PRESENTATION ON LOAD CURVE, LOAD DURATION CURVE,INTEGRATED LDC AND MASS CURVE

SUBMITTED TO:- SUBMITTED BY:-KAMAL ARORA SHIKHAR VIJAYDEAN OF CPU B.TECH 5TH SEM EE

Definition of Load Curve:- The curve showing the variation of load on the power station with respect to time. The power demands of different consumers vary in accordance with

their activities.

The result of this variation in demand is that load on a power station is never constant rather it varies from time to time. Daily Load curve

DIFFERENT LOAD

Domestic load Commercial load Industrial Load BASE LOAD: The unvarying load which occurs almost the whole day on

the station PEAK LOAD: The various peak demands of load of the station

TYPE OF LOAD CURVES

Daily load curve –Load variations during the whole day Monthly load curve – Load curve obtained from the daily load curve Yearly load curve - Load curve obtained from the monthly load curve Load Duration Curve Integrated Load Curve Mass Curve

IMPORTANCE OF DAILY LC The daily load curves have attained a great importance in generation as they supply the following information readily : 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/day = Area (in kWh) under 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.

IMPORTANCE OF DAILY LC

The ratio of the area under the load curve to the total area of 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.

Load Duration Curve There are some facts about the LDC and can be summarized as: 1)The LDC is an arrangement of all load levels in a descending order of magnitude. 2)The area under the LDC represents the energy demanded by the system . 3) can be used in economic dispatching, system planning and reliability evaluation. 4) it is more convenient to deal with it than the load curve.

Load Duration Curve

Integrated Load Duration Curve

A plot of number of units generated (kWh) for a given demand (kW) is called integration load duration curve on Y-axis, load demand in kW or MW is plotted while on z-axis corresponding number of units generated are obtained. Such a curve corresponding to load duration curve shown in Fig

Integrated Load Duration Curve This curve is obtained from load duration curve. Let the load demand be 3

kW from the load duration curve in section I. The number of units generated corresponding to this demand will be area under section I which is shown as U1  in integrated load duration curve. Similarly the other pints are also obtained to get a total curve.

The number of units consumed by a load upto a particular time of a day can also be shown on a curve which is called as mass curve.

MASS CURVE  A mass curve is the plot of accumulated inflow (i.e. supply) or outflow (i.e.

demand) versus time. The mass curve of supply (i.e. supply line) is, therefore, first drawn and is superimposed by the demand curve. The procedure to construct such diagram is as follows:

From the past records, determine the hourly demand for all 24 hours for typical days (maximum, average and minimum).

Calculate and plot the cumulative demand against time, and thus plot the mass curve of demand.

Read the storage required as the sum of the two maximum ordinates between demand and supply line as shown in fig.

Repeat the procedure for all the typical days (maximum, average and minimum), and determine the maximum storage required for the worst day.

MASS CURVE

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