THREE PHASE POWER TRANSFORMER

THREE PHASE POWER TRANSFORMER:

The Transformer shall comply with IEC726, VDE 0532 etc. and the general specifications will be as follows:

Oil immersed Indoor/Outdoor Type Power Transformer:

a.             Rated capacity                                     :               As per Schedule KVA  

b.             Rated frequency                                  :               50 Hz

c.             Rated primary voltage                        :               11 KV

d.             Rated secondary voltage                   :               0.415KV

e.             Tap changing ( off load)                    :               ±  2.5%, ± 5%, ± 7.5%

f.              Phase connection                                :               DYN 11.

g.             L.V. neutral                                           :               Brought out

h.             BIL level (H.T. side)                             :               75KV (H.T. side)

i.              Maximum system voltage                 :               12KV (H.T. side), 0.5 KV (L.T. side)

j.              Cooling                                                  :               as per schedule.

The Tenderer shall furnish following data at 75 deg. C.

a.             Iron loss at rated voltage and frequency

b.             Copper loss (including supplementary eddy current loss ) at continuous rated current (50 c/s) and for winding at 40 deg.C ambient temperature with the changer in middle position.

c.             Impedance voltage with tap changer at middle position.

d.             Voltage drop referred to rated voltage at rated load with tap changer in middle position and at unit p.f.

e.             Permissible maximum symmetric three phase short circuit current referred to rated current.

f.              Rated no load current (RMS value referred to rated current).

g.             Type of windings with conductor materials.

h.             Class of insulation material.

i.              Voltage regulation.

j.              Temperature after continuous rated load at 40 deg. C ambient temperature.

                In windings

                Core

k.             one minute double power frequency induced tests voltage applied to:

                H.V. line terminal

                L.V. line terminal

                L.V.  Neutral.

l.              Impulse test voltage 1.2/50 micro  second fully wave positive and negative polarity applied to:

                H.V. line terminal

                L.V. line terminal

                L.V. Neutral

m.           Weight of:

                Iron core

                Copper

The transformer shall be designed and manufactured in accordance with the requirement of B.S. 171: 1970 equivalent.