Comparison of the advantages and disadvantages of transformer connection mode
With the increasingly exhaustion of natural resources in China, it is a hot issue to reduce the loss of transformers, improve the safety and reliability of the transformer itself, and the efficiency of its actual work, and optimize the design of the transformer.
The advantage of Dd wiring is that there is no three harmonic electromotive force and the main maladies of Yy connection; a balanced line voltage can be used for a large three-phase unbalanced load; for a low voltage transformer with a large output current, this connection is more economical because the current of each coil of the transformer is a phase current and is lost to use. The household is 3 times the line current larger than the phase current.
The shortcomings of the Dd connection of the transformer are: compared with the Y shape, the insulation is more used, the small section of the wire reduces the ability of the mechanical force to withstand the short circuit and can not extract the neutral point. Sometimes it can not meet the requirements of the system and the users, and in the three-phase transformer group composed of the single-phase transformer, if each phase voltage is not consistent, it will be the same. Circulation is generated in the loop, which affects efficiency.
The Dy connection has the advantages of no neutral line voltage instability, strong load capacity, no three harmonic voltage and zero sequence voltage on the line outside the winding, strong resistance to lightning overvoltage with two side intrusion, and relatively small loss.
The disadvantages of the Dy wiring of the transformer are: complex manufacturing process, poor mechanical strength and high voltage withstand at the primary side.
The advantage of Dd wiring is that there is no three harmonic electromotive force and the main maladies of Yy connection; a balanced line voltage can be used for a large three-phase unbalanced load; for a low voltage transformer with a large output current, this connection is more economical because the current of each coil of the transformer is a phase current and is lost to use. The household is 3 times the line current larger than the phase current.
The shortcomings of the Dd connection of the transformer are: compared with the Y shape, the insulation is more used, the small section of the wire reduces the ability of the mechanical force to withstand the short circuit and can not extract the neutral point. Sometimes it can not meet the requirements of the system and the users, and in the three-phase transformer group composed of the single-phase transformer, if each phase voltage is not consistent, it will be the same. Circulation is generated in the loop, which affects efficiency.
The Dy connection has the advantages of no neutral line voltage instability, strong load capacity, no three harmonic voltage and zero sequence voltage on the line outside the winding, strong resistance to lightning overvoltage with two side intrusion, and relatively small loss.
The disadvantages of the Dy wiring of the transformer are: complex manufacturing process, poor mechanical strength and high voltage withstand at the primary side.