## Automatized AVR tuning with Python in DIgSILENT PowerFactory

Sometimes it is needed to tune an AVR (automatic voltage regulator) to fulfill specific requirements. Requirements such as rise time, overshoot, and settling time are often used to specify the desired behavior for a given step response of the AVR. Since it is difficult to tune the controller by hand, this post presents an automatized…

## DQ0-transformation: calculate active and reactive power from instantaneous voltage and current signals

The DQ0-transformation, or direct-quadrature-zero transformation, is a very useful tool for electric power engineers to transform AC waveforms into DC signals. In particular, for three-phase systems, the use of DC signals simplifies the calculations immensely. The DQ0-transformation is the product of the Clarke and Park transformation. The Clarke transformation converts the abc-phase-components to αβγ-components while…

## Unit commitment in electric power systems: solving a mixed-integer non-linear optimization problem

Unit commitment (UC) in electric power systems is a (hard-to-solve) mixed-integer non-linear optimization problem. UC aims at scheduling the generation units such that they satisfy the demand at every time instant while minimizing the overall cost (or maximizing the welfare). On top of that, a large number of constraints must be respected, e.g. capability limits…

## An approach to determine generation shift keys (GSKs) for defined market areas

Generation shift keys (GSKs) describe how a change of the net position of a market area affects the power outputs of the generation units within the area. In other words, the GSK describes how the change of the net position is mapped to the different generation units. Transmission system operators (TSOs) use GSKs for various…

## Load model identification in electric power systems: a linear least-squares approach

Load modeling is one of the most important aspects when it comes to the stability analysis of electric power systems. The way we model loads significantly impacts the results of the analyses. The so-called ZIP model considers the voltage dependency of loads and serves this purpose very well. ZIP stands for the three defined load…

## Split lines or cables into a pre-defined number of sections in DIgSILENT PowerFactory

In this post, I present an approach to automatically split lines or cables in DIgSILENT PowerFactory into a pre-defined number of sections. The main idea is to loop over every line and split it into a pre-defined number of sections. The sections assume the same line type as the original line. Whereas the length of…

## A template for rate-of-change-of-frequency (RoCoF) analysis of synchronous generators/condensers

The importance of grid connection studies increases around the world. TSOs focus more on the grid impact of new generation units as the energy transition moves forward. Adding more converter-based units changes the power system dynamics fundamentally, e.g. higher frequency gradients. That’s also why TSOs require rate-of-change-of-frequency (RoCoF) analyses before the approval of prospective units….

## A template for fault-ride-through (FRT) analysis of synchronous generators/condensers

The importance of grid connection studies increases around the world. TSOs focus more on the grid impact of new generation units as the energy transition moves forward. Adding more converter-based units changes the power system dynamics fundamentally. That’s also why most TSOs require a fault-ride-through (FRT) analysis of prospective units before approval. Similarly important is…

## How to create a measurement file for DIgSILENT PowerFactory from a CSV, TXT, or XLSX file?

Many times when you model time-domain simulations in DIgSILENT PowerFactory you want to use time-series data stored in CSV, TXT, or XLSX files. In PowerFactory you can integrate these time series by means of measurement files (*.ElmFile). These measurement files are simple ASCII files with a column for each variable including the time. The time…

## Automatized short-circuit analysis with Python in DIgSILENT PowerFactory

Sometimes you want to know the short-circuit currents and short-circuit powers at different locations in the power system. This could be of importance for different reasons. For example, design of protection systems or identification of weak grid areas in terms of short-circuit power. Therefore, in this post, I present an approach for automatized short-circuit analysis…