ABB RELION REX640 Technical Manual page 590

Section 4
Protection functions
584
PCSRTPC
BLOCK
LNPLDF
UNBLOCK
PHIPTOC
UNBLOCK
PHHPTOC(2)
PHHPTOC(1)
PHLPTOC
PCSRTPC
BLOCK
LNPLDF
UNBLOCK
PHIPTOC
UNBLOCK
PHHPTOC(2)
PHHPTOC(1)
PHLPTOC
GUID-08B60EFC-8614-4986-ADBE-42DC25734245 V1 EN
Figure 322: Protection communication supervision detects failures on
communication
In-zone transformer
RED 615
PROTECTED
ZONE
1500A/1
20kV
L
LV
GUID-4FDDAD87-93C3-4411-85F0-DD31A0C38E9F V1 EN
Figure 323: In-zone transformer example about CT ratio correction calculation
The CT ratio correction calculation starts with the rated load current calculation for
HV and LV sides. The rated load current is defined as the rated power of the
transformer divided by the square root of three times the nominal phase-to-phase
voltage at the HV or LV side.
Yd11
40MW
110kV
HV
1MRS759142 C
RED 615
RED 615
PHLPTOC
RED 615
PHHPTOC(1)
PHIPTOC
RED 615
300A/1
~
REX640
Technical Manual