Various Systems of electric Power Transmission

Various Systems of electric Power Transmission | Types of power transmission system

AC  system	DC system
a. Single-phase A.C. system :   Single-phase, two-wire Single-phase two-wire with mid-point earthed Single-phase, three-wire   b. Two-phase A.C system : Two-phase, four-wire Two-phase, three-wire c. Three-phase A.C. system : Three-phase, three-wire Three-phase, four-wire	D.C. system : D.C. two-wire D.C. two-wire with mid-point earthed D.C. three-wire

Comparison between various system of power transmission

Describe electrical power transmission types | Different electrical transmission systems

We all already know that, for transmission of electric power, 3-phase, 3-wire a.c. system is commonly used. Yet, other systems can also be used for transmission in some circumstances. 

The various possible systems of transmission are :

1. D.C(Direct Current) system 

(a) D.C two-wire

• Two-wire d.c. system with one conductor earthed:- In the 2-wire d.c. the system, one outgoing conductor or wire is positive and the other is the return conductor or negative wire. In this type of system, load is connected between the two wires.

D.C. two-wire system

(b) D.C. two-wire with mid-point earthed

• Two-wire d.c. system with mid-point earthed:- The below figure shows the two-wire d.c. system with mid-point earthed. The maximum voltage between and conductor and earth wire is V_m so that the maximum voltage between two conductors is 2V_m.            

D.C. two-wire with mid-point earthed

(c)  D.C. three-wire

• Three-wire d.c. system:- In this system, there are two outers and a mid or neutral wire which is earthed at the generator end as in the diagram. If the system load is balanced the current in the neutral conductor is zero.

D.C. three-wire system

2. Single-phase A.C. system

(a) Single-phase(1-Φ), two-wire

• 1-Φ, 2-wire a.c. system with one wire earthed:- In this system the maximum voltage between conductors is V_m and the root-mean-square voltage between them is V_m ⁄ √2.

Single-phase, two-wire a.c. system

(b) Single-phase(1-Φ), two-wire with mid-point earthed

• 1-Φ, 2-wire a.c. system with mid-point earthed:- In this system 2-wire feature equal and opposite voltages to earth that is V_m and the max. voltage between the 2-conductor is 2V_m.

Single-phase, two-wire with mid-point earthed

(c) Single-phase(1-Φ), three-wire

• 1-Φ,3-wire system:- This system principle is similar to 3-wire d.c. system. The system comprises two outers and a neutral wire taken from the mid-point of the phase winding.

Single-phase, three-wire a.c. system

3. Two-phase A.C. system

(a) Two-phase(2-Φ), four-wire

• 2-Φ, 4-wire a.c. system:- This system can also be considered as two independent 1-Φ systems.

Two-phase, four-wire a.c. system

(b) Two-phase(2-Φ), three-wire

• 2-Φ, 3-wire a.c. system:- In this system, the neutral conductor is taken from the junction of 2-Φ windings whose voltage in quadrature with each other.

Two-phase, three-wire a.c. system

4. Three-phase A.C. system

(a) Three-phase(3-Φ), three-wire

• 3-Φ, 3-wire a.c. system:- It is universally selected for a.c. transmission. Commonly in this type of system star or delta connection is used.

Three-phase, three-wire a.c. system

(b) Three-phase(3-Φ), four-wire

• 3-Φ, 4-wire a.c. system:- In this system four conductors are used three for phases and 4th conductor for neutral connection. The neutral is taken from the neutral point of phase wires(star connection) junction. The neutral wire cross-section area is half of the line wire area.

Three-phase, four-wire a.c. system

--- All types of power transmission diagram

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