ABB RET670 - Page 215

Pickup Curr
IBase
CT
CTprim
VDepFact_ sec
100
1
100
× ×






× −






VVHighLimit
VBase
VT
VTprim
strainVoltage
−
( )
× ×
× −
25
100
25
10sec
Re
00 100
× ×




















+ ×VBase
VT
VTprim
Pickup Curr
IB
sec _
aase
CT
CTprim
VDepFact
× ×






sec
100
ANSIEQUATION2433 V2 EN (Equation 92)
Third part of the characteristic (VHighLimit/100*VBase ≤ Restrain voltage):
Picup Curr
IBase
CT
CTprim
_ sec
100
× ×
ANSIEQUATION2434 V1 EN (Equation 93)
Example (rated secondary current = 5A):
CT ratio 10 000/5A
VT ratio 10 kV/100 V
Pickup_Curr 100%
VDepFact 25%
VHighLimit 100%
IBase 10 000 A
VBase 10 kV
A test for each section of the characteristic of the function VRPVOC may be
performed; that may be achieved by applying the following voltages:
First section of the characteristic:
If VDepMode = Slope, the minimum measured phase-to-phase voltage is lower than
0,25*VBase; if VDepMode = Step, the minimum measured phase-to-phase voltage
is lower than VHighLimit/100*VBase:
• VA: Ampl = 10 / √3; Angle = 0°
• VB: Ampl = 10 / √3; Angle = 240°
• VC: Ampl = 100 / √3; Angle = 120°
Second section of the characteristic only:
If VDepMode = Slope, the minimum measured phase-to-phase voltage is between
0,25*VBase and VHighLimit/100*VBase:
• VA: Ampl = 50 / √3; Angle = 0°
• VB: Ampl = 50 / √3; Angle = 240°
• VC: Ampl = 100 / √3; Angle = 120°
Last section of the characteristic:
If VDepMode = either Slope or Step, the minimum measured phase-to-phase voltage
is higher than VHighLimit/100*VBase:
1MRK 504 165-UUS - Section 11
Testing functionality by secondary injection
Transformer protection RET670 2.2 ANSI 209
Commissioning manual