# Electrical Terms

## Power-Angle Curve

Consider a synchronous machine connected to an infinite bus through a transmission line of reactance Xl shown in a figure below. Let us assume that the resistance and capacitance are neglected. Equivalent diagram of synchronous machine connected to an infinite bus through a transmission line of series reactance Xl is shown below: Let, V = V<0⁰ …

## Capacity Factor

The capacity factor is defined as the ratio of the total actual energy produced or supply over a definite period, to the energy that would have been produced if the plant (generating unit) had operated continuously at the maximum rating. The capacity factor mainly depends on the type of the fuel used in the circuit. The capacity …

## Diversity Factor

Definition: Diversity factor is defined as the ratio of the sum of the maximum demands of the various part of a system to the coincident maximum demand of the whole system. The maximum demands of the individual consumers of a group do not occur simultaneously. Thus, there is a diversity in the occurrence of the load. …

## Symmetrical & Unsymmetrical Faults

Normally, a power system operates under balanced conditions. When the system becomes unbalanced due to the failures of insulation at any point or due to the contact of live wires, a short–circuit or fault, is said to occur in the line. Faults may occur in the power system due to the number of reasons like …

## Nominal T model of a transmission line

In a nominal T model of a medium transmission line, the series impedance is divided into two equal parts, while the shunt admittance is concentrated at the centre of the line. The nominal T model of a medium transmission line is shown in the figure. Here, Series impedance of the line Z = R + …

## Single Line-to-Ground Fault

Generally, a single line-to-ground fault on a transmission line occurs when one conductor drops to the ground or comes in contact with the neutral conductor. Such types of failures may occur in power system due to many reasons like high-speed wind, falling off a tree, lightning, etc. Circuit diagram of single line-to-ground fault Suppose the …

## Capacitance of Transmission Line

Transmission line conductors constitute a capacitor between them. The conductors of the transmission line act as a parallel plate of the capacitor and the air is just like a dielectric medium between them. The capacitance of a line gives rise to the leading current between the conductors. It depends on the length of the conductor. …

## Inductance of Transmission Line

In the medium and long transmission lines inductance (reactance) is more effective than resistance. The current flow in the transmission line interacts with the other parameter, i.e the Inductance. We know that when current flow within a conductor, magnetic flux is set up. With the variation of current in the conductor, the number of lines …

## Nominal Pi Model of a Medium Transmission Line

In the nominal pi model of a medium transmission line, the series impedance of the line is concentrated at the centre and half of each capacitance is placed at the centre of the line. The nominal Pi model of the line is shown in the diagram below. In this circuit, By Ohm’s law By KCL …

## Medium Transmission Line

A transmission line having a length of more than 80 kms but less than 250 kms is considered as a medium transmission line. The parameters (Resistance, Inductance, and Capacitance) are distributed uniformly along the line. For a  medium transmission line, charging current is appreciable and due to the length of the line the shunt admittance …