Previous in Forum: electrical   Next in Forum: Generator Plant Mgr
Close
Close
Close
7 comments
Anonymous Poster

DG Set for residential purpose-70kva

04/19/2009 12:19 AM

Please enlighten us whether to go in for Air cooled Diesel Genetator set or Coolant type DG set as it is recommended by no.of people to go in for Air cooled type in view of maintenace problems involved.This unit is for residential purpose. I also would like to know no. of earth pits required and their distances as well as location and also location of AMF panel whether it is to be located nearer to the unit or near to main distribution panel which is nearly 20 mts away from the proposed DG set as different vendors are indicating different nos. & locations.I would be looking forward to +ve response as some readers may advise to refer to the supplier.Iappreciate if some one can suggest how connections are given to AMF panel from individual utility points.What are the precautions to be taken while installation of DG sets.

Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
2
Member

Join Date: Mar 2009
Posts: 9
Good Answers: 1
#1

Re: DG Set for residential purpose-70kva

04/19/2009 1:32 AM

Primarily it's depends on rating of DG set & availability of water for cooling tower use.

Rating of DG set is 70KVA only so its advisable to go for air cooled.

No. of earth pits required are normally varies as per local authority. In general 2 nos. for neutral & 2 nos. body & 1 no. for panel board. ( panel board & body earthing can be combined to form a grid to reduce earth resistance value.) Distance between the earthing should be twice the length of earth rod, normally 3-5m. If ground resistivity is less (soft soil ) then u can ue plate earthing. If it's a hard rock strata then pipe earthing (boring ) is advisable. Location of the earth pit should be outside the DG set canopy or DG room. If DG room is not yet constructed then it can be done near the foundation of DG set.

AMF panel location should be near to the DG set.

You can refer DG manual for the lifting precautions.

Reply Good Answer (Score 2)
Commentator

Join Date: Jun 2008
Posts: 77
#2
In reply to #1

Re: DG Set for residential purpose-70kva

04/19/2009 8:30 AM

Thanks for the detailed reply which is educative.

Reply
3
Guru

Join Date: Jan 2007
Location: Sitting directly behind my keyboard in Albuquerque - USA
Posts: 592
Good Answers: 19
#3

Re: DG Set for residential purpose-70kva

04/20/2009 3:05 AM

70 kVa is huge for a residence. Bloody huge. You must have 500 m2 residence with ACs going 24/7 in Qatar !!!! Be careful of correct size. Small diesel engines MUST remain loaded at least 35% (preferably 50%) or they have problems with unburned diesel fuel dilution of the lube oil and carbon in exhaust components. It is better to run a diesel at 80%-90% load than at 20% load.

Use a 1500 RPM (50 Hz) or 1800 RPM (60Hz) unit for noise reduction. If you get a 3000 RPM (50 Hz) or 3600 RPM (60 Hz) or will be VERY noisy. 1000 RPM is best but quite difficult in such a very small unit.

Take care for altitude and ambient temperature de-rating. This machine will de-rate 3% for each 300 m above the first 200 m altitude. If in desert, the temperature will de-rate output of engine and generator as generator (alternator) is cooled by air. I also recommend air cooled. Deutz is best air cooled gen set .... period !! They know all conditions arctic, desert, altitude, etc. http://www.deutz.de/live_deutz_com/html/default/ssod-6x5c8y

Take care for cold temperature and diesel fuel forming wax. Do not mount sensitive electrical panels on the vibrating machine.

Put machine on concrete that is 3 x 4 weight of machine and on spring isolators between machine and concrete to avoid vibration transfer to structures. If it goes on a roof, build a steel 'box' that can hold 4 x concrete weight of machine, pour the steel box full of concrete, mount unit to top of concrete, then, mount the entire 'block' on springs. The gen set and concrete must be 'one', then springs isolate the mass from the roof structure to prevent vibration annoyance.

__________________
If it eats, it's going to be trouble!
Reply Good Answer (Score 3)
Commentator

Join Date: Oct 2007
Location: Caribbean
Posts: 79
Good Answers: 2
#4
In reply to #3

Re: DG Set for residential purpose-70kva

04/20/2009 8:48 AM

PetroPower,

Very good answer.

You strike me as someone who is an authority on diesel engine gensets or rather gensets period.

I learned quite a lot from your answer even though I have been in the power generation business for 30 years.

All my experience has been in large MW sized gas, steam and combine cycle power plants.

Only our emergency lighting generator rated at 25KVA !!! is the only diesel gen we have , the 1000 MW of plant are as stated above.

I have justifiabley given you a "Good Answer" for your response.

__________________
Learn more, Do more , Be more
Reply
Guru
Hobbies - HAM Radio - CE3AM....4X4SW....CE3NSW

Join Date: Aug 2006
Location: Santiago Chile.
Posts: 845
Good Answers: 7
#5
In reply to #3

Re: DG Set for residential purpose-70kva

04/20/2009 9:02 AM

Good answer, and I have marked it as such...Only thing is you really didn't completely answer his basic question... what type of cooling is recommended?Even though i basically agree with your choice of generator, I would say depending on the enviroment.... If in dry windy hot desert or noise prevention for example, I would go for liquid cooled for reasons of dust, ambient temp.or noise box. If an outdoor installation or in a protected shelter where unlimited supply of fresh air is available I would go for air cooled one. However I suggest an update programme for you too... Go to Discovery channle or Travel and living to learn that 500m2 in Qatar or Dubai etc. is only found in their shuntytowns. The sultan of Oman has a humble 12,000m2 82 rooms palace...also he never said that this DG is for a single home... Wangito..

__________________
Never trade luck for skill.
Reply
Participant

Join Date: Apr 2009
Posts: 3
#6

Re: DG Set for residential purpose-70kva

04/21/2009 7:39 AM

Good Reply.

Off course depents on location, environment.

Verify the rating as if genset running less than 50% then it is not econimal as well as as mentioned it gives lots trouble.

AMF panel require near to genset, it will help during testing, maintenance of genset.

More important of AMF genset is reliabilty.Pls check go through genset features specially about automation.

Reply
Commentator

Join Date: Jun 2008
Posts: 77
#7
In reply to #6

Re: DG Set for residential purpose-70kva

04/21/2009 10:45 PM

Thank you all.The major problem is that the site doesn't permit the installation of AMF panel near the DG set and to be located nearly 18 meters away from the DG set.Simliarly earth pits are also to be away from the proposed DG set.Appreciate good workable suggestions.

Reply
Reply to Forum Thread 7 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
Copy to Clipboard

Users who posted comments:

djacob (1); PetroPower (1); pokalasrao (2); rajendra.kamble (1); ShakilShaikh (1); wangito (1)

Previous in Forum: electrical   Next in Forum: Generator Plant Mgr

Advertisement