1. Less material
Single-phase transformers of the same capacity are 20% less iron and 10% less copper than three-phase transformers. Especially when the coil core structure is adopted, the no-load loss of the transformer can be reduced by more than 15%, which will reduce the manufacturing cost and the use cost of the single-phase transformer at the same time, thereby obtaining the optimum life cycle cost.
2. Low line investment
The use of a single-phase power supply system in the grid saves 33% to 63% of the wire. Calculated by economic current density, the wire weight can be saved by 42%. According to the mechanical strength, the wire consumption can be reduced by 66%. Therefore, the construction investment of the entire transmission power can be reduced. This is very meaningful in the lighting of rural areas and towns in China and the electricity consumption of residents.
3. Conducive to modern production
Due to its simple structure, single-phase transformers are suitable for large-scale modern production and are conducive to improving product quality and efficiency. The application of single-phase transformers can be flexibly installed on electric poles, which is convenient to go deep into the load center, reduce the power supply nearby, and improve the quality of power supply. Generally, single-phase transformers supply power in a small range, and the fault coverage is small, which is conducive to improving the reliability of power supply. At the same time, because single-phase transformers are lightweight, easy to install and maintain, and flexible to use, they can be used in single-phase or three-phase transformers.
4. Low construction investment
Construction of single-phase power supply systems in light-load areas at the cost of small capacity transformers can reduce construction investment. The transformation of the single-phase power supply system in high-load areas must have a large economic investment. The author sees that some single-phase transformers are piloted in residential areas. The practice is to convert large transformers into multiple small transformers and install them near the load to shorten the distance between the low-voltage trunk line. Since the distance from the power point to the load is constant, the low-voltage is shortened. The power supply distance must inevitably extend the high-voltage power transmission distance. This type of transformation requires a large amount of investment. For example, 30 units in 3 units originally used one 160 kVA three-phase transformer and switched to three 50 kVA single-phase transformers. Table 2 lists The changes in materials and losses of the two transformation schemes have obviously increased construction investment. One application of single-phase transformers
is to reduce the line loss of low-voltage trunk lines by introducing high-voltage lines into load centers and increasing investment in high-voltage line construction. Second, the no-load loss and load loss after using multiple small-capacity transformers are more than the original single large-capacity transformer. Third, the purchase funds for multiple small-capacity transformers are also greater than the purchase funds for a single large-capacity transformer. Due to the large amount of electricity used by residents abroad, several or each one uses a single-phase transformer because of the wealth of the country and the large amount of capital invested by the power sector.