[dwsyns03-210912-01.tif, 1, en_US]
Figure 8-56 Synchronization of 2 Busbars via Cross-Coupling, Connection via 4 Voltage Inputs
Definition of the Variables
The definition of the variables is important for understanding the following implementation. The reference
side 1 indicates the function with 1. This yields the reference values voltage V1, frequency f1, and phase angle
α1. The side to be synchronized indicates the function with 2. The electrical variables of side 2 are then the
voltage V2, frequency f2, and phase angle α2.
When forming the differential variables, the function is oriented to the definition of the absolute measuring
error (Δ x = measured value – real value). The reference value and hence the real value is side 1. This results in
the following calculation specifications:
Differential voltage dV = V2 – V1
A positive sign means that the voltage V2 is greater than the voltage V1. In other cases, the sign is negative.
Differential frequency df = f2 – f1
A positive result means that according to the example from Figure 8-54 the busbar frequency is greater than
the line frequency.
Phase-angle difference dα = α2 – α1
The representation is limited to ±180
o
. A positive result means that α2 leads by a maximum of 180
o
. In the
case of a negative value, α2 lags by a maximum of 180
o
. Figure 8-57 shows the circumstances. The phase
angle α1 was added to the zero axis as a reference system.
If asynchronous systems are present and the frequency f2 is greater than f1, the angle dα then changes from
the negative value to 0 and then to the positive value. As shown in Figure 8-57, the direction of rotation is
counterclockwise (mathematically positive). At f2 < f1, the direction of rotation is clockwise.
Control Functions
8.4 Synchronization Function
1130 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017
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