ABB RELION 620 Series Technical Manual page 832

Section 5
Protection related functions
5.4.6
5.4.7
Table 790: PHIZ Group settings (Basic)
Parameter
Security Level
Table 791: PHIZ Non group settings (Basic)
Parameter
Operation
System type
826
high-impedance faults do not pose imminent danger to power system equipment.
However, they are a considerable threat to people and property. The IEEE Power
System Relay Committee working group on High Impedance Fault Detection
Technology defines High Impedance Faults as those that 'do not produce enough fault
current to be detectable by conventional overcurrent relays or fuses.
PHIZ always needs sensitive Io measurement.
High-impedance fault (PHIZ) detection requires a different approach than that for
conventional low-impedance faults. Reliable detection of PHIZ provides safety to
humans and animals. PHIZ detection can also prevent fire and minimize property
damage. ABB has developed innovative technology for high-impedance fault
detection with over ten years of research resulting in many successful field tests.
Signals
Table 788: PHIZ Input signals
Name
Io
BLOCK
CB_CLOSED
CB_OPEN
Table 789: PHIZ Output signals
Name
OPERATE
Settings
Values (Range) Unit
1...10
Values (Range) Unit
1=on
5=off
1=Grounded
2=Ungrounded
Type Default Description
Signal 0 Earth current measured using SEF CT
BOOLEAN 0=False Block signal for activating the blocking mode
BOOLEAN 0=False Circuit Breaker Closed input
BOOLEAN 0=False Circuit Breaker Open input
Type Description
BOOLEAN Operate
Step Default
1 5
Step Default
1=on
1=Grounded
1MRS757644 F
Description
Security Level
Description
Operation Off / On
System Type
Technical Manual
620 series