Skin Effect and Proximity Effect: Skin Effect and Proximity Effect – The distribution of current throughout the cross-section of a conductor is uniform only when DC is passing through it. On the contrary when AC is flowing through a conductor, the current is non-uniformly distributed over the cross-section in a manner that the current density […]

### INDUCTANCE & RESISTANCE

## Resistance

Resistance: Though the contribution of line resistance to series line impedance can be neglected in most cases, it is the main source of line power loss. Thus while considering transmission line economy, the presence of line resistances must be considered. The effective AC resistances is given by Where I is the rms current in the […]

## Bundled Conductors

Bundled Conductors: Bundled Conductors – It is economical to transmit large chunks of power over long distances by employing EHV lines. However, the line voltages that can be used are severely limited by the phenomenon of corona. Corona, in fact, is the result of ionization of the atmosphere when a certain field intensity (about 3,000 […]

## Double Circuit Three Phase Lines

Double Circuit Three Phase Lines: It is common practice to build Double Circuit Three Phase Lines so as to increase transmission reliability at somewhat enhanced cost. From the point of view of power transfer from one end of the line to the other, it is desirable to build the two lines with as low an […]

## Inductance of Three Phase Lines

Inductance of Three Phase Lines: The basic equations developed can, however, be easily adapted to the calculation of the Inductance of Three Phase Lines. Figure 2.10 shows the conductors of a three-phase line with unsymmetrical spacing. Assume that there is no neutral wire, so that Unsymmetrical spacing causes the flux linkages and therefore the inductance […]

## Inductance of Composite Conductor Lines

Inductance of Composite Conductor Lines: Inductance of Composite Conductor Lines – We are now ready to study the inductance of transmission lines composed of composite conductors. Future 2.6 shows such a single-phase line comprising composite conductors A and B with A having n parallel filaments and B having m’ parallel filaments. Though the inductance of […]

## Flux Linkages of one Conductor in a Group

Flux Linkages of one Conductor in a Group: Flux Linkages of one Conductor in a Group – As shown in Fig. 2.5, consider a group of n parallel round conductors carrying phasor currents I1, 12,…, In whose sum equals zero. Distances of these conductors from a remote point P are indicated as D1, D2,…, Dn. […]

## Conductor Types

Conductor Types: Conductor Types – So far we have considered transmission lines consisting of single solid cylindrical conductors for forward and return paths. To provide the necessary flexibility for stringing, conductors used in practice are always stranded except for very small cross-sectional areas. Stranded conductors are composed of strands of wire, electrically in parallel, with […]

## Inductance of a Single Phase Two Wire Line

Inductance of a Single Phase Two Wire Line: Inductance of a Single Phase Two Wire Line – Consider a simple two-wire line composed of solid round conductors carrying currents I1 and 12 as shown in Fig. 2.3. In a single-phase line, It is important to note that the effect of earth’s presence on magnetic field […]

## Flux Linkages of an Isolated Current Carrying Conductor

Flux Linkages of an Isolated Current Carrying Conductor: Flux Linkages of an Isolated Current Carrying Conductor – Transmission lines are composed of parallel conductors which, for all practical purposes, can be considered as infinitely long. Let us first develop expressions for flux linkages of a long isolated current-carrying cylindrical conductor with return path lying at […]