Dry-type Distribution Transformers Solution for Public Building

This article describes in detail the selection of dry-type distribution transformers in the process of configuring the public building power grid.

From the economic considerations of long-term operation, more efficient and energy-saving dry-type distribution transformers should be used first.

Daelim is a transformer manufacturer with 16 years of experience in the design and production of dry-type distribution transformer. It can provide transformer solutions for your public building grid.

Daelim’s professionalism and efficiency have been recognized by customers in dozens of countries and regions around the world.

DAELIM’s dry-type distribution transformer has obtained IEEE, ANSI, CSA, and IEC certifications.

Can provide the most professional transformer solutions for your power grid construction.

Dry-type Distribution Transformers Solution for Public Building

Dry-type Distribution Transformer

Pad-mounted Distribution Transformer

Here are some other articles you might enjoy:

Distribution Transformer Selection of An Office Building

-The author compared the economic evaluation indices of commonly used dry-type transformer and SCBH15 amorphous alloy transformer by the calculation of total owning cost ( TOC).

Wiring method of Dry-type Transformer

-Introduced the common wiring methods of dry-type transformers, how to connect the input and output terminals of the transformer, and what are the low-voltage outlet methods of dry-type transformers.

Selection And Maintenance of 10 kV Dry-type Transformer

-This article analyzes the selection of 10 kV dry-type transformer and further elaborates the maintenance work of the Cast Resin Dry-type Transformer.

Why look for energy-saving distribution transformers for public buildings?

Public buildings are a high-density area of building energy consumption at this stage. Public building area accounts for less than 4% of the total urban building area, but its energy consumption accounts for 22% of the total building energy consumption.

Public buildings are densely populated, and power dry-type distribution transformersare important equipment for public buildings. The installed density is several times higher than that of other buildings, and dry-type distribution transformer are mostly used.

When designing the power supply and distribution of public buildings, it is necessary to analyze the safety, economy, and energy saving, and finally determine the dry-type transformer model.

Dry-type distribution transformer network

What is the efficiency of a dry-type transformer?

Due to the continuous improvement of magnetic materials, the no-load loss value of dry-type distribution transformer is constantly adjusted down.

But so far, the conductivity improvement of copper has only increased by 3%, unlike the magnetic material that has undergone four generations of improvement in permeability.

Therefore, in the later period, the latest energy-saving models only reduce no-load loss, and their load loss has not changed.

This is because under the current material, design, and technological level, to reduce load loss, the only way to greatly increase the use of winding copper wire, resulting in increased dry-type transformer costs, increased volume, and lower cost performance.

Daelim uses the most advanced technology on the market to produce a three-phase epoxy dry-type transformer.

This dry-type transformer greatly reduces no-load loss while reducing load loss. Save you a lot of electricity, save energy and money.

10kv class 9 dry-type non-excitation voltage regulating distribution transformer no-load loss and load loss value

Rated Capacity(kVA)

No-load loss (W)

Load loss/W

Short circuit resistance (%)

B(100℃))

F(120℃))

H(145℃))

30

220

710

750

800

4

50

310

990

1060

1130

80

420

1370

1460

1560

100

450

1570

1670

1780

125

530

1840

1960

2100

160

610

2120

2250

2410

200

700

2510

2680

2870

250

810

2750

2920

3120

315

990

3460

3670

3930

400

1100

3970

4220

4520

500

1310

4860

5170

5530

630

1510

5850

6220

6660

630

1460

5940

6310

6750

6

800

1710

6930

7360

7880

1000

1990

8100

8610

9210

1250

2350

9630

10260

10980

1600

2760

11700

12400

13270

2000

3400

14400

15300

16370

2500

4000

17100

18180

19460

1600

2760

13000

13700

14500

8

2000

3400

15900

16900

18000

2500

4000

18800

20000

21400

No-load loss and load loss value of 10kv class 10 dry-type non-excitation voltage regulating distribution transformer

Rated Capacity(kVA)No-load loss (W)Load loss/WShort circuit resistance (%)
B(100℃))F(120℃))H(145℃))
301906707107604
5027094010001070
80370129013801480
100400148015701690
125470174018501980
160540200021302280
200620237025302710
250720259027602960
315880327034703730
400980375039904280
5001160459048805230
6301340553058806290
63013005610596064006
8001520655069607460
10001770765081308760
125020909100969010370
16002450110501173012580
20003050136001445015560
25003600161501717018450
160024501228012960139008
20003050150201596017110
25003600177601889020290

No-load loss and load loss value of 10kv class 11 dry-type non-excitation voltage regulating distribution transformer

Rated Capacity(kVA)No-load loss (W)Load loss/WShort circuit resistance (%)
B(100℃))F(120℃))H(145℃))
301706707107604
5024094010001070
80330129013801480
100360148015701690
125420174018501980
160480200021302280
200550237025302710
250640259027602960
315790327034703730
400880375039904280
5001040459048805230
6301200553058806290
63011705610596064006
8001360655069607460
10001590765081308760
125018809100969010370
16002200110501173012580
20002740136001445015560
25003240161501717018450
160022001228012960139008
20002740150201596017110
25003240177601889020290

No-load loss and load loss value of 10kv class amorphous alloy iron core non-excitation voltage regulating dry-type distribution transformer

Rated Capacity(kVA)No-load loss (W)Load loss/WShort circuit resistance (%)
B(100℃))F(120℃))H(145℃))
30706707107604
509094010001070
80120129013801480
100130148015701690
125150174018501980
160170200021302280
200200237025302710
250230259027602960
315280327034703730
400310375039904280
500360459048805230
630420553058806290
6304105610596064006
800480655069607460
1000550765081308760
12506509100969010370
1600760110501173012580
20001000136001445015560
25001200161501717018450
16007601228012960139008
20001000150201596017110
25001200177601889020290

10KV Class Three Phase Epoxy-resin Dry-type Transformer no-load loss and load loss value

Rated Capacity(kVANo-Load loss/WOn Load loss/WShort circuit resistance (%)
502709904
1004001570
1605402120
2006202520
2507202750
3158803460
4009703980
50011604880
63013405870
80015206950
1000176081206
125020909690
1600245011730
2000332014450
2500400017170

What is the power loss of a dry-type transformer?

1. Power loss analysis of distribution dry-type transformers

The power loss of a dry-type transformer is composed of active and reactive power.

The active power loss of a dry-type transformer consists of the following two parts:

One part is the active power iron loss produced by the main magnetic flux in the dry-type transformer core. The iron loss has nothing to do with the load of the dry-type transformer. When the power supply voltage and frequency are unchanged, its value is unchanged;

The other part is the copper loss generated in the primary and secondary windings when the dry-type transformer passes the load current, which can be approximated as the loss ΔPK measured in the dry-type transformer short-circuit experiment. Copper loss is related to the size of the load, and it is proportional to the square of the current.

The reactive power loss of dry-type transformers also consists of two parts:

Part of the reactive power is used to generate the main magnetic flux, that is, the excitation current or the no-load current I0, which has nothing to do with the size of the load;

The other part of the reactive power is consumed by the reactance of the primary and secondary coils, which is proportional to the square of the load current under the rated load.

2. Calculation of active and reactive power loss of power dry-type transformers

Dry-type distribution transformer Active power loss
Dry-type distribution transformer Active power loss
Dry-type distribution transformer Reactive power loss
Dry-type distribution transformer Reactive power loss
  • In formula (1), in formula (2), S c— transformer calculation load, kV A;
  • S r— rated capacity of the transformer, kV A;
  • ΔP0— no-load active power loss of transformer, kW;
  • ΔPK— full load active power loss of transformer, kW;
  • ΔQ 0— Transformer no-load reactive power loss, kvar,
    ΔQ 0 = (I0% S r)/ 100;
  • I0% — the percentage of the transformer no-load current to the rated current;
  • ΔQ K—Reactive power loss of transformer at full load, kvar,
Calculation formula for power loss of dry-type distribution transformer
Calculation formula for power loss of dry-type distribution transformer

uK% — The percentage of the transformer impedance voltage to the rated voltage. In the above power loss calculation formula, S c/ S r is the load factor β during operation of the transformer, and the relationship between the active and reactive power losses of the transformer and the load factor of the transformer can be expressed as:

Dry-type distribution transformer active and reactive power loss and transformer load factor
Dry-type distribution transformer active and reactive power loss and transformer load factor

3. Annual active power loss of transformer

Transformers in civil buildings are generally equipped with on-site reactive power compensation, so that the power factor of the transformer reaches the limit required by the power supply part, and the reactive power loss of the transformer is no longer considered from the perspective of operating costs. The annual active power loss ΔWT of the transformer is:

Annual active power loss of dry-type distribution transformer
Annual active power loss of dry-type distribution transformer

t is the number of operating hours of the transformer throughout the year. When the transformer is put into operation throughout the year, τ is the number of hours of maximum load annual loss.

4. Benefit evaluation of distribution transformers

(a) Total Owning Cost of the transformer:

Total Owning Cost of the Dry-type distribution transformer
Total Owning Cost of the Dry-type distribution transformer
  • C 0 The initial purchase cost of the transformer is a fixed value;
  • C ΔP0 The cost of no-load loss of the transformer is related to the annual operating hours of the transformer;
  • C ΔPK The cost of transformer load loss is related to the maximum load annual loss hours and the average load rate of the transformer.
  • For 10 type, 11 type and amorphous alloy dry-type transformers with different capacities, the annual electricity saved when operating in the same environment is shown in Table 5.
  • C 0 The initial purchase cost of the transformer is a fixed value;
  • C ΔP0 The cost of no-load loss of the transformer is related to the annual operating hours of the transformer;
  • C ΔPK The cost of transformer load loss is related to the maximum load annual loss hours and the average load rate of the transformer.

For 10 type, 11 type and amorphous alloy dry-type transformers with different capacities, the annual electricity saved when operating in the same environment is shown in Table 5.

(b) Recovery period of transformer investment price difference

The load loss of Type 10, Type 11 and amorphous alloy dry-type transformers is the same, and the difference in total cost of ownership is only related to the initial purchase cost and no-load loss cost.

The payback period of the investment price difference of using different types of transformers is:

The payback period of the investment price difference of different types of transformers
The payback period of the investment price difference of different types of transformers

Since the price ratio of amorphous strips and high-quality cold-rolled silicon steel sheets is about 2.5:1, and because the working magnetic density is slightly lower and the amount of wires is large, the current domestic price of amorphous distribution transformers is about 1.3 ~ of that of silicon steel plates. 1.4 times.

(c) Examples of the recovery period of transformer investment price difference

Take 10/ 0.4kV, D yn11 connection group, 1 600kV A dry-type transformer with impedance voltage of 6% as an example.

At this stage, the initial purchase cost of amorphous alloy dry-type transformers is about 380,000 yuan, the initial purchase cost of SC B11 dry-type transformers is about 320,000 yuan, and the initial purchase cost of SC B10 dry-type transformers is about 280,000 yuan.

The electricity price adopts the general commercial electricity price of 1 yuan/kWh as the calculation condition, and the payback period of the investment difference of the amorphous alloy dry-type transformer compared with the SC B11 dry-type transformer is:

The payback period of the investment difference of the amorphous alloy transformer compared with the SC B11 transformer

The payback period of the investment difference of the amorphous alloy dry-type transformer compared with the SC B10 dry-type transformer is

The payback period of the investment price difference of the amorphous alloy transformer compared with the SC B10 transformer

The payback period of the investment difference of the amorphous alloy dry-type transformer compared with the SC B10 dry-type transformer is

The payback period of the investment difference between SC B11 transformer and SC B10 transformer

In Conclusion

As a policy regulation for weighing investment and energy-saving benefits, the general calculation of investment recovery period should not exceed 5 years, and the longest period should not exceed 7 years.

The use of more energy-efficient amorphous alloy dry-type transformers or SC B10 and SC B11 dry-type transformers can recover the investment within 5 to 7 years.

However, considering that the normal life of dry-type transformers is generally 25 to 30 years, from a long-term perspective, the use of more energy-saving amorphous alloy dry-type transformers can obtain huge economic benefits.

Compared with the SC B10 dry-type transformer, the energy-saving and economic efficiency of the SC B11 dry-type transformer is not significantly improved.

The above calculation is a static investment payback period, without considering the time value of an investment in money.

Share on facebook
Share on twitter
Share on linkedin

About Bin Dong

Hello, I am Bin, General manager of Daelim which is a leading transformer manufacturer. If you have problems when you are looking for the equipment, what you need to do is tell us.

Custom Dry-type DistributionTransformer

If you find that the existing distribution transformer types or power cannot meet your requirements. You can choose to tell Daelim. Daelim has a team that has always had a wealth of design transformers, and can give you a specific design plan in the shortest time.

Daelim’s distribution transformers comply with IEEE, ANSI, CSA, IEC certification, and are used in North America (such as Canada, the United States, Mexico), South America (such as Ecuador, Chile), Europe (such as Spain, Lithuania) and some Asian countries. Daelim even has a professional installation team that can provide you with installation services.