ABB RET670 Applications Manual page 559

1MRK504116-UUS C
Application manual
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 142.
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 142.
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 143.
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 143.
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
• 80-95% Stator earth fault protection (measured or calculated 3Vo) (59GN)
• Rotor earth fault protection (with external COMBIFLEX RXTTE4 injection
unit) (64F)
• Underimpedance protection (21)
• Voltage Controlled/Restrained Overcurrent protection (51C, 51V)
Section 3
IED application
553