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The parameters and indicators of the systems of electric supply for consumers are necessary to be permanently specified for the prognosis, estimation and monitoring of their reliability. In this connection the basic system problems of the electric supply reliability maintenance and improvement are considered in this paper. The responsibility of the designers, technical and administrative personnel...
The measurement of grounding system impedance may be affected by power system frequency interference and its harmonics. The Shifted Frequency Method (SFM) is potentially insensitive to the electromagnetic interference. In this paper, we evaluate this method in the hydroelectric power plant for two different load conditions of the connected overhead power lines. Presented field tests results further...
The increase in nonlinear appliances in households is largely driven by their affordability. In the case of lighting appliances, it is necessary to use energy-saving light sources. A case study of the possibility of simultaneous connection of large amounts of lighting appliances and other nonlinear appliances used in households is conducted in this paper. A variant of distribution systems in housing...
Accurate models for predicting generation, demand, prices, and storage under uncertainties are essential for managing safe, sustainable and reliable electric grids. In this investigation, the use of data-mining methods for building models of electrical consumption and renewable generation aimed at integrating renewable generation for smart grid control is studied. The results presented are part of...
This paper analyses electromechanical oscillations in the northern area of the Nordic power system. Both spectral analysis and modal identification methods are used to analyze signals received from the phasor measurement units (PMU) installed in the system. Spectrograms are used to analyze the characteristics of electromechanical oscillations and to support the interpretation of the modal identification...
To improve operational reliability of electrical machines over a long period of time, the diagnostic tests should be performed. This justifies the monitoring of machines, particularly those which do not have the reserve at the workplace: the power generators, hoisting machines in mines, etc. The issue of monitoring and diagnosis of electrical machines is focused on assessing the technical condition...
Permanent magnets have become more and more important in today's technology of electrical machines. This paper gives an overview of usability of different types of magnetic materials in electrical machines. The research is based on a synchronous generator construction using NdFeB, SmCo, ferrite and Alnico permanent magnets. The reason of the research is to determine, which kind of magnets are suitable...
In this paper three new variations of the two main distance relay algorithms which are based on Discrete Wavelet Transform (DWT) are introduced. Typically, distance relay algorithms based on DWT are designed to have faster tripping time relative to those which are based on the Discrete Fourier Transform (DFT). In this paper an investigation into how improvements in tripping time affect the security...
The control of the individual converters in a voltage-source-converter high-voltage dc (VSC-HVDC) based multi-terminal dc grid is central for the overall performance of the system. A few different variants of power drooped against dc voltage control have been proposed in the literature for the purpose of distributing the power mismatch, following a disturbance, on several converters. One such variant...
Impedance as one of the most important parameters of a battery has been studied a lot. While most works only consider the impedance is related with the state-of-charge (SOC), very little attention has been put upon the rate dependence of impedance. In this work, the impedance of a battery has been considered to be dependent on the SOC and the charging or discharging rate. A series of charging and...
Pilot Wire Relay and Pilot Monitoring Relay are electromechanical relays installed to protect long critical line feeder in PT Badak NGL. Pilot Wire Relay is a form differential relaying which protect longer lines through pilot wire, while pilot monitoring relay monitors the condition of pilot wire itself and gives transfer trip signal. However, Badak LNG has experienced two misoperations of auxiliary...
In an isolated and rural locations where the energy is derived from renewable sources, the load will suffer from large fluctuations due to the unpredictable nature of the underlying phenomena (wind or solar). This paper presents the implementation of practical control for standalone renewable energy source able to feed an isolated load with regulated voltage and satisfactory energy quality in remote...
Nowadays energy consumption minimization is very important. It can be done using renewable energy sources or by minimization of energy consumption. In industry case a lot of systems as CNC machines or industrial robots can regenerate energy. Regenerated energy is dissipated in breaking rheostats. To use regenerated energy usually use fast energy storage devices like flywheels or supercapacitors. In...
A series resonant tank in the quasi-Z-source (qZS) DC-DC converter with a voltage doubler rectifier could significantly increase the input voltage regulation range by adding the buck mode realization possibility. This paper discusses two different control approaches of the qZS series resonant DC-DC converter in the buck mode: variable frequency control and phase shift modulation. Both methods are...
Education outcome is very important for practical work in industry, design, research as well for lifelong education and theoretical work. Article deals with some aspects of all-around world discussion on education content, process and education meaning from society point of view.
Power Quality is a generic term focusing on several issues, going from reliability to the quality of service provided by the energy supplier. It addresses limiting aspects such as harmonic distortion, flicker, sags, swells and transients… It is important for the students to understand the differences between the large amounts of events that fit into poor power quality category. Moreover it is important...
Shunt flexible transmission systems (FACTS) devices are employed to control the damping of electrical power system oscillations. It can operate either in capacitive mode or in inductive mode. Static var compensator (SVC) is utilized for controlling reactive power of power system and regulating the voltage. This paper presents the effects of a SVC-FACTS controller on the electromechanical oscillations...
Electrical transmission grids are planned to be in compliance with redundancy specifications, such as the deterministic (N-1) criterion. Due to increasing power transmission, the grid components experience a higher utilization rate. One essential issue of transmission grid planning is the necessity of the grid enforcement and the dimensioning of its components. Considering a similar level of grid...
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