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The rapid growth of renewable energy capacity, in particular photovoltaic systems, is creating challenges associated with changing the rate of transient processes in the power system. This is due to the approach PV systems are connected to the grid using power converters and the absence of a rotating mass in the PV power plant. One of the most pressing challenge is the participation of PV stations in the process of frequency control in power systems, including in emergency modes. Simultaneously with PV power plants, it is efficient to use energy storage systems, including hydrogen ones. This is due to the fact that it is possible to obtain hydrogen for such energy storage systems using excess energy from PV power plants. The article proposes to solve the problem of frequency regulation in the power system by using an algorithm that allows to control the frequency in the power system using a synthetic inertia block of PV station, including at different levels of insolation and temperature of PV panels. The robustness of the proposed algorithm allows it to be used at different levels of power generated by the PV station, as well as in emergency modes. [ABSTRACT FROM AUTHOR]

The most important hydrogen energy storage technologies, developed between 1974 and 2022, now enable the quality operation of global power grids that integrate alternative energy facilities (wind power, solar power, geothermal power, etc.). With the continuous large-scale penetration of converter-interfaced generation (CIG), based on the combined use of renewable energy sources (RES) and hydrogen energy storage systems (ESS), into practical power systems, the dynamic characteristics of the latter change significantly. New challenges with the power system control and stability arise due to the specific CIG properties. A positive-sequence time-domain simulation is frequently used to solve them. However, the known simplifications and limitations are inevitably applied in case of such simulation. These become critical for the CIG with RES and hydrogen ESS models due to their fast dynamics. Therefore, the validation of such simulation results becomes relevant. This paper proposes a novel validation approach based on the use of a benchmark tool Hybrid Real-Time Power System Simulator (HRTSim) instead of field measurements. A major feature of the proposed approach is the possibility of a guaranteed validation of the benchmark tool using any state of the modeled power system. A hybrid implementation of a detailed three-phase model of CIG is also developed for the HRTSim, which provides an adequate simulation of the full range of dynamic processes. The results of validation of a positive-sequence simulation of a practical power system with CIG, which includes both RES and hydrogen ESS, using the developed approach presented in this paper have allowed to identify the causes of calculation errors, as well as factors affecting them. [ABSTRACT FROM AUTHOR]

In modern converter-dominated power systems, total inertia is very variable and depends on the share of power generated by renewable-based converter-interfaced generation (CIG) at each specific moment. As a result, the limits required by the grid codes on the rate of change of frequency and its nadir or zenith during disturbances become challenging to achieve with conventional control approaches. Therefore, the transition to a novel control strategy of CIG with a grid-forming power converter is relevant. For this purpose, a control algorithm based on a virtual synchronous generator (VSG) is used, which simulates the properties and capabilities of a conventional synchronous generation. However, due to continuously changing operating conditions in converter-dominated power systems, the virtual inertia formed by VSG must be adaptive. At the same time, the efficiency of adaptive algorithms strongly depends on the used VSG structure. In this connection, this paper proposes an enhanced VSG structure for which the transfer function of the active power control loop was formed. With the help of it, the advantages over the conventional VSG structure were proven, which are necessary for the effective adaptive control of the VSG parameters. Then, the analysis of the impact of the VSG parameters on the dynamic response using the transient characteristics in the time domain was performed. Based on the results obtained, adaptive algorithms for independent control of the virtual inertia and the parameters of the VSG damper winding were developed. The performed mathematical modeling confirmed the reliable and effective operation of the developed adaptive control algorithms and the enhanced VSG structure. The theoretical and experimental results obtained in this paper indicate the need for simultaneous development and improvement of both adaptive control algorithms and VSG structures used for this purpose. [ABSTRACT FROM AUTHOR]

Integration of wind generation units around the world is a promising solution to the energy crisis. In power systems with a predominant share of wind power plants connected through power converters, their influence on the dynamic properties of the power system becomes significant. One of the important problems is reducing the total inertia of the power system. In view of this, transmission system operators place demands on plug-in wind farms to manage active power and participate in frequency support. The proposed solution is the use of synthetic inertia in the control system of wind turbines. Research in this field focuses on improving the frequency stability and coordination of the synthetic inertia controller with other wind turbine control systems. However, the influence of synthetic inertia and its tuning on the stability of the power system are poorly studied. The paper analyzes the effect of synthetic inertia on the transient stability of the power system. It is shown that by adjusting the synthetic inertia parameters, it is possible to provide not only the required inertial response, but also to increase the transient stability of power systems. The influence of the measurement time window and calculation of the rate of change of frequency, which is important under certain modes, is also investigated. The results are obtained for a test scheme and a real-scale power system scheme. [ABSTRACT FROM AUTHOR]

The penetration of renewable-based converter-interfaced generation and flexible alternating current transmission systems significantly changes properties and dynamic characteristics of modern electric power systems, which leads to the need to take measures to ensure security of their operation. These measures may consist in using the capabilities of new penetrated units or in adapting conventional means. Such adaptation consists in reconfiguration of control systems, development of new systems or approaches to settings determination, which include tuning of automatic voltage regulators with power system stabilizers of conventional synchronous generation. This paper proposes a new approach to tuning of automatic voltage regulators, based on the use of the most complete and reliable information about processes in modern power systems. This approach allows to get settings that are most adequate to practical conditions of operation as part of power systems. For this purpose, the hybrid real-time power system simulator and concept of hybrid modeling are used, and within this paper, and the hybrid modeling tools necessary for the tuning process have been developed. The result of the study is a comprehensive assessment of the reliability of the simulation results obtained using the developed tools, which allows to conclude about the possibility of their application. [ABSTRACT FROM AUTHOR]

In case of sharp disturbances in the electric power system (EPS), emerging transients may be accompanied by a loss of synchronism. This incident may lead to cascade-fault severe consequences for the whole EPS. One of such consequences may be the occurrence of an active power overgeneration in one part of the electric power system. In this regard, it is necessary to apply actions to implement targeted effects on transients in EPS. The most technologically and economically advantageous is the use of fast turbine valving control (FTVC). The task of this automation is to maintain the dynamic and static stability of overgenerated area. However, the effectiveness of FTVC is mainly dependent on its control action (CA). Tuning the parameters of FTVC is not a trivial task, because it is necessary to take into account the processes and their mutual influence in the equipment not only directly involved in the FTVC but also in the EPS as a whole. The article shows the results of FTVC action with various CA configuration. The use of complete and reliable mathematical models of equipment not only directly involved in FTVC but also EPS, as well as a tool capable of working with similar types of models, allowed the optimization of FTVC CA parameters. [ABSTRACT FROM AUTHOR]

Currently, the world is widely introducing renewable energy sources including solar power plants (SPP). In order to predict their work, it is necessary to adequately simulate the processes occurring in solar panels, not only in standard conditions, but also in conditions of partial shading. At present, the effect of partial shadowing is considered from the point of view of changes in the luminous flux, however, for a more adequate and comprehensive simulation, it is also necessary to take into account the temperature change in the shaded areas of SPP, especially considering the area of powerful SPP, the temperature of individual sections of which can radically differ, which is undoubtedly will lead to a change in the output characteristics of the SPP. Failure to take this factor into account, when modeling high-power SPP leads to results that do not correspond to real data. [ABSTRACT FROM AUTHOR]

• Increasing the reliability of the EPS probabilistic characteristics is obtained. • The optimization algorithm provides full accounting of probabilistic characteristics. • The optimal WPP capacity and placement with the lowest power losses is determined. Due to the trend of increasing electricity consumption that has observed over the past decades, the sustainable development of electric power systems is a relevant task. Taking into account the desire of the leading countries for energy independence, low-carbon energy based on renewable energy sources is being actively penetrated nowadays. One of the main tasks for the renewable energy sources installation into existing electric power systems with no additional changes in network is to maximize power generation with the lowest power losses and to comply with the grid requirements. Considering the stochastic nature of renewable energy, various optimization algorithms are being developed and used for this task. In this regard, numerical methods of deterministic and probabilistic modeling of power systems with, e.g., wind turbine generators are used to determine the optimal placement and capacity. The main problem is that obtaining a reliable result by actual statistical and heuristic methods, based mostly on a group of Monte Carlo methods, does not have a full solution in the whole range of functional dependence, due to the complexity of modeling the input arguments of rare repeatability. As part of the solution to the optimal power flow problems, namely, not exceeding the specified probability density functions of the state parameters, it can lead to false conclusions. This paper proposes a methodology for calculating the probabilistic characteristics of steady-state parameters, increasing the reliability and speed of their calculation by taking into account the values of rare repeatability. The results of research is the refinement of the power flow values (compared with the Monte Carlo method) using the developed method based on selection of interval boundaries of input and output probabilistic data (SIBD method), and the definition of minimum possible power losses as part of the problem of determining the optimal wind power capacity and placement in power system for IEEE-14 and IEEE-57 schemes. [ABSTRACT FROM AUTHOR]

• The synthesis of the modern VSG models into generic structures is performed. • The comprehensive assessment of the generic VSG structures is carried out. • The most reliable VSG structure for grid-connected operation is highlighted. The large-scale penetration of renewable energy sources has a significant impact on the steady-state operation and emergency control of modern electric power systems (EPS). Moreover, as a rule, the mentioned impact is negative. Therefore, the challenge associated with the development of a 'comprehensive' control strategy for renewables becomes extremely relevant. Such a strategy should ensure the same reliable operation of EPSs, as in the case of conventional synchronous generation. Among the existing directions, the concept of a virtual synchronous generator (VSG) is the most preferable. Within this paper, the synthesis and combination of the state-of-the-art concepts of VSG into generic structures has been performed. For the obtained structures, a comprehensive assessment and an experimental comparison were performed. On the basis of the results obtained, the benefits and drawbacks of the generic structures are highlighted, and a conclusion is made about the VSG structure, demonstrating the most effective and reliable operation. [ABSTRACT FROM AUTHOR]

• Novel approach for relays tuning using detailed mathematical model. • Hybrid Real-Time Power System Simulator is used as a source of necessary data. • Proposed approach allows to adapt protection settings to practical conditions. The correct operation of relay protection (RP) devices largely determines the security of electric power systems (EPS). The key point that in turn determines the behavior of protection in various emergency modes is a determination of their settings. The existing methodologies and tools often do not allow to provide RP settings adequate to the practical conditions of their functioning. This statement is confirmed by the statistics of faults in EPSs. The main reason for this issue is the inability to reliably reproduce transients in EPS via the software programs used in practice to calculate the RP settings. The Hybrid Real-Time Power System Simulator (HRTSim), developed by the authors, allows to reliably reproduce the entire range of normal and emergency modes and processes in EPS of any scale, topology and configuration by using detailed three-phase models of all power system components. Taking into account this possibility and features of the HRTSim, the task of detailed modeling of RP devices, including instrument current and voltage transformers, becomes relevant. The implemented special tools for RP modeling and the HRTSim in general allow to develop a new methodology for RP tuning. At the same time, the typical elements – relays – can be identified for each type of RP that determine their operation algorithm. This paper presents an analysis of the main relays of the most modern microprocessor-based RP devices and proposed principles of their tuning. The developed approach allows to adapt the RP settings to the practical conditions of their functioning in EPSs and to minimize the probability of RP maloperation. [ABSTRACT FROM AUTHOR]