CHAPTER 6: PROTECTION SETPOINTS
VOLTAGE ELEMENTS
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
6–93
Case 2
Behavior when the element trips by exceeding the undervoltage count threshold. The
element operates due to the voltage drop counter exceeding the programmed number
of voltage drops. The sample settings and the expected behavior are shown here.
Figure 6-39: System behavior from Case 2
Case 3
Behavior when the element does not trip even when there are multiple voltage drops
however all within the safe range of the characteristic curve. The time window for
voltage drops is a jumping time window from one set of time to another. It is not a sliding
time window. Hence, there is no Trip observed because the time for voltage drop expires
before the programmed threshold could be reached. The timer resets before the next
voltage drop. The sample settings and the expected behavior are shown below here.
Curve Settings:
As shown in the red characteristic curve
Pickup:
0.90 x VT
Dropout:
105.5 % of PKP (0.95 x VT)
Voltage Drops:
2
Curve Settings:
As shown in the red characteristic curve
Pickup: 0.90
x
VT
Dropout:
105.5 % of PKP (0.95 x VT)
Voltage Drops:
2
PICKUP
DROPOUT
t
xVT
Vnom
Operating
Characteristic
PKP
dropout delay
Ph UV
Counter
1
2 = threshold
3
threshold exceeded
counter reset to 0
TRIP by
Counter
Time
slot for
voltage
drops
timer reset
timer expires
t
t
t
t
1.00
0.95
0.90
timer started
Summary of Contents for Multilin 850
Page 10: ...VIII 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL ...
Page 135: ...CHAPTER 3 INTERFACES SOFTWARE INTERFACE 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL 3 41 ...
Page 151: ...CHAPTER 3 INTERFACES SOFTWARE INTERFACE 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL 3 57 ...
Page 153: ...CHAPTER 3 INTERFACES SOFTWARE INTERFACE 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL 3 59 ...
Page 439: ...CHAPTER 7 MONITORING FUNCTIONS 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL 7 19 ...
Page 644: ...11 20 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL FLEXELEMENTS CHAPTER 11 METERING ...