Environmental Engineering Reference
In-Depth Information
Figure 5.26
Curve of the Torque of a Synchronous Machine with Cylindrical
Rotor as a Function of the Load Angle
ϑ
and the Internal Voltage
V
p
unacceptable strain on the mains and could even damage the generator.
Therefore, the following
synchronization conditions
must be fulfilled before
connecting a synchronous generator to the mains:
•
same phase sequence of mains and stator (same sense of rotation)
•
equality of the frequencies of stator and mains
•
equality of the voltage amplitude of stator and mains
•
equality of phase characteristic of the stator and mains voltage.
The synchronization of a modern synchronous generator usually happens fully
automatically. The following synchronization conditions must be fulfilled as a
minimum (VDEW, 1994):
•
voltage difference
∆
V
< ± 10%
V
N
•
frequency difference
∆
f
< ± 0.5 Hz
•
phase angle difference
∆ϕ
< ± 10°.
Asynchronous machines, which are described in the next section, do not need
such a synchronization process.
