Working in thermal power plant with 2x25 mw capacity each governor is 505. When both the unit are connected to grid no problem occurs. But as the grid fails one turbine has to be made master and other as slave. In that case the slave follows the frequency of master. the selection is done manually by a selector switch.

But many times when grid fails the turbine gets tripped due to over frequency.

I want to know is there any option in the 505 governor where it automatically takes the frequency to 50hz when the grid fails?

Pl. HELP

 

Several things are not clear from this post, like if the plant is being separated from the grid when the problem occurs; in other words, is it being "islanded" and supposed to maintain frequency for the load which is also separated from the grid?

If so, has the operation of the plant recently changed, or is this a new plant that has been "designed" to operate independently of a grid during grid problems?

The quote below is taken from the Woodward 505 Digital Governor Manual 85003, Revision A, page 23, obtained from this URL obtained from a Google search:

http://www.dsf-technologies.com/upload/proddocspdf/proddocspdf_2_397.pdf (remove any spaces inserted by the control.com website software):

[Quote}
If the utility tie breaker opens, the control automatically resets the speed reference to the reset-speed set point. This may be synchronous speed or, if plant frequency needs to be maintained after separating from the utility, the reset speed must be above synchronous speed. This speed is determined from the amount of droop programmed into the control and the amount of load the generator is expected to carry. In a droop system, plant frequency varies with generator load. The speed set point can be adjusted manually to compensate for these load changes. The control also is capable of isochronous speed control on an isolated bus. In this type of application, both synchronous-speed and below-synchronous-speed set points could be set at the turbine’s synchronous speed.

<b>Droop</b>

The control is not equipped with a droop/ isochronous switch. If droop is
configured in the Program Mode, it always is engaged and active when the
control is operating in the Run Mode.
[End Quote]

Now, as some have recently said (krush, in particular), Woodward manuals are better than GE manuals. It's certainly not clear to me.

I interpret it to say that if droop control is programmed there is no function to switch to droop control.

But the whole business about plant frequency varying with generator load in a droop system is just, ... well, ... it wouldn't be tolerated at any plant I've ever worked at, and apparently not at the original poster's plant either. Not from an "automatic control system" (governor).

 

There is another thread response which is more appropriate to this thread:

http://www.control.com/post.php?id=1303993320

But, if we have the information correct, it doesn't appear that this control system has the ability to automatically switch from droop to isochronous.

If the plant was supposed to operate in "island" mode, it doesn't seem the proper control system was selected, or that it was programmed properly to accomplish the desired control.

 

QUOTE:

If the utility tie breaker opens, the control automatically resets the speed reference to the reset-speed set point. This may be synchronous speed or, if plant frequency needs to be maintained after separating from the utility, the reset speed must be above synchronous speed. This speed is determined from the amount of droop programmed into the control and the amount of load the generator is expected to carry. In a droop system, plant frequency varies with generator load. The speed set point can be adjusted manually to compensate for these load changes. The control also is capable of isochronous speed control on an isolated bus. In this type of application, both synchronous-speed and below-synchronous-speed set points could be set at the turbine's synchronous speed.

Droop

The control is not equipped with a droop/ isochronous switch. If droop is configured in the Program Mode, it always is engaged and active when the control is operating in the Run Mode.

End QUOTE

I will translate what the above quote is saying. The unit does not have an isochronous mode. When the "utility tie breaker" opens, the governor will automatically reset the SPEED REFERENCE to a setpoint that is programmed (I presume the owner can adjust this setpoint).

If you need the unit to run in "island mode", you need to estimate what the island load is going to be and use the droop % setting to calculate what setpoint to program for the "reset-speed set point". The operator will then be required to manually make adjustments to the speed reference to achieve desired island frequency as loading changes. Another option would be to utilize a woodward system with isoch load sharing....you can pick up modules like a 723 on eBay for under $2000.

Another "trick" that MIGHT work would be to turn the droop setting to 0 (zero). That would essentially be isochronous. Woodward actually says to do this on UG-8 mechanical governors.

Alas CSA, GE wouldn't even place their manual on the interwebs for us to find to have this discussion . Notice the lack of any confusing constant-settable droop....

 

I'm a former Woodward Governor Field Engineer. Send me the part number of the 505 and I will help you with your problem.

From your description, it sounds like the 505 offline dynamics need to be tuned to prevent the over frequency shutdown.

Depending on the part number of your 505 what you want to accomplish is very possible. When the utility breaker opens one unit can shift to frequency control and the other remain in droop as the swing machine.

However, when the utility breaker opens and all your powering is house loads, you may only want to trip droop machine.

 

dear sir,

could you please refer me the setting procedures for speed, frequency, droop for woodward 505 steam governer?

i will be thankful.

 

thanks!

 

I'm a former Woodward Governor Field Engineer. Send me the part number of the 505 and I will help you with your problem.

From your description, it sounds like the 505 offline dynamics need to be tuned to prevent the over frequency shutdown.

Depending on the part number of your 505 what you want to accomplish is very possible. When the utility breaker opens one unit can shift to frequency control and the other remain in droop as the swing machine.

However, when the utility breaker opens and all your powering is house loads, you may only want to trip droop machine.

Hello Sir,
Would you please get in touch, we need you assistance please
at [email protected]

 

dear sir,

could you please refer me the setting procedures for speed, frequency, droop for woodward 505 steam governer?

i will be thankful.

Hello Sir,
If you got the answer please tell me as i am looking for your help