The universally adopted electric power system is three-phase AC operating at a constant frequency such as 50 Hz in India and 60 Hz in USA, etc. The power system delivers power to the consumers through its transmission and distribution systems.It is important that the electric power supply should be satisfactory. Let us take a look at the primary requirements to have satisfactory electric supply.Good Voltage RegulationThe power system must have a good voltage regulation because the voltage variations disturb the operation of both power equipment and lights. For example, an electric motor is designed to have its best operating characteristics ... Read More

A thermal or steam power plant is a generating station which converts heat energy of coal combustion into electrical energy. A modern thermal power plant consists of a number of necessary and auxiliary equipment. In this article, we will take a look at the most important equipment of a thermal power plant.BoilerA boiler is a device in which water is converted into steam by utilising the heat energy of coal combustion. There are two types of steam boilers viz −Water Tube Boiler - In a water tube boiler, water flows through the tubes and the hot gases of combustion of ... Read More

Electric power can be transmitted either by AC transmission system (i.e. the voltage and current are alternating) or DC transmission system (i.e. the voltage and current are direct or unidirectional). Each transmission system has its own advantages and disadvantages. Therefore, we need to discuss the technical advantages and disadvantages of the AC and DC transmission systems so that we can select the right system for the electric power transmission.AC Transmission SystemThe AC transmission system is the one in which the alternating current is employed for the transmission of electric power. Nowadays, electric power is almost generated, transmitted and distributed in ... Read More

Sources of EnergyThe electrical energy is obtained from energy available in the various forms in the nature. The main sources of energy used to generate electrical energy are −The SunThe Sun is the main source of energy. The heat energy radiated by the Sun is to be focused over a small area with the help of reflectors. Then, this heat energy can be used to produce steam and the steam energy can be used to drive the turbine, which in turn drives an alternator to generate electrical energy.This method of generating electrical energy has limited applications because −It requires a ... Read More

A gas turbine power plant is the type of power generating station in which gas turbine is used as the prime mover for the generation of electrical energy.The schematic diagram of a gas turbine power plant is shown in the figure.The main components of a typical gas turbine power plant are as follows −CompressorRegeneratorCombustion ChamberGas TurbineAlternatorStarting MotorCompressorThe compressor is an apparatus used to increase the pressure of air taken from the atmosphere. In gas turbine power plants, rotatory type compressors are generally used.The air at atmospheric pressure is drawn by the compressor through an air filter which removes the dust ... Read More

Electricity TariffThe electricity tariff is defined as the rate at which the electrical energy is sold to a consumer.However, the tariff should include the total cost of producing and supplying electrical energy plus the profit to the power company. In practice, the tariff cannot be same for all types of consumers because the cost of production of electrical energy depends upon the magnitude of electrical energy consumed by the user and his load conditions. Therefore, the tariff is fixed by considering the different types of consumers such as domestic, industrial and commercial, etc.Objective of TariffLike any other product, the electrical ... Read More

The power factor of the load connected to the power system considerably affects the voltage regulation and efficiency of a transmission line.Effect of Load Power Factor on Voltage RegulationThe expression for percentage voltage regulation of a transmission line, when a load of lagging power factor is connected to the system, is given by, $$\mathrm{\%\:Voltage \:Regulation\:=\:\frac{\mathit{IR}\:cos\:\phi _{\mathit{R}}\:+\:\mathit{IX_{\mathit{L}}}cos\:\phi _{\mathit{R}} }{\mathit{V_{\mathit{R}}}}\:\times \:100\%\:\:\:...\left ( 1 \right )}$$Where, suffix R denotes the receiving end quantities.Also, the percentage voltage regulation for leading power factor is given by, $$\mathrm{\%\:Voltage \:Regulation\:=\:\frac{\mathit{IR}\:cos\:\phi _{\mathit{R}}\:-\:\mathit{IX_{\mathit{L}}}cos\:\phi _{\mathit{R}} }{\mathit{V_{\mathit{R}}}}\:\times \:100\%\:\:\:...\left ( 2 \right )}$$Therefore, from equations (1) and (2), the following points can ... Read More

Variable Load on Power StationThe load on an electric power system changes from time to time due to uncertain demands of the consumers, this variation in load of a power station is termed as variable load on power station.An electric power station is designed to meet the load requirements of the consumers. From the standpoint of equipment needed and operating routine, an ideal load on a power station would be of constant magnitude and of steady duration.However, in actual practice, such a steady load on the power station cannot be realised. It is because the consumers require different blocks of ... Read More

Power FactorThe cosine of angle between voltage and current in an AC circuit is called the power factor of the circuit. In other words, the power factor is defined as the ratio of active power to the apparent power in the circuit, i.e., $$\mathrm{Power\: factor, cos\:\phi\:=\:\frac{Active\: power\: (in \:Watts)}{Apparent\: power\: (in\: VA)}}$$Where, $\phi$ is the power factor angle.Causes of Low Power FactorFrom the economic point of view, the low power factor of the load connected to a power system is undesirable. The main causes of low power factor are given as follows −The AC electric motors consist of inductive winding. ... Read More

The useful output of a power generating station is the kW output which is delivered by the station to the electrical supply system. Sometimes, a power generating station needs to deliver more kW to meet the increased power demand. This can be achieved by any of the following two methods −By increasing kVA capacity – In this method, the kVA capacity of the power generating station is increased at the same power factor to meet the increased kW demand. Although, this causes extra cost to increase the kVA capacity of the power station.By improving power factor – In this method, ... Read More