ABB RELION REX640, Technical Manual, Page: 1718 / 1960

Manual
blocking
type
Enumeration Description
5 EXT External blocking has an effect in the manual operation mode
6 OC, EXT Conditions 2 and 5 together: Load current and external block-
ing have effect in the manual operation mode
7 UV, EXT Conditions 3 and 5 together: Block lowering (under) voltage
and external blocking have effect in the manual operation
mode
8 OC, UV, EXT All conditions 2, 3 and 5 together: Load current and block
lowering (under) voltage and external blocking have effect in
the manual operation mode
If the Custom Man blocking setting is "Custom disabled", the blocking schema
regarding the acting operation mode "Manual" or “Parallel manual” is as given in
Table 1577 . Other operation modes follow the default schema.
Table 1577: Blocking schema for selection "Custom disabled"
Active
operation
mode
Comman
d
Load
current Block
lower
voltage
Runback
raise
voltage
High
circulatin
g current
External
block Extreme
positions
Manual,
Parallel
manual
Raise x x
Lower x
Table 1578: Blocking schema for selection "OC, UV, EXT"
Active
operation
mode
Comman
d
Load
current Block
lower
voltage
Runback
raise
voltage
High
circulatin
g current
External
block Extreme
positions
Manual,
Parallel
manual
Raise x x x x x
Lower x x x x
Table 1579: Blocking schema for selection “UV, EXT”
Active
operation
mode
Comman
d
Load
current Block
lower
voltage
Runback
raise
voltage
High
circulatin
g current
External
block Extreme
positions
Manual,
Parallel
manual
Raise x x x x
Lower x x x
Load current
The load current blocking is mainly used for preventing the tap changer from
operating in an overcurrent situation. For example, if the current is not high enough
to activate the protection relay of the substation, it can still be fatal for the
diverter switch of the tap changer. This operation can be adjusted with the setting
Control functions 1MRS759142 F
1718 REX640
Technical Manual