EMR-5000
IM02602012E
Voltage vector surge.
As shown in the voltage/time diagram, the instantaneous value of the voltage jumps to another value and the phase
position changes. This is called phase or vector surge.
The relay measures the cycle duration. A new measuring is started at each zero passage. The measured cycle
duration is internally compared with a reference time and from this the deviation of the cycle duration of the voltage
signal is ascertained. In case of a vector surge as shown in the above graphic, the zero passage occurs either earlier
or later. The established deviation of the cycle duration is in compliance with the vector surge angle.
If, depending on
the parameter setting, in all three, in two or in one of the phases, the vector surge exceeds the set threshold and if there
are no blocking commands for the frequency element, an alarm and a trip command is issued instantaneously.
Tripping of the vector surge is blocked in case of loss of one or more phases of the measuring voltage.
Working Principle
(Please refer to block diagram on next page.)
The vector surge element supervises the three phase voltages »
VA«, »VB« and »VC«. If any of the three phase
voltages is below 15% Vn, the vector surge calculation is blocked. According to the frequency supervision mode set in
the Device Planning (78V), the phase voltages are compared to the set vector surge threshold.
If in any of the phases,
the vector surge exceeds the set threshold and if there are no blocking commands for the frequency element, an alarm
and a trip command is issued instantaneously.
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V(t)
V(t)
V(t)`
Trip
t
t=0
78V vector surge
Voltage Vector Surge
