Which of the following helps in selecting the size and number of

SOLUTION

Load Curve: The curve showing the variation of load on the power station with respect to time is known as a load curve.

The load variations during a whole day are recorded half-hourly or hourly and are plotted against time on the graph. The curve obtained is known as a daily load curve as it shows the variations of a load during the day.

The monthly load curve can be obtained from the daily load curves of that month. For this purpose, the 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.

The yearly load curve is obtained by considering the monthly load curves of that particular year. It is generally used to determine the annual load factor.

Importance of the load curve:

• The daily load curve shows the variations of load on the power station during different hours of the day
• The area under the daily load curve gives the number of units generated in the day
• Units generated in a day = Area (in kWh) under the daily load curve
• The highest point on the daily load curve represents the maximum demand on the station on that day
• The area under the daily load curve divided by the total number of hours gives the average load on the station in the day
• The ratio of the area under the load curve to the total area of the rectangle in which it is contained gives the load factor
• The load curve helps in selecting the size and number of generating units
• The load curve helps in preparing the operation schedule of the station