What is Delta To Star Transformation


Delta to Star Transformation is a method of transforming a three-phase electrical network from delta (Δ) configuration to star (Y) configuration. In power systems, this transformation is useful in simplifying the analysis of three-phase circuits. The transformation maintains the same electrical characteristics, such as voltage, current, and power, but simplifies the circuit analysis by reducing the complexity of the circuit.


The characteristics of delta to star transformation are:

  • It is a method of simplifying the analysis of three-phase circuits.
  • It is based on the principle of equivalence, which states that two circuits are equivalent if they have the same voltage-current relationships.
  • It involves the transformation of a three-phase network from delta (Δ) configuration to star (Y) configuration while maintaining the same electrical characteristics.
  • It is a reversible transformation, meaning that the network can be transformed back to its original configuration.
  • It is used to increase the impedance seen by the load and thereby increase the voltage drop across the load.


The construction of delta to (Y) transformation involves the following steps:

  1. Identify the three-phase network that needs to be transformed.
  2. Draw the circuit diagram for the network in delta (Δ) configuration.
  3. Apply the transformation rules to convert the network from delta to star configuration.
  4. Draw the new circuit diagram in star (Y) configuration.


In a three-phase electrical network, the voltage and current waveforms are out of phase with each other. By using delta to star transformation, the voltage and current relationships can be simplified, making the circuit easier to analyze. The transformation involves the conversion of the network from delta (Δ) configuration to star (Y) configuration by using a set of transformation rules. These rules maintain the same electrical characteristics of the circuit, such as voltage, current, and power.


Delta to (Y) transformation is used in various applications such as:

  • Analysis and design of three-phase motors and generators.
  • Design and analysis of power distribution systems, such as power grids and substations.
  • Control and protection of electrical systems, such as switchgear and protective relays.
  • Design and analysis of electrical transformers, such as step-up and step-down transformers.
  • Analysis and design of electrical circuits, such as power supplies and inverters.

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