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23.26 %

40 MVA+12 % to -16 %

110 kV

123.20 kV

92.40 kV

12.5 kV

1847.52 A

22 TAPS

10 TAP

1.27 %

2 STEPS

2.55 %

500 A

12500V / 100V = 125

300A / 1A = 300

IC = V |Z|

112.20 kV

CORRESPONDING SECONDARY VOLTAGE: 12.75 kV

250 V

11.72

2.73

IC = 91.72 A

= 90 A

Current carrying capacity of OLTC as per manufacturer = 500 A

Corresponding current on Secondary side = 4400 A

Set over current Blocking at = 80% OF 4400A

= 3520.00 A

Relay current = 11.7333 A

PRIMARY VOLTAGE ON LOWER TAP:

RESULTANT VOLTAGE:

BASE IMPEDANCE (IN OHMS):

TRAFO IMPEDNACE (IN OHMS):

RECOMMENDED SETTING

NUMBER OF TAPS:

NOMINAL TAP IS NO.:

LOWER THAN OTHER PARALLELED TRANSFORMER(S).

STEP VOLTAGE:

VOLTAGE REGULATION AFTER:

REGULATION SETTING:

TRANSFORMER REGULATION:

PRIMARY SIDE RATED VOLTAGE (NOMINAL TAP):

PRIMARY SIDE RATED VOLTAGE (MAXIMUM TAP):

OVERCURRENT BLOCKING

RATED SECONDARY SIDE CURRENT:

CALCULATION OF CIRCULATING CURRENT

FOR CALCULATION PURPOSES, ASSUME TRANSFORMER IS TWO TAPS

PRIMARY SIDE RATED VOLTAGE (MINIMUM TAP):

SECONDARY SIDE RATED VOLTAGE (AT NOMINAL PRIMARY TAP):

OLTC RATED CURRENT:

CT & VT DATA

VT RATIO FACTOR:

CT RATIO FACTOR:

AVR SETTING CALCULATION

BASIC TRANSFORMER DATA

VECTOR GROUP: YNyn0(d5)

TRANSFORMER RATED POWER IN MVA:

PERCENTAGE IMPEDANCE:

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Recommended O/C blocking I> = 11.7333 A

Recommended Band width Us = 2.55%

corresponding to two tap to avoid the hunting of the OLTC.

BANDWIDTH SELECTION

It is necessary to keep the band width approximately