Important Short Questions and Answers: Power System Operation and Control - Introduction

1. What is load curve?

^Ø   The curve drawn between the variations of load on the power station with reference to time is known as load curve.

^Ø   There are three types, Daily load curve, Monthly load curve, Yearly load curve .

2. What is daily load curve?

^Ø   The curve drawn between the variations of load with reference to various time period of day is known as daily load curve.

3. What is monthly load curve?

^Ø   It is obtained from daily load curve.

^Ø   Average value of the power at a month for a different time periods are calculated and plotted in the graph which is known as monthly load curve.

4. What is yearly load curve?

^Ø   It is obtained from monthly load curve which is used to find annual load factor.

5. What is connected load?

^Ø   It is the sum of continuous ratings of all the equipments connected to supply systems.

6. What is Maximum demand?

^Ø   It is the greatest demand of load on the power station during a given period.

7. What is Demand factor?

^Ø   It is the ratio of maximum demand to connected load.

Demand factor= (max demand)/ (connected load)

8. What is Average demand?

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

Daily average demand = (no of units generated per day) / (24 hours)

Monthly average demand = (no of units generated in month) / (no of hours in a month) Yearly average demand = (no of units generated in a year) / (no of hours in a year)

9. What is Load factor?

^Ø            The ratio of average load to the maximum demand during a given period is known as load factor.

Load factor = (average load) / (maximum demand)

10.        What is Diversity factor?

             The ratio of the sum of individual maximum demand on power station is known as diversity factor.

Diversity factor = (sum of individual maximum demand)/(maximum demand).

11.        What is Capacity factor?

             This is the ratio of actual energy produced to the maximum possible energy that could have been produced during a given period.

Capacity factor = (actual energy produced) / (maximum energy that have been produced)

12.        What is Plant use factor?

             It is the ratio of units generated to the product of plant capacity and the number of hours for which the plant was in operation.

Units generated per annum= average load * hours in a year

13.        What is Load duration curve?

             When the load elements of a load curve are arranged in the order of descending magnitudes the curve then obtained is called load duration curve.