The Filipino Electrical Engineer

In this part of the tutorial, we shall be able to produce a Normal Inverse time-current curve. Given the values below, we will be plotting the values on an XY Scatter graph with data points connected without markers.

Try plotting the values and I presume that you will be getting a graph similar to Figure 1.

Figure 1

As electrical engineers, doing protective devices coordination is always a part of our tasks. You may say that I could always use ETAP or EDSa or SKM Power Tools to do the job.

If your company has the money to buy all these software, then you are right. The most important thing however is, do you know how to use the sophisticated power system analysis software.

At the end of this tutorial, the electrical engineer will be able to create coordination grpahs for any particular application. This tutorial also aims to provide tips during the process.

The requirements of this tutorial are the following

• You have MS Excel - at least MS Excel 2003 - lower versions may do as well.
• You know how to use MS Excel
• You know how to create graphs.

This is a sample of coordination curve we shall be doing on the next part of the tutorial.