A6/028659

Test Report CESI Approved Page 1

CESI

Centro Elettrotecnico Sperimentale Italiano Giacinto Motta spa

Via R. Rubattino 54 20134 Milano - Italia Telefono +39 022125.1 Fax +39 0221255440 http://www.cesi.it

Capitale sociale 8 550 000 Euro interamente versato Codice fiscale e numero iscrizione CCIAA 00793580150

Registro Imprese di Milano Sezione Ordinaria N. R.E.A. 429222 P.I. IT00793580150

Client MF Trasformatori s.r.l. - Calcinato (BS) Italy

Tested equipment Non-enclosed three-phase dry-type power transformer with three windings, with encapsulated windings, for continuous duty, with cooling by air natural convection (AN): MF - 1930/965/965 kVA - 15 kV / 0,59/0,59 kV

Tests carried out Verification of dynamic ability to withstand short-circuit

Standards/Specifications IEC 60076-11 {Ed.1.0} (2004-05)

Test date from September 28, 2006 to September 29, 2006

The results reported in this document relate only to the tested equipment.

Partial reproduction of this document is permitted only with the written permission from CESI.

No. of pages 14 No. of pages annexed 14

Issue date October 31, 2006

Prepared BU COM - M. Assolari

Verified BU COM - F. Pizzi

Approved BU COM - V. Scarioni

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M2001IG

Tests witnessed by Mr. Bai

MF Trasformatori s.r.l.

Identification of the object not requested

Only for laboratory requirement, in order to reproduce the test conditions, all the laboratory data are contained in the document marked: A6/025224

The measurement uncertainties of the test results reported in this document comply with the following limits: voltage : ± 5 % ; current : ± 5 % ; time : ± 5 %

The measurement uncertainties are estimated at the level of twice the standard deviation (corresponding, in the case of normal distribution, to a confidence level of about 95 %) and have to be considered as maximum estimated values referred to that type of measurement.

Activity code 56022M

M2002IG

A6/028659 Test Report CESI

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Contents Page Test date

Rated characteristics of the tested object assigned by the Client 4 Verification of dynamic ability to withstand short-circuit 5 to 8 Requested values 5 Test arrangements and test procedures 5 Short-circuit tests with three-phase current 6 September 28, 2006 Test circuit M0022 7 Measurement of short-circuit inductance 8 September 28, 2006 Verification after short-circuit tests 9 to 12 Dielectric routines tests 9 September 28, 2006 Partial discharge measurements 10 to 12 September 29, 2006 Photographs of test object and test arrangements 13 to 14 Pages annexed: Oscillogram (total pages: 14)

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M2027IG

Rated characteristics of the tested object assigned by the Client Dry-type power transformer with three windings Manufacturer MF Trasformatori s.r.l. – Calcinato (BS)Manufacturer's serial number 260406/1Year of manufacturing 2006Number of phases 3Rated voltage of the high-voltage winding (primary winding) 15 kV ± 4 x 2,5 %Rated voltage of the low-voltage windings (secondary windings) 590/590 VRated voltage ratio 15 kV / 0,59-0,59 kVRated frequency 50 HzRated power 1930/965/965 kVARated current of the high-voltage winding (primary winding) 74,3ARated current of the low-voltage windings (secondary windings) 944/944 AShort-circuit impedance Vcc1-(2-3) 16,56 %Ratio X/R 16,095Connection symbol Dd0y11Cooling method ANTotal mass 5100 kgClimatic class C2Environmental class E2Fire behaviour class F1Service class VI Characteristics of the windings Highest voltage for equipment applicable to the high-voltage winding 17,5 kVHighest voltage for equipment applicable to the low-voltage windings 1,1 kVRated insulation levels LI 95 AC 38 / AC 3Insulation class FType of construction with circular concentric coilsHigh-voltage winding conductor aluminiumLow-voltage windings conductor metal foil (aluminium) Traction transformer conforms to CEI EN 50329 Standard Name and signature of Client's witness:

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M2028IG

Verification of dynamic ability to withstand short-circuit Requested values Test current values were calculated neglecting the system impedance.

Short-circuit current (*) Tap-changer position Ur ZSC X/R k x √2 r.m.s. value peak value

- kV % - - A A

5-6/7-8 15,0 16,56 16,095 2,55 259,0 660,4

1-2/7-8 16,5 16,36 16,663 2,55 238,3 607,7

5-6/11-12 13,5 16,83 15,692 2,55 283,2 722,0

(*) Values of phase short-circuit current of the high-voltage winding (delta-connected). Test arrangements and test procedures The transformer was tested connecting a three-phase supply to the high-voltage winding (primary winding). The low-voltage windings were short-circuited before the application of the voltage to the other winding of the transformer (pre-set short-circuit). During each test were recorded the line-to-line supply voltages, the phase currents of the high -voltage winding and the fault current, if any, between the mass (insulated) of the transformer and earth. Nine tests were performed (three tests on each limb): • three tests with the tap-changer on the principal tapping (with the maximum peak current on the middle limb), • three tests with the tap-changer in the position corresponding to the highest voltage ratio (with the maximum peak

current on one of the outer limbs), • three tests with the tap-changer in the position corresponding to the lowest voltage ratio (with the maximum peak current

on one of the other outer limbs).

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M2029IG

Short-circuit tests with three-phase current Test circuit: M0022 Test frequency: 50 Hz Reference number of the oscillograms: MP-A6/025224 Conditions of the transformer before the tests: as supplied by the Client Transformer prearranged on the voltage ratio: 15 kV / 0,59-0,59 kV Date: September 28, 2006

Tap-changer No-load Test current

Test Oscillogram position supply peak r.m.s. average Duration

voltage value value value

No. No./sheets - V A A A s

176,1 451,4 174,5 1 1/1 5-6/7-8 --

176,2 175,6 0,1

258,9 662,5 256,1 2 2/1 “ --

258,9 258,0 0,5

258,8 662,5 256,5 3 3/1 “ --

259,0 258,1 0,5

257,7 656,8 254,7 4 4/1 “ --

257,8 256,8 0,5

614,2 241,5 238,0 5 5/1 1-2/7-8 -- 241,4

240,3 0,5

608,5 241,4 236,2 6 6/1 “ -- 240,7

239,4 0,5

622,8 242,3 237,7 7 7/1 “ -- 241,5

240,5 0,5

278,9 275,8 8 8/1 5-6/11-12 --

709,5 279,9 278,2 0,5

277,0 273,8 9 9/1 “ --

702,8 277,9 276,3 0,5

278,9 275,7 10 10/1 “ --

707,6 279,5 278,0 0,5

Conditions of the transformer after the tests: see notes

- Externally did not show any damage.

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M0022IG

Test circuit M0022

The symbols used in this diagram are the same as those on the oscillograms.

Correspondence between laboratory circuit phase and test object terminal

Laboratory circuit phase Test object terminal

R U

S V

T W

M2032IG

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Measurement of short-circuit inductance The measurement of short-circuit inductance was performed before the short-circuit tests and after every series of three tests by means of a Schering bridge (Maxwell diagram) which allows a reproducibility of at least ± 0,2%. For all measurements the transformer was set-up in the following conditions: • the tap-changer was placed in the position corresponding to the highest voltage ratio, • the terminals of the low-voltage windings were short-circuited, • the measurement points were applied to the terminals of the high-voltage winding, delta-connected. Date: September 28, 2006

U-V U-W V-W U-V U-W V-W U V W U V W1-2/7-8 147,05 146,50 147,74 - - - 220,500 222,587 218,8641-2/7-8 after the test no. 4 147,20 146,54 147,78 0,10 0,03 0,03 220,835 222,590 218,871 0,15 0,00 0,001-2/7-8 after the test no. 7 147,06 146,48 147,84 0,01 -0,01 0,07 220,484 222,845 218,761 -0,01 0,12 -0,051-2/7-8 after the test no. 10 147,25 146,60 147,92 0,14 0,07 0,12 220,859 222,887 218,927 0,16 0,13 0,03

tap-changer position measurement effected

short-circuit inductance variation

measured at the terminals from the initial measurement calculated for single limb from the initial value

before the tests

short-circuit inductance variation[mH] [%] [mH] [%]

Maximum variation of short-circuit inductance stated by Standard: 4%.

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M2034IG

Verification after short-circuit tests Dielectric routines tests (at 100% of the original test values) • Separate-source AC withstand voltage test The single-phase test voltage was applied between the terminals of the winding under test and the terminals of the other windings and core and frame, connected together to earth. Date: September 28, 2006

Winding Tap-changer Tapping voltage Test parameters under test position of HV winding voltage frequency duration

- - kV kV Hz s high-voltage 5-6/7-8 15,0 38,0 50 60 low-voltage d “ “ 3,0 50 60 low-voltage y “ “ 3,0 50 60

Test result: no collapse of the test voltage occurred. • Induced AC voltage test (ACSD) The three-phase test voltage was applied to the terminals of the low-voltage winding y and the relevant neutral terminal was connected to earth. Date: September 28, 2006

Winding Tap-changer Tapping voltage Test parameters under test position of HV winding voltage frequency duration

- - kV kV Hz s low-voltage y 5-6/7-8 15,0 1,18 150 40

Test result: no collapse of the test voltage occurred.

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A0153IG

Circuit A0153

Induced AC voltage test circuit for partial discharge measurement - Test circuit at 150Hz, three-phase connection CO - frequency converter NUOVA SACCARDO; power 80 kVA; input voltage 380V/660V at 50 Hz; output voltage

660 V ± 10 % at 150 Hz G - Faraday cage R - three-phase voltage regulator; power 187 kVA; voltage 380-658V/ 0÷690-1200V E - earth connection V1 - direct reading digital voltmeter FLUKE; CESI No. 06393 n - neutral connection K - charge pulse generator AMPERE; CESI No. 02526 D - capacitive voltage divider PASSONI & VILLA; type CD; C= 300 pF; V= 250 kV; scale factor 2551,0; CESI

No.39116-39117 V2 - direct reading digital voltmeter AGILENT 34401A; CESI No.55077 Ca - Cb - Cc - coupling capacitor PASSONI & VILLA; C= 2000 pF; voltage 150 kV; CESI No.23772-23773-23774 (one for

each phase) AKV - matching coupling quadrupole HAEFELY TRENCH; type AKV 573; CESI No. 13290 K - special, multi-wire, connecting cable PD - partial discharge detector HAEFELY TRENCH; type TE 571; CESI No. 13281

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A0160IG

Circuit A0160 Partial discharges measurement Direct circuit - Scheme 1a

P - calibrator AMPERE; CESI No. 02526 Ck - coupling capacitor PASSONI & VILLA; C= 2000 pF; voltage 150 kV; CESI No.23772-23773-23774 (one for each

phase) AKV - matching coupling quadrupole HAEFELY TRENCH; type AKV 573; CESI No. 13290 K - special, multi-wire, connecting cable PD - partial discharge detector HAEFELY TRENCH; type TE 571; CESI No. 13281

A1262IG

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Partial discharge measurement (after short-circuit test) Test object: Non-enclosed three-phase dry-type power transformer with three windings, with encapsulated windings, for continuous duty, with cooling by air natural

convection (AN): MF – 1930/965/965 kVA - 15 kV / 0,59/0,59 kV Test circuit: A0153 Measurement circuit: A0160 (direct calibration 5 pC, oscillogram No.11) Arrangement: see photographs from No.3 to No.4 Test frequency: 150 Hz

Atmospheric conditions and correction factor

b td/tw h Relative humidity

kPa °C g / m3 %

100,23 25,0 / 17,0 10,07 43,9

Date: September 29, 2006

Applied induced voltage Partial discharge measurement Required voltage

lv side HV side Phase

(phase-to-phase) (phase-to-phase) (phase-to-phase)

Duration of the voltage

application

Temperature of the test object voltage increase voltage decrease

Oscillogram Notes

V1 V2 VHV=V2*K2*√3 PD level PD level

kVrms Vrms Vrms kVrms s °C pC pC No.

1,8Ur direct reading on HV side 6,07 27,0 30 --- --- -- 1W

1,3Ur direct reading on HV side 4,39 19,5 180 25,0

--- ≤ 0,5 12

1,8Ur direct reading on HV side 6,07 27,0 30 --- --- -- 1V

1,3Ur direct reading on HV side 4,39 19,5 180 25,0

--- ≤ 0,5 13

1,8Ur direct reading on HV side 6,07 27,0 30 --- --- -- 1U

1,3Ur direct reading on HV side 4,39 19,5 180 25,0

--- ≤ 0,5 14

Ur is the rated voltage of the high-voltage winding (primary winding) equal to 15,0 kV (phase-to-phase) K2 is the scale factor of the capacitive voltage divider (D) equal to 2566,4

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M2009IG

Photo no. 1

Photo no. 2

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M2009IG

Photo no. 3

Photo no. 4