UNBALANCE LOAD, REVERSE POWER IN SYNCHRONIZATION

Hi ,

We have five 3512B CAT generators with Woodward 2500 synchronizing panels.
Have issue with generator one only(given name 1),So when this 1 gen. is online with any other generators, will be having load sharing issue specially at the time of sudden increase of load. At this time power factor leads to 0.1 and active power goes to negative and sometimes breaker trips because of reverse power. It happens once in a week or twice.
I have tried swapping Woodward 2500 from other generator, speed controller 2301 and also changed the PWM converter but still the results are same.
If need more data to analyze, i will provide it.
Thanks
 
Hi

Would be glad to give you some assistance if you can provide followings items:
A single line diagram
Event record /Sequence of event or trends...

Also is there kind of PMS(Power management system) installed..

OEM of the devices /equipments.. Like AVR generator protection relay if applicable..

Regards
James
 
Hi

Would be glad to give you some assistance if you can provide followings items:
A single line diagram
Event record /Sequence of event or trends...

Also is there kind of PMS(Power management system) installed..

OEM of the devices /equipments.. Like AVR generator protection relay if applicable..

Regards
James
Hi James,

Thanks for the reply.
I have attached single line diagram and event record.
OEM
Generator:- caterpillar 3512 B
Synchronizing:- woodward-2500
speed controller:- 2301 A
AVR:- DECS-100
 

Attachments

Hi @JSMHARISH

thank you for this reply and added informations ..

Can you share a event record with Frequency and Mvar display ?? if possible..

Also do you have a PMS ( power management system )

I will review features of Woodward 2500 and Speed controller 2301

It looks like this is an island mode operation ? do you confirm ?

The functionnality/philosophy of Load sharing should be reviewd for a smoother operation of this utility
 
Hi @JSMHARISH

thank you for this reply and added informations ..

Can you share a event record with Frequency and Mvar display ?? if possible..

Also do you have a PMS ( power management system )

I will review features of Woodward 2500 and Speed controller 2301

It looks like this is an island mode operation ? do you confirm ?

The functionnality/philosophy of Load sharing should be reviewd for a smoother operation of this utility
Yes it is island mode of operation.
Do not have records of frequency/Mvar but i assure you there is no change in RPM or frequency while this happens.
 
Thank you for this answer..

It may be a confusion /fight between Woodward 2500 and Woodward 2301 ,Are you ok with the droop /isochonous seeting for the load sharing operating mode?

You can check load gain adjsutement on the Woodward 2301 manual for that purpose
 
Also check if :

Active power load share factor/ parameter is correctly set on the Woodward 2500 ( see page 303 of Woodward 2500 manual)
James
i have swapped the 2500 with other generator which is working fine. Gen1 Woodward working fine in Gen2 but gen2 Woodward shows same problem in Gen1.
Same i did for 2301 and result was same.
so above swapping confirms that both modules are ok with correct parameters.
moreover i have tried gain setting but it does no helped me as well.

I had access of DECS (AVR) and matched all settings from other generator like droop setting 5%.

Now i have a doubt is this all is possible because of RRA(Rotating rectifier assembly, excitation voltage) or AVR, because i can not see any voltage fluctuations on common bus.
 
James
i have swapped the 2500 with other generator which is working fine. Gen1 Woodward working fine in Gen2 but gen2 Woodward shows same problem in Gen1.
Same i did for 2301 and result was same.
so above swapping confirms that both modules are ok with correct parameters.
moreover i have tried gain setting but it does no helped me as well.

I had access of DECS (AVR) and matched all settings from other generator like droop setting 5%.

Now i have a doubt is this all is possible because of RRA(Rotating rectifier assembly, excitation voltage) or AVR, because i can not see any voltage fluctuations on common bus.
@JSMHARISH

Is that a new installation?


What is "normal operation " of the utility ? I mean load consumers list ? do you have that document available ?

I understand that there is no PMS ..can you confirm it will be better for understanding whats happening on this plant.

I advise you to read those lines and check if the installation comply with these rules..

GENERATOR LOAD SHARING PRINCIPLE EXAMPLES

Although the generator load sharing principle may seem complicated, taking a closer look at different methods of generator load sharing can help to make things more clear. For example, types of load sharing include:


  • Droop Load Sharing: Reactive droop compensation “allows the engine speed or alternator voltage to decline by a predetermined percentage of the output range as the load increases” (Cummins Power Generation).
  • Isochronous kW and kVAR Load Sharing: Isochronous systems make use of controls to calculate load information and determine how the percentage of the generators’ load compares to the system load. kW refers to real power sharing whereas kVAR refers to reactive power; both kW and kVAR loads are calculated by control systems in order to sufficiently share loads between generators.
  • Cross Current Compensation: When paralleled generators are run without intentional voltage droop, cross-current compensation occurs. Voltage regulators on each generator unit should be identical for successful load sharing.
  • Using Different Operating Modes: By utilizing single board paralleling controllers it becomes much easier to successfully add generators to existing systems as well as to complete upgrades to systems. Single board paralleling controllers also make it possible to operate paralleled generators in different load level modes (some generators may be set to a base, constant mode while other designated units will float and share loads as needed).

Proper generator load sharing is essential for the success of a parallel generator system and in turn for backup power. In case of emergencies when power failure occurs, redundancy is vital to keep mission-critical functions running without fail. Be sure to review different methods of and basics of the generator load sharing principle to find the best solution for your particular power generator needs. It can also be helpful to review before purchasing generators to help understand which units will be easily compatible for a paralleling set.
 
JSMHarish...
First, welcome to Control Automation.
1) Please provide generator parameters, kW, V, A, Pf, Hz, and operating hours since last maintenance, if any?
2) Did the problem suddenly appear or gradually over a long period of time?
3) Can you provide a chart listing kW and Pf for all 5 Gensets during a trouble period?
4) Do you experience problems when any genset is synchronized to the load bus?
Regards, Phil Corso
 
JSMHarish...
The generators are rated ekW=1,045, but are operating at 20-30% of rating! Why?
Usually, if not about 70%, then the present low-load operation will cause a host of problems! One, is the problem you are experiencing, another is reduced service-life!
Is a Mfg representative on-site? If not, I urge you get one as soon as possible!
Phil Corso ([email protected])
 
Perhaps you and Blake should quit changing components and find the fault in the measuring devices.

I have had a simple fault in a 5 amp CT ribbon cable cause huge problems.

Changing controllers on verifies that the controllers inputs are incorrect.
 
Hi

Wjhat we need to know now is nature of load consumers ( reactive capacitive inudctive load banks )?

Hi ,

We have five 3512B CAT generators with Woodward 2500 synchronizing panels.
Have issue with generator one only(given name 1),So when this 1 gen. is online with any other generators, will be having load sharing issue specially at the time of sudden increase of load. At this time power factor leads to 0.1 and active power goes to negative and sometimes breaker trips because of reverse power. It happens once in a week or twice.
I have tried swapping Woodward 2500 from other generator, speed controller 2301 and also changed the PWM converter but still the results are same.
If need more data to analyze, i will provide it.
Thanks
We dont know about Woodward 2301 module load sharing /governor /speed controller

Are you ok with the setting like isochronous/droop mode is ok on the module ..

Look at the OEM Manual there something describing it on page 18 on 52 clearly it is described how to have isochronous mode with that status of auxiliary contact..


James
 
Controls.Guy...
The Generator loads are not Inductive. They are 3-ph AC to DC Bridge Rectifiers.... which also distort generator current wave-shape !
Regards,
Phil Corso
 
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