Synchrounizing for generators?

[zaidi289]

Hi,
i have two generators 650 kva and 420 kva wants to synchrounize both of them manually through droop and volatge gain starting amperes are 53 at 430v 50.9 hz when i synchrounize them.Plz tell me the way out.

 

[zaidi289]

starting amperes after synchrounizing are 53A to 138A at 430V to 375V amperes at no load on both generators.

 

[waross]

If the ,open circuit voltages of the generators are not equal. the difference will drive large reactive currents circulating between the two generators.
Set the droop on the governors so that each set is running at 51.5 Hz at no load and drops to 50 Hz at full load. The generators will then share the KW load in proportion to their ratings.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[zaidi289]

i had checked voltages several times and matched it as they were out before.Amperes drop at 40 amperes from 53 amperes but i want it to be at 20 to 22 amperes.

 

[rcw retired EE]

How did you check voltages? Did you measure from phase 1 to phase 1 on the other generator? Or did you just measure the output voltages and adjust until the readings matched? Matching voltages will get the magnitude close but not the phase angle.

How are you synchronzing the generators? If you are not matching voltage and phase with a synchscope, a voltmeter between generators or an oscillscope monitoring the voltage waveforms, you will close the tie breaker out of phase which could cause lots of damage.

You have 40-53 amps but want 20 amps. Is that at no load? If so, why not zero? with no load, the generator's should be able to be adjusted to get the circulating currents clsoe to zero.

 

[waross]

Adjust your governor settings to share real power (Kilo-Watts). This is usually the frequency setting. (Raise-Lower.)
Adjust your voltage settings to minimize circulating current.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[zaidi289]

@rcwilson
Yes i am macthing the voltage from avr and with potentiometer
of both the generators and i also matched the phase from sycnhscope. 20 amperes that I wants is becaz its exciting current is 10 amperes rated on generator 3412 caterpillar and generators are of older models it will always be on 15 to 20 amperes there AVR is also of old version which have droop and voltage gain setting on AVR.