Modbus Point List Mapping Mitigations; Overview - ABB Relion REF615R Manual

1MRS240173-IB B
Section 2
2.1
REF615R
DPU2000R Modbus Point List Mitigation Manual

Modbus point list mapping mitigations

Overview

Thanks to today's modern computer's fast processing speed and the price drops of the
computer physical memories, data acquisition bandwidth has greatly improved and the
databases sizes has drastically expanded. As a result, data management has become a new
focus as a large volume of data can be acquired in a short period of time. To meet the
demand, IEC61850 as an object oriented communication protocol classifies each data
point of a SCADA system by its associated logical device, logical node, function names
and instances, etc. In this way, it models each basic data point from the field into a unique
data object on the network by a unique IEC 61850 path, and each of every attributes of the
data object is modeled by a unique IEC 61850 path as well.
The DPU2000R relay was developed by ABB in the 1990s and has served the industry
successfully for over a decade. As time went by, some of its hardware components and
software design modules have become obsolete, restricting its use in the future power grid
network communication systems.
The REF615R, as a new generation of ABB protection relay, offers much broader network
communication capabilities as it implements the state-of-the-art IEC61850 protocol as its
primary substation communication protocol, and on top of it, it still supports other
well-respected digital communication protocols such as Modbus and DNP3.
To reduce a system integrator's efforts to remap the Modbus point list after substituting an
REF615R for a DPU2000R, the REF615R has kept the majority of the Modbus register
assignments the same as in DPU2000R. While the DPU2000R's Modbus server links
every points' value directly from the software variables, the REF615R's Modbus server
accesses data values through that data object's IEC 61850 path. The Modbus register
assignments of points fundamental to the feeder protection and control task (52a, 52b, 51P,
50P-1, 51N, 50N-1, metering, etc.) are all easily inherited from DPU2000R, since each has
its unique IEC 61850 path. Modbus mapping for some of the points only relevant to the
DPU2000R's specific software and hardware design features are maintained by using
REF615R's programmability feature since they do not have the corresponding IEC61850
paths. However, some DPU2000R design featured points have to be left out since
inheriting them on the REF615R was neither necessary nor practical.
In the remainder of this document, from Section 3 to Section 5, the Modbus point list
mapping of the DPU2000R and the REF615R are compared in a tabular format. The
sections' sequence is the same as in the original DPU2000R's Modbus point list manual.
Modbus 6x registers are not supported in REF615R because WebHMI and PCM 600 tool
can be used to make settings and logic changes.
This document does not cover the Modbus point list mapping added in the REF615R that
do not exist in the DPU2000R. To view the entire Modbus point list mapping for

Modbus point list mapping mitigations

Section 2
9