ABB Relion 670 series - Page 319

For Zone 1,
Z R PPZ j X PPZ
RVset
1 1 1 1 1= + ⋅
IECEQUATION15015 V1 EN-US (Equation 88)
For Zone 2-5 and RV,
Z R Zx j X Zx
RVset
1 1 1= + ⋅
IECEQUATION15016 V1 EN-US (Equation 89)

AB
V
1
AB set
IZ
2
( 1 )
comp AB AB RVset
V V I Z   
1
1
comp AB AB set
V V I Z  
1
AB RVset
IZ
AB
I jX
AB
IR
ANSI 15000058 -1-en.vsdx
ANSI15000058 V1 EN-US
Figure 156: Simplified offset mho characteristic and voltage vector for phase A to B fault
Operation occurs if 90°≤β≤270 °.
Phase-to-ground fault
SEMOD154224-283 v2GUID-DB8CF641-0D3F-4F7A-A628-829F3DB0AC5B v1
The measuring of earth faults uses earth return compensation applied in a conventional way. The
compensation voltage is derived by considering the influence from the earth return path.
Compensation for earth return path for faults involving earth is done by setting the positive and
zero sequence impedance of the line. It is known that the ground compensation factor K
N
is,
1MRK 502 066-UUS B Section 7
Impedance protection
313
Technical manual