Current And Voltage Selection For Cvgapc Function - ABB REB670 Applications Manual

Section 10
Multipurpose protection
10.1.2.1
256
• Definite time delay or Inverse Time Overcurrent TOC/IDMT delay for both
steps
• Second harmonic supervision is available in order to only allow operation of the
overcurrent stage(s) if the content of the second harmonic in the measured
current is lower than pre-set level
• Directional supervision is available in order to only allow operation of the
overcurrent stage(s) if the fault location is in the pre-set direction (Forward or
Reverse). Its behavior during low-level polarizing voltage is settable (Non-
Directional,Block,Memory)
• Voltage restrained/controlled feature is available in order to modify the pick-up
level of the overcurrent stage(s) in proportion to the magnitude of the measured
voltage
• Current restrained feature is available in order to only allow operation of the
overcurrent stage(s) if the measured current quantity is bigger than the set
percentage of the current restrain quantity.
2. Two undercurrent steps with the following built-in features:
• Definite time delay for both steps
3. Two overvoltage steps with the following built-in features
• Definite time delay or Inverse Time Overcurrent TOC/IDMT delay for both
steps
4. Two undervoltage steps with the following built-in features
• Definite time delay or Inverse Time Overcurrent TOC/IDMT delay for both
steps
All these four protection elements within one general protection function works
independently from each other and they can be individually enabled or disabled. However
it shall be once more noted that all these four protection elements measure one selected
current quantity and one selected voltage quantity (see table
to simultaneously use all four-protection elements and their individual stages. Sometimes
in order to obtain desired application functionality it is necessary to provide interaction
between two or more protection elements/stages within one CVGAPC function by
appropriate IED configuration (for example, dead machine protection for generators).

Current and voltage selection for CVGAPC function

CVGAPC function is always connected to three-phase current and three-phase voltage
input in the configuration tool, but it will always measure only the single current and the
single voltage quantity selected by the end user in the setting tool (selected current
quantity and selected voltage quantity).
The user can select, by a setting parameter CurrentInput, to measure one of the following
current quantities shown in table 35.
1MRK 505 337-UUS -
35 and table 36). It is possible
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