Vacuum Interrupter Leakage Detection Section
When the
Yes
option is chosen for the
Leakage Current Error Check
mode, after every
Open
operation leakage current sensing is delayed by the
Delay Before VI Leakage
Detection Enabled
setpoint. Only current above the
Current Level for VI Leakage
Detection
setpoint is considered leakage current. The duration of leakage current at
each pole is totaled by the
Leakage Current Definite Time Element
Timers
. At
60 Hz, one cycle = 16 ms. When the number of mlliseconds recorded by any of the
Leakage
Current Definite Time Element
Timers
equals the number of cycles configured for
the
Definite Time Delay
setpoint, a VI Leakage Detection error is reported. When any
pole timer reaches 50% of the
Definite Time Delay
setpoint, an alarm is reported, and
at 80% of the
Definite Time Delay
setpoint, a warning is reported. When no VI leakage
current is detected for the duration of the
Definite Time Element Reset Timer
setpoint,
all
Leakage Current Definite Time Element
Timers
are reset to 0.
Figure 62. Default Reference Impedance (Z) Angle diagrams as plotted on their respective
resistance and reactance (r/x) planes, Direction X operating area is red, Direction Y operating
area is green. Note 1: Default Blocking Region for Direction Y (a= 33
°
). Note 2: Default
Blocking Region for Direction X.
Default
= 33
°
Default
= 33
°
Default
= 45
°
Default
= 45
°
Note
1
Note
2
Phase
Reference Impedance Angle
Negative Sequence
Reference Impedance Angle
Phase Reference Angle
Special Case (SLG Events)
Zero Sequence Reference Impedance
Angle Multigrounded
Direction X
Operating
Region
Direction X
Operating
Region
Direction X
Operating
Region
Direction X
Operating
Region
114 S&C Instruction Sheet 766-530
Protection Setup