CAPITULO III MARCO TEÓRICO-CONCEPTUAL
3.7 Evolución de la salud
10.1 Each transformer shall be provided with a rating plate of stainless steel or brass fitted in a visible position, showing the items indicated below. The entries on the rating plate shall be indelibly marked by engraving and shall include the data in accordance with IEC Publication 60076-1 and Table-I and Table-II,
1) Manufacturer’s type designation ________________
2) Manufacturer’s name ________________
3) Type of Transformer ________________
4) Reference specification number ________________
5) Manufacturer’s serial number ________________
6) Year of manufacture ________________
7) Number of phases ________________
8) Number of windings ________________
9) Type of cooling ________________
10) Rated power ONAN/ONAF1/ONAF2
a) 55º C winding temperature rise _____________MVA b) 60º C winding temperature rise _____________MVA c) 65º C winding temperature rise ______________ MVA 11) Rated voltage HV/LV/Tertiary ____________ kV 12) Rated current HV/LV/Tertiary ____________ A
13) Rated frequency ____________ Hz
14) Vector group symbol ____________
15) Winding normal temperature rise ____________deg C 16) Top oil normal temperature rise ____________deg C 17) Impulse withstand voltage HV/LV/Tertiary ____________kV peak 18) Power frequency withstand voltage
HV/LV/Tertiary ____________kV rms
19) HV and LV windings uniformly insulated
or graded ____________
20) Impedance voltage at rated current on ________MVA base (measured value):
a) HV – LV ____________percent
b) LV – Tertiary ____________percent
c) HV – Tertiary ____________percent
21) Maximum exciting current_____MVA base ____________percent 22) Type of tap-changer ____________
23) Tapping range ( and indication of the
winding which is fitted with tappings) ____________percent
24) Number of taps ____________
25) Permissible higher operating voltage for
the tapping including principal tapping ____________percent 26) Diagram showing tap-changer connections ____________
27) Short-circuit impedance at principal tap and extreme taps alongwith indication of the winding to which the impedance is referred
a) HV – LV _________ohm per phase
b) LV – Tertiary _________ohm per phase c) HV – Tertiary _________ohm per phase
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28) A table giving tapping voltages tapping currents and tapping Power
at all taps for each winding _____________
29) Weight of case and fittings _____________Kg 30) Weight of core and coil _____________Kg
31) Weight of oil _____________Kg
32) Total weight _____________Kg
33) Shipping weight of heaviest part _____________Kg 34) Weight of heaviest part of untanking _____________Kg
35) Quantity of oil _____________ Ltrs.
36) Reference specifications transformer oil _______________
37) Losses at 75º C _____________
a) Iron loss, 100% voltage _______________kW b) Copper loss, 100% _______________kW upper rated power (at OWAF2)
10.2 Approval of the rating plate(s) shall be obtained from WAPDA/NTDC
11 LOSSES
11.1 The manufacturer shall design the transformers for optimum losses.
11.2 In the evaluation of tenders for Auto-transformer, the following rates shall be used for the capitalization of losses and auxiliary power consumption by cooling fans.
Capital Cost of no-load losses = US$ 5200/- per kilowatt.
Capital Cost of on-load losses = US$ 2700/- per kilowatt.
Capital Cost of auxiliary consumption = US$ 2700/- per kilowatt.
11.3 The capitalized costs of iron losses at 100 percent voltage, load losses at principal tap and corresponding to the 100 percent upper rated power of 160 MVA, 250MVA and 315 MVA 3-phase and reference temperature of 75 deg C, and total auxiliary power consumption of fans needed to deliver 100 percent upper rated power of 160 MVA, 250MVA and 315 MVA,3-phase (i-e.
excluding 25% extra fans ),shall be added to quoted prices, The losses to be taken shall be guaranteed losses corresponding to 2-windings loading (HV/LV) plus 10 percent tolerances.”
12 TESTS
12.1 Routine Tests
12.1.1 The following routine tests shall be made on each transformer and accessories in accordance with the IEC Publications and details listed hereunder:
12.1.2 Auto Transformers
12.1.2.1 The following tests shall be made on each transformer in accordance with IEC Publications 60076-1.
1) Measurement of winding resistance 2) Voltage ratio measurement and check of voltage vector relationship
3) Measurement of impedance voltage (principal tapping), short circuit impedance
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and load loss
4) Measurement of no-load loss and current at normal, 105, 110 and 120% voltage 5) Tests on on-load tap-changer
6) Measurement of capacitance and Dissipation Factor of windings and bushings.
7) Measurement of installation of resistance.
12.1.2.2 The following tests shall be made on each transformer in accordance with the following specifications:
1) Switching impulse test Clause 14 IEC 60076-3 2) Separate source voltage
withstand test Clause 10 IEC 60076-3 3) Induced over voltage with-
stand test and measurement Clause 11.4 Method 2 of partial discharges IEC 60076-3
4) Power factor Dissipation Clause 7.4 ANSI C
factor test 57,12.90-1980
12.1.2.3 Unless specified to the contrary, the following operational tests shall be made on assembled auto transformer at the manufacturer’s works as mentioned below:
a) Buchholz Relay
This test shall be carried out on any one transformer out of a group of transformers of same make, type, rating and with same type of Buchholz relay installed. Tests shall be carried out to indicate proper installation and functioning of relay for operation with slow and fast evolution of gas in the auto transformer.
b) Cooling Equipment
Test shall be carried out on each set of cooling equipment to indicate proper operation of cooling equipment with auxiliary supply variation listed in clause 3.7 and without exceeding temperature rises specified in clause 5.3.
c) Temperature Indicators
Tests shall be made for proper calibration and functioning of oil temperature indicators and winding temperature indicators.
d) Tank pressure test at 10 N/cm² for 12 hours.
e) Assembled transformer pressure test at 15 N/cm² for approximate 18 hours.
12.1.2.4 Insulating Oil Tests
Tests shall be carried out in accordance with IEC & 60422,60296 for each consignment of the insulating oil.
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12.1.2.5 On-load Tap-Changer and Motor Drive Mechanism
The following tests shall be made on each on-load tap-changer and motor drive mechanism in accordance with IEC Publication 60214.
a) On-load Tap-changer
1) Mechanical test Sub clause 8.1 2) Sequence test Sub clause 9.2 3) Dielectric test on
auxiliary circuits Sub clause 9.3
b) Motor Drive Mechanism
1) Mechanical test Sub clause 13.1 2) Dielectric test on
auxiliary circuits Sub clause 13.2
In addition to above the report of the routine tests carried out by tap change manufacturer in accordance with latest IEC standards shall also be supplied.
12.1.2.6 Auto Transformer Bushings
The following routine tests shall be made on each bushing of each auto transformer in accordance with IEC Publication 60137
1) Measurement of the dissipation
factor Clause 58
2) Dry one minute Power frequency
withstand voltage test Clause 59 3) Partial discharge test Clause 60 4) Power frequency voltage
withstand test of the test
tapping insulation (for condenser
bushings) Clause 61
5) Test for leakage of internal
filling (for oil filled bushings) Clause 62 12.1.2.7 Bushing Current Transformers
The following routine tests shall be made on each bushing C.T of each auto transformer in accordance with IEC Publication 60044-1
1) Verification of terminal markings Clause 8.1 2) Power frequency test on primary
Windings and partial Clause 8.2
discharge measurement.
3) Power frequency test between sections of primary and secondary
Windings and on secondary Clause 8.3
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windings
4) Over voltage inter-turn test Clause 8.4 5) Routine test for measuring accuracy Clause 11.5
6) Routine test for composite error Clause 12.6 7) Saturation curve test Clause 12.6
12.2 Type Tests
12.2.1 The following type tests shall be carried out on one auto transformer in each group of auto transformers with the same characteristics and ratings. In the case of the main auto transformer, the type tests are mandatory but in case of the on-load tap-changer, bushing, current transformers and bushings, duly certified and complete test reports for test carried out on similar units shall be acceptable in lieu of the actual tests.
12.2.2 Auto Transformer Main Units
12.2.2.1 The following type tests shall be made on one transformer in each group of transformers with the same characteristics and ratings. The tests shall be made in accordance with following IEC Publications.
1) Test of temperature rise Clause 3 of IEC 60076-2 2) Full wave lightning impulse voltage
withstand test on line and neutral
terminals Clause 12 of IEC 60076-3
3) Test with lightning impulse
chopped on tail Clause 13 of IEC 60076-3 4) Measurement of the harmonics on
No-load current Clause 8.6 of IEC 60076-1 5) Measurement of zero sequence
impedance Clause 8.7 of IEC 60076-1
6) Measurement of acoustic sound
level As per IEC 551
7) Measurement of Power taken by
fan motors
12.2.2.2 WAPDA/NTDC reserves the option to specify short circuit test for transformers.
12.2.3 On-Load Tap-Changers and Motor Drive Mechanism
12.2.3.1 The following type tests shall be carried out on one on-load tap-changer in each group of on load tap-changers with the same characteristics and ratings in accordance with IEC Publication 60214.
1) Temperature rise test of contacts Sub clause 8.1
2) Switching tests:
a) Service duty test Sub clause 8.2
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b) Breaking capacity
3) Short circuit current test Sub clause 8.3 4) Transition resistors current test Sub clause 8.4 5) Mechanical endurance test Sub clause 8.5 6) Applicable dielectric tests Sub clause 8.6 7) Mechanical load test Sub clause 12.1 8) Over run test Sub clause12.2 12.2.4 Bushings
12.2.4.1 The following type tests shall be carried out on one bushing in each group of bushings with the same characteristics and ratings in accordance with IEC Publication 60137.
1) Wet one minute Power frequency
voltage withstand test Clause 52 2) Dry lightning impulse voltage
withstand test Clause 53
3) Thermal stability test Clause 55 4) Measurement of radio interference Clause 56 5) Temperature rise test Clause 57 12.2.5 Bushing Current Transformers
12.2.5.1 The following type test shall be carried out on one bushing type current transformer in each group of bushing current transformers with the same characteristics and ratings in accordance with IEC Publication 60044-1
1) Short time current tests Clause 7.1 2) Temperature rise test Clause 7.2 3) Impulse voltage tests for service
in exposed installations Clause 7.3 4) Measuring accuracy test Clause 11.4 5) Type tests for composite error Clause 12.5 6) Radio Interference measurement Clause 7.5
12.2.5.2 The temperature rise tests specified in clause 12.2.2 shall be carried out for all Power ratings of each transformer as well as for 55 deg C and 65 deg C temperature rise conditions.
12.2.5.3 The type test reports shall incorporate design information and details sufficiently to identify the auto transformers and accessories with that of other transformers of the same design and construction. The information shall include the performance data as well as drawings such as specified in clause 16.
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12.2.6 Sample Tests
12.2.6.1 The following sample tests shall be carried out on transformers bushings in accordance with IEC Publications 137
1) Thermal stability test Clause 55 2) Test for leakage at flange or
other fixing device Clause 63