Load Duration Curve – Here’s all you need to know

A load duration curve abbreviated as LDC is very often used by Power Engineers in the field of electric power generation to demonstrate the relationship between generating capacity requirements and capacity utilization.

A load duration curve is a graphical representation of the load elements of a load curve arranged in descending order of magnitudes.

This curve is obtained from the same data as the load curve but with the ordinates arranged in descending order. The maximum load is represented on the left, while the decreasing loads are represented on the right in the descending order of load values. The area under the load duration curve is equal to that of the corresponding load curve.

Consider the load curve shown on the left side of the below figure.

From 0 to 4 hours, the electrical load is 6 MW, from 4 to 8 it’s 20 MW, then from 8 to 16 hours it stays at 25 MW and so on.

The resulting daily load duration curve of left side shows the number of hours during which each load prevailed. Daily load duration curve can be extended to weekly, monthly or yearly load duration curves

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