Hitachi Relion 650 Series Technical Manual page 94

Section 9
Control
Contact separation target
zero crossing of phase L3)
The target contact separation instant Y is obtained by extrapolating future zero crossings (using the
received average half cycle time) and selecting a reachable one, that is, farther in the future than the
expected mechanical opening time. The breaker release instant is then defined as:
Breaker release instant = Y − (Mech operating time + miscellaneous compensation)
where,
Mech operating time = INPRIOPLx input value
miscellaneous compensation = COMPOFOLx + ARCEXTLx
where,
COMPOFOLx is the total compensation of environmental factors affecting CB opening time;
ARCEXTLx is the adaptive correction value for re-ignitions / re-strikes, received from ACBMSCBR.
These calculations are performed for the three phases to obtain the respective CB release instants
(time stamps). Finally, the function checks whether these timestamps are farther in the future than
25ms (PIO hardware time). If this condition holds true, the function issues the same instants as three
open commands on the OPCMDL1, OPCMDL2, and OPCMDL3 outputs. Otherwise, the function
adds a safe time of one power cycle to the determined timestamps and then issues the open
commands.
The function raises two outputs OPCMDINP (issued with a timestamp) and OPOPRGNL (issued
without a timestamp) upon receiving the input command CMDOPEN. The duration of OPCMDINP is
same as the duration of input command received by the function. The output OPOPRGNL is
activated by the function as soon as one of the switching commands OPCMDL1, OPCMDL2 or
OPCMDL3 is activated and remains active until all three commands are deactivated.
Information common to controlled closing/opening operations
The time difference between the controlled switching command for each phase and the input
command is given by the outputs CMDDELYLx, where,
CMDDELYLx = time diff (OPCMDLx, CMDOPEN) or
CMDDELYLx = time diff (CLCMDLx, CMDCLOSE),
based on the type of input command received (either open or close command).
These values are updated when the function issues controlled switching commands and are
published for a duration of 2 seconds if no input command is received within this duration. For an
uncontrolled operation, these outputs are published as 0.0.
When the function receives an input command, it issues a binary output STRDPOW in the very next
task-time indicating the start of point-on-wave controlling. This output remains active until the last
controlled command output is deactivated. Since this output is an indication of controlled switching
operation, it does not get activated during a bypassed or a blocked operation.
Deactivation of switching command outputs
Once the controlled switching commands are released by the function, the outputs must remain
active for some time to guarantee reliable execution of the CB operation. SSCPOW uses a
88
= OpenTargetL1 + OpenTargetL3-L1 – 240° (based on positive going
L3
For controlled opening, the mechanical target contact separation instants are defined
by settings.
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