Difference Between Single Phase And Three Phase Systems (With Table)

The terms, Single phase, and three-phase system are related to the power supply or electricity. In this modern times, electricity is a basic necessity of human life. We use electricity in our daily life. Alternating current is a type of electric power that is delivered in either a single-phase system or a three-phase system.

Single Phase vs Three Phase System

The main difference between the single-phase system and the three-phase system is that in a single-phase system two wires are used to supply the power while in the three-phase system three or four wires are used. Also, the voltage of the single-phase system is 230V while of the three-phase system is 415V.

In a single-phase system, two wires are used to supply the AC power, which is called Phase and Neutral. The phase wire is used to carry the current to the load. While the neutral wire is used to provide a return path of the current. Also, In a single-phase system the supply of the voltage is not even, it rises and falls, due to which a constant power cannot be delivered to the load.

In a three-phase system, generally, three conductor wires are used. Sometimes a fourth wire which is a neutral wire is also used. The power output of a three-phase power remains constant. It does not drop to Zero.

Comparison Table Between Single-Phase And Three-Phase Systems

Parameters of ComparisonSingle-Phase SystemThree-Phase System
What is it?An ac power supply uses two wires: Phase and Neutral.An AC power supply with three phases, i.e., three conductor wires and one neutral (Which is used sometimes).
ConfigurationsThe basic configuration of a sinusoidal wave. No types.Two circuit configurations: Star and Delta.
VoltageThe voltage of the single-phase system is 230V.The voltage of the three-phase system is 415V.
EfficiencyIts efficiency is less than a 3-phase system.Its efficiency is higher.
ComplexityThe design and operation are simple.It is a bit complex.

What is a Single-Phase System?

Through a single-phase system power is supplied. Two wires are used in this system: Phase and Neutral. The phase wire is used to carry the current to the load. And to provide a return path to the current, the neutral wire is used.

A single-phase system is a sinusoidal wave. The voltage peaks at 90 degrees during the positive cycle and during the negative cycle, it is at 270 degrees. Since the supply rises and falls the power is not delivered constantly to the load. The voltage of the single-phase system is 230V.

A Single-phase system is suitable for small areas like houses and small shops. Generally, a single-phase supply is used for loads up to 2500 Watts so any place which requires power up to 2500 watts can run by a single-phase system.

The advantage of this system is that the design and operation of the single-phase system are easy. Though the disadvantage is that its efficiency is low and the possibility of fault is more in this system. It cannot handle heavy electronic loads. And also, Small single-phase motors which are usually less than 1kW cannot get started through this system supply. This is because there isn’t sufficient initial torque for it to start.

What is a Three-Phase System?

A three-phase system is a system in which three or four wires are used to supply power. Mostly, a fourth wire is used which is a neutral wire along with the three conductor wires. In this system, each AC Power Signal is 120 degrees out of phase with each other. Also, during a full cycle of 360 degrees, each phase is at a peak twice the time, in voltage. And the power never drops to zero, since the power output remains constant.

In a three-phase system, there are two types of circuit configurations: Star and Delta. The star configuration has a neutral wire and sometimes there is a ground wire too. A Neutral wire is not used in the Delta configuration. Mostly, the delta configuration is used in all high voltage systems.

A three-phase supply is suitable for larger places like industrial areas, offices, malls, etc. as this system can handle higher loads and can supply a steady stream of power. Though many countries use a three-phase system supply for residential areas too. Larger loads can run very easily through this system. The main advantage of this system is that its overall efficiency is higher as well.

Main Differences Between Single-Phase And Three-Phase Systems

  1. In the single-phase system, two wires named neutral and phase are used to supply the power. While in the three-phase system three (or sometimes four) wires are used.
  2. The single-phase system cannot supply constant power while in the three-phase system the power output remains constant.
  3. The voltage of a single-phase supply is lower (230V) than that of a three-phase supply (415V)
  4. The efficiency of a single-phase system is lower than that of a three-phase system.
  5. The overall complexity of the network is less in the single-phase system than three-phase system since only two wires are used in a single-phase system while the three-phase system uses more wires.
  6. The single-phase system is suitable for small areas like small houses while the three-phase system is suitable for large areas like shops and industries.
  7. In the single-phase system, the chance of fault is higher than that of a three-phase system.

Conclusion

Single-phase and three-phase systems are systems through which the AC power supply is distributed. The systems are used in different areas according to the need of the power supply.

Single-phase systems use two wires, phase and neutral. The voltage is low in the single-phase system and also this system cannot provide constant power. And since there is only one phase wire the chance of fault is higher in this system. This system is suitable for places which do not need a large supply of electricity like houses.

A three-phase system uses three or four wires. The efficiency of this system is more and therefore is used in places where a large quantity of electricity is required like offices and industries.

References

  1. https://ieeexplore.ieee.org/abstract/document/4126819/
  2. https://ieeexplore.ieee.org/abstract/document/228328/
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