Radomir Gono

Reliability analysis of distribution networks

Monitoring of failures and outages in the transmission and distribution of electrical energy is necessary for determination of the reliability of network components and the supply of electrical energy to consumers. Incorrect input data leads, of course, to false results even if the correct computing method is used. The paper deals with obtaining of reliability indices of distribution network analyzing data about failures and outages of electric power supply from several distribution areas from the Czech Republic and the Slovak Republic. Data sources produce heterogeneous domain data. It is necessary to store them in one common scheme to be able to analyze and query such data. Scheme comes from Distribution Network Grid Code. We proposed multi-dimensional data structure to storage of the data that enable effective querying. Data from particular companies are transformed. The transformation language has been developed for this reason. For evaluation of reliability it is necessary to have data on the number and range of the examined piece of equipment. Thus it is not only the case of data on e.g. the number of failures and the mean duration of a failure of the line of the given type and the given voltage level, but also the case of data on the total range of the observed piece of equipment, i.e. here on the total length of the line of the given type and the given voltage level. The result of analysis is the determination of the failure rate and mean failure duration for particular items of equipment or for group of equipments. With more detailed databases, other pieces of information may be found that are important for operators, such as the most frequent cause of failures, areas of the greatest amounts of undelivered energy, etc.

Reliability Database of Industrial Local Distribution System

Calculatin of the supply reliability is impossible without trustworthy input parameters. It is possible to find reliability indices of electricity transmission or distribution system but there is hardly any of local distribution system at heavy industry. The paper shows the way how to get reliable results—collection and processing of information and documentation from the dispatcher logs on the operation of the local distribution system within the premises of an industrial plant. The first part focuses on development of equipment passportization and processing of documentation for system operation. Additionally, the work deals with calculation of reliability indices of overhead lines and components. The final part brings the comparison of reliability indices of the input overhead lines of the industrial local distribution system with overhead lines of the distribution system of the Czech Republic.

Quality analysis of electricity supply from small hydro power plants with Banki and pump turbines

This paper deals with the legislative framework amending supply of electricity. It outlines an analysis of the important quality parameters of electricity supplied by small hydropower stations in the waterworks buildings in practice.

Operation of industrial local distribution system

This paper deals with the agenda associated with management of a power control centre within a power supply plant together with operation of a local distribution system within the premises of such power supply plant. The main part aims at the analysis of power supply reliability concerning a selected section of the system at 6 kV distribution plant. The background data used for calculation are sourced from the database comprising events recorded in the control centre logs.

The input analysis of parameters and expected operation modes of energetic technologies in technological centre ENET

This paper deals with a description and partial analysis of energy production units and their implementation in the laboratories of ENET technological centre in Ostrava - Vitkovice. The paper refers to individual types of conventional and non-traditional sources of electric power that are connected to the technological centre distribution grid, together with analysis of their topological configuration, with a presentation showing division of individual power sources into logical technological groups with definition of either nominal or estimated operating parameters. The data summarised in this paper will serve mainly as input material to design a dynamic model, for modelling of transients and short-circuit ratios mainly on non-traditional energy sources, as well as full energetic systems already implemented. That is why the paper also addresses an introduction of concept and expected software products for future creation of the model.

Utilization of small hydropower

The paper deals with the current situation in using small hydropower plants - SHP in the Czech Republic. It outlines a short history of small-scale hydropower in the Czech Republic, describes the principle of financial support for renewable energy sources and utilizing drinking water flow from water reservoir to water pipeline for electricity production.

Energy Use of biogas from waste water

Paper deals with using biogas produced by wastewater treatment plant for electricity production. In the first part technology of the biogas production in waste water treatment plant (WWTP) is described, and then production of electricity and bargain redemption price are discussed.

Advanced Control of the Dynamic Voltage Restorer for Mitigating Voltage Sags in Power Systems

The paper presents a vector control with two cascaded loops to improve the properties of Dynamic Voltage Restorer (DVR) to minimize Voltage Sags on the grid. Thereby, a vector controlled structure was built on the rotating dq-coordinate system with the combination of voltage control and the current control. The proposed DVR control method is modelled using MATLAB-Simulink. It is tested using balanced/unbalanced voltage sags as well as fluctuant and distorted voltages. As a result, by using this controlling method, the dynamic characteristics of the system have been improved significantly. The system performed with higher accuracy, faster response and lower distortion in the voltage sags compensation. The paper presents real time experimental results to verify the performance of the proposed method in real environments.

Analysis of properties of power inverter digital model at the ENET technological centre

This paper describes the analysis of power generating units and their implementation, these are located within the technological centre in Ostrava-Vitkovice. Further issues concerned in this paper deal with digital simulation using computer model created using the EMTP — ATP software to evaluate particular process courses that may occur on the power inverter installed in the technological centre. The data summarised in this paper will serve mainly as input details for development of a dynamic model. The data from this digital model will be then compared to the values measured on the real power inverter.

Dynamic model of asynchronous machine

This paper deals the mathematical description of an asynchronous machine. Differential equations are then used to create a dynamic model of asynchronous machine. For the possibility of evaluation the quality of the created model are created at the conclusion the basic characteristics of representing the asynchronous machine. Graphs show almost identical measured and the simulated values. The model is created with a lot of simplification, therefore the simulation model will be not behave identically in all cases, as the real asynchronous motor.