In modern power systems isolated generators are veryrare. Power systems are highly
interconnected and many generators share the load. The first problem of an engineer is
connectinga synchronous generator onan existingbus.
CONNECTING a GENERATOR to a BUS
The above figure illustrates a generator G1 which is already connected to a power
grid under load. Generator 2 has to be connected or “brought on line”
1. The prime mover of the generator has to bringthe speed of the shaft close to the
rated speed of the generator.
2. The excitation of the generator has to be increasedto give a no-load output
voltage as close as possible to the existingbus voltage
We want to create a phasor rotation for generator 2 output similar to the
bus voltage phasor.
3. Observe the lights which are connected across the switches: theyshould beat, first
get brighter and then dimas the phasors for generator and bus respectivelyshift.
If the 3 lights beat concurrently, the phase sequence is correct, else if lightsbeat
out of phase, one pair of phases should be reversed.
4. Adjust now the prime mover to slowlyincrease/decrease the speedof generator 2.
One should observe a slow beat of the light brightness.
5. When the lamps beat slowly, the switches should be closed when the lightsare
extinguished(line-line voltage at minimum).
interconnected and many generators share the load. The first problem of an engineer is
connectinga synchronous generator onan existingbus.
CONNECTING a GENERATOR to a BUS
grid under load. Generator 2 has to be connected or “brought on line”
1. The prime mover of the generator has to bringthe speed of the shaft close to the
rated speed of the generator.
2. The excitation of the generator has to be increasedto give a no-load output
voltage as close as possible to the existingbus voltage
We want to create a phasor rotation for generator 2 output similar to the
bus voltage phasor.
3. Observe the lights which are connected across the switches: theyshould beat, first
get brighter and then dimas the phasors for generator and bus respectivelyshift.
If the 3 lights beat concurrently, the phase sequence is correct, else if lightsbeat
out of phase, one pair of phases should be reversed.
4. Adjust now the prime mover to slowlyincrease/decrease the speedof generator 2.
One should observe a slow beat of the light brightness.
5. When the lamps beat slowly, the switches should be closed when the lightsare
extinguished(line-line voltage at minimum).
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