Settings For Each Step (X = 1, 2, 3 And 4) - Hitachi Relion 670 Series Applications Manual

1MRK511407-UUS Rev. N
SOTF: This parameter can be set: Disabled/SOTF/Under Time/SOTF+Under Time.
SOTFSel: This setting will select the signal to activate SOTF function; CB position open/CB position
closed/CB close command.
StepForSOTF: If this parameter is set on step 3, the step 3 pickup signal will be used as current set level.
If set on step 2, the step 2 pickup signal will be used as current set level.
HarmBlkSOTF: To On/Off harmonic restrain of the Under-time logic.
tSOTF: Time delay for operation of the SOTF function. The setting range is 0.000 - 60.000 s in step of
0.001 s. The default setting is 0.100 s.
t4U: Time interval when the SOTF function is active after breaker closing. The setting range is 0.000 -
60.000 s in step of 0.001 s. The default setting is 1.000 s.
ActUndrTimeSel: Describes the mode to activate the sensitive undertime function. The function can be
activated by Circuit breaker position (change) or Circuit breaker command.
tUnderTime: Time delay for operation of the sensitive undertime function. The setting range is 0.000 -
60.000 s in step of 0.001 s. The default setting is 0.300 s.
8.2.3.5

Settings for each step (x = 1, 2, 3 and 4)

Operation: Sets the protection to Enabled or Disabled.
DirModeSelx: The directional mode of step x. Possible settings are Disabled/Non-directional/Forward/
Reverse.
Characteristx: Selection of time characteristic for step x. Definite time delay and different types of inverse
time characteristics are available.
Inverse time characteristic enables fast fault clearance of high current faults at the same time as
selectivity to other inverse time phase overcurrent protections can be assured. This is mainly used in
radial fed networks but can also be used in meshed networks. In meshed networks, the settings must be
based on network fault calculations.
To assure selectivity between different protections, in the radial network, there has to be a minimum time
difference Dt between the time delays of two protections. To determine the shortest possible time
difference, the operation time of protections, breaker opening time and protection resetting time must be
known. These time delays can vary significantly between different protective equipment. The following
time delays can be estimated:
Protection trip time:
Protection resetting time:
Breaker opening time:
The different characteristics are described in the technical reference manual.
tx: Definite time delay for step x. The definite time tx is added to the inverse time when inverse time
characteristic is selected. Note that the value set is the time between activation of the start and the trip
outputs.
Pickup"x": Operate residual current level for step x given in % of IB.
Phasor measurement unit RES670
Application manual
15-60 ms
15-60 ms
20-120 ms
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Section 8
Current protection
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