Performance Parameters and Their Impact on Cost

1.Short-Circuit Impedance

The short-circuit impedance affects the voltage regulation and reactive power losses of transformers. A higher short-circuit impedance improves voltage regulation but results in a larger short-circuit current magnitude, influencing the power grid and system. For shell-type transformers, the presence of the winding's ampere-turns allows some flexibility in short-circuit impedance without significant cost changes.

2. Load Losses

 Load losses include DC resistance losses, eddy current losses in conductors, circulating current losses between parallel conductors, and stray losses in structural components.

(1) DC Resistance Losses: Increasing the cross-sectional area of conductors to reduce DC resistance losses increases the winding's volume and conductor length, leading to higher manufacturing costs.

(2) Eddy Current Losses in Conductors: Techniques such as parallel arrangement, combination, or transposition of conductors can reduce eddy current losses but may increase manufacturing costs.

(3) Circulating Current Losses Between Parallel Conductors: Measures to reduce circulating current losses between parallel conductors and stray losses in structural components might lead to increased manufacturing costs.

(4) Stray Losses in Structural Components: Stray losses, part of the total losses in large transformers, can be effectively reduced by adding magnetic shielding or electromagnetic shielding on the tank wall and clamps. Using low-loss magnetic materials in structural components may further decrease stray losses, but these measures may come with increased manufacturing costs.

3. No-Load Losses

The no-load losses of transformers mainly consist of core losses, comprising hysteresis losses and eddy current losses. To reduce no-load losses, it is necessary to decrease the magnetic flux density, which may result in increased magnetic material usage. Alternatively, using high-permeability, low-loss magnetic materials or thinner magnetic materials also increases transformer manufacturing costs. However, excessively thin magnetic materials might compromise the planarity of silicon steel sheets, weakening the mechanical strength of the core.

4. Sound Level

To ensure that the sound level of transformers is below the standard value, manufacturers may employ special design methods and measures. These may include reducing the selected magnetic flux density, using special winding and tightening methods, implementing corresponding vibration reduction structures, and choosing low-noise fans. However, these measures contribute to increased manufacturing costs. Therefore, when opting for low-noise transformers, an economic analysis should be conducted. In certain cases, taking appropriate measures, such as installing isolation walls at the transformer installation site, may be a more cost-effective choice.

5. Relationship Between Transformer Capacity, Weight, Size, and Performance

Under the same voltage level, short-circuit impedance, structural form, design principles, conductor current density, and core magnetic flux density, different-capacity transformers exhibit the following approximate relationships:

(1) Transformer capacity is proportional to the fourth power of linear dimensions.

(2) Effective material weight of the transformer is proportional to the 3/4 power of the capacity.

(3) Effective material consumption per unit capacity is proportional to the -1/4 power of the capacity.

(4)  When conductor current density and core magnetic flux density remain constant, losses in effective material are proportional to the capacity's 3/4 power.

(5) Losses per unit capacity of the transformer are proportional to the -1/4 power of the capacity.

(6) Transformer manufacturing costs are proportional to the 3/4 power of the capacity. Therefore, under the same load conditions, choosing a single large-capacity transformer is more economical than using multiple small-capacity transformers.

LuShan, est. 1975,  is a Chinese professional manufacturer specializing in power transformers and reactors for 49 years. Leading products are single-phase transformer, three-phase transformers, DC inductors, AC reactors, filtering reactor, expoxy resin high-voltage transformer and intermediate, high-frequency products. Our transformers and reactors are widely used in 10 application areas: rapid transit, construction machinery, renewable energy, intelligent manufacturing, medical equipment, coal mine explosion prevention , excitation system, vacuum sintering, central air conditioning.

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