power transformer installation, needs of soak pit, firewall
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Cell Selection and Reselection
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Planning and optimization parameters
Cell Selection and Reselection
Cell_selection_and_Reselection
transformer
Descripción: power transformer
Selection and Reselection ParameterFull description
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transformerFull description
proceso del cual podemos determinar una cadena de suministro
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Distribution transformer is one of the most important equipment in power network. Because of, the large amount of transformer distributed over a wide area in power electric systems,the data acquisition and condition monitoring is important issue. The
Fault level calculation For Mhada- Bandra
Transformer Selection 1. It was decided to provide.
2. Each transfo transformer rmer not to be be loaded beyond beyond 60% 60% of it’s capaci capacity ty to cater cater to higher higher starting starting currents of AC plant and other pump. 3. 2 Nos. of 2500KVA, 11KV, 433V indoor Dry type cast resin transformers. 1 working and other standby for all the three Transformers. 4. 2 Nos. of of 2000KVA, 2000KVA, 11KV, 11KV, 433V indoo indoorr Dry type type cast resin resin transfo transformers rmers
Cable Sizing The sizing of L. T. cables has been done using the fact that the circuit breaker will interrupt fault current in 8 c.p.s. (i.e. 0.16secs) and compensation required for temperature and bunching of cables in cable trays. The sizing of H.T. cables is done on the basis of available data of fault level at site (350MVA) The block diagram is given below 1 No. 2500 kVA
A
B
Transformer
C
INCOMER
Mhada’s HT Panel
Supply Co. HT panel 11kV Cable
1.1
11kV
2 Nos. 2000 kVA
Cable
Transformer
Main LT Panel
Calculation fo for Cable A: System
11kV(E)
At supply point (i.e. outgoing of Tata Electric Circuit Breaker) Is c
=
350 MVA √3 x 11kV
= 18.37 kA
Assuming conductor area to A mm² and time duration of 1 sec Isc
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Fault level calculation For Mhada- Bandra The said cable should cater to normal full load current corresponding to 6.5 MVA at 11kV 6500 kVA Imax = √3 x 11kV =
------------------------------------ (b)
341 Amps
From the cable manufacturer’s data table 3C x 400 mm² cable is necessary to satisfy conditions (a) and (b) for XLPE (E) cable Length of Cable ‘A’ is about 30 Mtrs. Impendence of Ca Cable A = 0.10 x 30 /1000 = 0.003Ohms
Ohms
The equivalent impedence for 350 MVA fault level is 11kV 11 kV/√ /√ 3 350 MVA/√3 x 11kV
=
0.346 Ohms.
Therefore total impedence at the owner’s 11 kV V.C.B panel is 0.3460 + 0.002 = 0.348 Ohms And prospective short circuit current is Isc
1.2
=
11 kV/√3 = 0.34922Ohms
18.24kA
Calculation fo for Cable B:
Full load current on Cable ‘B’ is equivalent to 2500 kVA at 11kV is ----2500 √ 3 x 11
=
131.21Amps
From manufacturer’s data for XLPE(E) cables the size of cable ‘B’ should be 3C x 150 mm² cable assuming fault will be closed in 0.3 seconds. 1.3
Calculation fo for Cable C :
Full load current is
2500 kVA
=
3478 Amps
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Fault level calculation For Mhada- Bandra The impedence at the secondary side of the transformer is the sum of equivalent impedence of Tata Electric Supply network, the cable ‘A’, the cable ‘B’ (all reflected on secondary side) plus impedence of the transformer Assuming transformer impedence to be 6.25% is V² x X% , where V is secondary voltage = (415)² x 6.25 2500 x 10³ 100 =
