8.
Confirm the settings for C
i
(Compensation Factor) and X
i
(Transformer Short Circuit
Impedance). Using these setting values and the measured quantity of circulating current from
the local HMI (I
cc_i
), calculate the value for circulating current voltage adjustment U
ci
.
_
Udi Ci Icc i Xi
=
×
×
EQUATION2088 V1 EN-US
(Equation 45)
The voltage regulation algorithm then increases (for transformer
T2
) or decreases (for
transformer
T1
) the measured voltage by Udi and compares Ui against the voltage deadband
limits U1 and U2 for the purposes of voltage regulation.
EQUATION2090 V3 EN-US
(Equation 46)
9.
To cause a tap change, the calculated value for circulating current voltage adjustment must
offset the injected quantity for bus voltage U
B
so that Ui is outside the voltage deadband
created by setting
UDeadband
and equation
.
EQUATION2092 V2 EN-US
(Equation 47)
EQUATION2094 V2 EN-US
(Equation 48)
(for the purposes of this test procedure)
Therfore:
_
2
Ci Icc i Xi U
Uset
×
×
>
-
EQUATION2096 V1 EN-US
(Equation 49)
(
)
(
)
2
_
U
Uset
Icc i
Ci Xi
-
>
×
EQUATION2098 V1 EN-US
(Equation 50)
10.
Using the settings for
USet
,
UDeadband
, C (Compensating factor) and
Xr2
(transformer short
circuit impedance) calculate the magnitude of Icc
_i
necessary to cause a tap change
command.
11.
Inject current equal to
I2Base
for Transformer 1 and (
I2Base
- |Icc_
i
|) for Transformer 2 so that
the magnitude of calculated circulating current will cause a raise command to be issued for
Transformer 2 and a lower command for Transformer 1. Magnitude and direction of circulating
currents measured for each transformer can be observed as service values on the local HMI
and raise/lower commands detected from the binary output mapped in the Signal Matrix.
Section 11
1MRK 511 403-UEN Rev. L
Testing functionality by secondary injection
176
Bay control REC670
Commissioning manual
© 2017 - 2022 Hitachi Energy. All rights reserved
Summary of Contents for REC670
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