What is Load Curve ? | Daily Load Curve & Important Factor

 What Is Load Curve?

The curve showing the variation of load on the Power station with respect to (w.r.t.) time is known as a load curve.

The load on a power station is never constant; it varies from time to time. These load variations during the whole day (i.e., 24 hours) are recorded half-hourly or hourly and are plotted against time on the graph. The curve thus obtain known as daily load curve as it shows the variations of load w.r.t time during the day. Figure below shows a typical daily load curve of a power station.

 Note:-  IN EASY WAY TO UNDERSTANDING

1.These load variations during the whole day are recorded half hourly or hourly and are plotted against time on the graph. The curve thus obtained is known as daily load curve.

2.The monthly load curve can be obtained from the daily load curves of that month.

➢ For this purpose, average values of power over a month at different times of the day are calculated and then plotted on the graph.

➢ The monthly load curve is generally used to fix the rates of energy.

3. The yearly load curve is obtained by considering the monthly load curve of that particular year.

➢ The yearly load curve is generally used to determine the annual load factor.

Important Terms:

(i) Connected load:  It is the sum of commences ratings of all the equipment’s connected to supply system.

(ii) Maximum demand: It is the greatest demand of load on tire power station during a given period.

(iii) Demand factor:  It is the ratio of maximum demand on the power station to its connected load i.e. 

The value of demand factor is usually less than 1. It is expected because maximum demand on the power station is generally less than the corrected load.

(iv) Average load:  The average of loads occurring on the power station in a given period (day or month or year) is known as average load or average demand.

(v) Load factor:  The ratio of average load to the maximum demand during a given period is known as load factor i.e.,

Load factor is always less than 1 because the average load is smaller than the maximum demand. Higher the load factor of the power station, lesser will be the cost per unit generated.

(vi) Diversity factor:  The ratio of the sum of individual maximum demands to the maximum demand on power station is known as diversity factor i.e.,

(vii) Plant capacity factor: It is the ratio of actual energy produced to the maximum possible energy that could have been produced during a given period i.e.,

(viii) Plant use factor: It is ratio of kWh generated to the product of plant capacity and the number of hours for which the plant was in operation i.e.,