Base Quantities For Cvgapc Function - ABB RES670 Technical Manual

1MRK 511 408-UUS A
11.1.6.2
11.1.6.3
Phasor measurement unit RES670 2.2 ANSI
Technical 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 189.
2. rated phase current of the protected object in primary amperes multiplied by √3
(1.732*Iphase), when the measured Current Quantity is selected from 10 to 15, as
shown in table 189.
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 190.
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 190.
Built-in overcurrent protection steps
Two overcurrent protection steps are available. They are absolutely identical and
therefore only one will be explained here.
Overcurrent step simply compares the magnitude of the measured current quantity (see
table 189) with the set pickup level. Non-directional overcurrent step will pickup if the
magnitude of the measured current quantity is bigger than this set level. However
depending on other enabled built-in features this overcurrent pickup might not cause
the overcurrent step pickup signal. Pickup signal will only come if all of the enabled
built-in features in the overcurrent step are fulfilled at the same time.
Second harmonic feature
The overcurrent protection step can be restrained by a second harmonic component in
the measured current quantity (see table 189). However it shall be noted that this
feature is not applicable when one of the following measured currents is selected:
• PosSeq (positive sequence current)
• NegSeq (negative sequence current)
• UnbalancePh (unbalance phase current)
• UnbalancePh-Ph (unbalance ph-ph current)
Section 11
Multipurpose protection
M13751-133 v3
M13751-136 v3
M13751-254 v2
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