Multipole as an Element of Electric Circuit and Its Equivalent Diagrams

A multipole in electric circuit theory (unlike to electric or magnetic field multipole calculation methods) is a circuit or a part of a circuit, which is connected to other circuits by a definite number of terminals (poles). An expression is given for determining the number of parameters of the equivalent diagramof a multipole depending on the number of poles. Unlike the generally known four-pole theory that can be used only if both incoming currents of the four-pole (and the same for both outgoing currents) are mutually equal, a so called generalized four-pole is considered, which does not comply with the so-called rule of regularity. In general case, the equivalent diagram of such a generalized, passive four-pole (that conforms to the reciprocity principle) should contain six passive elements unlike the “usual” regular four-pole, equivalent diagram of which needs only three resistances. Mathematical analogy of an electric circuit multipole and a charged system of bodies is shown. An expression is given for determining the number of parameters of the equivalent diagram depending on the number of poles. A double T-type diagram of a generalized four-pole is considered. Equivalent diagrams of an active multipole have been created by replacing the inner sources with outer sources of current or voltag

Impact of the limitations of transmission line capacity on pricing

The paper considers the influence of the capacity of cross-border lines on the price formation in different electricity market zones. Nonlinear programming is used for optimum unit commitment (UC) and dispatch of power plants, also considering electricity import options. Mandatory procurement of electricity is taken into account in the algorithm proposed in this paper. The computational effectiveness of the algorithm is discussed. The influence of cross-border capacity limitations on the pricing is proved

Biogas Power Plant Operation Considering Limited Biofuel Resources

The problem of operational planning of a biogas combined heat and power (CHP) plant under conditions of limited biofuel resources is analyzed in this paper. The power plant operation mode depends on the biomass amount and its delivery. Consideration of parameters with high dispersion, such as the ambient temperature, thermal energy consumption and energy price, makes the problem solution much more complicated and requires new algorithms and software tools. This paper proposes an algorithm of stochastic optimization to estimate the maximum value of income by taking into account the random nature of variables. When the biomass resource is limited, the need of its optimal distribution for all the time periods considered becomes of top importance. In this paper, a case study is conducted on a realistic biogas CHP plant that demonstrates the feasibility of our stochastic optimization algorithm. It is concluded that the proposed algorithm can increase the efficiency of the biogas power plant operations under conditions of limited resources. The main distinction of this paper is that a biogas CHP plant optimization model is considered from the point of view of income maximization under market conditions taking into account the limited biomass resources

Par vienotu grafisko apzīmējumu sistēmu elektroshēmās

Rakstā aplūkoti galvenie jautājumi, kas radušies, latviešu valodā adaptējot standartu IEC 60617 “Grafiskie apzīmējumi elektroshēmās” (“Graphical Symbols for Diagrams”), ko izstrādājusi Starptautiskā elektrotehnikas komisija. Tulkojums veikts atbilstoši latviešu literārās valodas normām un ievērojot apstiprināto speciālo terminoloģiju. Adaptētais standarts papildināts ar 65 piezīmēm un angļu valodas saīsinājumu atšifrējumu. Līdz šim elektroietaišu projektēšanas biroji un citi uzņēmumi Latvijā elektroshēmās viena un tā paša elementa apzīmēšanai bieži izmanto atšķirīgus grafiskos apzīmējumus, kas apgrūtina dokumentācijas izpratni un lietojumu praksē. Tāpēc standarta tulkojums veicinās elektrotehniskās projektdokumentācijas unifikāciju un Latvijas uzņēmumu konkurētspējas paaugstināšanu starptautiskā līmenī. Standarts adaptēts Rīgas Tehniskajā universitātē pēc AS “Latvenergo” un AS “Augstsprieguma tīkls” pasūtījuma. Rakstā iekļauti 4 attēli un dotas atsauces uz 12 izmantotajiem informācijas avotiem

Standarta IEC 60617:2012 "Grafiskie apzīmējumi elektroshēmās" adaptācija latviešu valodā

Starptautiskais standarts IEC 60617:2012 "Grafiskie apzīmējumi elektroshēmās" adaptēts latviešu valodā 2014. gadā Rīgas Tehniskās universitātes Enerģētikas un elektrotehnikas fakultātē pēc AS "Latvenergo" un AS "Augstsprieguma tīkls" pasūtījuma. Standartā iekļauti 1907 grafiskie apzīmējumi. Adaptētā standarta prezentācijas eksemplārs papildināts ar ievadu, adaptētā standarta satura, struktūras un lietojuma aprakstu. Pielikumā iekļautas nacionālās paskaidrojošās piezīmes un angļu valodas saīsinājumu atšifrējums

University Impact on Power Supply Economy, Reliability and Sustainability Enhancement Decreasing Climate Changes

Research in prior scientific areas carried out by Riga Technical university (RTU), in general, and the Institute of Power Engineering as part of the University is of vital importance not only for the development of industry and national economy but is also a significant part of the education and training of young professionals for the Latvian power system and for engineering, design and construction companies. New challenges in the energy and power engineering field as well as economic and political changes in the Baltic countries have revealed a need for educational program refinement and academics requalification. To perform these changes effectively, proper formation of the research project portfolio as well as bids of the Latvian and European industry have been taken into account. The paper describes the most important achieved scientific and practical results. To solve a wide range of complex tasks and to ensure excellence of scientific research, a virtual research laboratory has been created; a brief description of the laboratory is given in the paper

Modeling of Water Utilization in Hydroelectric Power Plants on the Daugava River

In this paper the task of modeling water utilization in the hydroelectric power plants on the Daugava River is outlined. Difficulties caused by the complexity of the task are discussed and the necessity to decompose it is considered. Unit commitment proves to be especially important subtask as it introduces several constraints and limitations. A possibility to solve it using dynamic programming approach has been offered and the veracity of the mathematical model of reservoirs has been tested in this paper