Demand side management in the distribution system with photovoltaic generation

Posljednjih godina učinjen je znatan napor na uključivanju obnovljivih izvora električne energije u elektroenergetski sustav. Nepredvidiva prozvodnja obnovljivih izvora električne energije stvara neravnotežu između proizvodnje i potrošnje, što onda zahtijeva elektrane s brzim odzivom, ili sustave skladištenja električne energije. Opće prihvaćeno rješenje za uravnoteženje potrošnje je koncept naprednih mreža, a jedan od elemenata učinkovitosti naprednih mreža je sposobnost za uravnoteženje potražnje i opskrbe u stvarnom vremenu. U ovom radu razvijen je model dijela distribucijske mreže grada Osijeka i to na temelju rezultata mjerenja ukupne potrošnje obiteljske kuće u Osijeku, potrošnje klimatizacijskog uređaja te proizvodnje fotonaponske elektrane. Također, predložen je algoritam za upravljanje potražnjom u stvarnom vremenu. Algoritam sadrži usklađeno upravljanje klimatizacijskim uređajima ovisno o proizvodnji fotonaponskih elektrana te o potrošnji u distribucijskoj mreži, a u cilju snižavanja vršne potražnje u distribucijskoj mreži.Recently, there has been made a great effort to include electricity generation from the renewable energy sources into the power system. Random renewable generation creates the imbalance between electricity production and consumption, which requires power plants with fast response or energy storage systems. Generally accepted solution for load balancing is the concept of smart grids and one of the elements of smart grid efficiency is the ability of real-time demand-supply balancing. In this paper, the model of the part of power distribution network of the city of Osijek has been created based on results of the power measurements of total electricity consumption in a family house in Osijek, air conditioning system consumption and PV power plant production. Also, algorithm for real-time load management is proposed. It assumes coordinated control of air conditioning system units depending on the production of PV power plants and electricity consumption of distribution network, in order to reduce peak demand in the distribution network

Review of Non-Traditional Optimization Methods for Allocation of Distributed Generation and Energy Storage in Distribution System

The integration of distributed energy sources transforms passive distributed grid, in which the energy flows only in one direction (from the source to the consumer), in an active one, in which energy flows in both directions. To maximize positive impacts, which distributed generation (DG) can provide to the distribution network, it is necessary to determine the optimal allocation of distributed generation. The optimal allocation can be determined by using the optimization method. There are two main categories: exact methods (traditional) and heuristic (non-traditional) methods. Exact methods search for global optimum while heuristic methods achieve satisfactory solutions with greater computation speed. This paper gives a brief review of non-traditional methods used for determining optimal location and optimal power of DG with the aim to reduce real power losses and to improve voltage characteristics. Also, there is a review of the application of those methods in determining the optimal power, optimal location and optimal cycle of charging/discharging of electrical energy storage systems

Voltage Optimization in PV-Rich Distribution Networks—A Review

There is a rising trend to integrate different types of distributed generation (DG), especially photovoltaic (PV) systems, on the roofs of existing consumers, who then become prosumers. One of the prosumer impacts is voltage violations, which conventional strategies find hard to solve. However, some prosumers, such as those with PV with inverters in their configurations, can actively participate in voltage optimization. To help find the optimal PV inverter setting with the objective of voltage optimization, an optimal power flow (OPF) can be a promising and reliable tool. This paper tries to shed light on the complex problem of voltage optimization in distribution networks (DNs) with PV prosumers. Relevant scientific papers are analyzed and optimization characteristics such as objective functions, variables, and constraints are summarized. Special attention is given to the systematization and classification of papers according to the mathematical formulation of the optimization problem (linear, nonlinear, integer, etc.) and the applied solving methods. Both analytical and computational intelligence optimization methods as well as their advantages and limitations are considered. Papers are also categorized according to the distribution network model used for testing the developed solutions

Voltage Optimization in PV-Rich Distribution Networks—A Review

There is a rising trend to integrate different types of distributed generation (DG), especially photovoltaic (PV) systems, on the roofs of existing consumers, who then become prosumers. One of the prosumer impacts is voltage violations, which conventional strategies find hard to solve. However, some prosumers, such as those with PV with inverters in their configurations, can actively participate in voltage optimization. To help find the optimal PV inverter setting with the objective of voltage optimization, an optimal power flow (OPF) can be a promising and reliable tool. This paper tries to shed light on the complex problem of voltage optimization in distribution networks (DNs) with PV prosumers. Relevant scientific papers are analyzed and optimization characteristics such as objective functions, variables, and constraints are summarized. Special attention is given to the systematization and classification of papers according to the mathematical formulation of the optimization problem (linear, nonlinear, integer, etc.) and the applied solving methods. Both analytical and computational intelligence optimization methods as well as their advantages and limitations are considered. Papers are also categorized according to the distribution network model used for testing the developed solutions

Optimal Re-Dispatching of Cascaded Hydropower Plants Using Quadratic Programming and Chance-Constrained Programming

Stochastic production from wind power plants imposes additional uncertainty in power system operation. It can cause problems in load and generation balancing in the power system and can also cause congestion in the transmission network. This paper deals with the problems of congestion in the transmission network, which are caused by the production of wind power plants. An optimization model for corrective congestion management is developed. Congestions are relieved by re-dispatching several cascaded hydropower plants. Optimization methodology covers the optimization period of one day divided into the 24 segments for each hour. The developed optimization methodology consists of two optimization stages. The objective of the first optimization stage is to obtain an optimal day-ahead dispatch plan of the hydropower plants that maximizes profit from selling energy to the day-ahead electricity market. If such a dispatch plan, together with the wind power plant production, causes congestion in the transmission network, the second optimization stage is started. The objective of the second optimization stage is the minimization of the re-dispatching of cascaded hydropower plants in order to avoid possible congestion. The concept of chance-constrained programming is used in order to consider uncertain wind power production. The first optimization stage is defined as a mixed-integer linear programming problem and the second optimization stage is defined as a quadratic programming (QP) problem, in combination with chance-constrained programming. The developed optimization model is tested and verified using the model of a real-life power system

Determining the Optimal Location and Number of Voltage Dip Monitoring Devices Using the Binary Bat Algorithm

Voltage dips represent a significant power quality problem. The main cause of voltage dips and short-term interruptions is an electrical short circuit that occurs in transmission or distribution networks. Faults in the power system are stochastic by nature and the main cause of voltage dips. As faults in the transmission system can affect more customers than faults in the distribution system, to reduce the number of dips, it is not enough to invest in a small part of the transmission or distribution system. Only targeted investment in the whole (or a large part of the) power system will reduce voltage dips. Therefore, monitoring parts of the power system is very important. The ideal solution would be to cover the entire system so that a power quality (PQ) monitor is installed on each bus, but this method is not economically justified. This paper presents an advanced method for determining the optimal location and the optimal number of voltage dip measuring devices. The proposed algorithm uses a monitor reach area matrix created by short-circuit simulations, and the coefficient of the exposed area. Single-phase and three-phase short circuits are simulated in DIgSILENT software on the IEEE 39 bus test system, using international standard IEC 60909. After determining the monitor reach area matrix of all potential monitor positions, the binary bat algorithm with a coefficient of the exposed area of the system bus is used to minimize the proposed objective function, i.e., to determine the optimal location and number of measuring devices. Performance of the binary bat algorithm is compared to the mixed-integer linear programming algorithm solved by using the GNU Linear Programming Kit (GLPK)

International Scientific Conference ''Organization and Maintenance Technology'' - OTO 2019 : Conference Proceedings of the 28th International Scientific Conference ''Organization and Maintenance Technology''

Organizacija i tehnologije održavanja 2019. odvija se pod okriljem Panon-a, Instituta za strateške studije - Osijek, Fakulteta elektrotehnike, računarstva i informacijskih tehnologija - Osijek, Građevinskog i arhitektonski fakultet - Osijek i Centara kompetencija d.o.o. za istraživanje i razvoj - Vinkovci. Od prvog skupa ''Organizacija održavanja u novim uvjetima'' održanog 20. travnja 1990. na Elektrotehničkom fakultetu Osijek održano je još 29 skupova u jedanaest različitih gradova Slavonije i Baranje. Kontinuirani rad odraz je potrebe za dijalogom i razmjenom iskustava na području održavanja kojim se promiče razvoj tehnike i znanosti. Dosadašnja iskustva kroz 522 prezentiranih i publiciranih radova ukazuju na pad zastupljenosti radova autora strojarske struke, najviše radova autora elektrotehničke, a zatim građevinske, ekonomske, poljoprivredne i prehrambeno tehnološke struke. Udio autora koji su zaposleni na tehničkim fakultetima Sveučilišta J.J. Strossmayera značajno dominira u ukupnom broju radova. Potreba visokoobrazovanog kadra koji danas bavi održavanjem za cjeloživotnim obrazovanjem nameće potrebu daljnjeg razvoja skupova OTO prema znanstvenoj izvrsnosti. Znanstveno stručni skupovi OTO predstavljaju priliku za neposrednu razmjenu iskustava stručnjaka iz svih područja održavanja s ciljem istraživanja i analize primjene novih metoda i postupaka. Skup nastoji podići razinu znanja o održavanju uzimajući u obzir kontinuirani napredak tehnike i tehnologije u svim sferama gospodarstva, infrastrukture i javnih službi. Dvadeset osmi međunarodni znanstveno stručni skup Organizacija i Tehnologija Održavanja kolokvijalno OTO 2019 održan je 12. 12. 2019. godina u Vinkovcima u organizaciji Panon-a – Institut za strateške studije - Osijek, Fakulteta elektrotehnike, računarstva i informacijskih tehnologija - Osijek, Građevinskog i arhitektonski fakultet - Osijek i Centara kompetencija d.o.o. za istraživanje i razvoj - Vinkovci. Službeni jezici Skupa su hrvatski i engleski. Odabrani radovi prezentirani na OTO 2019 će biti pozvani za objavu u proširenom obliku u časopisima: Electronic Journal of the Faculty of Civil Engineering Osijek e-GFOS (http://e- gfos.gfos.hr), International Journal of Electrical and Computer Engineering Systems (www.etfos.unios.hr/ijeces/) i Journal of Energy (http://journalofenergy.com/). Zbornik sadrži 25 recenziranih radova