Features of development of electric power industry of Ukraine from the point of view of the formation of the perspective structure of generating capacities of UES of Ukraine and development of renewable energy sources (RES) are characterized. In the analysis of the problem of introduction of RES in the energy system of our country and the use of advanced tariff systems, three levels are identified: the highest level - the UES of Ukraine; middle level – regional energy companies; lower-level - local energy supply systems. It is shown that the study of choosing a strategy for better implementation of dynamic electricity prices, as well as trends in business models for local electricity markets with a combination of physical, communication, information, and business levels are relevant. The peculiarities of Microgrid development as a basic element of the functioning of local electricity markets under the condition of formation of optimal modes of generation and consumption of electricity using dynamic charging, which can provide a significant part of imbalance compensation due to the widespread introduction of RES. The article considers the formation of dynamic prices at the level of local power systems (Microgrid), which have features of both the operation and implementation of business models. The elements of the business model for the local electricity market, which is proposed for the sole owner of all generators and consumers, are analyzed when Microgrid is considered as an independent element of the local market, where a dynamic balance between supply and demand. It is determined that at the level of local energy supply systems charging must be based on dynamic models that will take into account the dynamic nature of generation and regulation of electricity consumption in the system and stimulate appropriate desired actions by the consumer. It is proposed to use the tariff calculation not for the time interval, but for the state, as well as to control the optimal levels of generation and consumption of electricity to use the reference tariff and the formation of reference profiles of generation and consumption of electricity. Modified Frieze reactive power was used to estimate the discrepancy between current and optimal power regimes. References 37, table 1.

No abstract

No abstract

In the energy balancing system of distributed generation systems with RES (renewable energy sources), in particular with wind turbines, the effective use of the battery of the balancing system depends on the charge-discharge modes that are implemented. To be effectively used in an energy balancing system, the RES control system should coordinate the processes of energy generation and accumulation in the system through the implementation of operational management with forecasting. Depending on the characteristics of the battery and the accuracy of the measurement or prediction of the energy the battery capacity (or the number of batteries) that will provide the specified control range (controlled operation area) needs to be chosen. Empirical relations (equations) devoted to the dependence of the battery capacity on the discharge current and to the change of voltage at the terminals of the battery during direct current discharge were listed. Among the equations Peukert’s law was chosen. A general view of the dependence of the battery capacity on the discharge current was shown. The formula for Peukert's constant (coefficient) was given. 5 Packert's law limitations were listed including the fact that the effect of temperature on the battery is not taken into account. The influence of depth charge-discharge and the number of discharge cycles on the capacitance was shown. In the process of using the battery and increasing the number of charge-discharge cycles, the capacity decreases. Peukert’s formula was extended to be influenced by temperature: both the Peukert’s capacity and the Peukert’s coefficient depend on the temperature because the Peukert’s coefficient depends on the capacity. For further calculations, a rechargeable battery HZB12-180FA from manufacturer HAZE Battery Campany Ltd was chosen. The temperature was taken into account by empirical dependences from the manufacturer and then they were approximated by 3rd order polynomials. Graphical results of the approximation were shown. The formula of dependency between the power of the wind turbine and the wind speed was shown. The connection between wind speed prediction error, amount of power that could not be obtained because of that and the number of batteries that would provide the specified control range (controlled operation area) was shown. Thus, for calculation of the number of batteries the depth of discharge, temperature and prediction (measurement) error were taken into account. Example dependences of the number of batteries on the wind speed error at temperatures of -20 °C, 0 °C and 20 °C were shown. Curves of dependence of the number of batteries of the balancing system on the ambient temperature and the error of wind speed forecasting was constructed. As an example, when the prediction error increases from 10% to 15%, the number of batteries needs to be increased by 1.17 times, and when the temperature decreases from 20 °C to 0 °C, the number of batteries needs to be increased by 1.48 times. The results of the work can be used at the stage of planning the wind turbine when choosing the number and capacity of the batteries to be installed. Possible areas of further research are using Peukert's formulas, generalized for other or different types of batteries, using other formulas, except for Peukert’s one, for taking into account the dependence of battery capacity on discharge current, using a non-empirical approach to include dependency on temperature.

Formulas for calculating the process of energy change, taking into account its random nature, in the space of two and three variables in distributed systems are given. A graph of a discrete mapping of the energy change process and a Lameri diagram are presented to investigate the stability of this process. It is noted that due to the stochastic nature of the energy change process, the system can leave the steady-state zone. The method of finding the differential of a random process with the Wiener component according to the Ito formula is presented. The technique of applying the law of the iterated logarithm to the Wiener process is presented, and graphs of its typical trajectories are shown both at the entire observation interval and around zero. The necessity of application in distributed generation systems the energy storage for ensuring their stable operation is substantiated. References 11, figures 8.