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6.2.2.
List of Data of Protection Operation and Protection History Display
The tables below list data which can be checked as one-point traceback and protection history display during
protection operation.
Data item
Display
Unit
Description
Remarks
DC voltage
command
V
DC voltage command.
DC voltage
V
The DC voltage.
AC current
A
The maximum value of absolute
three-phase AC current
instantaneous values.
It is different from the
display of the monitor item.
AC voltage
V
An effective value of AC line
voltage.
AC frequency
Hz
An AC frequency.
AC power
kW
An AC active power.
Positive power is defined as
flowing into power system.
In the tables, AC current shows a current value immediately before a protection operation occurs, out of sampled
values every operation period. Therefore, when current changes at fast rise (such as output short-circuit),
it may not show a correct current value when the protection occurs.