Hitachi Relion 650 Series Technical Manual page 93

1MRK 511 557-UEN Rev. A
SCATOFLx is a correction value for statistical scatter of the CB closing time.
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
close commands on the CLCMDL1, CLCMDL2, and CLCMDL3 outputs. Otherwise, the function
adds a safe time of one power cycle to the determined timestamps and then issues the close
commands.
The function raises two outputs CLCMDINP (issued with a timestamp) and CLOPRGNL (issued
without a timestamp) upon receiving the input command CMDCLOSE. The duration of CLCMDINP
output is same as the duration of input command received by the function. The output CLOPRGNL is
activated by the function as soon as one of the switching commands CLCMDL1, CLCMDL2 or
CLCMDL3 is activated and remains active until all three commands are deactivated.
Controlled opening operations
Controlled opening is the technique of issuing the CB opening commands such that primary contact
separation will occur at a desired phase angle in each phase, to minimize the risk of re-ignitions or
re-strikes in the CB or to ensure pre-determined electrical or magnetic conditions in the load.
Controlled opening of a CB can be done by using either a voltage or a current reference signal. If the
current signal is not suitable as reference for current-based opening, the function fails to set a
reference for controlled switching and enters contingency mode as explained in
Figure 40
the latest zero crossings, the target contact separation angle, expected arcing time, mechanical
operating time, environmental factor compensation and adaptive correction after detection of re-strike
or re-ignition. When the voltage or current reference signal is found healthy and a CB Open
command is received on the CMDOPEN input, the function starts from the latest received zero
crossing of the reference signal, as shown in
interruption instant, which is usually expected to occur at a natural current zero for all load types
other than (coupled) transformer. Contact separation (instant Y) is expected to precede current
interruption by the target arcing time (not in the scope of this function) to allow sufficient time for
build-up of dielectric strength in the interrupter.
Latest zero
crossing
IEC19000901 V2 EN-US
Figure 42:
From the zero crossing, the function further moves ahead to achieve the mechanical (target) contact
separation instant Y by first adding the target contact separation angle. The target contact separation
for each phase (based on the respective phase) is defined by:
Contact separation target
Contact separation target
crossing of phase L2), and
Technical Manual
shows the calculated time delay for a controlled opening operation, which is a function of
Controlled
command instant
ZC
Input
command
Evaluation of controlled opening switching instants based on breaker current
= OpenTargetL1,
L1
= OpenTargetL1 + OpenTargetL2-L1 –120° (based on positive going zero
L2
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Figure 42. Instant X refers to the electrical (target)
Y
Target contact
Arcing time
separation
Mech operating time +
miscellaneous compensation
Section 9
GUID-4880E6BB-A965-4789-A806-26E43EA15EC6 v2
Section 9.3.7.5.1.
X
Time
IEC19000901-2-en.vsdx
Control
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