The cross section of HV cables are usually selected on the basis of short circuit current withstand capacity in addition to current carrying capacity. This data is usually given by cable manufacturers. After calculating the prospective short circuit current, select the appropriate cable from the...
I am planning to install a corrugated tank, oil filled, hermetically sealed distribution transformer of 11kv/433V, 160 KVA rating. The HV side protection is oil fuse switch and the mounting is outdoor, pad mounted, open to air. HV and LV are to connected by cables.
I would like to learn from...
Tnx to jbartos & bigamp for their learned and prompt response.
The transformer rating is 1600 KVA, 22kV/433V i.e. a full load current of 2250Amps. We propose to lay 6 runs per phase of 630 sq.mm. aluminium conductored, armoured cable i.e. 370 Amps per cable. Another precaution we are taking is...
Thanx jbartos & bigamp,
The cable is being run in an underground cable trench which is to partly outdoor and partly indoor. there are 6 runs ( 4 core per run )of the cable to be run between the transformer and LV panel and we propose to run it in two layers of 3 trefoils each. We propose to fix...
Dear All,
My problem relates to the method of laying and fixing single core armoured LV cables of 630 sq.mm. cross section in a trench over a distance of 20 meters. The cables are laid from the secondary of the distribution transformer to the LV breaker. All guidelines from cable manufacturers...
busbar, that is exactly my worry, to what extent can a 3 phase DG set carry an unbalanced, fluctuating load.
Graeme38, yes, the distribution will be designed to form equal kW load on each phase as far as possible. But the nature of individual load control ( simmerstat )is such that it may be...
I have an application for a diesel generator which calls for electric heating as a means of heat treatment on welded joints. The job in question is a large pressure vessel which requires about 75 kW in local heating. The heater elements are ni-chrome wires wound in-situ with suitable glass wool...
In the past 15 years, I have energized more then 300 transformers ranging from 63 KVA to 1750 KVA and on voltage levels of 11 kV, 22 kV and 33 kV. I have rarely faced a spurious blowing of a DO fuse while commissioning and most of the fuse failures reported are mostly during the wet season. The...
You mentioned the height ofthe poles but not of the surrounding structures, If you have significantly taller structures in the vicinity ( Radio Mast, Skyscrapers, Overhead water tanks etc.) it could provide a cone of protection to obviate the use of individual air terminals.
Otherwise, you...
In case you are referring to LT or LV ( LOW TENSION or LOW VOLTAGE upto 440V ) capacitors, a switch fuse or a circuit breaker are equally effective for isolation or protection. Cost is usually the consideration.
Personally I would prefer switch fuse because if one fuse blows, the remaining 2...
Dear All,
I am planning to run a 22 kV, 3 phase overhead line over a distance of 2 km using aerial bunched conductors ( XLPE insulated ) along with a bare messenger wire. Does anybody have any similar experience to share ? And are there any relevant construction standards on the web I could...
Dear All,
I need to find out about MICC Cable Termination methods. Has anybody got any practical experience or theoretical reference ?
The system is to be used fire alarm wiring of an oil rig.
Thanks in advance
If an A-CAD drawing showing the layout of an outdoor and also an indoor type 22 kV transformer sub-station is of any help, I can send it to you on e-mail.
Please confirm if you can open a .dwg file of size 300kb+
sunilji
Hi All,
I am searching for a modern, portable instrument for testing Efficiency of 3 phase Electric Motors in the range of 1 to 30 hp.
I welome replies from anyone with experience or information
Regards to All
Could someone please point me to data sheets on 22 KV XLPE insulated cables. I need to find out about possible deterioration when used overhead (on tray) open to sky & sun.
Also, the effect of such a cable on nearby data/control/power cables which are about 1 meter away from the HV cable...
Thanks redtrumpet and electricpete. I think I should have revealed the motive for aiming at unity power factor. The electric utility is offering a rebate in energy charges for a p.f. above 0.95. The incentive is 1% reduction in energy charges for every percentage point improvement in p.f. beyond...
I need to improve the power factor of a steel induction melting furnace plant from 0.95 to 0.99. The total kW load is 1700 kW ( out of which 1500 kW is the furnace load ).
The furnace is fed through a 11kv/550V,1750 KVA Trafo and rest of the auxillary load ( pumps, cranes, lights )is fed through...
Hi Again ! I need help with the following query :
What are the benchmark values for Transformer Grade oil?
I have a testing report ( Dissolved Gas Analysis ) that states the values of Hydrogen,sulphides etc. The lab people insist on a second test to find out the differential values before coming...
(A Diversion )
jbartos, you may be surprised to know that "A.C. Machines " by M.G.Say was the prescribed text book for the subject 'Electrical Machine Design' when I took my degree 22 years ago ! And I have still preserved it, finding it an invaluable reference time and again. Just...