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Current and Kw instabillity Diesel Gen

Current and Kw instabillity Diesel Gen

Current and Kw instabillity Diesel Gen

(OP)
Just wondering if anyone has encounted large current swings when parralling an alternator, controlled by an electronic engine

RE: Current and Kw instabillity Diesel Gen

Watch your synchroscope a little closer when closing the breaker. Droop should be 3% on both machines.

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

RE: Current and Kw instabillity Diesel Gen

Not enough info about system and issue. Is it temporary during initial paralleling or keeps on going? On load ? On no load? Do the gens trip? Yes, this kind of issues occur usually because of bad components or settings. The best bet would be to call service tech of the generator and switchgear system.

If temporary, it is most likely improper sync window, that is voltage, speed and excitation, droop setting etc are not matched closely enough at the time of paralleling.

If it does not settle down, the issues may be further in components like AVR, exciter and governor.




 

Rafiq Bulsara
http://www.srengineersct.com

RE: Current and Kw instabillity Diesel Gen

(OP)
It occurs when the engine is online, say 200kw current undulates by almost 100 amps to what it should be it is ongoing but doesnt trip the gen have replaced avr's etc but still no luck i am just curious if anyone has more problems in the ECU compared to external control

RE: Current and Kw instabillity Diesel Gen

check your fuel rack and governor linkage,for sticking or slackness. Ensure that linkage on all engines has the same set -up position on the governor.

Offshore Engineering&Design

RE: Current and Kw instabillity Diesel Gen

Look for a loose connection in your cross current compensation circuit. Better punctuation would be a help in understanding your problem.
We used to start some large motors with two generators in parallel, one with an electronic governor and one engine with a hydraulic governor. We couldn't start the motors first thing in the morning when the oil was cold. We had to warm up the engine for 15 or 20 minutes and then the dissimilar governors would work and play well together.
If your quadrature circuit (cross current compensation) has a poor connection, you may be shifting reactive current between the machines with very little impact on the engine control (throttle).

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

RE: Current and Kw instabillity Diesel Gen

Try checking your speed feedback signals to the governor controllers from both engines by putting a 'scope on them. If they are magnetic pickups from teeth on flywheels you may be missing pulses or they are smaller than the rest and therefore there are damaged teeth. I have had this.
Another area to check is the analogue speed reference to the actuator - for no loose connections.

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