Delta (Δ) connection, also known as the mesh or three-phase connection, is one of the primary ways to connect three-phase electrical circuits. It has several advantages in various applications compared to other types of connections, such as the star (Y) connection. Here are some advantages of using a delta connection in polyphase circuits:
Lower Line Currents: In a delta-connected system, the line currents are √3 times lower compared to a star-connected system for the same phase current. This can lead to reduced conductor size, lower losses, and cost savings in terms of materials.
Balanced Load Sharing: Delta connections inherently balance the load among the phases, making it suitable for applications where balanced load distribution is critical. This feature is particularly useful in industrial applications where motors or other loads are evenly distributed across the phases.
Higher Power Handling Capacity: Delta connections can handle higher power levels than star connections with the same voltage and current ratings. This makes them suitable for high-power industrial applications, such as large motors or heavy machinery.
Fault Tolerance: In case of a fault (short circuit) in one phase, the other two phases can continue to operate relatively unaffected. This fault tolerance can be advantageous in critical systems where continuous operation is essential.
Lower Voltage Unbalance: Delta connections can tolerate larger voltage imbalances without causing significant issues compared to star connections. This makes them suitable for applications where voltage stability is a concern.
Reduced Harmonic Distortion: Delta-connected systems can have lower harmonic distortion in the current waveform, which can be beneficial in applications sensitive to harmonic interference.
Simplified Transformer Connections: When delta-connected transformers are used, the neutral point does not need to be grounded, simplifying the transformer connections and potentially reducing the need for additional equipment.
Reduced Neutral Current: In balanced delta systems, the sum of currents in the neutral line is generally zero. This can result in lower neutral current compared to star-connected systems, where the neutral current can be significant.
Voltage Phase Shift: Delta connections introduce a phase shift of 30 degrees between line and phase voltages, which can be advantageous in certain applications, such as improving the starting torque of induction motors.
It's important to note that the choice between delta and star connections depends on the specific requirements of the application, including load characteristics, fault tolerance, voltage stability, and harmonic considerations. Each connection type has its own advantages and disadvantages, and the selection should be based on a thorough analysis of the particular system's needs.