ABB RELION REX640 Technical Manual page 1179

1MRS759142 F
5.4 High-impedance fault detection PHIZ (ANSI HIZ)
5.4.1 Identification
Function description
High-impedance fault detection
5.4.2 Function block
Figure 669: Function block
5.4.3 Functionality
A small percentage of earth faults have a very large impedance. They are comparable
to load impedance and consequently have very little fault current. These high-
impedance faults do not pose imminent danger to power system equipment.
However, they are a substantial threat to humans and properties; people can touch
or get close to conductors carrying large amounts of energy.
ABB has developed a patented technology (US Patent 7,069,116 B2 June 27, 2006, US
Patent 7,085,659 B2 August 1, 2006) to detect a high-impedance fault.
The high-impedance fault detection function PHIZ also contains a blocking
functionality. It is possible to block function outputs, if desired.
5.4.4 Analog channel configuration
PHIZ has two analog group inputs which must be properly configured.
Table 1128: Analog inputs
Input
I3P
IRES
REX640
Technical Manual
See the preprocessing function blocks in this document for the possible
signal sources.
IEC 61850 IEC 60617
identification identification
PHIZ HIF
Description
Three-phase currents
Residual current (measured or calculated)
Protection related functions
ANSI/IEEE C37.2
device number
HIZ
1179