WOODWARD MSLC AND DSLC OPERATION

[LASP]

Hello all,
We have WoodWard DSLC and MSLC and experience some problems whit the kvar.
Someone know if the DLSC control the PF in the load and unload ramp?
We experience reactive KVAR when the machine synchronize and in the unload process. The genset work fine in base load or import / export no problem with the p.f. when the MSLC synchronize to the main, all the genset change from load sharing to base load, in this change the kw begins to ramp to the base load set o.k. no problem but all the genset experience change in the kvar, all the genset absorbed kvar (negative kvar) and all units trip in reverse kvar.

Any comments?

thanks

 

[catserveng]

The DSLC does try to control in the ramp regions, however depending on CT ratio, the signal get small enough to not be able to control well.

The best way to prevent these problems is to have your generator nominal voltage set slightly above your bus or system nominal, that way when the DSLC voltage bias is at zero the generator will be putting out some VAR's when it first comes on or is going off line. The other thing that contributes to this kind of problem is how your interface between the DSLC and your AVR is set up, you need to assure the resolution of the DSLC voltage bias and maximum range matches your AVR. You also need to make sure your PT and CT calibrations were done correctly so the DSLC/MSLC is controlling to the correct values. About 95% of the time I'm called to correct problems with these controls I find the initial setup and calibrations were either poorly done or not done at all. It takes some time to get things dialed in right, but when properly done these controls work very well and provide long term reliable operation.

Hope that helps.

Mike L.

 

[LASP]

hello Mike
thanks for the info.
the DSLC is connected to the Cat. DVR regulator, do you know how to interconnect the voltage bias signal to the DVR? What value of resistor need I?

we take the connection diagram from the EGCP-2 but the voltage bias is +-3V


thanks

 

[catserveng]

Sorry,
I'm traveling this week and don't have my older files with me. As I remember the EGCP-2 Volt bias is pretty close. Your best bet is to contact Woodward, they have a good collection of interconnect drawings for many different AVR's.

What is your nominal generator voltage? What DSLC part number, usually for a CAT it's a 9905-373.

If you can't get any help I'll be home Labor Day and can look it up then.

Mike L.

 

[niallnz]

For the DVR connect the bias lines to terminals 7(in) & 45(com). Place 500ohm resistor in parallel with the DSLC output and a 1.62kOhm resistor in series with the DVR input terminal 7.

Adjustment Procedure:
1. Measure across terminals 32(+) and 33 (-) prior to connecting to DVR = 0.0 volts
2. Connect to DVR, measure across terminals 7 and 45 = 2 volts
3. The Cat DVR uses 2 volts as the zero bias point, taking a 0 - 4 volt input to change the voltage reference +/- 10%.
4. Start Generator
5. Adjust Volts Bias Offset for Rated Voltage
6. Save this value
7. The items in the Reactive Load menu may need adjusted for stable Power Factor control.

Cheers
Niall