3-phase transformers typically have at least 6 windings- 3 primary and 3 secondary. The primary and secondary windings can be connected in different configurations to meet different requirements. In common applications, the windings are usually connected in one of two popular configurations: Delta or Wye.
DELTA CONNECTION
In a delta connection, there are three phases and no neutral. An output delta connection can supply a 3-phase load only. The line voltage (VL) is equal to supply voltage. Phase current (IAB = IBC = ICA) is equal to Line current (IA = IB = IC) divided by √3 (1.73). When a transformer’s secondary is connected to large, unbalanced load, the delta primary provides a better current balance for the input power source.
WYE CONNECTION
In a wye connection, there are 3-phases and a neutral (N) – four wires in total. An output of wye connection enables the transformer to supply a 3-phase voltage (phase-to-phase), as well as a voltage for single phase loads, namely the voltage between any phase and neutral. The neutral point can also be grounded to provide additional safety when required: VL-L = √3 x VL-N.
DELTA / WYE (D/Y)
D/y Advantages
The primary delta and secondary wye (D/y) configuration stands out for its capability to deliver a three-wire balanced load to the power-generating utility, accommodating various applications seamlessly. This configuration is frequently chosen for supplying power to commercial, industrial, and high-density residential sectors.
This setup is capable of supplying both 3-phase and single-phase loads and can create a common output neutral when the source lacks on. It effectively suppresses noise (harmonics) from the line to the secondary side.
D/y Disdvantages
If one out of three coils becomes faulty or disabled, it can jeopardize the entire group’s functionality, and the 30-degree phase shift between primary and secondary windings may result in greater ripple in D.C. circuits.
Post time: Aug-20-2024