Search results for "landed"

Frequency constrained optimal Power Flow based on Glow-worm Swarm Optimization in Islanded Microgrids

2015

This work presents an application of a swarm optimization method to solve the optimal power flow problem taking into account the constraints of frequency and line ampacity in three-phase islanded Microgrids. Each generation unit is equipped with a Power Electronics Interface. In the considered formulation, the droop control parameters are considered as variables to be adjusted by a higher control level, while the frequency is kept in rated bounds. Another typical constraint for OPF formulation, the max ampacity of each line, is also considered. Two case studies with different dimensions and electrical features have been considered and the obtained results show the efficiency of the proposed…

Nonlinear droop control for minimum power losses operation in islanded microgrids

2017

In this work, a modified primary regulation technique is proposed to control one of the inverter interfaced units feeding an islanded microgrid. The proposed approach employs an off-line minimum losses Optimal Power Flow, OPF, to extract a lookup table for the composition of the droop curve. Simulations prove that generators reach an operating point that corresponds to a minimum loss operation for the relevant power flow distribution. Since OPF has been implemented with frequency and voltage dependent models, the results of the modified droop are stable and also energy efficient. Further studies will address further analysis on systems showing different R/X ratio and modeling of more genera…

Abuso del diritto e diritto penale: un pericoloso ossimoro.

2020

L’articolo tratta del delicato e complesso concetto di abuso del diritto, nato nel campo del diritto civile e poi approdato in sede penale nel settore del diritto penale tributario. Nell’articolo si ritiene che tale nozione non è compatibile con i princìpi fondamentali del diritto penale italiano e che, pertanto, non vi dovrebbe avere ingresso.

A parametric study on unbalanced three phase islanded microgrids with inverter interfaced units

2013

In this paper, the solution of the power flow for unbalanced three phase microgrids systems is proposed. The study aims at the integration of inverter interfaced units using the control law used for primary voltage and frequency regulation, so as to take into account possible small variations of these parameters to account for sudden load changes. The proposed study deals with unbalanced systems which is the typical case of small distribution systems and shows how the power losses term varies as the regulators parameters vary as well, thus showing that these are sensitive parameters that could have an important role in optimal management of such systems.

Józef Wacław Dąbrowski (1797–1862). Wołynianin w armii Królestwa Polskiego

2021

W artykule, w oparciu o nieznane i tym samym niewykorzystywane dotąd przez historyków wspomnienia, przedstawione zostały dzieciństwo i młodość Józefa Wacława Dąbrowskiego, oficera wojska Królestwa Polskiego, dowódcę w randze kapitana i majora oddziałów powstańczych jesienią 1830 – latem 1831 r. Koleje jego losów i kariera wojskowa są tak typowe, jak i odbiegające od znanych i omawianych w literaturze przedmiotu schematów. Typowe, gdyż dzięki wywodzeniu się z kręgów średnio zamożnego ziemiaństwa rozpoczął służbę wojskową od stopnia kadeta, aby przed upływem roku awansować na podchorążego i uzyskać skierowanie do szkoły podchorążych, stanowiącej niezbędny etap służby potrzebny do awansu ofice…

Vidzemes Lielais Zviedru Kadastrs kā saimniecības vēstures avots

1942

Kadastrs - sistematizēti kādu zemes vai ūdens nogabalu vai citu objektu dati; ar nodokļiem apliekamo zemju saraksts un novērtējums pilsētās un laukos. Zemes kadastru sāka ar zemes uzmērīšanu un vērtēšanu, vienlaikus veicot muižu redukciju, atsavinot lielāko daļu muižas zemju, kuras nodeva Zviedrijas valsts pārziņā. Tas bija labi izstrādāts kadastrs, un to izmantoja no 1691. līdz 1911. gadam, t. i., 220 gadus. Tas pasaulē ir samērā mazpazīstams, un tagadējās Latvijas un Igaunijas teritorijā tam bija tikai lokāla nozīme. Muižu redukcija .17. gs. 2. pusē, pieaugot absolūtisma tendencēm Eiropā, Zviedrijas karalis Kārlis XI (Karl XI) centās nostiprināt varu visā valstī. Viens no pasākumiem bija …

Multi-objective optimized management of electrical energy storage systems in an islanded network with renewable energy sources under different design…

2014

The subject addressed in this paper is the definition of some strategies for the design and the optimaized management of EES (Electrical Energy Storage) systems, for an existing islanded distribution network supplying the Island of Pantelleria (Italy) in the Mediterranean Sea. In the paper the authors have drawn interesting conclusions through the application of an efficient MO (multi-objective) optimization algorithm, the NSGA-II, minimizing the energy losses in the grid, the total electricity generation cost and the greenhouse gas emissions. The results obtained for different installation scenarios of the EES are presented and discussed, putting into evidence the technical, environmental …

INVERTER-BASED DISTRIBUTED GENERATORS, MODELING AND CONTROL

In the last few years, electrical power generation is moving from a centralized generation towards distributed generation including on-site Renewable Energy Sources (RESs). In order to overcome RES related issues, as intermittent and fluctuating power, storage elements are included in the on-site generation system. The interaction between distributed generator (DG) units including RES, storage and front-end power converters should be carefully modeled in order to analyze the power system stability. An accurate modeling of DGs is required. In this thesis, a new modeling approach has been proposed for the inverter-based DGs based on the concept of electrostatic synchronous machines. Detailed …

A distributed minimum losses optimal power flow for islanded microgrids

2017

Abstract In this work, the minimum losses optimal power dispatch problem for islanded microgrids with distributed energy resources (DER) is solved by means of a distributed heuristic approach. Optimal power management is performed almost in real time, with a predefined schedule, i.e. every 5 min, and the solution is applied to generators when the current operating solution violates voltage or current constraints or when the current configuration produces too large power losses. The operating point of both inverter-interfaced generation units as well as rotating production systems can be modified simply using local information. The latter are voltage measurements and power injections or load…

Obraz życia ziemiaństwa rosyjskiego w świetle wspomnień Zofii Kowalewskiej

2017

Artykuł przedstawia obraz życia ziemiaństwa rosyjskiego w latach 60. XIX wieku na przykładzie Wspomnień z dzieciństwa Zofii Kowalewskiej (1850-1891), wybitnej rosyjskiej matematyczki, utalentowanej pisarki i publicystyki. Autorka zapisków okres dzieciństwa i wczesnej młodości spędziła na obrzeżach imperium carskiego, w rodzinnym majątku Palibino. We wspomnieniach memuarystka ukazuje przede wszystkim środowisko, z którego się wywodzi, prezentuje sposób wychowania i kształcenia szlacheckich dzieci, charakteryzuje atmosferę domu rodzinnego, przedstawia formy spędzania czasu wolnego, spośród których najważniejsze to: czytanie książek zgromadzonych w domowej bibliotece, spotkania towarzyskie ora…