Rate Of Change Of Voltage Protection; Rate Of Change Of Voltage Protection Implementation; Rate Of Change Of Voltage Logic; Figure 112: Rate Of Change Of Voltage Protection Logic - GE MiCOM P40 Agile Technical Manual

Chapter 10 - Voltage Protection Functions
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 would 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 VOLT 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/dt Meas Mode
VA
dV/ dt
VAB
dv/dt1 AvgCycles
Reset
Freq Not Found
dv/dt1 Threshold
dv/dt Meas Mode
VB
dV/ dt
VBC
dv/dt1 AvgCycles
Reset
Freq Not Found
dv/dt1 Threshold
dv/dt Meas Mode
VC
dV/ dt
VCA
dv/dt1 AvgCycles
Reset
Freq Not Found
dv/dt1 Threshold
dv/dt 1 Function
Positive
Both
Negative
Disabled
dv/ dt1 Blocking
V< Operate mode
Any Phase
Three Phase

Figure 112: Rate of Change of Voltage protection logic

216
Averaging
-1
×
Averaging
-1
×
Averaging
-1
×
1
1
1
dv/dt1 TimeDelay
&
1
DT
&
dv/dt1 TimeDelay
&
1
DT
&
dv/dt1 TimeDelay
&
1
DT
&
dv/dt 1 StartA/AB
dv /dt1 Trip A/AB
dv/dt1 StartB/BC
dv/ dt1 Trip B/BC
dv/dt1 StartC/CA
dv/dt 1 Trip C/CA
1
&
1
dv/dt1 Start
&
&
1
&
1
dv/dt 1 Trip
&
&
P14xEd1-TM-EN-1
P14x
V00806