I have 2 150kw generators with Easygen 3000 controllers that autosynch the gens to the bus and auto load share. Normal operation is 1 gen online, 1 gen set for autostart. We parallel only to set up split bus for DP, and come off split bus back down to 1 gen. We also parallel to switch gens daily. Normal running load is hotel and blowers is about 90 amps when underway. Amperage varies on each leg by 3-10. Dockside with no blowers amperage load is about 30 without the air handlers and compressors running.
When both gens are in parallel, there is usually an uneven load share. It varies from 30-40 amps, sometimes lower if there is a small load (dockside). I don’t have a kvar meter on the easygen panel (at least not that I can find, there’s like 1300 possible settings on this fucking thing). Voltage on both gens is within a volt, cycles are even when in parallel, usually .1 or .2 cycles apart before synch. PF on one gen usually reads 1, and the other will usually show lag of around .85. RPM’s on the engines are 1800-1802 at synch.
How can I find KVAR? Replacing the diode ring on these gens requires swinging the gen according to the vendor who did it last (CT Droop was wired incorrectly at install) and I’m reluctant to let it ride even though shore support is blowing me off.
The best I can do to get these gens set to better load is to adjust voltage while only 1 is online. The voltage adjustment rheostat is overly sensitive to ship vibrations and doesn’t stay set and there is no way to lock it down short of glue or silicone, which I don’t think is the way to go. But that won’t get the PF to 1 on each anyway the best I can do manually is about .95
With both on line in parallel, adjust voltage of one with higher amps “DOWN” and one with lower amps “UP”. Small adjustments!
This will not actually change the bus voltage but will adjust / balance the VARs. Without a VAR meter the amps and pF of the machines will be an indirect indication you have them balanced.
Check kW and balance with “governor” up and down. UP will increase kW of than machine.
This is the short story and adjusting anything without some background is always risky. Still it should work but you should do some reading I recommend [I]Preventive Maintenance of Electrical Equipment[/I] by Charles I. Hubert.
Oh by the way you will never get the power factor (pF) to 1 unless you have purely resistive loads (toasters). As long as you have 3 phase motors or other inductive laods running you will have VAR’s present. You are correct in trying to balance the VAR’s as well as kW’s as the reactive power - if not monitored - could cause you to approach the kVA limit of the generator. Good luck.
Its possible you are fighting the Easy gen when making adjustments to the voltage regulator or gov controller on the generator itself. When doing the initial voltage, droop, gain and stability settings you generally have to have any outside paralleling units or load sharing controllers disconnected and run the unit locally and you will need min 50% load, preferably a load bank with 100%, but if they won’t give you any support that is not likely. This can be a little time consuming and a pain in the ass but it has to be done, the controllers usually have a small offset set in them for compensation, IE when you unhook it from the gov controller your speed will jump up and need to be turned down on the controller, then reset when you are done and its hooked back up. I haven’t used a easy gen but on similar units, deep sea. Had a hell of a time getting them dialed in. Some other issues that can effect it are actuator reactivity, had really good luck with governors of america controllers as far as sorting that out, and switching to direct actuated fuel pumps, no linkage.( with these you need almost no stability on the gov controller)
As I said never used easy gen so this all might be hoey…
Another thing… Some controllers can be configured as lead and lag with a multitude of setting as such, if the same unit is always running X factor under the other one this may be the case. If the load differential is either one or it is swinging back and forth then probably not. If its a stamford gen and voltage controller I would only attempt doing anything at the dock as you said the pots are very touchy.
This is why we need engineers! Complete gibberish to me. For all of you thinking of going the “engine” route, do it! We need more people like these ^^^^
[QUOTE=KPChief;130165]With both on line in parallel, adjust voltage of one with higher amps “DOWN” and one with lower amps “UP”. Small adjustments!
This will not actually change the bus voltage but will adjust / balance the VARs. Without a VAR meter the amps and pF of the machines will be an indirect indication you have them balanced.
Check kW and balance with “governor” up and down. UP will increase kW of than machine.
This is the short story and adjusting anything without some background is always risky. Still it should work but you should do some reading I recommend Preventive Maintenance of Electrical Equipment by Charles I. Hubert.[/QUOTE]
I can’t adjust voltage manually on the sets while in parallel, only with one online. Well, not from the voltage controller anyway, maybe there’s a way to do it in easygen. I found a copy of the manual online last night but I haven’t had a chance to break into it yet.
Thanks for the advice and the book reference.
If its a stamford gen and voltage controller I would only attempt doing anything at the dock as you said the pots are very touchy.
It is in fact a Stamford. Do you know if that diode ring actually is pressed on, or was that electrician full of shit?
I would start with the setup manual for the generator voltage regulator, go through the initial setup on it, if its off or the CT is toast or incorrect, they take a oddball CT, it will throw everything else off. As you know the droop is only for load sharing and has nothing to do with independent operation. I have never had to mess with the diodes on the little ones, sorry no help there. Just the big guys with manual excitation and it was “oops forgot to turn it off when I idled the main” Not sure which model you have but you should be able to get the manual here Stamford
For excellent woodward controls phone support ask for Guy Romano here, GCS PNW. Used to be Case Marine but they sold off the woodward div
Not familiar with the Easygen either (we use Woodward DSLC, 723 and Basler AVR’s) but after a quick look through the Woodward site there seem to be a whole lot of ways the system could be configured. That link to the AVR shows a “hand trimmer” could be fitted. This is usually a lockable pot on the switchboard face. This is what I was referring to when I suggested an adjustment to balance VAR’s.
Without studying your switchboard drawings and knowledge of how the Easygen is configured can’t offer much specific beyond general advise previously given that you have to adjust the excitation of the two generators to balance VAR’s (and amps should come into line). As TSCOTT has said start with the AVR manual and drawings to suss it out.
Just curious though, why can’t you access the voltage adjustment on the AVR with both online? It doesn’t have a lock-nut on the pot? Doesn’t sound very marine environment friendly.
You mentioned “diode ring” so I assume this is a brushless generator. If the units run well as single generators I doubt anything is wrong with the rectifier part of the brushless exciters - after all they are just static devices to convert AC to DC for the main field. Exciter armatures are usually pressed or shrunk on the main generator shaft but - at least on bigger generators - the mounting plates for diodes / conductor terminals are somehow bolted on to the shaft to allow replacement of diodes. On a small generator I suppose it is not out of the question that that plate is somehow integral with the exciter armature. It doesn’t sound like diodes are the issue right now though.
Just guessing here…It’s unlikely that the trim input is getting used in the AVR, the easy gen is most likely giving the governor controller on the engine a input voltage to adjust the speed for paralleling. If you try to set the droop and voltage on generator with this connected the controller will try to compensate essentially offsetting your adjustments, and yes I learned this the hard way. A good test is to parallel with minimal load and see how fast it brings it on and balances, compare both units, how many swings it takes to sync going one way and the other etc; then in parallel bring a on a significant load, a crane or other motor on a soft start is great for this due to the amperage ramp. If you have bad imbalance one will generally pickup the load ahead of the other and they will start throwing it back and forth, be careful worse case it will throw one into reverse power and dump the breaker. These are things you can describe to a tech to paint them a accurate picture of whats going on.
I would run the following checks
voltage reg Droop, CT( without a load bank it will be hard to get this perfect, its most important that they are the same, its also very easy to fry the CT as you said it was wired incorrectly before that is a big red flag)
gov controler Gain and stability (these are a likely culprit on spike or momentary loads causing instability) Same scenario having them the same is crucial.
Easy gen settings, Gain etc, there is a good chance you may need a laptop, cable, dongle and the software to access some of these settings, but hopefully they are accessible via the unit display. In most cases these should be set up identically unless they are significantly different gen’s, but this is where tech support would be the right call to make
I know voltage reg Droop and CT are good, that was checked by a switchboard engineer a few months back. New Regulator and generator on that side.
controller will try to compensate essentially offsetting your adjustments
Yep.
I haven’t had time to go through all the easy gen settings. There are so many, and I’m not really qualified to start fiddling for “what if”
Power generation and paralleling knowledge is a pretty deep pool, and I just have a wet toe.
Just curious though, why can’t you access the voltage adjustment on the AVR with both online? It doesn’t have a lock-nut on the pot? Doesn’t sound very marine environment friendly.
Its just a knob on the face of the panel separate from the easygen, 1 for each gen. When in parallel, easygen takes over. The QMED tried to adjust voltage last night and found out that fooling with voltage while in parallel puts us black ship.
No lock nut, not even tight to turn. You can roll a volt by looking at it crosseyed. The switchboard engineer who fixed the CT droop issues was supposed to come up with a solution for the pot, but it didn’t happen.
Thats a new one on me. only external pot I have seen on a board is for speed or cycle fine adjust on a old system, the newer controllers do all of this on their own. In any case getting out the drawings sounds like its in order and a new pot sounds like a good start. If penny pinching is involved look at Allied more turns are better.
[QUOTE=KPChief;130165]With both on line in parallel, adjust voltage of one with higher amps “DOWN” and one with lower amps “UP”. Small adjustments!
This will not actually change the bus voltage but will adjust / balance the VARs. Without a VAR meter the amps and pF of the machines will be an indirect indication you have them balanced.
Check kW and balance with “governor” up and down. UP will increase kW of than machine.
This is the short story and adjusting anything without some background is always risky. Still it should work but you should do some reading I recommend [I]Preventive Maintenance of Electrical Equipment[/I] by Charles I. Hubert.[/QUOTE]
Back on the evil SEA SKIMMER, I always had to balance the amps after I paralleled generators. I learned this by experience. I did it just the way you stated, with the voltage regulator settings. Now, this was an old, antiquated POS cobbled together by a crazy man, but I did get it to work. Often my assistants would take it upon themselves to parallel generators on their watch (needed to just to start the ballast/bilge pumps). If I forgot to tell them about balancing the load, or they forgot to do it, it was black out time after a few minutes as one generator would keep taking more of the load. . . . Of course we didn’t have that fancy schmancy EasyGen. . . .Oh, and I did have assistance in getting the solution with my handy copy of Hubert’s book. I was lucky enough to have him as a teacher my Plebe year. . . .
I never have worked with any fancy auto pickup gensets. The vessels I worked with the older mechanical governors and Delco regs were a little more critical to parallel and had to stay on top to keep the loads balanced. AC ammeters are not as accurate as the KW meters which is why they are used to balance the loads.
The last cargo gensets I worked with were 2-1250KVA units with Gulf Coast Power boards. We’d still manually parallel and balance the load but the electronic governors and joined voltage regs balanced well through out the cargo transfer. Driving 14-200hp pump motors and IG system was a pretty good inductive load running 75% of capacity.
[QUOTE=xcorps;130211] Its just a knob on the face of the panel separate from the easygen, 1 for each gen. When in parallel, easygen takes over. The QMED tried to adjust voltage last night and found out that fooling with voltage while in parallel puts us black ship.
No lock nut, not even tight to turn. You can roll a volt by looking at it crosseyed. The switchboard engineer who fixed the CT droop issues was supposed to come up with a solution for the pot, but it didn’t happen.[/QUOTE]
Yeah making small adjustment to voltage regulator on line should not cause a black out. You probably should be looking at a service call if that is happening.
Just by way of speculation and general info - From what I saw in the Easygen literature one output should be to the engine governor and that is going to be the control that load shares “real power” (kW). This Easygen thing also provides or can provide a fair amount of generator protection including operation of the generator breaker. But I did not see where it has an active role in voltage regulation so not sure how “it takes over”. But hey I see it has several analog outputs and maybe one heads on over to the AVR. Just not what I typically see on the plants I’ve worked on. More typically the AVR’s would be connected via a “cross current loop” to allow the AVR’s to excite their generators and control / share the “reactive power” (kVAR). When for whatever reason they are not sharing VAR’s properly this is where small adjustment of the trim pot can be used to fine tune the VAR part of the generator load. Proper operation means machines share kW and kVAR. If you see nice sharing of kW (and in absence of a VAR meter) you see gen amps not being shared the one generator is underexcited and this should be corrected by the AVR manually or automatically or by Easygen if that is in the loop.
This is the sort of device to use if possible. The black lever on the side will lock the adjustment.
[ATTACH=CONFIG]3851[/ATTACH]
[QUOTE=cmakin;130220]Oh, and I did have assistance in getting the solution with my handy copy of Hubert’s book. I was lucky enough to have him as a teacher my Plebe year. . . .[/QUOTE]
I was lucky enough to be in his “juice” class as well. Can’t beat the hands on stuff he had us do including paralleling generators.
They show up fine here, look like good pots, there are another locking type that are a large dial with a thumb screw parallel to the knob on the outside of the dial that work well to. Thanks for the previous post very informative in normal speak. Some of us new guys have more time with the fancy fancy but not the basics. It is most likely the easy gen is driving the gen breaker and opened it on high or low voltage fault based on the previous info, it should have a event log to show this. They most likely have there own CT’s and are providing all safeties and faults, control power being fed from a redundant 24dc source. We have Woodward gpc30 for all 3 units on the boat I’m on now and they are certainly not above weird random behavior, so I could expect the same from the easy gen stuff. The droop set up I mentioned in the previous post is critical for eliminating the need to tweek later on. With two identical units if they are setup right from the get go you should not have recirculating current issues, which is what it sounds like is happening. Any time the trim pot or voltage is adjusted on one unit after the commissioning it is going to throw the initial AVR setup off. The units I messed with before were two 350kw scanias and they would get spike loads of 100kw or more 24/7 during operation, once the AVR’s were set right they never had to get touched again.
If you want real armchair over the shoulder internet support from kooks you need to post pics and prints though, haha
Proper operation means machines share kW and kVAR. If you see nice sharing of kW (and in absence of a VAR meter) you see gen amps not being shared the one generator is underexcited and this should be corrected by the AVR manually or automatically or by Easygen if that is in the loop.
I was looking for the way to word that properly so I can get a tech sent. Thanks!
[QUOTE=xcorps;130304]I was looking for the way to word that properly so I can get a tech sent. Thanks![/QUOTE]
Someone should be able to read your email and know what the problem is and what you need in about six seconds.This means it has to be short.;
I would use three very short paragraphs with short sentences.
First paragraph, the problem:
During ________ ops I am not able to parallel the generators.
Second paragraph, what you want:
Pls send a tech to assist with troubleshooting and repair.
Third paragraph amplifying info. 90% of the time nobody will read very far into this paragraph.
I have spend about xx man hours trouble shooting and have not been able to determine the problem. My concern is (going off-hire / delay / explosion / damage) Next _______ ops are xx Feb. Vessel is at ______ pier.
Exact layout can vary but has to be short and to the point. The point being that you need assistance and if you don’t get it they are at risk of losing money… Not the specific details unless they ask.
