Test Report CESI A6/ Approved Page 1. MF Trasformatori s.r.l. - Calcinato (BS) Italy

Transcription

1 A6/ Test Report CESI Approved Page 1 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 /965/965 kva - 15 kv / 0,59/0,59 kv Tests carried out Verification of dynamic ability to withstand short-circuit PUBBLICATO A (PAD ) Standards/Specifications IEC {Ed.1.0} ( ) 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 Verified Approved BU COM - M. Assolari BU COM - F. Pizzi BU COM - V. Scarioni CESI Centro Elettrotecnico Sperimentale Italiano Giacinto Motta spa Via R. Rubattino Milano - Italia Telefono Fax Capitale sociale Euro interamente versato Codice fiscale e numero iscrizione CCIAA Registro Imprese di Milano Sezione Ordinaria N. R.E.A P.I. IT

2 A6/ Test Report CESI Approved Page 2 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/ 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 M2001IG

3 M2002IG 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 M 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) Test Report CESI A6/ Approved Page 3

4 A6/ Test Report CESI Approved Page 4 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 /1 Year of manufacturing 2006 Number of phases 3 Rated 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 V Rated voltage ratio 15 kv / 0,59-0,59 kv Rated frequency 50 Hz Rated power 1930/965/965 kva Rated current of the high-voltage winding (primary winding) 74,3A Rated current of the low-voltage windings (secondary windings) 944/944 A Short-circuit impedance V cc1-(2-3) 16,56 % Ratio X/R 16,095 Connection symbol Dd0y11 Cooling method AN Total mass 5100 kg Climatic class C2 Environmental class E2 Fire behaviour class F1 Service class VI Characteristics of the windings Highest voltage for equipment applicable to the high-voltage winding 17,5 kv Highest voltage for equipment applicable to the low-voltage windings 1,1 kv Rated insulation levels LI 95 AC 38 / AC 3 Insulation class F Type of construction with circular concentric coils High-voltage winding conductor aluminium Low-voltage windings conductor metal foil (aluminium) Traction transformer conforms to CEI EN Standard Name and signature of Client's witness: M2027IG

5 A6/ Test Report CESI Approved Page 5 Verification of dynamic ability to withstand short-circuit Requested values Test current values were calculated neglecting the system impedance. Tap-changer Short-circuit current (*) U position r Z SC 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/ ,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). M2028IG

6 A6/ Test Report CESI Approved Page 6 Short-circuit tests with three-phase current Test circuit: Test frequency: Reference number of the oscillograms: Conditions of the transformer before the tests: Transformer prearranged on the voltage ratio: M Hz MP-A6/ as supplied by the Client 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 1 1/1 5-6/ ,4 174,5 175,6 0,1 176,2 258,9 2 2/ ,5 256,1 258,0 0,5 258,9 258,8 3 3/ ,5 256,5 258,1 0,5 259,0 257,7 4 4/ ,8 254,7 256,8 0,5 257,8 5 5/1 1-2/ ,2 241,5 238,0 240,3 0,5 241,4 6 6/ ,5 241,4 236,2 239,4 0,5 240,7 7 7/ ,8 242,3 237,7 240,5 0,5 241,5 8 8/1 5-6/ ,9 275,8 278,2 0,5 709,5 279,9 9 9/ ,0 273,8 276,3 0,5 702,8 277, / ,9 275,7 278,0 0,5 707,6 279,5 Conditions of the transformer after the tests: see notes - Externally did not show any damage. M2029IG

7 A6/ Test Report CESI Approved Page 7 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 R S T Test object terminal U V W M0022IG

8 M2032IG 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 short-circuit inductance variation short-circuit inductance variation tap-changer [mh] [%] [mh] [%] measurement effected position measured at the terminals from the initial measurement calculated for single limb from the initial value U-V U-W V-W U-V U-W V-W U V W U V W 1-2/7-8 before the tests 147,05 146,50 147, , , , /7-8 after the test no ,20 146,54 147,78 0,10 0,03 0,03 220, , ,871 0,15 0,00 0,00 1-2/7-8 after the test no ,06 146,48 147,84 0,01-0,01 0,07 220, , ,761-0,01 0,12-0,05 1-2/7-8 after the test no ,25 146,60 147,92 0,14 0,07 0,12 220, , ,927 0,16 0,13 0,03 Maximum variation of short-circuit inductance stated by Standard: 4%. Test Report CESI A6/ Approved Page 8

9 A6/ Test Report CESI Approved Page 9 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, low-voltage d 3, low-voltage y 3, 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, Test result: no collapse of the test voltage occurred. M2034IG

10 A6/ Test Report CESI Approved Page 10 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 V/ V E - earth connection V 1 - direct reading digital voltmeter FLUKE; CESI No n - neutral connection K - charge pulse generator AMPERE; CESI No D - capacitive voltage divider PASSONI & VILLA; type CD; C= 300 pf; V= 250 kv; scale factor 2551,0; CESI No V 2 - direct reading digital voltmeter AGILENT 34401A; CESI No C a - C b - C c - coupling capacitor PASSONI & VILLA; C= 2000 pf; voltage 150 kv; CESI No (one for each phase) AKV - matching coupling quadrupole HAEFELY TRENCH; type AKV 573; CESI No K - special, multi-wire, connecting cable PD - partial discharge detector HAEFELY TRENCH; type TE 571; CESI No A0153IG

11 A6/ Test Report CESI Approved Page 11 Circuit A0160 Partial discharges measurement Direct circuit - Scheme 1a P - calibrator AMPERE; CESI No C k - coupling capacitor PASSONI & VILLA; C= 2000 pf; voltage 150 kv; CESI No (one for each phase) AKV - matching coupling quadrupole HAEFELY TRENCH; type AKV 573; CESI No K - special, multi-wire, connecting cable PD - partial discharge detector HAEFELY TRENCH; type TE 571; CESI No A0160IG

12 A1262IG 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 t d /t w h Relative humidity kpa C g / m 3 % 100,23 25,0 / 17,0 10,07 43,9 Date: September 29, 2006 Phase Applied induced voltage Duration of the Partial discharge measurement Required voltage Temperature of lv side HV side voltage the test object voltage increase voltage decrease (phase-to-phase) (phase-to-phase) (phase-to-phase) application Oscillogram V 1 V 2 V HV =V 2 *K 2 * 3 PD level PD level kv rms V rms V rms kv rms s C pc pc No. 1W 1,8Ur direct reading on HV side 6,07 27, ,0 1,3Ur direct reading on HV side 4,39 19, ,5 12 1V 1,8Ur direct reading on HV side 6,07 27, ,0 1,3Ur direct reading on HV side 4,39 19, ,5 13 1U 1,8Ur direct reading on HV side 6,07 27, ,0 1,3Ur direct reading on HV side 4,39 19, ,5 14 Notes Ur is the rated voltage of the high-voltage winding (primary winding) equal to 15,0 kv (phase-to-phase) K 2 is the scale factor of the capacitive voltage divider (D) equal to 2566,4 Test Report CESI A6/ Approved Page 12

13 A6/ Test Report CESI Approved Page 13 Photo no. 1 Photo no. 2 M2009IG

14 A6/ Test Report CESI Approved Page 14 Photo no. 3 Photo no. 4 M2009IG

15

16

17

18

19

20

21

22

23

24

25

26

27

28