GE MiCOM P145 Agile User Manual

4 RATE OF CHANGE OF VOLTAGE PROTECTION
Where there are very large loads, imbalances may occur, which could result in rapid decline in system voltage. The
situation could be so bad that shedding one or two stages of load w
ould be unlikely to stop this rapid voltage
decline. In such a situation, standard undervoltage protection will normally have to be supplemented with
protection that responds to the rate of change of voltage. An element is therefore required, which identifies the
high rate of decline of voltage and adapts the load shedding scheme accordingly.
Such protection can identify voltage variations occurring close to nominal voltage thereby providing early warning
of a developing voltage problem. The element can also be used as an alarm to warn operators of unusually high
system voltage variations.
Rate of Change of Voltage protection is also known as dv/dt protection.
4.1 RATE OF CHANGE OF VOLTAGE PROTECTION IMPLEMENTATION
The dV/dt protection functions can be found in the the VOL
T PROTECTION column under the sub-heading DV/DT
PROTECTION. The dv/dt protection consists of two independent stages, which can be configured as either phase-
to-phase or phase-to-neutral using the dv/dt Meas mode cell.
4.2 RATE OF CHANGE OF VOLTAGE LOGIC
dv/dt1 Threshold
dv /dt1 Trip A/AB
dv/dt Meas Mode
V00806
dv/dt1 StartA/AB
dv/ dt1 Blocking
Freq Not Found
dv/dt1 Start
dv/dt1 Trip
V< Operate mode
Any Phase
Three Phase
Averaging
dv/dt1 AvgCycles
-1
dv/dt1 Function
Negative
Positive
Both
Disabled
dV/dt
Reset
&
1
&
1
&
&
&
1
&
&
1
1
DT
&
×
dv/dt1 Threshold
dv/ dt1 Trip B/BC
dv/dt Meas Mode
dv/dt1 StartB/BC
Freq Not Found
Averaging
dv/dt1 AvgCycles
-1
dV/dt
Reset
&
1 DT
&
×
dv/dt1 TimeDelay
dv/dt1 TimeDelay
dv/dt1 Threshold
dv/dt1 Trip C/CA
dv/dt Meas Mode
dv/dt1 StartC/CA
Freq Not Found
Averaging
dv/dt1 AvgCycles
-1
dV/dt
Reset
&
1
DT
&
×
dv/dt1 TimeDelay
1
1
1
VA
VAB
VB
VBC
VC
VCA
Figure 112: Rate of Change of Voltage protection logic
Chapter 10 - Voltage Protection Functions P14x
216 P14xEd1-TM-EN-1

GE MiCOM P145 Agile Specifications

General

Brand	GE
Model	MiCOM P145 Agile
Category	Control Unit
Language	English