remote commands. The active operation mode of OL5ATCC must be set to "Manual"
or "Parallel manual” and the Local/Remote control LR state monitored data of the
protection relay has to be "Local" to execute the control commands manually from
HMI or via configuration inputs. If OL5ATCC is set to "Manual" or “Parallel manual”
but the LR state is set to "OFF" or "Remote", no manual control commands can be
given.
For remote commands, the active operation mode of OL5ATCC must also be set to
"Manual" or “Parallel manual” and the LR state monitored data has to be "Remote".
The manual raising or lowering commands can be given locally either via the
Manual
control
parameter ("Cancel"/"Lower"/"Raise") located in the HMI menu Control>
OL5ATCC1 or via the configuration inputs LOWER_LOCAL or RAISE_LOCAL.
A raising command is given by selecting the enumeration value "Raise" and
the lowering command is given by selecting the enumeration value "Lower". An
accepted manual raising or lowering command activates the corresponding output
RAISE_OWN or LOWER_OWN to control the voltage of the own transformer.
Parallel manual voltage regulation
While in single manual mode the voltage regulator acts independently, in parallel
manual mode the voltage regulator set to “Parallel manual” acts as master and the
others follow.
The parallel manual mode is intended for maintenance work and has no permanent
settings. When the mode is set again to automatic, the voltage is stepped back to
the set value.
Followers not responding to parallel manual command are indicated at output
PAR_FAIL and the number of failed followers at monitored data FAIL_FLLW.
In parallel manual mode, the TR_STATUS monitored data indicates “Master” status
to the other parallel transformers.
Voltage control vs. tap changer moving direction
OL5ATCC has the control settings
Lower block tap
and
Raise block tap
which give
the tap changer position that results in the lowest and highest controlled voltage
value (usually at the LV side of the transformer).
Raise block tap
can be set higher
than
Lower block tap
and
Lower block tap
can be set higher than
Raise block tap
.
When the value of
Raise block tap
exceeds the
Lower block tap
value, the raise
control activates the RAISE_OWN output. This results in raising the tap changer
position, and the measured voltage rises. Furthermore, the RAISE_OWN output value
is TRUE. If the own tap changer position is connected (that is, the own tap changer's
quality is good), the tap changer alarm is activated if the tap changer does not
move upwards within
Cmd error delay time
after the pulse activation. As a result,
ALARM_REAS in the monitored data contains a command error value. The default
value of the
Cmd error delay time
setting is 20 seconds.
The lowering control works in a similar way, as shown in
Figure 916
. In the output
data, the LOWER_OWN output value is TRUE. An alarm is generated if the tap changer
does not move downwards in
Cmd error delay time
after the pulse activation,
assuming that the own tap changer position is connected.
In the second case, the parameters are set so that the value of Lower block tap
exceeds the value of Raise block tap. The raising control activates the RAISE_OWN
output. The result should be that the tap changer lowers its position and the
measured voltage rises. Furthermore, the RAISE_OWN output value is TRUE in the
1MRS759142 F
Control functions
REX640
Technical Manual
1701
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