A (the deadband range). The dchg trigger is set, which sends report on data dhange to the client. The deadbanded magnitude is set to the instantaneous magnitude (4 A).
3	3A	The difference between the instantaneous magnitude and deadbanded magnitude is less than 5 A (the deadband range). The dchg trigger is not set, no reports are sent to the client. The deadbanded magnitude remains at its existing value (4 A).

NOTE: Deadband setting range: 1-100. If the db value is configured to a value greater than 100, then it will be considered as 0.

The following figure shows the configuration of deadband values for measurements data: