Control Panel 2

[burntcoil]

I am working to design the first Generator Control Panel for Diesel Generators upto 2MVA. The Panel will be mounted on the Generator Skid. During a site visit I noticed the following components were part of one of the existing Generator Panel.

1. Air Circuit Breaker
2. Genset Controller
3. Emergency Stop Push Button
4. CTs
5. Batter Charger (probably 5A)
6. Other components like MCBs etc.

Can anyone explain me the operation of such Control Panels. What is the purpose of battery charger and from where it will be fed in standalone generator operations? The controller is ON usually even if the generator is standby, so the DC power is taken from the generator battery mounted on the skid? What signals are taken to the controller from the engine and from alternator.

Thanks in advance for your help.

Regards,

Shabir

 

[waross]

The battery charger is not used in stand-alone (islanded) operation. In standby mode it is fed from the normal source. You overlooked the ECM (engine control module). The governor is also an important component. An AVR is quite useful. Any sign of a PMG? Are you sure that you are ready to start designing gen-set panels??

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

 

[ScottyUK]

Have a look online for a Cummins, Cat, SDMO or Wilson panel. There's plenty of information online. You might stumble across some specs published online, especially by utilities in the middle east, which might be of use.

I do share Bill's concern about whether you have sufficent knowledge to design a panel. There are some truly awful panels out there on small diesel sets: even the big names don't always get it right, and they should know everything required from the panel which makes it even more puzzling why their panels are sometimes so poorly laid out and constructed.

 

[catserveng]

A good general resource is the Electrical Generating Systems Association, their website is

http://www.egsa.org

They have a number of standards and an excellent reference book. Not sure where you are in the world but they also have a very good set of training classes,

http://www.egsa.org/Portals/7/Documents/EGSA Schools Brochure 14 Online.pdf

Control Panel design isn't all that hard, but there are a number of details to consider, and the fact that there are so many variations in how generator sets come equipped.

Bill brought up governors, many smaller engines and non-electronically controlled engines require a governor, most electronically controlled engines have the governor built into the ECM. So in the application you are building for will make an accommodation for a governor? Will the unit ever share load or parallel to something else? Then it will need some kind of loadshare module or controller, unless you plan to run in sped droop which in my experience is less common these days for the size units you are targeting.

Same issue regarding a voltage regulator, many manufacturers install the AVR in the generator, in some it is part of an overall controller, in others it is up to the installer to select, provide and install. Again the parallel question, are you? How do you expect to do it? In droop, using an active VAR share controller, or?

Pretty hard to make a one size fits all generator control panel that would work across a fairly large size range and accommodate different engine/generator manufacturers.

If you want to build a good control panel, first you need to define the operation. Standalone may mean one unit only supplying the load, but I work on a large number of "islanded" system with multiple units. Like your battery charger question, if the unit is a standalone, single unit providing prime or continuos power to a site, and is equipped with a battery charge alternator, then you probably don't need a battery charger. What if the unit is stopped for longer periods with the controls in a ready or standby mode, or in extreme environmental conditions where a battery would discharge just sitting fairly quickly, then a battery charger would be a pretty good idea.

After you figure out how the unit will work, then you need to know what kind of unit. Fuel types, like liquid or gaseous fuels drive different needs for interface to the controls. Is exhaust emissions a concern where you plant to put these panels? Will the panel be required to interface with exhaust aftertreatment? How about other engine systems such a non-package mounted coolers (remote radiators) or fuel coolers (required by many newer engines).
When you figure out the unit, how will it come equipped, electronically controlled with built in governing and AVR? How about onboard start/stop controls? Does the generator set supplier engine and generator protections meet your needs, or are supplemental protections required?

And remember, you want to install this on the skid with the engine/generator, which means is will be exposed to heat and vibration. Controls, components and wiring will need to be selected for severe service, and installed in a manner that helps protect against damage while in operation.

Scotty nailed it when he said there are some really bad panels out there, I've worked for some of the companies named, and some products were good and some really bad. Biggest problem in my opinion was in trying to find a "one size fits all" solution for generators from small to large, gas and diesel. Next biggest problem was trying to do it on the cheap.

I think the best basis for building a good control panel is understanding the engine/generator set control needs not just from the perspective of an equipment supplier, but from the installer, servicing technicians and end users point of views as well.

My two cents, Mike L.