Functions
2.9 Jump of Voltage Vector
SIPROTEC, 7RW80, Manual
C53000-G1140-C233-1, Release date 10.2010
107
2.9 Jump of Voltage Vector
Consumers with their own generating plant, for example, feed power directly into a network. The incoming
feeder line is usually the technical and legal ownership boundary between the network operator and these con-
sumers/ producers. A failure of the input feeder line, for example, due to a three-pole automatic reclosure, can
result in a deviation of the voltage or frequency at the feeding generator which is a function of the overall power
balance. When the incoming feeder line is switched on again after the dead time, asynchronous conditions may
prevail that cause damage to the generator or the gear train between generator and drive.
One way to identify an interruption of the incoming feeder is to monitor the phase angle in the voltage. If the
incoming feeder fails, the abrupt current interruption causes a phase angle jump in the voltage. This jump is
detected by means of a delta process. As soon as a preset threshold is exceeded, an opening command for
the generator or bus-tie coupler circuit-breaker is issued.
This means that the vector jump function is mainly used for network decoupling.
2.9.1 Functional Description
Frequency Behaviour on Load Shedding
The following figure shows the evolution of the frequency when a load is disconnected from a generator.
Opening of the generator circuit breaker causes a phase angle jump that can be observed in the frequency
measurement as a frequency jump. The generator is accelerated in accordance with the power system condi-
tions.
Figure 2-31 Change of the Frequency after Disconnection of a Load (Fault recording with the SIPROTEC 4 device –
the figure shows the deviation from the nominal frequency)
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