The paper proposes a model of detection for voltages and harmonics using wavelet-probabilistic network (WPN). WPN is a two-layer structure, containing the wavelet layer and probabilistic network. It uses the wavelet transformation (WT) and probabilistic neural network (PNN) to analyze distorted waves and classify tasks. In this thesis, the field programmable gate array (FPGA) is employed for the hardware realization of WPN. In the implementation process, by the use of the hardware description language, the WPN algorithm has been embedded into the FPGA chip. Firstly, we divide the mathematical formula of basic WPN algorithm into several parts in order to set up each module individually, then we integrate all modules to complete the design of basic WPN algorithm with digital circuits by the bottom-up process.

The most important advantages of Multilevel Inverters are the absence of a coupling transformer for medium voltage applications and low harmonic current content. In this way, relocatable and economical STATCOM systems can be realized. Complex control algorithms and the isolation problems of measurement devices and power supplies are the main challenging parts of this type of application. In this study, the design, realization, and the performance of a Voltage Source Type Cascaded Multilevel Converter Based STATCOM will be investigated in terms of digital computation, control hardware and the semiconductors devices commercially available in the market. This research work is fully supported by the Public Research Grant Committee (KAMAG) of TUBiTAK within the scope of National Power Quality Project of Turkey with the project No: 105G129.

Power quality has a great effect on the operation of system loads. To analyze its effects and the possible economic losses due to system disturbances, there is an immediate need of a power quality monitoring system. With an effective communication system, network disturbance data can be gathered and analyzed efficiently such that outage duration and its consequent losses can be reduced. This thesis presents communication network performance simulation results of different types of communication schemes used in a power quality monitoring system. Discrete event simulation method is used to study the end-to-end delay times of different communication architectures. Based on these simulation results, system designers can choose the best option to meet their data communication requirements in power quality monitoring.

No description available.

The modern society uses more and more electronic devices needed to being able to function together. This put higher demands on the electrical grid together with that the typical load have changed from the past. Therefore utility companies are obliged to keep the voltage within certain limits for this to function. What exact these limits have been have not always been clear since they have not been gathered in one single document.  This thesis is a cooperation with Kraftringen who also has been the initiator. Kraftringen would like to become more proactive in their work regarding electric power quality. For becoming more proactive continuously measurements have to be done but the locations have to be carefully selected in the beginning to get a wider perspective of the grid. Energy markets inspectorate (EI) is supervisory of the electric power quality in Sweden and since 2011 they have published a code of statutes (EIFS 2011:2 later 2013:1) intended to summarize limits on voltage. Some of the electrical power quality aspects are not mentioned in EIFS 2013:1 and standards have to be used to find limited values. Flicker and interharmonics are not mentioned in EIFS 2013:1 and for values on flicker the standard SS-EN 50160 has to be used and for interharmonics the standard SS-EN 61000-2-2 state limit values. Besides all this there are standards with stricter limits than EIFS 2013:1 e.g. for total harmonic distortion on voltage were SS-EN 61000-2-2 suggest 6 % instead of 8 %. Three different field studies have been conducted in order to get some perception of the present situation regarding electric power quality. Two measurements were conducted on a typical office building because they represents a large part of the typical load in Lund. The third measurement was conducted on a substation in a rural area to get a perception of the situation outside urban areas.  These measurements shown that the overall electric power quality was within given limits according to EIFS 2013:1 and different standards. However, conducted measurements shown some interesting results. Both the typical office buildings have a slightly capacitive power factor which results in that the voltage inside the building is going to be slightly higher than at the substation. Since the voltage level at the measured urban substation was above nominal voltage level with about 2-5 % this could be problematic. Another eventual problem with a load with a capacitive power factor is resonance with the inductive parts of the grid like transformers leading to magnified harmonic levels. It is suggested that Kraftringen expand their number of permanent electric power quality measurement locations to get a better overview of the present situation. The best suited locations to start with are such that have received complaints earlier, preferably measured on the low voltage side of the transformer for also register the amount of zero sequence harmonics. Next step in the measurement expansion would be substations known to be under higher load than others or substations with a PEN-conductor in a smaller area than the phase conductors, supplying a typical office load with high amounts of third harmonics and unbalance. From this it would be appropriate to spread out the measurement locations geographically to better get to know the grids behaviour.

The theme of Master project of Energetics engineer is to analyze the power paremeters of noncontrollable speed AC drive. Is to analyze the power paremeters of variable speed AC drive. Is to accomplish the power paremeters of variable and noncontrollable speed AC drive. Describe the results of investigate and render the respective findigs.

Darbe analizuojamos dažnio keitiklio į tinklą generuojamos aukštesniosios eilės harmonikos. Atlikti nagrinėjamo dažnio keitiklio tuščiosios veikos ir apkrovos bandymai, bei išmatuotos generuojamos į tinklą aukštesniosios eilės srovės harmonikos. Nustatyta netiesinių iškreipių faktoriaus priklausomybė nuo maitinimo įtampos dažnio ir apkrovos. Taip pat atliktas vieno iš tinklo taršos slopinimo įrenginių – linijinio droselio bandymas. Nustatyta, kad netiesinių iškreipių faktorius, priklausomai nuo apkrovos kito nuo 30 % iki 80 %, dirbant 50 Hz dažniu. Didinant maitinimo įtampos dažnį, netiesinių iškreipių faktorius kito nuo 43,3 % iki 79,5 %, esant nurodytąjai variklio apkrovai. Naudojant linijinį droselį, santykinis netiesinių iškreipių faktorius sumažinamas 5,8 %, dirbant 25 Hz, ir 9 %, dirbant 50 Hz maitinimo įtampos dažniu. Nustatyta, kad dažnio keitiklio į tinklą generuojamos aukštesniosios eilės srovės harmonikos gerokai viršino leistinąsias ribines vertes, atitinkamai 5-oji – 3,3 karto, 7-oji – 4,7 karto, 11-oji – 5,9 karto, 13-oji – 8,5 karto ir 15-oji – 1,8 karto. Taigi naudoti harmonikų filtrus rekomenduotina, norint užtikrinti sistemos patikimumą ir ilgesnį eksploatacijos laiką, taip pat filtrų pagalba galima apsaugoti tinklo iškraipymams jautrią įrangą. / The work analyses the higher order harmonics into power system generated by the frequency inverter. Perform issue frequency inverter non load and load test and established generates into network higher order harmonics. Established total harmonic distortion dependence of the mains frequency ant the load. Also was made research of one network pollution reduction equipment – line choke. It was found that harmonic distortion, depending on the load was varied from 30 % to 80 %, at 50 Hz operating frequency. Increasing mains voltage frequency, harmonic ranged changed from 43,3 % to 79,5 %, at full asynchronous motor load. Using line choke total demand distortion is reduced from 5,8 % at 25 Hz, to 9 % at 50 Hz mains frequency. Established that frequency inverter pollution of higher current harmonics significatly higher than allowable, accordingly, the 5 th – 3,3 time, the 7 th – 4,7 times, the 11 th – 5,9 times and the 15 th – 1,8 times. Thus, the use of harmonic filter ir recomended to ensure system reliability and longer service life, as well filter heps to protect for current distortion sensitive equipment.

No description available.

The quality of electric power has been a constant topic of study, mainly because inherent problems to it can bring great economic losses in industrial processes. Among the factors that affect power quality, those related to transients originated from capacitor bank switching in the primary distribution systems must be highlighted. In this thesis, the characteristics of the transients resulting from the switching of utility capacitor banks are analyzed, as well as factors that influence there intensities. A practical application of synchronous closing to reduce capacitor bank switching transients is presented. A model that represents a real distribution system 12.47kV from Shelbyville sub-station was built and simulated using MATLAB/SIMULINK software for purposes of this study. A spectral analysis of voltage and current waves is made to extract the acceptable capacitor switching times by observing the transient over-voltages and, harmonic components. An algorithm is developed for practical implementation of zero-crossing technique by taking the results obtained from the SIMULINK model.

Wind turbines connected to the distribution network can be the cause of voltage fluctuations and resulting fluctuations in the light intensity emitted by light bulbs. These fluctuations may cause people disturbance. A model has been developed to obtain a flicker prediction which is useful in the design process of a wind farm. The model is based exclusively in the frequency domain (FD). This new approach allows very fast and efficient evaluation. The impact of individual parameters is often easier to recognise and evaluate in a FD-representation. The following factors leading to flicker disturbances from a wind farm have been considered in detail: The wind spectrum: Effects of terrain and wind farm wakes on the wind turbulence spectrum have been considered and existing models have been expanded. The wind coherence: A new coherence model for large separation distances has been derived for use within a wind farm. Effects of the terrain on the coherence of power produced by turbines within a wind farm have been considered. The wind turbine: A simplified dynamic wind turbine model allows the prediction of turbine specific contributions to flicker for a variety of wind turbines using a minimal set of parameters. The flickermeter: Flicker measurements are found to sometimes neglect the impact of low frequency voltage variations. These are found to be very important for the correct flicker prediction. A new FD-flickermeter has been developed. The model has been validated against experimental data and a sensitivity analysis shows which parameters are most likely to influence the voltage flicker and which are best altered to minimise the flicker.