# Computer practical training

Objective

In addition to the lecture "Netzplanung und Netzführung I", the Chair of Energy Systems and Energy Management offers a computer practical course designed to implement and deepen the theoretical knowledge acquired during the lecture with the help of a simulation software.
Within the framework of computer engineering, the topics of power flow and short circuit current calculation as well as the reliability analysis in electrical networks are dealt with. Furthermore, frequently occurring errors in the network calculation will be highlighted during the course.
The PSS®SINCAL tool from Siemens will be used as power systems analysis software. A total of seven teaching units are planned.

Exercise 1: Introduction to Sincal

The aim of the first exercise is to classify the power systems analysis software PSS®SINCAL from Siemens as a tool for network planning and to familiarize with the basics of the operation. It shows you how to set up the software and adapt it to your needs. Using a small example network, you learn how to add resources to your network model and to parameterize them. Then, after a correct input of all data, how to perform a power flow calculation.

Exercise 2: Parameter input from data sheets and diagrams

The implementation of the topology of a network into a network calculation program such as PSS®SINCAL is the first step towards the creation of a realistic network model. However, in order to achieve plausible results during the simulation, it is imperative to correctly map the resources of the network with its individual properties. The aim of this exercise is to show the data input of typical network resources into a simulation program such as PSS®SINCAL using data sheets and diagrams.

Exercise 3: Power flow calculation

The power flow calculation is used to determine the state of a network in normal operation. In this case, a steady state and symmetrical relationships are always assumed (quasi-stationary calculation). Failure analysis, on the other hand, is a special form of power flow calculation in which one operating device is switched off one after the other and a power flow is calculated. Subsequently, the new, setting network state is judged. Any overvoltage or equipment overloads are determined. The load flow calculation as well as the (n-1) failure analysis are very important in network planning and network operation. The third computer training exercise has two aims: firstly, you should get to know the method of power flow calculation; second, you should develop a feeling for how electrical networks react in certain situations. The first step is to deepen the characteristics of the different power flow calculation methods. Since the power flow problem is an under-determined problem due to the parameter diversity, it often results in non-physical specifications by the user and thus to the non-convergence of the power flow calculation. Therefore, the exercise will show how to ensure the convergence of the power flow. In the second step, the network state is evaluated by means of a convergent power flow. Here, you will learn which setting options you have and how these must be used to achieve a permissible system state of the network. In addition, you will check the network model for compliance with the (n-1) principle as part of an (n-1) failure simulation.

Exercise 4: Short circuit current calculation

Short-circuit current calculations are used to describe the network condition in the case of malfunction. They are therefore indispensable for the interpretation of network resources. Thus, they give, inter alia, Information on the maximum thermal and mechanical stress on the network equipment in the event of a fault. Before any change in the configuration within a network, short-circuit current calculations must therefore be carried out so that the network protection can be set correctly and the system and the personnel safety can be ensured. The three-pole short circuit is a symmetrical error and for this reason must be calculated with relatively little effort. However, the single-pole fault most frequently occurs. The effects of this error depend to a large extent on the neutral point treatment of the respective network. The aim of this exercise is to give you an introduction to the short circuit current calculation with professional power systems analysis software. You will then discuss and compare the effects of the different neutral point treatments.

Exercise 5: Power flow and short circuit current calculation

In the previous exercises, the basic application of the PSS®SINCAL power systems analysis software from Siemens was presented. In addition to operating the program itself, the main focus was on the correct parameterization of the models as well as the execution and evaluation of power flow and short-circuit current calculations. The aim of this exercise is to repeat what has been treated so far on selected examples and to consolidate what has been learned.

Exercise 6: Basics of the reliability analysis of electrical networks

The aim of this exercise is to give an introduction to the reliability calculation. Reliability calculations in electrical networks are used to check the supply reliability and to provide information on the impact of supply interruptions on the consumer. The basic concepts, the procedure for manual calculations and the calculations are presented with the network calculation program PSS®SINCAL. In addition, the different calculation methods are displayed and compared. Furthermore, the problem of data procurement in the reliability analysis by means of a selected statistic will be shown.

Exercise 7: Reliability analyzes using the test network

The aim of this exercise is to deepen the basics for the reliability analysis of electrical networks, based on the test network. They examine the different reliability in the individual networks. In addition, you will learn how network utilization, topology, and simulation of subordinate or superimposed network groups influence the reliability characteristics of the consumer nodes and which problems can arise.

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