ABB 615 Series - Page 383

Yo j
I
V
j
A
kV
j
gFd
ph
≈ − ⋅ = − ⋅ = − ⋅
10
15 3
1 15. milliSiemens
GUID-97B578C9-6433-40A1-8900-69BC344E4756 V1 EN (Equation 28)
The result is valid regardless of the neutral grounding method.
In this case, the resistive part of the measured admittance is due to leakage losses of the
protected feeder. As they are typically very small, the resistive part is close to zero. Due
to inaccuracies in the voltage and current measurement, the small real part of the apparent
neutral admittance may appear positive. This should be considered in the setting of the
admittance characteristic.
Fault in the forward direction, that is, inside the protected feeder.
Ungrounded network:
Yo Y
Bgtot
=
GUID-5F1D2145-3C0F-4F8F-9E17-5B88C1822566 V1 EN (Equation 29)
≈ ⋅
−








j
I I
V
gTot gFd
ph
GUID-A59B653A-E421-4A65-BD70-77512A1106BE V1 EN (Equation 30)
Compensated network:
Yo Y Y
Bgtot CC
= +
GUID-F3810944-D0E1-4C9A-A99B-8409F4D3CF05 V1 EN (Equation 31)
≈
+ ⋅ ⋅ −
( )
−
( )
I j I K I
V
Rcc gTot gFd
ph
1
GUID-8F6E7E63-7784-46F1-B1B4-5872F11BDF8C V1 EN (Equation 32)
High-resistance grounded network:
Yo Y Y
Bgtot Rn
= +
GUID-F91DA4E4-F439-4BFA-AA0D-5839B1574946 V1 EN (Equation 33)
1MAC059074-MB A Section 4
Protection functions
615 series ANSI 377
Technical Manual