Functionality - ABB RELION REX640 Technical Manual

1MRS759142 C
9.10.3
9.10.4
REX640
Technical Manual

Functionality

The tap changer control with voltage regulator function OL5ATCC (on-load tap
changer controller) is designed for regulating the voltage of power transformers with
on-load tap changers in distribution substations. OL5ATCC provides a manual or
automatic voltage control of the power transformer by using the raising or lowering
signals to the on-load tap changer.
The automatic voltage regulation can be used in single or parallel transformer
applications. The parallel operation can be based on the Master/Follower principle
(M/F), Negative Reactance Principle (NRP) or Minimizing Circulating Current
(MCC).
OL5ATCC includes the line drop compensation (LDC) functionality, and the load
decrease is possible with a dynamic voltage reduction.
Either definite time characteristic (DT) or inverse time characteristic (IDMT) is
selectable for delays between the raising and lowering operations.
The function contains a blocking functionality. It is possible to block the voltage
control operations with an external signal or with the supervision functionality of the
function.
Analog channel configuration
OL5ATCC has two analog group inputs which must be properly configured.
Table 1409: Analog inputs
Input
I3P
U3P
See the preprocessing function blocks in this document for the
possible signal sources.
There are a few special conditions which must be noted with the configuration.
Table 1410: Special conditions
Condition
U3P connected to real measurements
Improper analog channel configuration causes a validation error if the analog
channels are not completely configured or they do not match with certain settings. For
troubleshooting, check the contents of this chapter and also the preprocessing blocks
Control functions
Description
Three-phase currents
Three-phase voltages
Description
The function can work with one voltage connected
to channel 1, two voltages connected to channels
2 and 3, or all three voltage channels connected.
Section 9
1539