A New Approach to Calculating Electrical Energy Losses on Power Lines with a New Improved Three-Mode Method

Increasing the energy efficiency of the electricity sector is the commitment of all national transmission operators. One of the main goals is to reduce losses in electrical networks. Electrical networks are one of the most important parts of the electric grid. Delivery reliability and the quality of electricity directly depend on the electrical networks. It is well known that losses in the transmission network can be defined as the difference between the electricity taken and delivered. Determining the losses in overhead power lines has several basic tasks. One task is to determine the difference between calculated losses and actual losses, to determine the reason for the difference between calculated and actual losses, and to present the necessary data for taking measures to reduce losses. The second task is an estimation of the loss index for planning and formulation of various plans. The purpose of this paper is to present a new approach to reduce the difference between calculated and actual losses by modifying the method in three modes, or a new approach to calculating the loss index. The proposed method in this paper significantly reduces the error in relation to the classic three-mode method, which represents the original contribution of this work

Generator Assessment of Hydro Power Station Adequacy after Reconstruction from Classical to HIS SF6 Substation

Reliability analysis of substations and generator assessment of power plant stations are very important elements in a design and maintenance process. This paper presents a generator adequacy assessment of a classical “H” scheme for an open conventional substation, which is often used, and a new HIS - High Integrated Switchgear with SF6 gas isolation. Generator adequacy indices of both types of classical and HIS switchgear were compared and the results showed a high level of reliability and availability of the HIS presented substation. The input data were the annual reports of Croatian TSO-Transmission System Operator (HOPS) and statistics of operation events of Croatian National Electricity (HEP Inc.). For the HIS substation, the input reliability data were used from relevant international literature since only few of HIS substations are installed in Croatia. The generator is modelled with a three-state Markov state space model and Monte Carlo simulations were used for the generator assessment analysis. Adequacy indices LOLP and EDNS were obtained using DIgSILENT software

Thermal and Arc Flash Analysis of Electric Motor Drives in Distribution Networks

The paper presents thermal analysis and arc flash analysis taking care of protection relays coordination settings for electric motor drives connected to the electrical network. Power flow analysis is performed to check if there are any voltage and loading violation conditions in the system. Fault analysis is performed to check the short circuit values and compute arc flash energy dissipated at industrial busbars to eliminate damage to electrical equipment and electrical shocks and hazard to personnel. Computers enable the use of smart algorithms used by electrical engineers in providing accuracy of these actions. A fast and accurate procedure for proper incident arc flash energy computation and overcurrent relays coordination in distribution networks is presented. The paper presents the use of the Arc Flash module for arc flash energy computation during the short circuit on LV and HV busbars with soft motor starters. A sample case of one real network is presented which uses soft motor starters as well as the influence on arc flash energy in one transformer station supplying the industrial network in Bosnia and Herzegovina

Designing Automatic Meter Reading System Using Open Source Hardware and Software

The importance of quality of the measured values is very dependent on the device that measures these values: the size of the sample, the time of measurement, periods of measurement, the mobility and the robustness of the device, etc. Contemporary devices intended for the measurement of physical quantities that are on the market vary in price, as well as and the quality of the measured values. The rule "the more expensive the better" is not necessarily always a rule that is valid because it all depends on the characteristics and capabilities of the device, and the customer’s needs. In this paper, a device based on "Open Source" components of hardware and software will be presented. Device was used to measure voltages and currents on low voltage networks, on which a virtually unlimited number of sensors can be added, and the device is assembled of components available on electronic components Internet

Transient Phenomena during the Three-Phase 300MVA Transformer Energization on the Transmission Network

Connecting the transformer to the network may incur inrush current, which is significantly higher than the rated current of the transformer. The main cause of this phenomenon lies in the nonlinearity of the magnetic circuit. The value of the inrush current depends of the time moment of the energization and the residual magnetism in the transformer core. While connecting, the operating point of the magnetization characteristic can be found deep in the saturation region resulting in occurrence of large transformer currents that can trigger the transformer protection. Tripping of protection immediately after the transformer energization raises doubts about the transformer health. Inrush current can cause a number of other disadvantages such as the negative impact on other transformers connected on the same busbar; the increase of the transformer noise due to the large current value, the increase of the voltage drops in the network. The paper presents a simulation of the 300 MVA transformer energization using the MATLAB/Simulink software. 

Effect of extraction technique on the content of bioactive components and antioxidant activity of aqueous extracts of fresh and dried nettle (Urtica dioica L.)

The samples of stinging nettle were collected during June in the Tuzla region. Aqueous extracts were prepared from fresh and dried leaves in order to determinate and compare content of bioactive components and antioxidant potential. Conventional soxhlet, ultrasound assisted extraction and traditional maceration extraction were used as extraction methods. Quantitative determination of phenols and flavonoids was carried out using spectrophotometric methods. Antioxidant activity of nettle aqueous extracts was determined using ferric reducing antioxidant power and DPPH free radical scavenging activity. Extracts obtained by Soxhlet extraction showed the highest total phenolic and flavonoid content and expected the highest antioxidant campacity, while extracts obtained by maceration gave the lowest results

Improved method of Three modes for the estimation of losses in the transmission network

Povećanje energetske učinkovitosti elektroenergetskog sektora je opredjeljenje svih nacionalnih prijenosnih operatera. Jedan od temeljnih ciljeva je smanjenje gubitka u elektroenergetskim mrežama. Električne mreže su jedan od najvažnijih dijelova elektroenergetskog sustava. Pouzdanost isporuke te kvaliteta električne energije neposredno ovisi o vrsti i izgrađenosti elektroenergetske mreže. Poznato je da se gubici u prijenosnoj mreži mogu definirati kao razlike preuzete i predane električne energije. Određivanje gubitaka na vodovima ima nekoliko temeljnih zadaća. Prva zadaća jeste odrediti razliku između izračunatih gubitaka i stvarnih gubitaka te odrediti razlog za tu razliku i da pokaže neophodne smjernice za poduzimanje mjera za smanjenje gubitaka. Drugi zadaća je procjena indeksa gubitaka za planiranje i formulaciju različitih planova. U ovom rada je prikazan novi pristup za smanjenje pogreške između izračunatih i stvarnih gubitaka korištenjem nove metode koja se bazira na tri modificirana moda, odnosno sasvim novim pristupom za izračun indeksa gubitaka. U ovom doktorskom radu predložena metoda znatno smanjuje pogrešku u odnosu na klasičnu metodu na tri moda. Također, razvijen je algoritam koji opisuje korake za implementaciju metode.Increasing the energy efficiency of the electricity sector is the commitment of all national transmission operators. One of the main goals is to reduce losses in electrical networks. Electrical networks are one of the most important parts of the electric grid. Delivery reliability and the quality of electricity directly depend on the electrical networks. It is well known that losses in the transmission network can be defined as the difference between the electricity taken and delivered. Determining the losses in overhead power lines has several basic tasks. One task is to determine the difference between calculated losses and actual losses, to determine the reason for the difference between calculated and actual losses, and to present the necessary data for taking measures to reduce losses. The second task is an estimation of the loss index for planning and formulation of various plans. The purpose of this paper is to present a new approach to reduce the difference between calculated and actual losses by modifying the method in three modes, or a new approach to calculating the loss index. The proposed method in this doctoral thesis significantly reduces the error in relation to the classic three-mode method. Also, an algorithm has been developed that describes the steps for implementing the method

No Home Like Your Own

No Home Like Your Own is a journey through my childhood memories of pre‐war Socialist Yugoslavia and the war in Bosnia and Herzegovina that followed the break up of the six republics that constituted Yugoslavia. These memories are transferred onto the canvas as landscape paintings that accompany the following stories.Master of Fine Arts (MFA)School of Art & DesignUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/77418/1/2010 Alibasic MFA Thesis.pd