What are the advantages of using three-phase transformers?

In power transmission, industrial power distribution, and large equipment power supply scenarios, three-Phase Transformers offer numerous advantages over three single-phase transformers of the same capacity, including lower cost, higher efficiency, and a more compact structure. These advantages can be summarized in the following six aspects:
1. Lower cost and fewer materials: Three-phase transformers use an integrated core and tank design, sharing a magnetic circuit and outer casing structure. Compared to three single-phase transformers, the amount of core materials such as silicon steel sheets and copper windings can be reduced by 20% to 30%. In addition, the labor and equipment costs for transportation and installation are also lower, thereby reducing the need for Substations and floor space.
2. Higher operating efficiency and lower energy consumption: The magnetic circuit design of the three-phase transformer is more optimized, with symmetrical magnetic circuit distribution within the core and mutual cancellation of magnetic circuits within the yoke, significantly reducing magnetic leakage loss and no-load iron loss. The integrated structure also reduces external connection points, lowering copper losses during load operation. The overall operating efficiency is 1% to 3% higher than three single-phase transformers connected in parallel, resulting in greater energy savings in the long term.
3. Simplified system layout and convenient wiring: A single three-phase transformer can directly output symmetrical three-phase power. Compared to three single-phase transformers, it reduces the number of bushings, insulators, and protection devices, simplifying the wiring of the primary and secondary sides. The phase difference of its output three-phase voltage is strictly maintained at 120°, directly meeting the power supply needs of three-phase motors, industrial frequency converters, and other equipment without the need for additional phase adjustment devices.
4. High reliability and easy maintenance: The integrated structure reduces mechanical connections and electrical contact points, lowering the probability of failures due to loose joints and insulation aging. Routine maintenance only requires oil level checks, temperature monitoring, and insulation testing on a single unit, significantly saving manpower and time costs compared to maintaining three single-phase transformers.
5. Suitable for large-capacity, high-voltage scenarios: Three-phase transformers are core equipment for high-voltage power grids (110kV, 220kV, 500kV) and large industrial loads (steel plants, chemical plants), with a single unit capacity reaching thousands or even tens of thousands of kVA. Single-phase transformers, on the other hand, are only suitable for small-capacity, single-phase power supply scenarios (such as rural household power supply and small household appliances).
6. Low electromagnetic interference: The symmetrical three-phase magnetic field design results in electromagnetic interference (EMI) that is far lower than that of three single-phase transformers operating in parallel, avoiding any impact on the normal operation of surrounding precision instruments and communication equipment.