All large AC power blocks are transmitted and distributed at high voltage levels via a three-phase transformer. Single-phase transformers can be electrically connected to form a three-phase transformer bank in a distribution system. But the standard is to combine a single phase coil into a three-phase transformer unit on a common core. The advantages of using a single-cell three-phase transformer over three single-phase transformers include:
A single three-phase transformer will operate more efficiently than three single-phase units.
Compared to a transformer bank consisting of three single-phase transformers, the busbar structure, switchgear and wiring used for three-phase transformers are easier to install and simpler to place.
Compared to three single-phase units, three-phase transformers are lighter in weight and require less space.
The price of a single three-phase transformer is lower, and less core material is required due to the equivalent kVA rating for about three single-phase units.
The main advantage of using a set of single-phase transformer units in a faulty situation. In the case of a single three-phase transformer, if there is a problem with the supply winding of one phase, the operation of the entire three-phase unit must be stopped. If a single-phase transformer in a three-phase bank fails, it is usually possible to disconnect it and restore some service until the replacement is stopped. However, the reliability of modern transformers is so high that most large transformers are three-phase.
Delixi three-phase transformers are usually designed and constructed for specific voltages. For example, transformers are capable of having a Delta primary of 4800 volts and a Wye secondary of 120/208 volts. A three-phase transformer has a core with three sets of windings. As shown in Figure 2, the primary and secondary windings are placed one after the other on the three feet of the corn cob.
Single-phase transformers can also be used to form a three-phase transformer bank. When connecting a single-phase transformer to form a three-phase voltage system, it is important to be the same. Their voltage, kVA, impedance, manufacturer and type should be the same.
The three-phase transformer connection is named after the way the voltage windings are connected inside the transformer. With regard to balanced loads, a three-phase "star" (also known as a delta joint) is used as a connection, in which one end of each winding of a multiphase transformer is connected to a common point (neutral point) and the other end is connected to its corresponding line and phase terminals. The polarity mark is fixed to any transformer. Delixi Electric in the high-voltage transformer coil star connection, the polarity of H2 coil ends are connected together. The H2 terminal is then connected to the neutral line (N). The wires (A, B, and C) are then articulated to each of the remaining H1 coil ends.
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