scholarly journals Obtaining Probability Distribution Laws of Power System Steady-State Mode Parameters

Stable operation of electrical power systems is one of the crucial issues in the power industry. Current vo­lumes of electricity consumption cause the need to constantly increase the generated capacity, repeatedly modifying and complicating the original circuit. In addition to this, given the current trend towards the use of digital power systems and renewable energy sources, more and more uncertainties difficult to predict by standard mathematical methods appear. Events in the power system are deterministic, i.e. random. Thus, it is difficult to fully assess the system stability, voltage levels, currents, or possible power losses. Finding the probability distribution laws can give us an understanding of all the possible states in which an object can exist. Obtaining them is complicated by the difficulty of accounting for all the correlations between the random arguments of the source data. These laws are necessary to determine the optimal operating modes, the possibility of solving the problem of determining the optimal renewable energy sources installation locations and the required amount of generated energy in a non-deterministic way. The purpose of this article is to test the developed SIBD method for obtaining the full probabilistic characteristics. This method, unlike the Monte Carlo methods, does not use a random sample of initial data, but completely covers the studied functional dependence. The problem was solved using the provisions of probability theory and mathematical statistics, numerical optimization methods in particular. The MATLAB Matpower application package was also used to solve technical computing problems.

Author(s):  
Jianqiang Luo ◽  
Yiqing Zou ◽  
Siqi Bu

Various renewable energy sources such as wind power and photovoltaic (PV) have been increasingly integrated into the power system through power electronic converters in recent years. However, power electronic converter-driven stability issues under specific circumstances, for instance, modal resonances might deteriorate the dynamic performance of the power systems or even threaten the overall stability. In this paper, the integration impact of a hybrid renewable energy source (HRES) system on modal interaction and converter-driven stability is investigated in an IEEE 16-machine 68-bus power system. Firstly, an HRES system is introduced, which consists of full converter-based wind power generation (FCWG) and full converter-based photovoltaic generation (FCPV). The equivalent dynamic models of FCWG and FCPV are then established, followed by the linearized state-space modeling. On this basis, converter-driven stability analyses are performed to reveal the modal resonance mechanisms of the interconnected power systems and the modal interaction phenomenon. Additionally, time-domain simulations are conducted to verify effectiveness of dynamic models and support the converter-driven stability analysis results. To avoid detrimental modal resonances, an optimization strategy is further proposed by retuning the controller parameters of the HRES system. The overall results demonstrate the modal interaction effect between external AC power system and the HRES system and its various impacts on converter-driven stability.


2018 ◽  
Vol 55 (2) ◽  
pp. 3-10
Author(s):  
A. Obushevs ◽  
A. Mutule

Abstract The paper focuses on the application of synchrophasor measurements that present unprecedented benefits compared to SCADA systems in order to facilitate the successful transformation of the Nordic-Baltic-and-European electric power system to operate with large amounts of renewable energy sources and improve situational awareness of the power system. The article describes new functionalities of visualisation tools to estimate a grid inertia level in real time with monitoring results between Nordic and Baltic power systems.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1047
Author(s):  
Ninoslav Holjevac ◽  
Tomislav Baškarad ◽  
Josip Đaković ◽  
Matej Krpan ◽  
Matija Zidar ◽  
...  

This paper presents a high-level overview of the integration of renewable energy sources (RES), primarily wind and solar, into the electric power system (EPS) in Croatia. It presents transmission system integration aspects for the particular case of this country. It explains the current situation and technical characteristics of the current conventional generation units and currently installed wind energy capacities. Based on the current situation future development scenario is determined and used to evaluate the impacts of the wide-scale integration of renewables. Grid connections aspects, power balancing, market participation, and inertia reduction aspects are considered. Furthermore, some specifics of both solar and wind integration are discussed identifying problems and potential solutions. Primarily through the provision of the inertial response of both solar and wind and through better forecasting of wind production. Finally, the outlook for the Croatian power system is given, that will most probably double its RES capacity in the coming 3-year period and a certain level of investments and changes of current operational practices will need to be provided.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2193
Author(s):  
Mateusz Szablicki ◽  
Piotr Rzepka ◽  
Adrian Halinka

This publication discusses the risks of further use of classical overcurrent protections in modern power systems. The increasing penetration of renewable energy sources has caused a lot of challenges, among other things, the development of energy communities that balance local generation and consumption. Usually the interconnection line between the energy community and power systems are only used to balance the shortage or overflow of energy. As a result, most of the time these connections can be low loaded. Such a state can cause incorrect operation of power system protection approached, because the current level values are smaller than the required activation level for the protections. This article presents the potential incorrect operation of digital power system protection with overcurrent function. The obtained simulation results clearly show that the correctness of protection operation is strongly dependent on the level load of lines and the parameters and structure of the protection decision algorithms. These problems occur during low load line periods because these were not taken into account during the classical digital protection design stage. In the future this can cause problems with the fulfillment of the basic protection requirements of stability, speed, sensitivity. This publication suggests extra problems for power system protection research.


2018 ◽  
Vol 58 ◽  
pp. 01012 ◽  
Author(s):  
Dmitry Krupenev

The paper deals with the problem of the accounting of renewable energy sources and energy storage systems in assessment of power system adequacy. Development of renewable energy sources and energy storage systems in the present day power systems is one of the main focuses. In power systems of some countries the share of electric energy generated by renewable energy sources is above 50 % in the energy balance. Therefore, the plans on development of the present day power systems must be elaborated with the proper accounting of operation of renewable energy sources and energy storage systems and the sound capacity reserves in terms of these facilities. The paper presents the algorithms for the accounting of renewable energy sources and energy storage systems. The experimental studies performed illustrate feasibility of the suggested algorithms.


The need for Interconnected power system is increasing day by day because of continuous growth of Electrical energy demand and to transmit Electric power to remote places at minimum cost and minimum losses. With the operation of power system in interconnected manner, maintaining the system security is difficult task i.e. whenever a disturbance occurs, the system undergoes stability problems. Even though Conventional energy sources are available, Electrical Engineers prefer Renewable energy sources integration because of Energy crisis and pollution problems related to the former, one such Renewable energy source is Wind power. Wind energy has major share in Renewable energy sources because of its abundant availability in the nature. Whenever Wind generators coupled to the power system, the system exhibits drooping voltage characteristics and this situation becomes worse during faults. This condition can be neutralised with FACTS (Flexible AC transmission system) devices, one such FACTS device is STATCOM (static synchronous compensator). STATCOMsupports reactive and real power exchange and also improves Transient stability of the system because of its superior characteristics and quick response. In this paper a 9 bus Wind farm integrated test power system is taken and stability studies are done. Since, Wind farm is integrated with the system whenever a fault occurs, overall system stability is reduced i.e. the conventional synchronous generators can withstand it, whereas the Wind generators can’t. So to enhance the Transient stability of the system, a STATCOM is installed and the system behaviour is observed.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4290
Author(s):  
Jianqiang Luo ◽  
Yiqing Zou ◽  
Siqi Bu ◽  
Ulas Karaagac

Renewable energy sources such as wind power and photovoltaics (PVs) have been increasingly integrated into the power system through power electronic converters in recent years. However, power electronic converter-driven stability has issues under specific circumstances, for instance, modal resonances might deteriorate the dynamic performance of the power systems or even threaten the overall stability. In this work, the integration impact of a hybrid renewable energy source (HRES) system on modal interaction and converter-driven stability was investigated in an IEEE 16-machine 68-bus power system. In this paper, firstly, an HRES system is introduced, which consists of full converter-based wind power generation (FCWG) and full converter-based photovoltaic generation (FCPV). The equivalent dynamic models of FCWG and FCPV are then established, followed by linearized state-space modeling. On this basis, converter-driven stability analysis was performed to reveal the modal resonance mechanisms between different renewable energy sources (RESs) and weak grids in the interconnected power systems and the multi-modal interaction phenomenon. Additionally, time-domain simulations were conducted to verify the effectiveness of dynamic models and support the converter-driven stability analysis results. To avoid detrimental modal resonances, a multi-modal and multi-parametric optimization strategy is further proposed by retuning the controller parameters of the multi-RESs in the HRES system. The overall results demonstrate the modal interaction effect between the external AC power system and the HRES system and its various impacts on converter-driven stability.


Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6082
Author(s):  
Changgun Lee ◽  
Seunghyuk Im ◽  
Jaeyeop Jung ◽  
Byongjun Lee

Renewable energy curtailment often occurs to accommodate large amounts of renewable energy sources in power systems while maintaining system stability and reliability. Widely known methods, such as new transmission line construction, the introduction of demand-side resources, and the reduction of conventional generator output, can minimize the occurrence of curtailment; however, there are difficulties in introducing them because of social and economic problems. For these problems, the Jeju power system adopted a battery energy storage system (BESS) resource to mitigate the curtailment and secure frequency stability with the high penetration of renewable energy. The small-size Jeju island power system is operated with reliability must-run (RMR) units and high-voltage direct current (HVDC) lines connected to the mainland. Since the number of RMR units contributes to frequency stability by providing inertia, reducing the number of operating units for curtailment mitigation is difficult. Therefore, in this paper, based on the current “Carbon-Free island” policy and operation plan of the Jeju power system, we proposed a BESS for reducing the number of RMR units, observe the effect of reducing curtailment using the BESS, and suggest a practical operation plan to reduce the number of RMR units under conditions that secure frequency stability.


2021 ◽  
Author(s):  
Vinay Kumar Tatikayala ◽  
Shishir Dixit

Abstract The concern for huge increasing electricity demand, fossil fuel depletion, developed infrastructure reliability, carbon footprint reduction insisted the power utility companies to uptake RES (Renewable Energy Sources). The improved adoption of RES like wind energy and solar energy into the prevailing transmission and distribution networks led to several problems. These problems could be rectified by optimizing the power system parameters like frequency response, inertia, stability, battery usage, efficiency and power loss. This review hence provide a comprehensive analysis on the impact of renewable energy sources like wind and solar energy on power system operation and control in accordance with the major findings of the existing works. This review highlights the difficulties in the installation of solar and wind power with adoptable solutions. The challenges of power systems regarding the encoding of non-linearized function could be rectified by AI (Artificial Intelligence). The paper also insists the importance of artificial intelligence algorithm in the optimization of power system parameters. Artificial intelligence methods is useful for resolving various issues in power systems such as control, scheduling, forecasting etc. Few artificial algorithms such as Atom search optimization, Particle swarm optimization, Salp swarm optimization were investigated in this review for improving the performance of the power system. In spite of optimization analysis, the paper investigate various storage system types for improving the power system in accordance with cost, application and operation characteristics. Proper understanding of these systems is necessary for the future designing and hence through revision of state of art characteristics has been performed in this paper.


2021 ◽  
Author(s):  
Guilherme Penha da Silva Júnior ◽  
Thiago Figueiredo do Nascimento ◽  
Luciano Sales Barros

The high integration of distributed generation (DG) system based on renewable energy sources (RES) in the power system requires changes regarding the control mode of these sources with some urgency. Such changes seek to maintain the stability of the power systems. Thus, there is a demand for using control techniques on DGs/RESs that can mitigate the disturbances caused by low inertia and the lack of control over the dispatched powers. As a solution, one can use virtual synchronous generator (VSG) techniques making the voltage  source inverter (VSI) control behave similarly to the traditional synchronous generator (SG). This paper presents a literature review and performance tests for the main VSG topologies used in DGs/RESs: ISE, VSYNC, VISMA and Synchronverter. The implementation of VSG in the DGs/RESs has made possible increase inertia in the grid and, additionally regulate the active and reactive powers separately and bidirectionally. So, it has been possible to meet power system requirements; being able to operation both grid-connected or island-mode, which is ideal for microgrids. The results obtained confirm the literature reports. It was observed that the Synchronverter topology presented advantages over the other VSG topologies.


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