This paper examines the operation of photovoltaic power plants (PVPP) in lightly loaded distribution networks, addressing stability challenges due to voltage and frequency fluctuations. Using DIgSILENT PowerFactory simulations, the study analyzes load profiles and PVPP interactions under low demand conditions. Results indicate that PVPP can induce overvoltage, voltage dips, and reactive power losses, reducing system efficiency. Optimization strategies, including advanced voltage and frequency regulation, are proposed to enhance stability. Findings emphasize the importance of proper PVPP controller tuning for reliable integration of renewables. Future work should explore network digitalization for improved flexibility and resilience.

In order to research the advantages of usage of photovoltaic plants in smart grids, an analysis focused on the impact of photovoltaic systems on the stability and reliability of electrical grids is conducted in this paper. The paper addresses the technical aspects of integrating photovoltaic systems, including their variable production and how it affects the changes in electricity supply and demand in a real distributed power grid. Innovative technologies, such as energy storage devices and advanced communication systems, are also considered, which enable better control and management of the grid. The integration of a photovoltaic plant into a 20 kV network with consumers in the household and industrial categories, as well as an electric vehicle charging station, is analyzed with varying loads. The results obtained highlight the contribution of PV plants to the grid stability, reliability, voltage conditions, and total active and reactive power losses.

The resulting shift in load and generation profiles on the low voltage (LV) network poses new risks for distribution system operators (DSOs), including issues like congestion and power quality. To address these risks, two approaches are considered: traditional grid reinforcement or flexibility services. An emerging solution for harnessing flexibility is the development of local markets. This paper is focused on defining scenarios for testing the local market, considering different network conditions (load profiles, available capacity limits in the lines), different market clearing mechanisms, and bids. The LV network under study is a real Slovenian LV network in Luče, currently featuring 9 flexible households and one community battery, as part of the X-FLEX project (Horizon 2020, grant agreement n°863927). The second part involves testing these scenarios and conducting an analysis of the results, ensuring network constraints compliance through power flow simulation (using OpenDSS), and performing a technical analysis of the market design based on these results.

Energy production is one of the most crucial scientific, technological, economic, and political challenges in today's world. In response to the increasing demands of the European Union for reducing CO2 emissions and mitigating climate change, countries are obligated to align their national energy plans with clearly defined objectives, aiming for climate neutrality by 2050. This paper explores the location potential and optimal implementation of biomass power plants in Bosnia and Herzegovina. Biomass power plants, particularly those utilizing wood and plant biomass, are a promising solution for simultaneously reducing pollution, addressing unnecessary waste, and improving the energy efficiency of the systems where they are installed. The paper concludes that the potential of wood and plant biomass in Bosnia and Herzegovina remains underutilized. From an eco-perspective, the paper will also examine the reuse of large degraded areas in mines, where the fast-growing energy crops like Miscanthus could be planted.

Recognizing the increasing importance of renewable energy sources, specifically wind farms, in today's power environments, this paper aims to clarify the complex interactions between these renewable energy facilities and distribution grids functioning under low-demand conditions. This particular case comes with inherent limitations that must be considered by taking into account all the factors that can influence the performance of the wind farm under these conditions. The modelling procedure and the simulation of the connection of the wind farm to the power system in rural area was performed using EMTP-RV software. The mean annual production of the wind power plant and the behaviour of the wind power plant in the event of failure in a real power system were calculated. Also, the power quality was examined in agreement with the Network Code of the transmission system of Bosnia and Herzegovina.

The contribution of renewable energy sources to the power system stability will have to be greater in the future. The problem will arise if the share of wind power plants in total production increases and large failures occur. Then, wind farms, which are often called inertia-less sources in the literature, will have to help maintain the frequency in a normal amount by changing the management method and based on fast PMU measurements. This can be done by using the synthetic inertia size, which is defined for sources that are derived from the system via energy converters and which do not participate in defining the total inertia of the system. This paper provides a better insight into the understanding of the concept of synthetic inertia, as well as insight into the current development of management and the application of synthetic inertia in maintaining the stability of the power system.

The increase in the number of wind farms and their share in the total electrical energy generation leads to the need for a different approach to this source in cases where the stability of the power system is potentially impaired. With the development of different types of wind power plants, equipped with power electronics devices, there is the possibility of quick power management and injection, in conditions when it is needed, where a huge amount of accumulated kinetic energy can also be used. This paper presents the influence of a wind power plant equipped with a full-scale converter on the transient stability in cases of close and distant short circuits, during the outage of a heavily loaded line. Special attention was paid to the Rate of Change of Frequency (RoCoF) in the power system in cases with and without a wind farm where fast power injections were possible.

Climate problems, the increasingly robust European emissions policy and falling prices of solar and wind have led to the shutdown of many thermal power plants and increased installation of renewable energy power plants. The installed capacity of wind and solar power plants in our country is not yet significant, but small hydropower plants are often considered as a good solution for the power supply to remote areas despite the problems that sometimes arise after the installation of these power plants. This paper describes a power quality problem of high voltages occurs after the installation of a small hydropower plant of 800 kVA in an area with predominantly industrial consumers. Many industries use high technology for manufacturing and require high power quality and reliability of power supply. Even modest power quality problems can have significant technical and economic effects on these consumers. Therefore, it was necessary to precisely monitor power quality to adequately address all related problem recorded during the plant performance test phase. Also, the observed problem has led to power plant outage on several occasions in a short period of time which resulted in a reduction in power generation. Techniques for mitigation the observed power quality issue are also considered in this paper. The implemented solution of the problem is verified by power quality monitoring and SCADA system measurements.

The steady increase in electricity demand has led to more installed generation capacity in wind farms, which, due to the stochastic nature of their production, may have characteristic and non-standard responses to some occurrences in the grid. The power output from the wind farm changes constantly, depending on the wind speed, so the impact of the network on the wind farm will inversely vary depending on the moment of the short circuit and the wind farm operating mode, since the values of currents and voltages in these fault systems depend on the power flows. Although wind power is known to contribute to the short circuit current / power at the point of its connection, this paper focuses on the response of the wind farm to short circuits in the network and the impact of these phenomena on the grid-wind relation. The aim of the paper is to determine the worst type of short circuit for wind turbine operation in the distribution system.