KW and KVAR Hunting

can i get idae of what percent droop u maintained while asyncronous mode.

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the droop for all genies is 3%. i hav provided close con tact to make them run in iso mode and hav checked that they r running in iso by woodward watch window software

If we have problem with KW and KVAR Hunting, we always check the governor system. You already made it on governor, but not for other related item such as magnetic pick-up (speed sensing), power supply to governor, then out-put of UG actuator. We have experience with gear broken in the mechanical part.

this is commissioning stage and i got this problem in sea trials-i am comissionning engineer from generator mfr. The problem is coming intermittently in one particular genie. I need steps to troubleshoot as the ship owner and the pms team blames me but i am clueless, do tell me if it can be possible due to typf of load as v hav thrusters drivn by converters or what to check on governor end

It may be caused by the load if the load type using reciprocating compressor or pumps, and load is high enough.

the problem is both genies go apart when such instantenous loading happens-sometimes only and sometimes both genies hunt synchronously- any way to add files?

It is look like one load sensing system response faster than the other as well as mechanical system or hydraulic system, then it become stable after a certain time.

Sorry I cannot point out the exact caused, bu I believe it is a problem with governor system.

I am attaching the pictures of Generators in action:

1. Gen 1 & 2 are OK, but see the KW & KVAR variations on 3 & 4 genies below.

2. Bow thruster on Gen1 & 2, it shows that there is something to do with the load, but what is that is not known:

3. Gen1&2 and 3&4 variations, pl tell is it the effect of load ?

Hi

Gain and reset settings are available in the Woodward governors. set these settings once again in the folllowing method.

1. Set the gain and the Reset at 50%

2. Run the DG on noload with rated RPM

3. Increase the gain slowly until the hunting starts

4. Decrease the reset slowly( settling time ), until the hunting stops

5. Again increse the gain and decrease the gain as above

6.Do the same for both DGs, your problem will be solved

Hi Anand,

Thanks for the procedure.

I will update this column with the history of happenings:

1. All engines were sent from factory with load trials carried out in 3% droop mode.

2. The factory PID settings were :

a. Prop Gain-3.6

b. Rated reset - 1.2

c. Gain Ratio - 3.0

3. After the PMS trials, during the initial sea-trials we found engine # 3 hunting, we tried without load, but observed heavy wild actuator movement even in no-load.

4. Gov. specialist changed Prop gain values for #3 engine to 3.4 rest original when we came back with 600 KW ship load (since we could not take the ship for sea-trial immediately-the full load for these engines is 2000 KW).

5. After that we proceeded for sea-trails, while on sea-trials, the gov. specialist dropped the settings from the above all and left the trials as the call was only for 2 days. After he left, the PMS team claimed the governors were de-tuned and demanded original settings claiming that we had reduced the settings which resulted in 20% less fuel as per them and said the PMS would not perform optimally in these conditions. I had no choice but to keep the pre-sea trial settings of 3.4, 1.2 and 3.0 for prop. gain, rated reset and gain ratio respectively while others at 3.6, 1.2 and 3.0. After this i observed the reported problems.

6. Now it is not possible to conduct load trials as the owners want a confirmed solution and the ship is supposed top be handed over to charterers.

7. My queries are, is it something to do with the PMS side (as the PMS side is not very open in sharing data), anything.... as i had overheard that the differential relay settings are not matching with my gen. settings. Does it affect in any way to this ?

8. I wanted to know can 1 engine behave like this only sometimes while remaining stable most of the times only due to governor settings ?

Check and make sure one of the CT's is not reversed at what you describe will be caused by that

Please read the woodward 2301D instruction manual, follow the connection either for droop or Iso, or load sharing on load sensing scheme. Have follow the trouble shooting as on instruction manual (see woodward 2301A if you dont have 2301D), Also check the connection to GENSYS.