 से लेक्दे किंंball चैफागे सुर चीछा ऱस� tankul karnic कढ़ाँ committee से मेंझनगी क्त् recommends कycz्टि रूत ंँ देशह करती एक से प्प्या फुीरे यह everywhere न्से कौन्तीथ मसाइसे उरॡबदत. now let us see first of all what do you mean by load curve and how it is plotted in order to plan the capacity of power plant to supply load to various types of consumer the following information is necessary with regard to load now here we are using the term load what does it mean let us think let us pause the video for a moment and what do you mean by load here the load is a any device which taps electrical energy from the electrical power system is called as a load on the system the load may be resistive for example electrical lamp it may be inductive for example induction motor or it may be capacitive or it may be some combination of them now let us see what are the various factors which are to be considered for planning of the power plant to supply the electrical power for particular region here the first factor is the present load to be supplied means what are the existing electrical loads which are there in the particular location secondly we have to see the growth of demand to be anticipated called future load as we know that electrical power demand will not be a constant it will go on increasing with the increase in civilization as well as industrialization so there will be every year there will be certain growth of demand which has to be anticipated and it is called as a future load then we have to also consider parallelly the type of load whether it is domestic, industrial or commercial because these depending upon the type load the requirement of electrical power will vary according to the time in a day next we have to also consider the magnitude of load and the duration of time during which it is required this will help us to plan the operation of the various types of various generators as per the requirement the next will be we cannot consider only the present load and demand growth increase in the demand of the load but we have to always plan for some reserve capacity to meet any sudden requirement the electrical power requirement may increase suddenly due to certain festivals or some other program so we have to always plan for some reserve capacity so these factors we consider while planning the power plant now let us see the definition of load curve a graphical plot showing the variation of demand for electrical energy of the consumer on a source of supply that is power system with respect to time is known as the load curve on load curve we plot the demand of electrical energy with respect to time now in if this curve is plotted over a period of time period of 24 hours it is known as daily load curve if it is plotted for week or month or year then it is named as weekly monthly or yearly load curve respectively so we can have load curve for a day for a week for a month or for a year depending upon the time period which is considered while plotting the load curve now let us see the various types of load curve depending upon the load now here I have shown in figure that residential or domestic load now under domestic load it consists of lights, fans, refrigerators, air conditioners, heaters, television, small motors for pumping of water etc most of the residential load occurs only for some hours during the day for example the lighting load occurs during the night time and domestic appliances load occurs only for a few hours in a day for this reason the load factor is the load factor is low for residential or domestic load and it is of the order of 10 to 12 percent as at the same time as we can see the load demand will vary according to the seasonal variation during winter season it may be high or during summer season it will be low this particular load curve is plotted for European countries in India the demand of load will be more in case of summer and demand of power will be less in case of winter now another type of load curve which we come across is the industrial load in industrial load it consists of load demand by industries the magnitude of industrial load depends upon the type of industry this industries can be small scale, medium scale or large scale small scale industry requires load up to about 25 kilowatt medium scale industry between 25 kilowatt to 100 kilowatt or little more and for large scale industry the load required is above 500 kilowatt industrial loads are generally not weather dependent as we can say that the industrial load pattern is almost same only in the afternoon during the lunch break the industrial load requirement drops down otherwise it will increase it will reach a steady and again it will come to minimum during the lunch break and again it is steady and it will decrease so this comes under the industrial load now the next type of load is commercial load which mainly consists of electrical loads due to shops, offices and hospitals now this type of load consists of lightings for shops, fans then electrical appliances used in restaurants etc. this type of load occurs for more hours during the day as compared to the residential load the commercial load has seasonal variations due to extensive use of air conditioners or space heating so as we can see during the day also it is continuously varying it is not remaining constant so this particular load curve is called as the commercial load curve depending the next is urban traction load under traction load it includes the load for tram cars, trolleys, buses, railways etc. this class of load has wide variations during the morning hour has wide variations during the morning hour it reaches the peak value as we can see here the value of traction load is peak during the morning hour because people have to go to their workplaces similarly after morning hours it decreases and again it starts decreasing it reaches minimum and again it starts increasing during the evening hours because the people start coming to their homes after closing of their offices the next type of load is called as the street lighting load or we can also call this particular load as municipal load under municipal load it consists of mainly the street lighting load or also the power required for water supply etc. the street lighting load is practically constant as we can see from this load curve the street lighting load is almost constant in a day and this particular load is supplied during the night hours for water supply the water is pumped to overhead tanks by pumps driven by electrical motors pumping is carried out during the off peak period usually during the night period this helps to improve the load factor so street lighting as well as water pumping is carried out during the night hours therefore it is almost practically constant and during day hours it is equal to 0 now let us see the next type of load which is called as irrigation load or water pumping load this type of load is the electrical power required for pumps driven by motors to supply the water to the fields generally this type of load is supplied for 12 hours during night period so this particular load as we can see that it is also continuously varying and during off peak period this reaches maximum the references are as follows