Frequent Start Protection; Directional Earth Fault Stages I - Allen-Bradley Rockwell Automation 857 User Manual

10-12
Technical Data
857-UM001A-EN-P – July 2009
Table 10.28 – Directional earth fault stages I
Pick-up current
Start voltage
Input signal
Mode
Base angle setting range
Operation angle
Definite time function:
- Operating time
IDMT function:
- Delay curve family
- Curve type
- Time multiplier k
Start time
Reset time
Reset ratio
Inaccuracy:
- Starting Uo&Io (rated value I
n
- Starting Uo&Io (Peak Mode when,
rated value Io = 1 .. 10A)
n
- Angle
- Operate time at definite time function
- Operate time at IDMT function
EI = Extremely Inverse, NI = Normal Inverse, VI = Very Inverse, LTI = Long Time Inverse,
MI= Moderately Inverse
This is the instantaneous time i.e. the minimum total operational time including the fault
detection time and operation time of the trip contacts.

Frequent start protection

Table 10.29 – Frequent start protection N> (66)
Settings:
- Max motor starts
- Min time between motor starts
Operation time
Inaccuracy:
- Min time between motor starts
ϕ>, I ϕ>> (67N)
0 0
0.01 - 8.00 x I
0n
0.05 ... 20.0 When I
1 – 20 %U
0n
I ( input X1-7 & 8)
0
I ( input X1-9 & 10)
02
I ( = I +I +I )
0Calc L1 L2 L3
Non-directional/Sector/ResCap
-180° to + 179°
±88° (10° - 170°)
0.10 – 300.00 s (step 0.02 s)
(DT), IEC, IEEE, RI Prg
EI, VI, NI, LTI, MI...depends on the family
0.05 – 20.0, except
0.50 – 20.0 for RXIDG, IEEE and IEEE2
Typically 60 ms
<95 ms
0.95
= 1 .. 5A) ±3% of the set value or ±0.3% of the rated value
±5% of the set value or ±2% of the rated value
(Sine wave <65 Hz)
±2°
±1% or ±30 ms
±5% or at least ±30 ms
1 – 20
0.0 – 100 min. (step 0.1 min)
<250 ms
±5% of the set value
0Calc