Among all the programs for modeling processes in electrical networks, one of the most common is EMTP (ATP, ATP-EMTP). A huge amount of research is carried out using EMTP, and this is clearly seen by the number of mentions of EMTP in various publications. Such success of the EMTP became possible due to the fact that this program is easy to use. In addition, for many years it was distributed for a nominal fee, that is, almost free of charge.

Without a doubt, EMTP has earned a good reputation for itself, because it helped solve a wide variety of tasks. The range of tasks to be solved has become especially wide thanks to the ability to add your own elements to EMTP, written by the user in a special programming language (“Fortran”).

The good reputation of EMTP works not only for the program itself, but is also gradually transferred to the research that is carried out in this program. In other words, if someone uses EMTP, then this fact alone is sometimes enough for us to start trusting these calculations. Of course we should be more careful when we decide to trust EMTP-results or any other program!

In case of EMTP there are several reasons for this distrust:
1️⃣ When working with the EMTP, you need to set a large number of data and parameters. At the same time, there can be no guarantee that the user correctly specified all of them.
2️⃣ When working with the EMTP, there are situations that elements overlap each other, and the user does not notice it. As a result, for example, instead of a resistance of 1000 ohms, there may actually be only 500 ohms (two elements of 1000 ohms superimposed on each other appeared to be connected in parallel).
3️⃣ The EMTP has a large number of models of overhead and cable lines, and depending on the type of model used, the calculation results may sometimes differ radically.
4️⃣ The EMTP has quite complex models of power transformers and synchronous machines, and for their use it is necessary to know a large number of data, which, frankly, it is not always clear where to get it from.
5️⃣ Mistakes that can be made when programming formulas and algorithms in Fortran can be completely unpredictable, just fatally affecting the EMTP results of calculations.

Thus, EMTP is an excellent program with a proven reputation. However, calculations performed in EMTP are not always trustworthy, since they require a highly qualified engineer, and, no less important, his extreme care when modeling, especially complex circuits.

Truly credible studies are only those that include three points at once:
1️⃣ Calculations by EMTP (or other software).
2️⃣ Calculations by formulas (in the case of complex problems, these will not be calculations, but some rough estimates by formulas).
3️⃣ Field tests, experiments in laboratories or in electrical networks.

Calculations in EMTP alone are not enough to convince readers. The good reputation of EMTP does not mean that we do not need formulas and field experiments.