ABB RELION REX640, Техническое руководство, Страница: 267 / 1960

When using this function for energy measurement,
Unit selection is set accordingly,
that is, real, active or apparent energy and the count value is divided by
Impulse
ratio to calculate the scaled value. The prefix for unit of Impulse ratio is defined by
setting
Impulse ratio prefix.
The energy meter defines the impulse ratio (also known as meter
constant), that is, it indicates the number of pulses the meter generated
per kWh (or MWh).
Impulse ratio must be set based on the energy meter
used.
For example, if the impulse ratio is 100 impulses / MWh, set
Impulse ratio
as 100 and
Impulse ratio prefix as Mega.
If the impulse ratio is 800 impulses / KWh, set
Impulse ratio as 800 and
Impulse ratio prefix as Kilo.
The scaled value is available at SCALED_VALUE in the Monitored data view. This
output is updated cyclically and sent to the station HMI over various communication
protocols depending on
Reporting interval setting. The start of Reporting interval
corresponds to the start of the function operation in the protection relay.
The activation of RESET resets SCALED_VALUE to zero.
If
Pulse quantity, Impulse ratio or Impulse ratio prefix is changed in
between, SCALED_VALUE is updated immediately based on the new
setting.
Binary output
VALUE_READ
activates for a fixed 200 ms each time the reporting
timer completes its cycle.
It is also possible to update SCALED_VALUE before completion of
Reporting interval
and make it available for communication by providing a pulse at
READ_VALUE
input.
The pulse width should be greater than 1 s. Besides updating
SCALED_VALUE
, the
READ_VALUE
activation also activates output
VALUE_READ
for 200 ms.
Activation of
FREEZE_COUNT
input immediately updates
SCALED_VALUE
output with
a pulse at
VALUE_READ
output.
Output
COUNT_SAT
activates when either SCALED_VALUE or COUNT_VALUE exceeds
the count range and it is not possible to count further.
Figure 149
and
Figure 150
explain PCGAPC operation.
1MRS759142 F Basic functions
REX640
Technical Manual
267