ABB RELION REX640 Technical Manual page 1047

1MRS759142 F
The function calculates the positive sequence impedance. Calculation is based on
fundamental frequency components of positive sequence current and voltage. If
the measured impedance stays between inner and outer characteristic longer than
predetermined time and moves farther inside the inner characteristic, then a power
swing condition is indicated.
4.7.6.4 Analog channel configuration
DSTRPSB has two analog group inputs which must be properly configured.
Table 980: Analog Inputs
Input
I3P
U3P
There are a few special conditions which must be noted with the configuration.
Table 981: Special conditions
Condition
U3P connected to real measurements
4.7.6.5 Operation principle
The
the function is enabled and respectively "Off" means function is disabled.
The operation of DSTRPSB can be described by using a module diagram (see figure
below). All the modules in the diagram are explained in the next sections.
Figure 584: Function module diagram
Impedance calculation
This module receives positive sequence voltage which is calculated from
fundamental frequency three phase voltages and positive sequence current
calculated respectively from fundamental frequency three phase currents. For the
module to calculate impedance it is required that the positive-sequence current is
above 0.1xIn.
Operation is based on positive sequence impedance (Z
positive sequence voltage and current as follows:
REX640
Technical Manual
Operation setting is used to enable or disable the function. When selected "On"
U3P
I3P
BLOCK
Description
Three-phase currents
Three-phase voltages
Description
The function can work with any two voltage
channels connected but it is recommended
to connect all three voltage channels.
U
1
Impedance
calculation
I
1
I
2
Protection functions
Power
swing
detection
SWING_ST
) which is calculated using
1
PSB
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