ABB RELION REX640 Technical Manual page 342

Section 4
Protection functions
336
Cross-polarizing as polarizing quantity
Table 371: Equations for calculating angle difference for cross-polarizing method
Faulte Used Used
d fault polarizing
phase current voltage
s
A I U
A BC
B I U
B CA
C I U
C AB
A - B I - I U -
A B BC
U
CA
B - C I - I U -
B C CA
U
AB
C - A I - I U -
C A AB
U
BC
The angle difference between the polarizing quantity U
marked as φ in an example of the phasors in a single-phase earth fault where the
faulted phase is phase A. The polarizing quantity is rotated with 90 degrees. The
characteristic angle is assumed to be ~ 0 degrees.
GUID-6EC57AED-3CE5-4CDF-8E44-A79712B07915 V1 EN
Figure 189: Single-phase earth fault, phase A
Angle difference
ANGLE A _ ( U ) -
ϕ
=
BC
GUID-7DE1B989-9FC4-4B39-886E-49F238723C17 V1 EN
ANGLE B _ ( U ) -
ϕ
=
CA
GUID-2582E2FC-6BE1-47BA-BF81-946DB42555BE V1 EN
ANGLE C _ ( U ) -
ϕ
=
AB
GUID-541C8B33-F03B-4318-9643-EBA07217DE56 V1 EN
ANGLE A _ ( U
ϕ
=
BC
GUID-14F08460-B195-45D4-B6C7-E4D6B0DF7181 V1 EN
ANGLE B _ ( U -
ϕ
=
CA
GUID-2FCD1D1D-87F3-47B9-B60C-FD2E527EE751 V1 EN
ANGLE C _ ( U
ϕ
=
AB
GUID-4E97305F-C786-4AEC-A58A-F7DAAAA71FB4 V1 EN
1MRS759142 C
o
( ) - I 90
ϕ ϕ
+
A
RCA
(Equation 14)
o
( ) - I 90
ϕ ϕ
+
B
RCA
(Equation 15)
o
( ) - I 90
ϕ ϕ
+
C
RCA
(Equation 16)
- U ) - ( - I I ) -
ϕ ϕ
CA A B
RCA
(Equation 17)
U ) - ( - I I ) -
ϕ ϕ
AB B C
RCA
(Equation 18)
- U ) - ( - I I ) -
ϕ ϕ
BC C A
RCA
(Equation 19)
and operating quantity I
BC
Technical Manual
o
90
+
o
90
+
o
90
+
is
A
REX640