05-21-2011 06:05 AM
Chaps, does any one may have an input in this?
Parallel operation, control of kVAR.
This particular Caterpillar Generator work fine as single machine.
Operational needs did change and this time it must work in parallel with bigger gensets.
I am unsure that DVR basic P/N 155-3832 Prom ID 1.05 is suited for this task.
Situation is described below.
Main generators are Toyo 1800 kVA and work with analog AVR. Control of kVAR is done with compensation of cross current.
715kW, 893kVA, 440V, 1171A, 60Hz.
Voltage Regulator DVR Basic 125-249VAC 50/60Hz
P/N 155 3832;S/N PJNDB 6905 PROM ID 1.05
CT and its resistor (1 ohm) are present and connected to DVR.
At this stage I am not going to connect it in system of cross current compensation of bigger generators.
Auxiliary NO contacts of other generators ACBs are in serie with auxiliary NO contact of CAT generator ACB.
When at least cat and one of other generators will be on line then terminal 41 on DVR is feed with 24VDC from terminal 50 of DVR.
This should switch DVR into optional kVAR control mode.
DVR Parameter No.31 should be set to 1 to achieve control of kVAR proportional to load of generator and dependent also on power factor of the network.
Unfortunately this parameter of DVR could not be accessed from keyboard, I could not change it.
There is several more parameters having the same issue.
All of them are marked with note 5 on DVR parameters table.
If those features are optional then what software or hardware is needed to get those function incorporated.
The questions what arise already are:
Does this particular type of DVR is suited for work in our application.
If answer is yes then tell me what more need to be done to achieve correct parallel operation.
If hardware or software of present DVR is inadequate for the task then please advice us a solution what need to be introduced.
Does anyone could post a link resulting in access to technical information about configuration of optional features of DVR and ordering codes please?
Solved! Go to Solution.
05-23-2011 07:50 PM
The reduced function DVR has no VAR/PF control mode that is typically used for paralleling to a utility grid or large network.
The DVR equipped generator can be paralleled in droop, in cross current compensation (not my favorite in a mixed system), or by using an additional control, such as a Woodward or Basler device.
Since your other two generators are operating in cross current with their own analog AVR's, you could try setting up the CAT unit for cross current as well, however in my experience you'll likely not be happy with the result.
Do you have droop currently set into the DVR? I usually start with 3-5% droop (droop pot about mid-scale) and try it there, since the two other units are larger, youwon't need to worry about precise VAR sharing, you just need to be sure it doesn't go into a leading power factor (absorbing VARs) or hogs the VAR load.
If you want to operate the smaller unit in VAr or Power Factor control mode, you can also add a controller like a Basler SCP-250.
The DVR is a discontinued item, replaced by the CAT CDVR. Retrofitting a CDVR is an option, but fairly expensive and requires some rewiring (not a direct replacement).
I have operated a large number of CAT units in droop with other systems, with no problems if properly setup and adjusted. This is likely your quickest and most cost effective parallel solution.
05-23-2011 08:11 PM
Thank you for your advice.
Now it is clear to me that parameters 31, 32, 33, and few other what are needed to set the DVR into kVAR control mode are inhibited on DVR basic..
Those are invisible on the menu and could not be changed to required values.
DVR's manual says those are optional parameters but doesn't explain how to activate those options.
Does activation requires hardware or software changes?
Do you know does Caterpillar used those DVR in other then "basic" version.
If yes do you know a part number for such DVR or for its option handling kVAR.
The drop mode, it work satisfactionary in situation with constant load on the grid. When load changes, then kVAR of Cat fluctuate out of safe range.
Pointer of Its A meter i waving all over the scale.
The load of this plant is variable because of application requirements, probably to solve the problem I will have to install new CDVR.
05-24-2011 11:46 AM
The DVR basic and enhanced versions are two different part numbers, these are of a vintage before flash upgrades.
The DVR enhanced version came out a few years after the basic, there are a number of units running with DVR's controlled by Basler SCP-250's for power factor/kVAR control. There is even a CAT EDS sheet showing the interconnection (sorry I don't have a copy). The only problem I regularly run into with a Basler SCP over a DVR (or VR3) is that the setup and wiring are not done correctly, and the output of the SCP can overdrive the remote voltage adjust input of the regulator, causing it to fail.
So you really have four choices,
1. Run in droop and adjust the unit manaually as load changes-cheapest and easyiest, but not very good control
2. Install a Basler SCP-250 over the DVR and operate in kVAR or PF control mode-relatively inexpensive but needs proper install.
3. Install a CAT CDVR , a pretty expensive and fairly involved conversion, but a good solid AVR with built in VAR/PF control functions, plus some added capablities and protections if used.
4. Other aftermarket solutions, many controls companies offer different means to control VAR share on paralleled units, some work good some don't, depends on local resources and expertise.
05-24-2011 08:50 PM
Thank you for your input.
At least I know that DVR has had two versions, each having different P/N.
This explains why I could not access DVR's parameters required to be set for parallel operation.
I could not get this information from Caterpillar service people who suppose to be fluent with theirs products.
You are right that it is very difficult to come across knowledgeable individuals.
Utilizing the freshly obtained knowledge I have sent them this:
Digging the topic I have find out that Caterpillar had used two versions of DVR:
1. The DVR Basic version what don’t have capability to work in kVAR control mode.
This one has P/N 155 3832.
We have proof already that this particular type won’t do the required job.
2. The DVR Enhanced version, it came on market a few years after Basic.
This version has capability to control kVAR in parallel operation.
The Enhanced version of DVR has different part number then the Basic.
Please dig out from yours records the part number of DVR Enhanced and deliver it.
The DVR Basic won’t do the job. No amount of thwacking and picking will change that.
If you don’t have this DVR enhanced, then the solution left is to install the CDVR.
Engineering needed to that was done by Caterpillar already, just dig out a proper CAT EDS what is showing references for wiring to do that conversion.
Mike, I think that our chat is nearing to an end ,until you have somewhere that part number of DVR Enhanced.
You were helpful, thank you for that.
P.S. What part of the world are you now? I am from Poland being now in Indonesia just south of Singapore.
05-25-2011 08:48 AM
In mean time I have learned about part number of DVR Enhanced it reads like this P/N 155 3835.
Maybe someone will need this information, that is why I am posting it here.
The local service has no stock on hand, that is why we go after CDVR.
05-25-2011 04:04 PM
The DVR regulators were discontinued several years ago, so either part number for a DVR should cross to tthe current CDVR when dealing with CAT.
If you're going to change the voltage regulator there is another possible option, especially for your size unit, that would be a Basler DECS100, quite a bit cheaper that a CDVR, not a smany features but have used many and CAT machines less than 1000 kW.
I live in San Diego, CA work thru most of the southwest these days, used to do a lot of travel, not so much these days. Good luck with your project.
05-25-2011 08:17 PM
Thank you for your advice.
Data obtained from you let me do informed decision and turn down attempt of "authorised service's" to install once again the same basic model of DVR.
They will install CDVR. I hope they know how to do so in proper way.
Proposed Basler solution could be cheaper but we have no time to pursue that option.
By the way, I do work (20 years already) for an US company based in Houston.
Main bussines, pipelines and structures for oil and gas at sea.
Main area of operation South East Asia with spelss up north up to Sahalin.
Sometimes Persian Gulf, Mexico Gulf (I am not related to the spill) and South America - Tierra del Fuego near to Horn Cap.
In theory I am a retired man - 69 of age.
Company however maintains another stand point, that is why I still travel for them doing mainly special projects, retrofits, commisionning and a like.
If you wish you may drop me a text message on Skype the address is CVoytek.
Thanks and regards.
I consider this topic is concluded already.