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CORPORACION COOPERATIVAALKARGO, S. COOPAritz Bidea nº 83 Atela Auzotegia48100 Mungía (Vizcaya) - SPAINTel.:+34 (94) 674.00.04Fax: +34 (94) 674.44.17Apartado 102 / P.O BOX 102e-mail: [email protected] DISTRIBUTION TRANSFORMERS
TEST
All transformers undergo the following individual or routine tests as per IEC-76 , BS171 and UNE 20101:
• Winding resistance measurement• Check on connection elements & polarity• Transformer ratio measurement & coupling check• No load losses & no load current measurements• Load losses measurement• Short-circuit voltage measurement (main connection point)• Dielectric tests• Induced voltage test in windings• Applied voltage test in windings
On request the following type tests can also be performed:
• Heating test• Lighting impulse test• Measuring of noise level• Oil characteristics• Others
OTHER PRODUCTS IN OUR MANUFACTURINGRANGE
• Transformers in silicone (LNAN)• Cast-resin dry type transformers from 50 to 5000 kVA with high voltage class ≤ 36 kV• Medium power transformers up to 30 MVA and 72.5 kV• Earthing transformers & reactances• Impregnated dry transformers• Auto-transformers• Transformers for rectifiers• Special transformers
Note: The data and descriptions in this catalogue refer to our present design and construction techniques, and do not constitute an undertakingon our part unless confirmed as such. We reserve the right to make such modifications and improvements as may be deemed convenient withoutprior notice.
50, 100, 160, 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500 kVA.
° Preferential power ratings are marked in bold print.
DISTRIBUTION TRANSFORMERS
This catalogue deals with transformers immersed in insulating fluid with natural self cooling (ONAN), three-phase, 50 - 2500 kVAfor indoor or outdoor use, 50/60 Hz, hermetically sealed.
The transformers described in this catalogue are designedand tested in accordance to European UnionHarmonisation Document HD428, UNE 21428 and IEC76 standards.
However, and by request, they can be manufacturedaccording to any other national or international standards,such us
HD-398, BS 171, NF C52.100, DIN 42.500, UNE 20.101,IEC 76
UNE 21320, UNE 48103, UNE EN 60551, UNE 20110,UNE 20145, UNE EN 50180, ETU 5201 E and UNESArecommendations. Another applicable documents are:ANSI C57, NEMA, ESI, HN, UTE.
MANUFACTURING STANDARD
GENERAL CHARACTERISTICS
RATINGS
HIGH VOLTAGEThis material is designed for voltages of ≤ 36 kV. Specific figures are not given for this parameter because of the wide variety of voltagesused. Transformers can be supplied on demand to run at two different primary voltages, the shifth between these input voltages has twobasic alternatives:• with a primary tap changer which can be switched with no load and no applied voltage• or by changing terminals under the cover.
LOW VOLTAGEThe secondary voltage under no load is allocated at 420 V, though other voltages can be supplied on demand. When usage requirestwo voltages, transformers with two simultaneous voltages can be supplied. In this case the no-load voltages are set to 420 and242 V. For the lower voltage output the power is K x Pr.
In simultaneous loads the power distribution is: P + P =Pr where: KPPPrK
= load supplied at 242 V= load supplied at 420 V= rated power= 0,75
1 2
1
2
All transformers are supplied with:
• 3 high voltage bushings• 4 or 7 low voltage bushings• 5-position tap changer on cover, workable with transformer off load• 2 lifting & tank removal eye-bolts• Filling hole with M-40 x 1.5 outside thread and threaded cover• Drainage & sampling plug at bottom of tank• 4 two-way, 90º directional wheels• 2 earthing connections at bottom with M-10 screws
BASIC EQUIPMENT
O P T I O N A L A C C E S S O R I E S
• Two-contact dial thermometer
• Terminal box
• HV plug-in bushing
• Thermostat
• LV and HV cable boxes
• Protection & control block for the followingfunctions:
• LV bar bushing
For conservator tank typetransformers:
• Two contacts Buchholz relay
• Silicagel air breather
• Magnetic level sensor with one or two contacts
• Oil Level indicator
• Others
Two-contact dial thermometer Terminal box
Protection & control block
HV plug-in bushing
LV bar bushing
Silicagel air breather Two contacts Buchholz relay
Detection of gas emissions from dielectric liquid(trip), detection of excessive increase in pressure on tank (trip),dielectric liquid temperature reading and liquid level display(adjustable alarm & trip contacts)
The connections normally used are as follows:
• For rated power levels of 160 kVA or less: Yzn11
• For rated power levels over 160 kVA: Dyn11.
As per IEC 76 and UNE 20101, in normal operating mode:
• 60º K max. in oil• 65º K average in windingsOther temperature rise levels on demand.
Transformers covered by document HD 428 (UNE 21428-1) must have one of the following oil expansion systems:
a) an external conservator tankb) an air chamber under the coverc) a hermetically sealed elastic tank
Alkargo recommends option (c), which is the one considered in this catalogue, as it has the following advantages:
VECTOR GROUP REFERENCE
INSULATION LEVELS
TEMPERATURE RISE
ADVANTAGES OF HERMETIC SEALING
As per IEC 76, BS 171 and UNE 20101 standards these areset in accordance with the highest voltage for the material,being the level immediately above the rated voltage.
1.
2.
3.
4.
5.
6.
Smaller size, as there is no need for an conservator tank or air chamber, making for easier transformer transportation and placement.
Lower overall weight.
Increased sturdiness and less risk of leaks, there being no weak points such as welds between the expansion tank and the cover, oillevel gauge, Silicagel air breather, etc.
Low maintenance due to the absence of elements such as the drier, overpressure valves and liquid level indicators.
No degradation of insulating liquid (oil) by oxidation or absorption of moisture, as there is no contact with the air. The liquid thereforeremains in ideal condition.
Better conservation of seals due to lack of contact with air, which means that they stay more flexible.
Material maximum 12 kV 17,5 kV 24 kV 36 kVadmissible voltage
Withstand voltage 28 kV 38 kV 50 kV 70 kV
Basic insolation level 75 kV 95 kV 125 kV 170 kV
K
C
E
F
L L
H
A
E
J
B
JJ
kVA
A
B
C
D
E
F
G
H
J
K
L
Kg.
l.
Kg.
50
990
720
1380
125
520
40
35
125
80
500
375
115
128
460
100
1070
720
1410
125
520
40
35
125
80
500
375
120
134
590
160
1170
720
1450
125
520
40
35
125
80
500
375
175
195
810
250
1240
870
1540
125
670
40
35
175
150
500
375
235
262
1040
400
1440
870
1590
125
670
40
35
175
150
500
375
260
290
1410
630
1580
960
1680
125
670
40
35
275
150
500
375
310
346
1670
800
1740
1040
1660
125
670
40
35
275
150
500
375
460
485
2240
1000
1860
1120
1740
125
670
40
35
325
150
500
375
490
547
2640
1250
1920
1120
1910
200
820
70
45
325
150
500
375
640
715
3330
1600
1860
1100
2110
200
820
70
45
355
200
500
375
830
927
3910
2000
2040
1160
2160
200
820
70
45
355
200
500
375
1030
1150
4850
2500
2100
1350
2210
200
1070
70
45
355
200
500
375
1170
1300
5550
GD
Highest voltage for material: 36 kV Low voltage B2: 420 V
Oriented grain, very low loss magnetic plate is used following UNE 36128. The type or class of plate is chosen on the basisguaranteed noise level and losses. The net cross section is maintained constant in limbs and yokes throughout the magnetic circuit,as a special configuration does away with the need for cross-section reducing grip bolts (section reduction).
The limbs and yokes are joined by 45º lugless joints, with complete one-piece yoke, and stacking is arranged so that eachplate profile is staggered with regard to the previous one, thus minimising the effect of the gap. The profile is stepped, with the numberof steps required to obtain the best coefficient of useful surface area.
Construction details
This winding is located next to and concentric with the magnetic circuit. Two clearly different types of wire are used depending onthe allocated current:
- Rectangular cross-section with rounded edges as per UNE 21179; or- Strips with conditioned edges.
In the former case each wire is insulated with thermal class A cellulose paper or class H enamel. Strips are used bare.
The rectangular wire winding is set up in a complete layer configuration with one or more concentric channels for cooling.The insulation between layers is always B status resin impregnated.
The width of the strip on strip type windings with conditioned edges covers the whole axial width of the coil, so that eachturn is a layer of winding. As the strip is wound a layer of type B resin impregnated paper is wound with it. This polymerises duringthe drying cycle, giving the winding the strength to withstand the mechanical stresses entailed by short circuits as per IEC - 76 andBS 171 standards.
This is wrapped around the low voltage winding to lie concentric with it, separated by an insulation structure giving the levelof insulation desired.
The conductors used are of two types:• circular cross-section wire• rectangular cross section strips.
The conductors are insulated with thermal class H enamel. The rectangular section wires or strips have thermal class A paperor thermal class H enamel. With both types of wire, the winding configuration is anti-resonant in one section, making it highly resistantto ray type pulse waves.
The insulation between layers is resin impregnated, polymerising during drying to give the winding the strength to withstandthe mechanical stresses entailed by short circuits.
I- MAGNETIC CIRCUIT
II- LOW VOLTAGE WINDING
III- HIGH VOLTAGE WINDING
Rated Power
Lenght (mm)
Width (mm)
Height (mm)
Wheels diameter (mm)
1Distance between wheel axis (mm)
Wheels width (mm)
Wheel free deep (mm)
L.V. bushing height (mm)
Distance between L.V. bushing axis (mm)
H.V. bushing height (mm)
Distance between H.V. bushing axis (mm)
Insolation fluid weight
Insolation fluid volume
Total weight
50
870
720
1270
125
520
40
35
125
80
385
275
115
128
460
100
950
720
1310
125
520
40
35
125
80
385
275
120
134
590
160
1170
720
1350
125
520
40
35
125
80
385
275
175
195
810
250
1240
870
1440
125
670
40
35
175
150
385
275
235
262
1040
400
1440
870
1490
125
670
40
35
175
150
385
275
260
290
1410
630
1540
960
1490
125
670
40
35
275
150
385
275
310
346
1670
800
1740
1040
1560
125
670
40
35
275
150
385
275
460
485
2240
1000
1860
1120
1640
125
670
40
35
325
150
385
275
490
547
2640
1250
1920
1120
1810
200
820
70
45
325
150
385
275
640
715
3330
1600
1860
1100
1990
200
820
70
45
355
200
385
275
830
927
3910
2000
2040
1160
2005
200
820
70
45
355
200
385
275
1030
1150
4850
2500
2100
1350
2055
200
1070
70
45
355
200
385
275
1170
1300
5500
kVA
A
B
C
D
E
F
G
H
J
K
L
Kg.
l.
Kg.
-The purpose of the fixing structureis to hold the windings in the correct axialposition with regard to the magnetic circuit,and to exert the pressure required on thatcircuit to minimise noise level. It comprisesfour beams: two made of layered wood withphenol resin at the top cylinder head and twomade of steel at the bottom one. Grippingfor height and thickness is via threaded steelrods which help to adjust the cover height.Distances between windings and tank aremaintained by two guide feet attached to thebottom beams.
-The tap changer, whose control ison the cover, is set between the cover andthe top of the magnetic circuit. It is a racktype unit with a clogged pinion which actsdirectly on the control shaft.
-The cover is made of plain steelplate reinforced by sections which also serveto attach the vertical rods which raise therest of the components. The cover isconsiderably bigger than the tank frame toprevent rain water getting into the sealseating area.
-The high and low voltage coverbushings are fitted for outdoor service. Ondemand, and according to the rated current,low voltage bushings are mounted on ananti-magnetic plate.
Highest voltage for material: ≤ 24 kV
Low voltage B2: 420 V
The data in the tables are approximate, and correspond to hermetically sealed oil transformers with electrical characteristicsas per the above tables. They are not valid for other loss levels, double voltages, different insulation voltages, silicone
transformers, etc. In these cases, please consult us.
DIMENSIONES & WEIGHTS
Rated Power
Lenght (mm)
Width (mm)
Height (mm)
Wheels diameter (mm)
1Distance between wheel axis (mm)
Wheels width (mm)
Wheel free deep (mm)
L.V. bushing height (mm)
Distance between L.V. bushing axis (mm)
H.V. bushing height (mm)
Distance between H.V. bushing axis (mm)
Insolation fluid weight
Insolation fluid volume
Total weight
The distribution transformer tank is elastic, enabling it to absorb the increase in volume of insulating fluid as it heats updue to the transformer operation without experiment permanent deformations. It comprises the following components:
• supporting frames• base• cooling fins• outer frame
- The supporting frames are welded to the base in a continuous, watertight bead to prevent rusting. They have holes forattaching wheel heads and dragging the transformer.
- The base is bath shaped, with earth connections and a drainage device on the sides.- The cooling fins are the fundamental part of the tank: they form the corrugated side walls and give it the required elasticity.
They are made of cold-rolled steel plate between 1 and 5 mm thick, bent without drawing. Elasticity is obtained by a suitablecombination of height, depth, plate thickness and resulting internal pressure.
- The outer frame of the tank is made of L-section steel, welded to the top of the corrugated side walls. The top of this framehouses the pressure limiters for the seal and bear the holes for the cover/tank fixing screws.
IV- ACTIVE PART
V- TANK
This is the name given to the set of elements which can be removed from the tank of the transformer. Apart from the core and windings,the main elements are:
• fixing and guide structure• tap changer• cover• cover bushing
100
320
1750
4
97,97
98,29
98,51
98,31
97,48
97,87
98,14
97,90
1,81
3,58
56
160
460
2350
4
98,27
98,53
98,70
98,51
97,85
98,17
98,38
98,14
1,54
3,43
59
250
650
3250
4
98,46
98,70
98,84
98,65
98,09
98,37
98,56
98,32
1,37
3,33
62
400
930
4600
4
98,64
98,84
98,98
98,80
98,30
98,56
98,72
98,50
1,22
3,25
65
630
1300
6500
4
98,78
98,96
99,07
98,93
98,47
98,70
98,84
98,66
1,10
3,18
67
800
1550
8100
6
98,81
99,00
99,12
98,98
98,52
98,75
98,91
98,73
1,18
4,44
68
1000
1700
10500
6
98,79
99,00
99,14
99,07
98,50
98,75
98,93
98,84
1,22
4,47
68
1250
2130
13500
6
98,77
98,97
99,13
99,06
98,46
98,72
98,91
98,82
1,25
4,49
70
2000
3100
20200
6
98,84
99,04
99,18
99,14
98,56
98,80
98,98
98,92
1,18
4,44
73
2500
3800
26500
6
98,80
99,01
99,18
99,13
98,51
98,77
98,97
98,92
1,23
4,48
76
1600
2600
17000
6
98,79
99,00
99,16
99,09
98,50
98,76
98,95
98,87
1,23
4,48
71
50
190
1100
4
97,48
97,89
98,17
97,97
96,88
97,37
97,73
97,48
2,26
3,77
52
50
230
1250
4,5
97,13
97,57
97,88
97,59
96,43
96,98
97,36
97,01
2,57
426
52
100
380
1950
4,5
97,72
98,07
98,29
98,03
97,17
97,60
97,88
97,55
2,03
4,02
56
160
520
2550
4,5
98,12
98,39
98,57
98,33
97,66
98,00
98,21
97,92
1,68
3,83
59
250
780
3500
4,5
98,32
98,56
98,70
98,43
97,91
98,20
98,38
98,04
1,49
3,72
62
400
1120
4900
4,5
98,51
98,72
98,84
98,59
98,15
98,41
98,55
98,25
1,32
3,62
65
630
1450
6650
4,5
98,73
98,91
99,02
98,83
98,41
98,64
98,78
98,54
1,16
3,51
67
800
1700
8500
6
98,75
98,94
99,06
98,90
98,44
98,67
98,83
98,62
1,23
4,48
68
1000
2000
10500
6
98,77
98,96
99,08
98,95
98,46
98,70
98,86
98,69
1,22
4,47
68
1250
2360
13500
6
98,75
98,95
99,09
98,99
98,44
98,69
98,86
98,73
1,25
4,49
70
1600
2800
17000
6
98,78
98,98
99,12
99,04
98,47
98,72
98,90
98,81
1,23
4,48
71
2000
3300
20200
6
98,83
99,03
99,16
99,10
98,55
98,78
98,95
98,87
1,18
4,44
73
2500
4100
26500
6
98,78
99,00
99,16
99,09
98,50
98,76
98,95
98,86
1,23
4,48
76
ELECTRICAL CHARACTERISTICS
The two tables below indicate the guaranteed rated figures as per document HD 428, UNE 21428-1 (1996) and IEC-76 standards.These figures are valid for a single secondary voltage, even if there is more than one primary voltage.
Highest voltage for material: ≤ 24 kV
Low voltage B2: 420 V
Highest voltage for material: 36 kV
Low voltage B2: 420 V
F.L. = Full Load
Rated Power (kVA)
No load losses (Wo)
Load losses (Wc) at 75°C
Short-circuit voltage (%) at 75°C
Efficiency (%), cos �=1 4/4 F.L.
3/4 F.L.
2/4 F.L.
1/4 F.L.
Efficiency (%), cos �=0,8 4/4F.L.
3/4 F.L.
4/4 F.L.
1/4 F.L.
Regulation voltage (%) . cos �=1
Regulation voltage (%) . cos �=0,8
Lw= Acoustic pressure level dB(A)
F.L. = Full Load
Rated Power (kVA)
No load losses (Wo)
Load losses (Wc) at 75°C
Short-circuit voltage (%) at 75°C
Efficiency (%), cos �=1 4/4 F.L.
3/4 F.L.
2/4 F.L.
1/4 F.L.
Efficiency (%), cos �=0,8 4/4F.L.
3/4 F.L.
4/4 F.L.
1/4 F.L.
Regulation voltage (%) . cos �=1
Regulation voltage (%) . cos �=0,8
Lw= Acoustic pressure level dB(A)
100
320
1750
4
97,97
98,29
98,51
98,31
97,48
97,87
98,14
97,90
1,81
3,58
56
160
460
2350
4
98,27
98,53
98,70
98,51
97,85
98,17
98,38
98,14
1,54
3,43
59
250
650
3250
4
98,46
98,70
98,84
98,65
98,09
98,37
98,56
98,32
1,37
3,33
62
400
930
4600
4
98,64
98,84
98,98
98,80
98,30
98,56
98,72
98,50
1,22
3,25
65
630
1300
6500
4
98,78
98,96
99,07
98,93
98,47
98,70
98,84
98,66
1,10
3,18
67
800
1550
8100
6
98,81
99,00
99,12
98,98
98,52
98,75
98,91
98,73
1,18
4,44
68
1000
1700
10500
6
98,79
99,00
99,14
99,07
98,50
98,75
98,93
98,84
1,22
4,47
68
1250
2130
13500
6
98,77
98,97
99,13
99,06
98,46
98,72
98,91
98,82
1,25
4,49
70
2000
3100
20200
6
98,84
99,04
99,18
99,14
98,56
98,80
98,98
98,92
1,18
4,44
73
2500
3800
26500
6
98,80
99,01
99,18
99,13
98,51
98,77
98,97
98,92
1,23
4,48
76
1600
2600
17000
6
98,79
99,00
99,16
99,09
98,50
98,76
98,95
98,87
1,23
4,48
71
50
190
1100
4
97,48
97,89
98,17
97,97
96,88
97,37
97,73
97,48
2,26
3,77
52
50
230
1250
4,5
97,13
97,57
97,88
97,59
96,43
96,98
97,36
97,01
2,57
426
52
100
380
1950
4,5
97,72
98,07
98,29
98,03
97,17
97,60
97,88
97,55
2,03
4,02
56
160
520
2550
4,5
98,12
98,39
98,57
98,33
97,66
98,00
98,21
97,92
1,68
3,83
59
250
780
3500
4,5
98,32
98,56
98,70
98,43
97,91
98,20
98,38
98,04
1,49
3,72
62
400
1120
4900
4,5
98,51
98,72
98,84
98,59
98,15
98,41
98,55
98,25
1,32
3,62
65
630
1450
6650
4,5
98,73
98,91
99,02
98,83
98,41
98,64
98,78
98,54
1,16
3,51
67
800
1700
8500
6
98,75
98,94
99,06
98,90
98,44
98,67
98,83
98,62
1,23
4,48
68
1000
2000
10500
6
98,77
98,96
99,08
98,95
98,46
98,70
98,86
98,69
1,22
4,47
68
1250
2360
13500
6
98,75
98,95
99,09
98,99
98,44
98,69
98,86
98,73
1,25
4,49
70
1600
2800
17000
6
98,78
98,98
99,12
99,04
98,47
98,72
98,90
98,81
1,23
4,48
71
2000
3300
20200
6
98,83
99,03
99,16
99,10
98,55
98,78
98,95
98,87
1,18
4,44
73
2500
4100
26500
6
98,78
99,00
99,16
99,09
98,50
98,76
98,95
98,86
1,23
4,48
76
ELECTRICAL CHARACTERISTICS
The two tables below indicate the guaranteed rated figures as per document HD 428, UNE 21428-1 (1996) and IEC-76 standards.These figures are valid for a single secondary voltage, even if there is more than one primary voltage.
Highest voltage for material: ≤ 24 kV
Low voltage B2: 420 V
Highest voltage for material: 36 kV
Low voltage B2: 420 V
F.L. = Full Load
Rated Power (kVA)
No load losses (Wo)
Load losses (Wc) at 75°C
Short-circuit voltage (%) at 75°C
Efficiency (%), cos �=1 4/4 F.L.
3/4 F.L.
2/4 F.L.
1/4 F.L.
Efficiency (%), cos �=0,8 4/4F.L.
3/4 F.L.
4/4 F.L.
1/4 F.L.
Regulation voltage (%) . cos �=1
Regulation voltage (%) . cos �=0,8
Lw= Acoustic pressure level dB(A)
F.L. = Full Load
Rated Power (kVA)
No load losses (Wo)
Load losses (Wc) at 75°C
Short-circuit voltage (%) at 75°C
Efficiency (%), cos �=1 4/4 F.L.
3/4 F.L.
2/4 F.L.
1/4 F.L.
Efficiency (%), cos �=0,8 4/4F.L.
3/4 F.L.
4/4 F.L.
1/4 F.L.
Regulation voltage (%) . cos �=1
Regulation voltage (%) . cos �=0,8
Lw= Acoustic pressure level dB(A)
50
870
720
1270
125
520
40
35
125
80
385
275
115
128
460
100
950
720
1310
125
520
40
35
125
80
385
275
120
134
590
160
1170
720
1350
125
520
40
35
125
80
385
275
175
195
810
250
1240
870
1440
125
670
40
35
175
150
385
275
235
262
1040
400
1440
870
1490
125
670
40
35
175
150
385
275
260
290
1410
630
1540
960
1490
125
670
40
35
275
150
385
275
310
346
1670
800
1740
1040
1560
125
670
40
35
275
150
385
275
460
485
2240
1000
1860
1120
1640
125
670
40
35
325
150
385
275
490
547
2640
1250
1920
1120
1810
200
820
70
45
325
150
385
275
640
715
3330
1600
1860
1100
1990
200
820
70
45
355
200
385
275
830
927
3910
2000
2040
1160
2005
200
820
70
45
355
200
385
275
1030
1150
4850
2500
2100
1350
2055
200
1070
70
45
355
200
385
275
1170
1300
5500
kVA
A
B
C
D
E
F
G
H
J
K
L
Kg.
l.
Kg.
-The purpose of the fixing structureis to hold the windings in the correct axialposition with regard to the magnetic circuit,and to exert the pressure required on thatcircuit to minimise noise level. It comprisesfour beams: two made of layered wood withphenol resin at the top cylinder head and twomade of steel at the bottom one. Grippingfor height and thickness is via threaded steelrods which help to adjust the cover height.Distances between windings and tank aremaintained by two guide feet attached to thebottom beams.
-The tap changer, whose control ison the cover, is set between the cover andthe top of the magnetic circuit. It is a racktype unit with a clogged pinion which actsdirectly on the control shaft.
-The cover is made of plain steelplate reinforced by sections which also serveto attach the vertical rods which raise therest of the components. The cover isconsiderably bigger than the tank frame toprevent rain water getting into the sealseating area.
-The high and low voltage coverbushings are fitted for outdoor service. Ondemand, and according to the rated current,low voltage bushings are mounted on ananti-magnetic plate.
Highest voltage for material: ≤ 24 kV
Low voltage B2: 420 V
The data in the tables are approximate, and correspond to hermetically sealed oil transformers with electrical characteristicsas per the above tables. They are not valid for other loss levels, double voltages, different insulation voltages, silicone
transformers, etc. In these cases, please consult us.
DIMENSIONES & WEIGHTS
Rated Power
Lenght (mm)
Width (mm)
Height (mm)
Wheels diameter (mm)
1Distance between wheel axis (mm)
Wheels width (mm)
Wheel free deep (mm)
L.V. bushing height (mm)
Distance between L.V. bushing axis (mm)
H.V. bushing height (mm)
Distance between H.V. bushing axis (mm)
Insolation fluid weight
Insolation fluid volume
Total weight
The distribution transformer tank is elastic, enabling it to absorb the increase in volume of insulating fluid as it heats updue to the transformer operation without experiment permanent deformations. It comprises the following components:
• supporting frames• base• cooling fins• outer frame
- The supporting frames are welded to the base in a continuous, watertight bead to prevent rusting. They have holes forattaching wheel heads and dragging the transformer.
- The base is bath shaped, with earth connections and a drainage device on the sides.- The cooling fins are the fundamental part of the tank: they form the corrugated side walls and give it the required elasticity.
They are made of cold-rolled steel plate between 1 and 5 mm thick, bent without drawing. Elasticity is obtained by a suitablecombination of height, depth, plate thickness and resulting internal pressure.
- The outer frame of the tank is made of L-section steel, welded to the top of the corrugated side walls. The top of this framehouses the pressure limiters for the seal and bear the holes for the cover/tank fixing screws.
IV- ACTIVE PART
V- TANK
This is the name given to the set of elements which can be removed from the tank of the transformer. Apart from the core and windings,the main elements are:
• fixing and guide structure• tap changer• cover• cover bushing
K
C
E
F
L L
H
A
E
J
B
JJ
kVA
A
B
C
D
E
F
G
H
J
K
L
Kg.
l.
Kg.
50
990
720
1380
125
520
40
35
125
80
500
375
115
128
460
100
1070
720
1410
125
520
40
35
125
80
500
375
120
134
590
160
1170
720
1450
125
520
40
35
125
80
500
375
175
195
810
250
1240
870
1540
125
670
40
35
175
150
500
375
235
262
1040
400
1440
870
1590
125
670
40
35
175
150
500
375
260
290
1410
630
1580
960
1680
125
670
40
35
275
150
500
375
310
346
1670
800
1740
1040
1660
125
670
40
35
275
150
500
375
460
485
2240
1000
1860
1120
1740
125
670
40
35
325
150
500
375
490
547
2640
1250
1920
1120
1910
200
820
70
45
325
150
500
375
640
715
3330
1600
1860
1100
2110
200
820
70
45
355
200
500
375
830
927
3910
2000
2040
1160
2160
200
820
70
45
355
200
500
375
1030
1150
4850
2500
2100
1350
2210
200
1070
70
45
355
200
500
375
1170
1300
5550
GD
Highest voltage for material: 36 kV Low voltage B2: 420 V
Oriented grain, very low loss magnetic plate is used following UNE 36128. The type or class of plate is chosen on the basisguaranteed noise level and losses. The net cross section is maintained constant in limbs and yokes throughout the magnetic circuit,as a special configuration does away with the need for cross-section reducing grip bolts (section reduction).
The limbs and yokes are joined by 45º lugless joints, with complete one-piece yoke, and stacking is arranged so that eachplate profile is staggered with regard to the previous one, thus minimising the effect of the gap. The profile is stepped, with the numberof steps required to obtain the best coefficient of useful surface area.
Construction details
This winding is located next to and concentric with the magnetic circuit. Two clearly different types of wire are used depending onthe allocated current:
- Rectangular cross-section with rounded edges as per UNE 21179; or- Strips with conditioned edges.
In the former case each wire is insulated with thermal class A cellulose paper or class H enamel. Strips are used bare.
The rectangular wire winding is set up in a complete layer configuration with one or more concentric channels for cooling.The insulation between layers is always B status resin impregnated.
The width of the strip on strip type windings with conditioned edges covers the whole axial width of the coil, so that eachturn is a layer of winding. As the strip is wound a layer of type B resin impregnated paper is wound with it. This polymerises duringthe drying cycle, giving the winding the strength to withstand the mechanical stresses entailed by short circuits as per IEC - 76 andBS 171 standards.
This is wrapped around the low voltage winding to lie concentric with it, separated by an insulation structure giving the levelof insulation desired.
The conductors used are of two types:• circular cross-section wire• rectangular cross section strips.
The conductors are insulated with thermal class H enamel. The rectangular section wires or strips have thermal class A paperor thermal class H enamel. With both types of wire, the winding configuration is anti-resonant in one section, making it highly resistantto ray type pulse waves.
The insulation between layers is resin impregnated, polymerising during drying to give the winding the strength to withstandthe mechanical stresses entailed by short circuits.
I- MAGNETIC CIRCUIT
II- LOW VOLTAGE WINDING
III- HIGH VOLTAGE WINDING
Rated Power
Lenght (mm)
Width (mm)
Height (mm)
Wheels diameter (mm)
1Distance between wheel axis (mm)
Wheels width (mm)
Wheel free deep (mm)
L.V. bushing height (mm)
Distance between L.V. bushing axis (mm)
H.V. bushing height (mm)
Distance between H.V. bushing axis (mm)
Insolation fluid weight
Insolation fluid volume
Total weight
All transformers are supplied with:
• 3 high voltage bushings• 4 or 7 low voltage bushings• 5-position tap changer on cover, workable with transformer off load• 2 lifting & tank removal eye-bolts• Filling hole with M-40 x 1.5 outside thread and threaded cover• Drainage & sampling plug at bottom of tank• 4 two-way, 90º directional wheels• 2 earthing connections at bottom with M-10 screws
BASIC EQUIPMENT
O P T I O N A L A C C E S S O R I E S
• Two-contact dial thermometer
• Terminal box
• HV plug-in bushing
• Thermostat
• LV and HV cable boxes
• Protection & control block for the followingfunctions:
• LV bar bushing
For conservator tank typetransformers:
• Two contacts Buchholz relay
• Silicagel air breather
• Magnetic level sensor with one or two contacts
• Oil Level indicator
• Others
Two-contact dial thermometer Terminal box
Protection & control block
HV plug-in bushing
LV bar bushing
Silicagel air breather Two contacts Buchholz relay
Detection of gas emissions from dielectric liquid(trip), detection of excessive increase in pressure on tank (trip),dielectric liquid temperature reading and liquid level display(adjustable alarm & trip contacts)
The connections normally used are as follows:
• For rated power levels of 160 kVA or less: Yzn11
• For rated power levels over 160 kVA: Dyn11.
As per IEC 76 and UNE 20101, in normal operating mode:
• 60º K max. in oil• 65º K average in windingsOther temperature rise levels on demand.
Transformers covered by document HD 428 (UNE 21428-1) must have one of the following oil expansion systems:
a) an external conservator tankb) an air chamber under the coverc) a hermetically sealed elastic tank
Alkargo recommends option (c), which is the one considered in this catalogue, as it has the following advantages:
VECTOR GROUP REFERENCE
INSULATION LEVELS
TEMPERATURE RISE
ADVANTAGES OF HERMETIC SEALING
As per IEC 76, BS 171 and UNE 20101 standards these areset in accordance with the highest voltage for the material,being the level immediately above the rated voltage.
1.
2.
3.
4.
5.
6.
Smaller size, as there is no need for an conservator tank or air chamber, making for easier transformer transportation and placement.
Lower overall weight.
Increased sturdiness and less risk of leaks, there being no weak points such as welds between the expansion tank and the cover, oillevel gauge, Silicagel air breather, etc.
Low maintenance due to the absence of elements such as the drier, overpressure valves and liquid level indicators.
No degradation of insulating liquid (oil) by oxidation or absorption of moisture, as there is no contact with the air. The liquid thereforeremains in ideal condition.
Better conservation of seals due to lack of contact with air, which means that they stay more flexible.
Material maximum 12 kV 17,5 kV 24 kV 36 kVadmissible voltage
Withstand voltage 28 kV 38 kV 50 kV 70 kV
Basic insolation level 75 kV 95 kV 125 kV 170 kV
TEST
All transformers undergo the following individual or routine tests as per IEC-76 , BS171 and UNE 20101:
• Winding resistance measurement• Check on connection elements & polarity• Transformer ratio measurement & coupling check• No load losses & no load current measurements• Load losses measurement• Short-circuit voltage measurement (main connection point)• Dielectric tests• Induced voltage test in windings• Applied voltage test in windings
On request the following type tests can also be performed:
• Heating test• Lighting impulse test• Measuring of noise level• Oil characteristics• Others
OTHER PRODUCTS IN OUR MANUFACTURINGRANGE
• Transformers in silicone (LNAN)• Cast-resin dry type transformers from 50 to 5000 kVA with high voltage class ≤ 36 kV• Medium power transformers up to 30 MVA and 72.5 kV• Earthing transformers & reactances• Impregnated dry transformers• Auto-transformers• Transformers for rectifiers• Special transformers
Note: The data and descriptions in this catalogue refer to our present design and construction techniques, and do not constitute an undertakingon our part unless confirmed as such. We reserve the right to make such modifications and improvements as may be deemed convenient withoutprior notice.
50, 100, 160, 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500 kVA.
° Preferential power ratings are marked in bold print.
DISTRIBUTION TRANSFORMERS
This catalogue deals with transformers immersed in insulating fluid with natural self cooling (ONAN), three-phase, 50 - 2500 kVAfor indoor or outdoor use, 50/60 Hz, hermetically sealed.
The transformers described in this catalogue are designedand tested in accordance to European UnionHarmonisation Document HD428, UNE 21428 and IEC76 standards.
However, and by request, they can be manufacturedaccording to any other national or international standards,such us
HD-398, BS 171, NF C52.100, DIN 42.500, UNE 20.101,IEC 76
UNE 21320, UNE 48103, UNE EN 60551, UNE 20110,UNE 20145, UNE EN 50180, ETU 5201 E and UNESArecommendations. Another applicable documents are:ANSI C57, NEMA, ESI, HN, UTE.
MANUFACTURING STANDARD
GENERAL CHARACTERISTICS
RATINGS
HIGH VOLTAGEThis material is designed for voltages of ≤ 36 kV. Specific figures are not given for this parameter because of the wide variety of voltagesused. Transformers can be supplied on demand to run at two different primary voltages, the shifth between these input voltages has twobasic alternatives:• with a primary tap changer which can be switched with no load and no applied voltage• or by changing terminals under the cover.
LOW VOLTAGEThe secondary voltage under no load is allocated at 420 V, though other voltages can be supplied on demand. When usage requirestwo voltages, transformers with two simultaneous voltages can be supplied. In this case the no-load voltages are set to 420 and242 V. For the lower voltage output the power is K x Pr.
In simultaneous loads the power distribution is: P + P =Pr where: KPPPrK
= load supplied at 242 V= load supplied at 420 V= rated power= 0,75
1 2
1
2
CORPORACION COOPERATIVAALKARGO, S. COOPAritz Bidea nº 83 Atela Auzotegia48100 Mungía (Vizcaya) - SPAINTel.:+34 (94) 674.00.04Fax: +34 (94) 674.44.17Apartado 102 / P.O BOX 102e-mail: [email protected] DISTRIBUTION TRANSFORMERS