Generator Automotion

Hello "Guest",

After reading through your story:

It does appear that the settings of protection relays were incorrect, causing the non-start of the standby generator.

It is understood that freezing conditions were commonly experienced at the site.

In answer to your numbered questions:

1. Unable to determine whether busbar size is correct. You would need to contact the Makers of the unit. You have 6 No. units, all the same, and it would be prudent to shut down each in turn, to establish the busbar status: discoloured or otherwise. Busbar discolouration may also be caused by contaminated air supply, not just overload.

2. Alternators of that size are commonly connected via busbar from alternator to the unit MCB, as with proper operation of the diesel engine, vibration is not a problem. Perhaps an instantaneous short circuit occurred, but from your description it is impossible to tell. An unbalanced engine or damaged bearing may cause excessive vibration, and as that occurs gradually, is often not noticed by plant operators.

3. While remote mounting of the unit MCB on a separated pedestal is a good idea from the vibration point of view, the units you have on that site are probably skid-mounted Turnkey plant. They arrive, you bolt them to the concrete floor, cable to the MCB and control panel, connect exhaust and fuel lines, switch on, they go.

4. You have not advised the Make/Model of the units, and it may well be that NATO took the cheapest tender at the time, leaving the site users sadder and wiser. NATO Authorities would be interested in the trouble, moreso if it could be established there was a design fault.

General:

Normally equipment supplied via NATO Purchase Order has to comply with very high Standards and Specifications. Thus it would be unwise of any Maker to sell defectively designed equipment. In fact the number of Makers worldwide of such equipment is not large, and a Manufacturer who sold defective equipment would soon discover that the order books suddenly became empty (Engineers talk to each other, via Forums and otherwise).

You may be aware that some makers of this type of equipment have a bad track record, with broken crankshafts in the case of a short circuit coming to mind.

In such a case as you describe, the best plan is normally to contact the Makers directly, and if that Maker is honourable, they are normally willing to advise and assist. I have known some Makers have flown out Senior Engineers, a small team of repairmen and technicians, plus a large selection of spares, and all at no charge, to retain a good customer - you go back to that Maker next time you purchase, don't you.

The plant units you describe may have been supplied to dozens or hundreds of installations, and there may be commonality of defects or problems, which only the Makers will know.

I do appreciate you may not wish to be more specific, in the public forum. Perhaps that is also why you haven't Registered as a Member at CR4.

If you are able to advise further details, you may send me a Private Message via CR4 Forum, but to do that, you will need to Register as a Member at CR4, (It's free, and only takes a few minutes).

Kind Regards....

hi

could u explain me how to set the relay's O/C, E/L, and time setings, at maximum load300 amps, ct's 400/5, pleaseeeeeeeeeee

Hello aamersyed

As I do not know the particular Maker, Model, of the units, relays or indeed anything about the settings, and do not have the Maker's Instruction Manual here either, I cannot advise you.

Nobody can advise you, unless they know the above, and have the Maker's Manual in front of them.

There are 6 identical units installed, it seems.

Maker's Manuals are sent out, 1 Manual for each unit, complete with all Drawings, Schematics, Protection relay setting instructions and all necessary for complete Plant Maintenance..

A second set of Maker's Manuals will have been separately sent to the Commissioning Electrical Engineer, and there should thus be 6 sets (All identified by Plant/Equipment Serial Number, 1 for each unit) in the Powerhouse.

The second set of 6 Maker's Manuals, sent to the Commissioning Electrical Engineer, should remain in the Engineering Office on-site, or at the local Headquarters where the Maintenance Engineer/s is/are based.

If you do not have those "As Built" Maker's Manuals, look around, ask Engineers for them.

If you are the Engineer, then urgently contact the Makers, ask for 2 full sets, to be sent separately, so you have one full set on-site, and the other full set at the Engineer's Office.

You may have to pay for these manuals, because 2 sets of full Manuals will already have been supplied as above.

Advise your progress, or lack thereof, with

Kind Regards....

Thanks for your analysises. The Power plant has been designed with a very very over ambitious project, or may be with a view to supply the power to the citizens outside the garrison once they get ride of the Talabans. And brand new installed by one of the largest n best known world wide MNC company for one of the fortune 500s company for core of engineers of US army. The plant is just in its 1st year of operation. The existing load is 80% of one set only but the Power Plant engineer was operating 2 sets on part load each. I noticed that the 2nd set in operation short cycles very offen which is not desiarable for a machine of its size. I am basically a mechanical engineer specialized in HVAC since 1969 but out of necessity picked up relevent electrical knowledges without which a HVAC engineer is not a good engineer. The external load banks to avoid short cycling has not been interfaced for automotion which i dont want to touch. As such I advised to take the entire load on one set which was just 80% only. All most all over Afganisthan, the same brand sets and same capacity are installed. As such i could make a comparitive study and noticed that they are not connected with solid bus bars but with cable n the Local control MCB is isolated from generator foundation and there was no such problems there. On my deep study and anayses, I arrived at the conclussion that no electrical fault has caused the MCB to trip and there was no announciations of any kind. The MCB just on tripping was unberably hot to touch and the precious trip push button on it required very gentle press only to trip the breaker. The heat has caused expansion of the spring in the push button and the vibration has contributed to the tripping. When it tripped, the generator was still runing on no load waiting for its lapse time to go off. As there was no electrical faults, the 15KV breaker of the set has not tripped without which the 15KV breaker and standby generator will not come on circuit. When we installed a push off micro switch smaller than a house fly at the foot of the Local Control MCB, the problem was solved. We did the same for all the other sets. If the load bank would have been on automotion, the short cycling of the 2nd generator would not have happened and this fault could not have come out. When I tried to contact the OEM for a vidio conference thro my boss, till I left Talabisthan after miraculessly escaping an attempt on my life, no response came from them and my passport was locked in bank locker by my family when I came on vacation as they dont want to receive my dead body after one month of my killing from Afghanisthan eventhough there was an insurance of US $ 75K.

My dear sir,

I am basically a Mech. Engineer n have registered in that faculty under my name Padmanabhan Iyer.

By the way reg. the suject under discussions, I solved the automotion problem only so that there is no power interruptions. The gemerators were tripping after 6 hrs or so runing due to above fault n the lead standby set comes on line without power interupptions till I left. The problems as I pointed out (i-e) over heating of bus bars, vibration and tripping of Local Control MCB was very much there and I dont know if the OEM acted in anyway or not. Their local dealer telephoned to the Power Plant Engineer advising him to send a written complaint and request to them to attend to the problem for which they will charge! The construction wing of the company has functionally not tested before clearing the OEM and the maintanence wing did not take over/hand over with due records. Now Maintenance wing has no provision to meet the expenses and if the end user comes to know the fault, construction wing will be in trouble. Being both are part of same company, one can not offered to pull the leg of the other and such a cover up. I did not activate and interface the Load Band so that they can run 2 generators at 60% load without hunting as I thought that it is a Higher Electrical Engineering matter as far as my knowledge in that faculty. U are well come on Mechanical Engineering section of this site to share any such experience for everybody's acedamic interests.

Regards,

Guest; you may have a poor electrical connection between the breaker & the bus bars this could cause the breaker to trip and the bus bars to discolor, dis colour. perry

Pure nonsense

Please come up above the level of Electrician. These are the fundamental things even an electrician check when he notice any over heating problems. Let us discuss the subject from the level of an Engineer.

The generating capacity should be 125% of the peak load which is why two were engaged. The auto start and protecttion system should recieve a review from an EE with demonstrated wide expirience in this field. Since there are many different ways to set up the protection and start systems no explaination of it given here would be adequate for comment. The generator building should never have a significantly lower pressure than outside ambient pressure. The combustion air should be ducted to each engine and the engine crankcase breathers. How are the engines cooled? Are the heat exchanger outside the building? Does it use recirculating ground water tubes? This GenSet looks like a comedy of design-stupid.

U dont get the problem of ventilation properly. The generator room is maintained with a possitive air pressure by roof mounted fans with filters but there was power interruption as I explained above over 20 minits during which time the faulty generator was still runing on idle load awaiting to lapse time to go on off mod. And since the power interruption has continued for more than 1 minits, the black start also came on line when there was no air supply for their radiators except from the floor drains. The radiator cooling system is one of the best design with modulating dampers on air side to maintain constant engine temperature

Any time you see discoloration of a Busbar you can assume there is excessive load, whether from a bad connection or from an actual overload. You don't say if this is a single or double bar. Only one genset causing problems or all reacting to a single problem. I would first check for a possible overload somewhere in the system, then check for a problem within limits of a single genset.

Jay

The Bus bars and connexions r ok. THe load is also less even for on set, 80% only which is not over loading 1MW generator. The supply from local control MCB goes to 15KV step up outdoor transformer from each generator. when the local control breaker trips due to non electrical faults the respective 15KV breaker is not tripping which is not allowing any standby set to come on line. By installing a micro switch which breaks the holding coil supply of the 15kv breaker, the problem was solved. This fault was noticed with all the 6 sets identical. The bus bar was definitely under sized and the vibration eventhough not violant but enough to contribute the precission trip button of the Local Control MCB to break.

Question?? Are you now saying you have found and fixed the problem???

Yes, u r right

U r grazy! same problems in all 6 units? Then how the problem solved when i just incorporated a micro switch interfacing it to break the 15KV breaker also whenever if Local control MCB trips?

Hello Guest, Guest and Guest,

It's a pity you haven't bothered to register at CR4.

The various "Guest" writers are similar to "Ghost" writers - not easy to see which "Guest" is which.

Kind Regards....

You Are so Right Sparky

The various "Guest" writers are similar to "Ghost" writers - not easy to see which "Guest" is which.

Once again we have this problem, it has become very irritating..............if not damned annoying.................or see which ghost is which.

Especially when it only takes a few minutes to sign up. Makes it a lot easier to know who you are talking back to, plus you still have reasonable anonymity if that is an issue

Uh... Think that maybe running two was the proper approach from a reliability standpoint? Sometimes reliability dictates operating in an un-economical mode.

Do you realise you have helped the Taliban and you are now responsible for killing several people?

You could have asked the question without reference to where you were, which would have made the information of no tactical interest. As it is you have told the enemy the location, size and capability of the coalition power supply as well as backup capability and areas of weakness.

Generally a very poor show on your part!

On the main topic, the overheating of the busbars may well be a harmonic vibration problem, made worse by the low air pressure from the stopped fans and reducing the air cooling effectiveness

Which Guest Ghost writer are you?

Are you implyimg they did not already know..............wake up your country may need you.................wherever that may be and whoever you are?????

............or perhaps you are an alien?????

I tell u one thing being on front line. Talabans have more informer within in the forces they are fighting against and their network of information is more reliable and efficient than CIA. I was told by one of the locals working under me that the Talabans have my BIO DATA with foto with them. They also tell who r in their hit lists. If a local working with us can lead any one of us into the hands of Talabans, they will get US. 1000 for Local, 2000 for India and Pakisthanis, 3000 for Middle east and 5000 for westerners. N this cash compared to the poverty and employment oppentunities for locals is a v gud amount and attracation. President Hamid Hazaari Govt pays US $ 5 per day for their solders plus boarding and lodging where as Talabans giving US $ 10 per day. N Talabans takes care of the family if they die in action, suiside attacks where as families of solders of Govt come to the road begging. Once when I had to come out of Garrison and go to Kabul via Talaban controld Qalat, Zabul and Gazni, it was officially informed by the security that I will travel by road in armourd vechile with one each before and one behind escorting me on a particular day and time. But I was woken up at 4 AM the previous day of travel n budled in to the armoured vechile and sent out along with escorts. This is the way Talabans keep track of movements of people in hit list. For leting out any information to them through this chatting, for your information, they already have the blue prints of the entire garrission with them and come as close as possible and attack with shoulder held rockets and run away before they could be chased. Any way let us close this matter here as this is going out of our engineering discussions.