Simply put, a three phase electric power transmission is a means of transmitting electric power using three wires. Transmission of an ac (alternating current) relies on this bit of technology. Also a type of polyphone system, it is the most widespread means used by electric power distribution grids all over the world to distribute power.
This method of power transmission was introduced by Nikola Tesla in between 1887 and 1888. The workings of this system are quite easy to grasp. There are three circuit conductors which carry three alternating currents that are of the same frequency and which also reach their immediate top values differently. Now, using one conductor as the reference, the other two currents are delayed in time by a third and two-thirds of a cycle of the electric current. This delay between phases gives a constant power transfer over each cycle of the current and also facilitates the production of a rotating magnetic field.
The most important and consequently common class of the three-phase load is the electric motor. This type of motor has a simple design, naturally high starting torque and high efficiency. Such motors have different applications in industry and are used in things such as fans, compressors and vehicles just to mention a few. The Conductors that are in use in the three phase power system are color-coded. However, different regions have different color codes that are unique to others as there is no established system of defining this. A Three phase power connection is simply three single phases coordinated and balanced at temperature of 120 degrees. Three phase connections may or may not have a neutral wire in the system. The neutral wire basically allows the system to use a higher voltage and at the same time creates an allocation for lower voltage appliances that incorporate the single phase connection. The absence of a neutral wire in high voltage connections is apparent and is easily explained by the fact that the loads allow for phase-phase connection and can be simply connected between phases. The power station is where the three phase power starts.
A power generator converts mechanical power into alternating electric currents. The power is transformed into the standard mains voltage after numerous conversions in the distribution and transmission network. It is at this point that the power can be channeled into several phases; single or three phase.
In the case of three phase power, the output of the transformer is usually connected in a star format with the mains voltage, with values like 120 volts in North America and 230 volts in Europe being recorded. There is usually a talk about ‘ground,’ in reference to the three phase connection. Power companies essentially use the earth as one of the wires in the power system. The earth is a good conductor and it is unlimited, which makes it a good return path for electrons. This analogy can be better demonstrated by the Car manufacturers who use the metal body of the car as one of the wires in the car's electrical system. They achieve this by attaching the negative pole of the battery to the body. ‘Ground’ in the power distribution grid is the same as the one outside you. Its compositions are dirt, rocks, etc. There are many advantages associated with this means of electrical transmission: (i) It is more economical than others because, at the same voltage, it makes use of minimal conductor materials to move power than the equivalent phases.
(ii)Three phase power is a very efficient form of electrical power distribution because all the three wires in its setup contain the same current and have a constantly balanced power load. (iii) It is more advantageous compared to any other form of transmission (1, 2 or 4) in 1-phase and 2-phase power for example, there are 120 moments per second when a sine wave is crossing zero volts whereas in the case of 3-phase power, one of the three phases is therefore always nearing a peak. This basically means that High-power 3-phase motors have a uniform power output and whereas a case for four phases may be presented, it will not work as effectively as it only adds a fourth wire, so the 3-phase is the best option. (iv) Its setup enables it to achieve their high conductor efficiency and there is generally high safety risks avoided by splitting up the total voltage into lesser parts and using the lesser voltages to power multiple loads. (v)Three-phase motors vibrate less. This enables them to last longer than single-phase motors given the same amount of power and the same conditions maintained. (vi) A three-phase motor is more compact and less costly than a single-phase motor of the kind.