2-China Triangle Transformer Development En

7/29/2019 2-China Triangle Transformer Development En

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HAIHONG CO.,LTD

Technological Development andContribution to Energy Conservation of

3D Core Transformers in China


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HAIHONG CO.,LTD

Technical Characteristics of 3D Core

Transformer2

Amorphous Alloy 3D Core

Transformer3

3D Core Transformer's Contribution to

Energy Efficiency

4

Table of Content

Preface1


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HAIHONG CO.,LTD

China is a country of the fastest growth of energy consumption in the world and also acountry suffering energy scarcity; energy conservation is a basic state policy for China to

build a conservation-minded society. To honor the two commitments of Chinese

government, namely the proportion of non-fossil fuel in primary energy consumption

should be around 15% by 2020; and CO2 emission of per unit of GDP should be down by

40-45% over 2005, the task of energy conservation and emission reduction is daunting.

According to estimation, power loss during transmission and transformation accounts foraround 7% of the gross generation; while transformer is important equipment in power grid

and the total loss caused by transformers accounts for around 3% of the gross generation.

Every 1% reduction of power loss of transformers could save 10 billion KWH per year.

Given the policy background of ensuring power supply, conserving energy and reducing

emission, it is inevitable to promote high-efficiency and energy-saving transformers.

I Preface


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HAIHONG CO.,LTD

Energy-saving transformers reduce power loss through two ways: first, structureimprovement, representative product is 3D Core Transformer; second, the adoption of

conducting magnetic material of low magnetic saturation, representative product is

Amorphous Alloy 3D Core Transformer.

The R&D of 3D structure transformer started in 1960s; due the constraints of materials and

technologies, by the end of 1990s, some domestic manufacturers introduced core equipment

and gradually developed 3D Core transformers. After 2003, core transformers havegradually won users' recognition and been put into use. With the technology R&D of 3D

Core Transformer maturing and supporting equipment being developed, there are more and

more manufacturers of 3D Core transformers with certain production capacity and 3D Core

transformers are being widely used.


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HAIHONG CO.,LTD

Since 2005, over 100,000 sets of 3D Core transformers have been put into operation

in various fields and the products performing excellently in performance parameters,

performance-to-price ratio, noise, quality reliability etc.Currently, the capacity of a single set of in-grid 3D Core oil-immersed transformer

could reach 6300kVA, voltage class could reach 35kV. Currently, the capacity of a

single set of dry type 3D Core transformer could reach 5000kVA, voltage class could

reach 35kV;

Currently, over 200 manufacturers could produce S13 oil-immersed transformer in

China, and over 60% of them could produce 3D Core transformer. The industrial base

is wide;

Currently, 3D Core transformers using Amorphous Alloy have been developed,

signifying another great breakthrough of 3D Core transformers in the field of energy-

saving transformers.


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HAIHONG CO.,LTD

II Technical Characteristics of 3D Core Transformer

3D Core is a structure with 3 identical single frame continuously wound by several

trapezoid tape; three pillars of the core shape a equilateral triangle and the 3 phases are

symmetrical.

3-phase magnetic circuits of the core are completely balanced; the magnetization direction

is identical with the direction of rolling of silicon steel, magnetic flux distribution is even

with neither lap nor seam; there is neither obvious high resistance area nor distortion ofdensity of magnetic flux at the seams.


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HAIHONG CO.,LTD

3D Core transformer is an energy-savingtransformer with better structure and

performance. It has the following

outstanding benefits:

(1) reduced material;

(2) reduced energy;(3) 3-phase equilibrium;

(4) low no-load current;

(5) low noise;

(6) strong overload capacity;

(7)strong emergent short-circuit

protection;

(8) low strength of electromagnetic field.


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HAIHONG CO.,LTD

Material reduction rationale of 3D Core Transformer-No.1

3D Core is continuously wound by several

trapezoid tape; different sizes of trapezoid

tapes are cut by special line cutting machine,

and the material utilization rate is almost

100%.

The upper and lower yoke and pillar

of the stack core will unavoidably

punch off waste materials of thetriangle; according to estimation,

such waste materials account for

around 5% of the gross weight of the

core.

Diagram of 3D Core

Diagram of stack core processing process


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HAIHONG CO.,LTD


HAIHONG CO.,LTD published a dissertation on the 05edition of the transformer magazine for 2012, titled Analysis

of Basic Characteristics of S13 3D Core Transformer. The

analysis and calculation of the weight difference of 3D and

stack cores under the condition of same diameter, profile,

window height and center distance show that S13 3D core

transformer could save around 20-25% of silicon steelcompared with S13 stack core transformer of the same

capacity.

3D Core under the same conditions

Stack Core under the same conditions

comparison of consumption of silicon steel

Stack core

3D core


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HAIHONG CO.,LTD


The fill-factor within the circle of the profile of pillar of 3D core; with same effective

pillar area, the diameter of 3D Core pillar is small, thus reducing the length of winding

wire and saving winding wire. Therefore, 3D core transformer could save winding wire

compared with stack core transformer.

Profile of 3D Core pillar Profile of Stack Core pillar

Fill-factor 0.95-0.96 Fill-factor 0.89-0.925


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HAIHONG CO.,LTD

Energy reduction rationale of 3D Core Transformer

Unit metal loss of core PtProcessing factor K0Gross weight of core

G

Formula of no-load loss of transformerP0 =K0G Pt

P0is directly proportional to G, K0 , Pt

Gross weight of core G 3D Core saves core material compared with Stack Core;

Processing factor K0 3D Core processing factor: 1.05-1.1, Stack Core processing factor: 1.15-1.3;

Unit metal loss of core Pt It depends on the performance of silicon steel sheet; using high brand number (low

loss) sheet could reduce no-load loss effectively.


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HAIHONG CO.,LTD

3-phase equilibrium of 3D Core Transformer

Phase A Phase B Phase C

Magnetic circuit connectingphase A and B

Magnetic circuit connecting phase

A and C

Magnetic circuit connecting

phase B and C Analysis of stack core 3-phase magnetic

circuit:

Length of coupled magnetic circuit between

Phase A-C: Lac=(2*M0+H0)*2

Length of coupled magnetic circuit between

Phase A-B and Phase B-C:

Lab=Lbc=(M0+H0)*2

Conclusion: the magnetic circuit betweenPhase A-C is longer and the magnetic

resistance is bigger, leading to bigger no-load

current of Phase A and Phase C, thus

disequilibrium of the 3-Phase.


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HAIHONG CO.,LTD

Low no-load current of 3D Core Transformer

ModelNo-load current (A)

Phase a Phase b Phase c

S9-M-315/10

3.30 2.70 3.47

3.69 2.93 3.82

3.79 3.06 3.58

S13-MRL-315/10

0.47 0.46 0.46

0.48 0.46 0.47

0.50 0.52 0.48

See the following table for the comparison of value of testing of no-load current of oil-immersed3D core and stack core:

The table shows that: The 3 phases of no-load current of oil-immersed stack

core transformer is imbalanced, with phase b the

smallest;

The 3 phases of no-load current of 3D core immersed

oil transformer is balanced and low.


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HAIHONG CO.,LTD

Low noise of 3D Core Transformer

On-site testing value: 43.5dB(A)

low noise of on-site operation

3D core is tightly and continuously wound silicon steel tapes byspecial core winding machine with no seams; the magnetic

conduction direction of the silicon steel tape is identical with

direction of magnetic circuit of the core, thus addressed the noise

problem due to the incoherent magnetic circuit of stack core,

minimizing the noise.

Compared with S11 stack core oil-immersed transformer, S13 3D

core oil-immersed transformer of the same capacity could reducenoise by 10-20dB (A).

The testing result shows that the noise of SCB13 3D core dry-type

transformer could be reduced to below 45dB(A).


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HAIHONG CO.,LTD

Strong overload capacity of 3D core transformer

As shown in the right picture, 3-phase coils of 3D Core transformer arein a layout of "", temperature difference of upper and lower metal

yokes give rise to air convection; due to the chimney effect at the

triangular area of the core, cold air will replenish to the center tunnel

from bottom up, and heat radiates out from the inner slope of the upper

metal yoke; the natural circulation takes away heat generated by the

transformer rapidly.

Meanwhile, the metal yoke of 3D core is semicircular with a slope of

30 degree, a thickness of 0.75 time of the diameter of core pillar; the

area exposed at the end of the coil is enlarged and the colling

conditions of 3-phase is the same. Capitalizing on the chimney effect,

heat could not concentrate at the triangular area and the temperature

increase at the center triangular area is similar to the temperature

increase at the top layer.

Diagram of theory of cooling of 3D Core transformer

Plane view of circular coil of 3D core Temperature increase testing model


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HAIHONG CO.,LTD

Strong short-circuit protection capacity of 3D core transformer

To reduce the length of upper and lower metal yokes of the core so as to save silicon steel,

traditional stack core transformer has olive-shaped core profile and corresponding olive-

shaped coil structure. The stress of the long and short axises of the olive-shaped coil is

uneven, compromising the short-circuit protection capacity of the transformer.

3D core transformer has circular core profile and circular coil, therefore the anti-impactcapacity is strong under short-circuit power impact.

Diagram of 3D core circular coilDiagram of stack core olive-shaped coil

Analysis and comparison from coil structure:


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HAIHONG CO.,LTD


There is no oil track at the arc section at two sides of the short axis of the olive-shaped

coil, so temperature at the two points are the highest; long-term overheating leads to

insulation aging, thus leading to short-circuit and other failures.

While 3D core transformer uses circular coil with oil track around the circular, leading

to appropriate distribution of oil flow, thus generating the optimum cooling effect.

Analysis and comparison from coil heat stability:

Plane view of olive-shaped coil of stack coresection without

oil track Top view


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HAIHONG CO.,LTD


Fixture and padding of plane coil transformer are mainly arranged at the two sides of

core; Majority of end area of Phase B coil under the metal yoke could not be tightly

pressed, thus the stress situation is inferior to Phase A and C. While the frame pieces and

paddings of the 3D triangular core transformer are distributed around the transformer and

the paddings are pressed tightly by metal press in the center; the 3-Phase stress are

symmetric and identical; Fixture of 3D core transformer is a triangular frame structure, integratedly welded. due to

the stability of triangular, the overall strength is big and the 3-Phase stress is identical, so

the short-circuit protection capability is strong.

Analysis and comparison from motion stability of coil

Body of 3D core transformerBody of plane core transformer


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HAIHONG CO.,LTD

Low strength of electromagnetic fields of 3D core transformer

The tight and symetrical coil structure of 3D coil greatly reduces scattering magnetic filedsaround the transformer. Limited magnetic leakage reduces electromagnetic radiation.

Analog picture of 3D core magnetic fields

Top view of 3D Core magnetic fields

Top view of stack core magnetic fields

Front view of 3D Core magnetic fields

Front view of 3D Core magnetic fields


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HAIHONG CO.,LTD

III Amorphous alloy 3D core transformer

Amorphous alloy 3D core transformer

combines the dual advantages of amorphous

alloy material and 3D core structure.

This product makes breakthrough on the

plane core structure of amorphous alloy

transformer and adopts the perfectcombination of 3D core structure and low loss

feature of amorphous alloy material,

addressed the bottleneck of traditional

amorphous ally plan core transformers, such

as loud noise, weak short-circuit protection,

small capacity, large volume, high material

consumption and non-renewable use of core,showing bright prospect for development.

Amorphous alloy belts


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HAIHONG CO.,LTD

IV Contribution to energy conservation of 3D core transformer

According to estimation, if all newly installed transformers in China uses 3D core

transformer, it could save over 100,000 tons of silicon steel per year, greatly reduce rods

and materials, saves energy of 1.45 million tons of standard coal and saves 3.088 billion

yuan of electricity and cutting 29,000 tons of SO2 emission.

According to statistics, there are 1.1 million sets of S7 and below high loss transformers in

operation; if part of them could install S13 3D core transformer, the economic and social

benefits will be tremendous. Take products with a capacity of 500kVA as an example:

ProjectNumber

of sets

Electricity

saving per

year

(KWH)

Saving

electricity bill

per year

(yuan)

In (tons) of

standard

coal

Cutting

(tons) of

CO2

emission

indirectly

Cutting

(tons) of

SO2

emission

indirectly

Replacing S7

with

S13

1 21,300 15,500 7.23 18.80 0.15

1.1

million23.43 billion 17.05 billion

7.953

million

20.68

million165,000

Note: electricity bill calculated at 0.73 yuan/KWH, standard coal consumption for power generation calculated at

340g/kwh according to the figure in 2010.

CO2 emitted by the burning of 1 kg of standard coal calculated at 2.6kg, and for 20g for SO2.


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HAIHONG CO.,LTD


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HAIHONG CO.,LTD

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2-China Triangle Transformer Development En