ABB REG670 - Page 273

7. Confirm that a circulating current is measured on the local HMI that is equal in
magnitude to 5% of I2Base, with polarity as discussed in step 6.
8. Confirm the settings for Ci (Compensation Factor) and Xi (Transformer Short
Circuit Impedance). Using these setting values and the measured quantity of
circulating current from the local HMI (Icc_i), calculate the value for circulating
current voltage adjustment Vci.
_Vdi Ci Icc i Xi= × ×
EQUATION2089-ANSI V1 EN-US (Equation 115)
The voltage regulation algorithm then increases (for transformer T2) or decreases
(for transformer T1) the measured voltage by Vdi and compares Vi against the
voltage deadband limits V1 and V2 for the purposes of voltage regulation.
Vi VB Vdi= +
EQUATION2091-ANSI V1 EN-US (Equation 116)
9. To cause a tap change, the calculated value for circulating current voltage
adjustment must offset the injected quantity for bus voltage V
B
so that Vi is
outside the voltage deadband created by setting VDeadband. Expressed by
equation 117 and equation 118.
2Vdi V VB> -
EQUATION2093-ANSI V1 EN-US (Equation 117)
VB Vset=
EQUATION2095-ANSI V1 EN-US (Equation 118)
(for the purposes of this test procedure)
Therfore:
_ 2Ci Icc i Xi V Vset× × > -
EQUATION2097-ANSI V1 EN-US
(Equation 119)
( )
( )
2
_
V Vset
Icc i
Ci Xi
-
>
×
EQUATION2099-ANSI V1 EN-US (Equation 120)
1MRK 502 073-UUS A Section 13
Testing functionality by secondary injection
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062 267
Commissioning manual