How 3-phase power is generated? Discuss the role of neutral point in a 3-phase system
Answers
Answer:
Electric power is created as three phase alternating current (AC) by rotating mechanical turbines powered by water, steam, or other methods to spin generators, transforming mechanical energy into electric energy.
Explanation:
- Generators in the United States rotate at 60 revolutions per second, or 60 hertz (Hz)
- The neutral point three-phase coils are housed in HVB/HVA source stations and are linked to the MV network. Neutral point three-phase coils enable the following.
- The addition of a predetermined impedance between this neutral point and the earth in order to reduce current during network phase-earth problems.
Explanation:
A three-phase electric power generator basically consists of three single-phase windings, which are named as stators and separated with 120 degrees away in 360 degrees circle of the cross sectional of the generator. Apart of stators, the permanent magnet is called as rotor, which is placed in the centre of the circle and rotating about its mechanical shaft. To be noted is that the rotating movements are relative movements between stator and rotor, which means that the rotor could be three-phase windings and stator could be permanent maget as well
With the knowledge of electromagnetic induction principle, the windings take turns to generate the induced currents, which are basically the three-phase generated oscillating currents and shifted 120 degrees from each others.
Role of neutral point in a 3 - phase system
The neutral point three-phase coils are located in the HVB/HVA source stations and connected to the MV network. Neutral point three-phase coils allow:
- The creation of an artificial neutral point
- The introduction of a defined impedance between this neutral point and the earth, in order to limit the current during phase-earth faults on the network.