Ing. Jan Špetlík, Ph.D.

This paper describes construction of current transformer model with consideration of nonlinear magnetic characteristics. Model consists only of the known values mentioned in the transformer data sheet, short circuit condition of connected network, and requirements specified in standard. If the protection concept designer gets into situation where the model of protected network have to be constructed, but parameters of current transformers are not known, must rely solely on information mentioned in the transformer data sheet. If the designed model have to be sufficiently accurate, description of nonlinear magnetization curve have to be included. This work offers possible way to obtain this description and use it for model.

The objective of the paper is to provide verification of power network behaviour with a new Hydropower Plant installation (HPP). The network is operated as an island, powered with the existing diesel generator sets. The generator sets are located in a factory which is representing the main consumption of the network contemporarily - Factory Power Plant (FPP). The paper is analyzing both single HPP operation and parallel operation of HPP and with the existing FPP. For this purpose there was developed the network model in MATLAB Simulink. Computations made hereinafter are evaluating reference load changes (including motor start-ups) in order to determine system responses (frequency change) on specified load changes at different operation states. The paper main aim is to specify proposals on stability improvements in case of unsatisfactory solutions (possible modifications are supposed to be GD2 or Tw changes on HPP part). All the simulations have to respect that frequency deviation shall not be greater than ± 3 Hz.

The basic of electrical part is given. Also the electrical equipment (like transformers, generators, motors, etc.) in power plants with main functions and problems are described. The chapter also explains how to design main electrical parts (i.e. how to solve the amount of own consumption of power plant). At the end some problems of designing alternators are mentioned.

The chapter describes the most important electrical faults - short circuits and the device endurance against them. Further there are mentioned general electrical protections principles and measurement transformers necessary to work with primary quantities. Finally there is a detailed list of the most important electrical protections including their principles and functions explanation with a focus on power plant block protecting.

The presented study describes various principles of penetration of synchronous machine-type DGS into the distribution network. The study was aimed at a possible operation area of the connected sources with regard to the stable operation in steady-state conditions and stable operation after clearing the fault. This study, however, provides a possible complex analysis view on DGS stability issues, which can answer the possibility of a connection. From this point of view, the following results are obtained.

Recently, there are continuously increase in the importance of distributed generations and their share in electric generation. This group includes chiefly asynchrony generators in the wind farm and partly synchrony generator. The paper includes the study that describes different principles of integrating distributed generations with synchrony generators to the distribution system with respect to the minimization of their negative impacts. The study aims at the possible area of operation of the connected sources respecting the stable operation at the steady state and after fault clearance state.

Today's trends are tending to environmental friendly sources utilization. This reality is affecting electrical energy transmission and distribution systems, means new technical solutions and brings new tasks to be solved. Many of new source types in power generation technologies need to be connected to distribution network, in which they are referred to as distributed generation. The stability properties of a hypothetic distribution system with regard to growing distributed generation penetration level has been analyzed. Dynamic stability analysis is based on system eigenvalues evaluation in various operation states and gives results concerning system stability after next sources connections. The transient stability on the other hand provides additional information of the system stability in the case of subjected to a reference fault.

This paper deals with the model comparison in the abc and 0dq components in case of transient phenomenon during the synchronizing of the electrical machine to the power network and the usage justifiability of 0dq model. The author has developed the DynaSolv simulator - based on the developmental environment MATLAB (0dq model) for the more machine system solution.

This paper deals with three dominant types of dispersed generation sources (and machines with appropriate parameters, abc model) and makes a comparison of behaviour each of them during occurred transient.

This paper deals with technical aspects of dispersed generation systems (DGS). Main technical problems connected with DGS operation is voltage and power stability. The most critical point is often to pass into islanded operation state. This phenomenon is analyzed in case study for real network part in ECK Kladno.

The author has developed the DynaSolv simulator - based on the developmental environment MATLAB (0dq model) for the more machine system solution. For more accurate transients solution the author developed abc model in Mathematica software.

This paper deals with technical aspects of dispersed generation systems (DGS). Main technical problems connected with DGS operation is voltage and power stability. The most critical point is often pass into islanded operation state. This phenomenon is analyzed in case study for real network part in ECK Kladno.

The report focuses on current development status of the distributed generation and its cooperation with system load.

The paper focuses on system stability in power systems. The main possible stability analysis methods are shown. Distributed energy sources influence on system stability is discussed. The problems are shown on case studies.

The paper deals with generator stability in islanded operation mode. The system analysis (generator, power system and disintegration automatic) is performed on case studies.

The paper deals with ferroresonance simulation in ATP-EMTP environment. Sample circuit model containing nonlinear transformer model with ferroresonance phenomena has been developed. The phenomena are described on case studies using developed model.