to-phase voltages VAB, VBC and VCA. This information about actual VT connection is
entered as a setting parameter for the pre-processing block, which will then take
automatically care about it.
12.1.2.2 Base quantities for CVGAPC function
The parameter settings for the base quantities, which represent the base (100%) for pickup
levels of all measuring stages shall be entered as setting parameters for every CVGAPC
function.
Base current shall be entered as:
1. rated phase current of the protected object in primary amperes, when the measured
Current Quantity is selected from 1 to 9, as shown in table
43.
2. rated phase current of the protected object in primary amperes multiplied by √3
(1.732 x Iphase), when the measured Current Quantity is selected from 10 to 15, as
shown in table 43.
Base voltage shall be entered as:
1. rated phase-to-ground voltage of the protected object in primary kV, when the
measured Voltage Quantity is selected from 1 to 9, as shown in table 44.
2. rated phase-to-phase voltage of the protected object in primary kV, when the
measured Voltage Quantity is selected from 10 to 15, as shown in table
44.
12.1.2.3 Application possibilities
Due to its flexibility the general current and voltage protection (CVGAPC) function can
be used, with appropriate settings and configuration in many different applications. Some
of possible examples are given below:
1. Transformer and line applications:
• Underimpedance protection (circular, non-directional characteristic) (21)
• Underimpedance protection (circular mho characteristic) (21)
• Voltage Controlled/Restrained Overcurrent protection (51C, 51V)
• Phase or Negative/Positive/Zero Sequence (Non-Directional or Directional)
Overcurrent protection (50, 51, 46, 67, 67N, 67Q)
• Phase or phase-to-phase or Negative/Positive/Zero Sequence over/under
voltage protection (27, 59, 47)
• Special thermal overload protection (49)
• Open Phase protection
• Unbalance protection
2. Generator protection
1MRK 506 369-UUS - Section 12
Multipurpose protection
Line distance protection REL670 2.2 ANSI 603
Application manual
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