We are evaluating whether 90MVA, 66/33 kV Tranformer switching is possible with one 43.5MVA Gas turbine Generator connected to 66kV busbar.The question is whether one 43.5 MVA Generaor will be able to withstand the switching inrush current of the 90MVA transformer(inrush is 5.3 times of I fl as...
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We are in theprocess of replacing the existing damaged submarine 15kV cable (EPR insulation) with new cable. Some of the vendors are offering XLPE insulated cable instead of EPR insulation.This cable is used for off shore gas platform where the reliability is main...
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The mentioned submarine power cum Communication (Optic fiber) cable of 20 km length has a outer sheath damage due to a Boat Anchor stuck and pulled the cable by 20 mtrs. The cable is still live and there is no abnormality is recorded. The underwater inspection shows a minor...
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We propose to introduce a MCB inside the Street Lighting Junction box ( EX e Certified) installed in Hazardous area.
Contractor propose to use a normal MCB with C curve.
The query is whether MCB should also be Ex cerified. Ex panel manufacturers like Stahl are providing Ex...
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Our consultant recommends U/f & df/dt relays setting with 100msec time delay for load shedding scheme (4 stages of load shed from 48.5 to 47.8 @ 1 Hz/sec)to avoid black out in case one/few generators sudden trip.( our electrical system is with own generation and no link with...
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Our installation is LNG production plant(Oil and Gas)
We have a failure of a 6.6KV power cable near to the equipment located in Hazardous area IEC Zone 2. Planning to cut the faulty portion of the cable and splice it with a short piece ofnew cable.
We are debating on the safety...
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LV switch board with 2 incomers + Buscoupler(with sync facility) is currently fed by one 2.5 MVA 6.6kV/415V, Dyn11 transformer and Proposed to add one more transformer from second source of 11kV. Engineering Contractor proposes a Transformer of 2.5MVA 11kV/415V Dzn0 vector...
Request to get info on Standards / best practice on bonding of Clean earth grid and Plant safety earth grid. If both need to be bonded, type of bonding and preferred loacation of bonding? Your valuable input will be appreciated
Ramesh
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Our Oil and Gas plant XLPE Cable specification is with outer sheath material of Fire Retardant PVC , but vendor is proposing LowSmoke&Fume type outer sheath. Which is better interms of Mechanical/Chemical and Fire retardant peoperty. also the cost difference.
Regards
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We had a failure of CT in a 6.6KV Motor feeder panel due to one secondary CT wiring connection was loose/Open in the terminal block. Is there any kind of online detection system or relay to detect the open circuit in the CT Secondary circuit. We are using SEPAM 2000 relay for the...
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The existing Transformer 33/6.6 kV Dyn 11 failed due to winding fault and we have got another spare transformer of 33/6.6kV Dyn11 with HV/LV terminal connection
C-B-A /c-b-a , where as original failed transformer had
U-V-W /u-v-W ( Please refer attached drawing).
To match the...
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Is there any international standard governing minimum depth for the LV/ HV/communication cables laid under ground. Also, is there any reason for the minimum depth requirement. This information will be helpful for me as we are preparing procedure for cable laying.
Thanks in...
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We are planning to add a Sub switch board (415V)using 800Amps ACB feeder from a main LV switch board of 4000Amps, 65kA 1 sec.
The sub switch board(800A) will be located about 300mts from the main Switch board and connected using 3 runs of 630Sqmm Cable. The consultant is...
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Low voltage 415V application Bus duct of 4000Amps, which type of insulation is better for 50 Deg Ambient (Gulf country) condition? Our specification is epoxy and vendor suggest MYLAR type. If some can share their experience/ knowledge on this will be helpful for us to decide...
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I am doing a project of adding a LV motor to the existing plant. The Power cable as per our specification is according to IEC 60502 and Contractor is offering BS 5467. Is there any technical difference in the construction of the cable between IEC and BS standards. One of my...
I am preparing the specification for LV switch board with 2 sections connected by a Bus coupler, rating of 415 V , 4000A fed from 2.5 MVA 6% Transformer(2 Nos, one for each section). normal mode of operation is 2 Incomers ON and Buscoupler OFF. There is an option for Synchronising both the...
I am preparing the specification for LV switch board with 2 sections connected by a Bus coupler, rating of 415 V , 4000A fed from 2.5 MVA 6% Transformer(2 Nos, one for each section). normal mode of operation is 2 Incomers ON and Buscoupler OFF. There is an option for Synchronising both the...
