Control Modes; Accessing Of Physical Outputs; Control Feedback; Analog Outputs - ABB RELION 620 Series Communication Protocol Manual

Section 3
Vendor-specific implementation
3.5.5.1
3.5.5.2
3.5.5.3
3.5.6
22
resets and acknowledgements, can only be controlled using ON. However, there may
also be single point objects that have two states, ON or OFF. Double point objects may
be controlled using ON or OFF.

Control modes

All DNP3 binary outputs support direct control at any time. Double-point objects
(circuit breakers and disconnectors) also support select before operate controls,
provided that the native IEC 61850 control objects are in SBO control model mode. A
double-point control is represented with one binary output point on DNP3 even if
there are two separate control relay outputs (open and close) from the protection relay.

Accessing of physical outputs

As opposite to an RTU device, it is impossible to control the protection relay's
physical output relays directly from remote communication. However, using generic
control points and dedicated Application Configuration tool application connections
this is possible.

Control feedback

When the binary output values are read from the protection relay, the last written value
is returned. However, while controlling an object, the final status change of the object
should be verified from the corresponding binary input object, if available.
In case of double-point control, the IEC 61850 standard defines a value attribute
named stSeld to be always available for the control object. In case of SBO, this value
shows if the control object is actually selected, for example, if it is already selected by
another controlling source. This value is found in the DNP3 memory map as a regular
DNP3 binary input. The stSeld value also goes on ("1") and off ("0") during a direct
control operation. The stSeld value is always held in true state ("1") by the protection
relay until the control operation is terminated.
In case of a long lasting control operation, for example, a motor controlled
disconnector, the stSeld value can stay true for several seconds after the control
operation is acknowledged and started. A new control operation cannot be started by
the protection relay until the previous one has finished.

Analog outputs

Analog outputs are cross-referenced to the .Oper.ctlVal attribute of the protection
relay's object class INC, controllable integer. If the INC object is readable, the .stVal
attribute of the object is mapped to DNP3 AI data.
The protection relay platform contains a few controllable analog objects, for example,
parameter setting group selection, tap changer control and fault record read selection.
All analog objects are of integer type. The values do not have to be scaled.
1MRS757646 C
620 series
Communication Protocol Manual