scholarly journals Low Inertia Systems Frequency Variation Reduction with Fine-Tuned Smart Energy Controllers

2021 ◽  
Vol 13 (5) ◽  
pp. 2979
Author(s):  
Minas Patsalides ◽  
Christina N. Papadimitriou ◽  
Venizelos Efthymiou
Keyword(s):  
Control Strategies ◽  
Frequency Variation ◽  
Distribution Grid ◽  
Power Sources ◽  
Variation Reduction ◽  
Renewable Power ◽  
Main Challenge ◽  
Grid Approach ◽  
Need To Evaluate ◽  
The Stability

The distributed and stochastic nature of Renewable Power Sources is certainly forming considerable challenges for the operation of the power system. Specifically, the stability of the system can be jeopardized when the penetration of inverter-based systems is high. Storage and the proper design of controllers is seen as part of the solution for supporting the future expansion of distributed systems. Thus, control strategies need to be designed to provide the appropriate support to the system and be capable of keeping the variation of the frequency within limits to keep the reliability of the system as high as possible. The main challenge is the appropriate parameterization of these distributed controllers and their coordination under the integrated grid approach in securing the stability of the system at all times. In this paper, a smart energy controller is utilized and incorporated into the projection case study for Cyprus’ real distribution grid for the year 2050 to evaluate its behavior and identify possible weaknesses in its usage. It was found that the parameterization and not only the architecture of such controllers is crucial in coping with the frequency variation and stability problem. From the simulation work and recorded results, it was observed that the smart energy controllers can maintain frequency variation within the desirable range when the parametrization of the controllers is chosen appropriately. This specific observation highlights the need to evaluate and configure the smart controllers while operating in the field, and possibly further research is required to provide the advanced capability to such systems to adjust dynamically during field operation, thereby achieving better response during abnormal conditions.

scholarly journals Frequency Domain Stability Assessment of Photovoltaic Power Generation Systems with Quasi-Z-Source Inverters

2021 ◽  
Vol 19 ◽  
pp. 160-165
Author(s):  
Luis Sainz ◽  
◽  
Ll Monjo ◽  
Keyword(s):  
Power Generation ◽  
Frequency Domain ◽  
Stability Assessment ◽  
Power Sources ◽  
Renewable Power ◽  
Photovoltaic Power ◽  
Space Matrix ◽  
The Stability ◽  
Power Generation Systems ◽  
Averaged Model

Photovoltaic power generation systems are one of the main renewable power sources, and quasi-Z-source inverters are becoming powerful devices to integrate these systems in AC grids. However, stability issues due to the damping behaviour of converters must be considered. There are several studies in this direction but instability concerns are not completely solved yet. This paper contributes with a procedure for the stability assessment of photovoltaic power generation systems with quasiZ-source inverters in the frequency domain. The study is based on the small-signal averaged model of the system expressed in the s-domain and the stability criterion derived from the frequency characteristics of the state-space matrix. The influence of the photovoltaic power generation system operating point on stability is studied by the proposed procedure. Eigenvalue analysis and PSCAD/EMTDC simulations are also performed to validate the obtained results.

scholarly journals State-Space Model of Quasi-Z-Source Inverter-PV Systems for Transient Dynamics Studies and Network Stability Assessment

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4150
Author(s):  
Lluís Monjo ◽  
Luis Sainz ◽  
Juan José Mesas ◽  
Joaquín Pedra
Keyword(s):  
Power Systems ◽  
State Space ◽  
State Space Model ◽  
Pv System ◽  
Pv Systems ◽  
Renewable Power ◽  
Ac Networks ◽  
Transient Interactions ◽  
The Stability ◽  
Averaged Model

Photovoltaic (PV) power systems are increasingly being used as renewable power generation sources. Quasi-Z-source inverters (qZSI) are a recent, high-potential technology that can be used to integrate PV power systems into AC networks. Simultaneously, concerns regarding the stability of PV power systems are increasing. Converters reduce the damping of grid-connected converter systems, leading to instability. Several studies have analyzed the stability and dynamics of qZSI, although the characterization of qZSI-PV system dynamics in order to study transient interactions and stability has not yet been properly completed. This paper contributes a small-signal, state-space-averaged model of qZSI-PV systems in order to study these issues. The model is also applied to investigate the stability of PV power systems by analyzing the influence of system parameters. Moreover, solutions to mitigate the instabilities are proposed and the stability is verified using PSCAD time domain simulations.

scholarly journals Power Hardware-in-the-Loop: Response of Power Components in Real-Time Grid Simulation Environment

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 593
Author(s):  
Moiz Muhammad ◽  
Holger Behrends ◽  
Stefan Geißendörfer ◽  
Karsten von Maydell ◽  
Carsten Agert
Keyword(s):  
Real Time ◽  
Power Distribution ◽  
Control Strategies ◽  
Power Grid ◽  
Energy System ◽  
Hardware In The Loop ◽  
Distribution Grid ◽  
Compensation Strategy ◽  
Software Environment ◽  
The Real

With increasing changes in the contemporary energy system, it becomes essential to test the autonomous control strategies for distributed energy resources in a controlled environment to investigate power grid stability. Power hardware-in-the-loop (PHIL) concept is an efficient approach for such evaluations in which a virtually simulated power grid is interfaced to a real hardware device. This strongly coupled software-hardware system introduces obstacles that need attention for smooth operation of the laboratory setup to validate robust control algorithms for decentralized grids. This paper presents a novel methodology and its implementation to develop a test-bench for a real-time PHIL simulation of a typical power distribution grid to study the dynamic behavior of the real power components in connection with the simulated grid. The application of hybrid simulation in a single software environment is realized to model the power grid which obviates the need to simulate the complete grid with a lower discretized sample-time. As an outcome, an environment is established interconnecting the virtual model to the real-world devices. The inaccuracies linked to the power components are examined at length and consequently a suitable compensation strategy is devised to improve the performance of the hardware under test (HUT). Finally, the compensation strategy is also validated through a simulation scenario.

scholarly journals Iterative stability analysis for general polynomial control systems

2021 ◽  
Author(s):  
Bo Xiao ◽  
Hak-Keung Lam ◽  
Zhixiong Zhong
Keyword(s):  
Stability Analysis ◽  
Lyapunov Function ◽  
Control Systems ◽  
Polynomial System ◽  
Stability Conditions ◽  
General Polynomial ◽  
Main Challenge ◽  
Detailed Simulation ◽  
Feasible Solutions ◽  
The Stability

AbstractThe main challenge of the stability analysis for general polynomial control systems is that non-convex terms exist in the stability conditions, which hinders solving the stability conditions numerically. Most approaches in the literature impose constraints on the Lyapunov function candidates or the non-convex related terms to circumvent this problem. Motivated by this difficulty, in this paper, we confront the non-convex problem directly and present an iterative stability analysis to address the long-standing problem in general polynomial control systems. Different from the existing methods, no constraints are imposed on the polynomial Lyapunov function candidates. Therefore, the limitations on the Lyapunov function candidate and non-convex terms are eliminated from the proposed analysis, which makes the proposed method more general than the state-of-the-art. In the proposed approach, the stability for the general polynomial model is analyzed and the original non-convex stability conditions are developed. To solve the non-convex stability conditions through the sum-of-squares programming, the iterative stability analysis is presented. The feasible solutions are verified by the original non-convex stability conditions to guarantee the asymptotic stability of the general polynomial system. The detailed simulation example is provided to verify the effectiveness of the proposed approach. The simulation results show that the proposed approach is more capable to find feasible solutions for the general polynomial control systems when compared with the existing ones.

Chaos Control for a Fractional-Order Jerk System via Time Delay Feedback Controller and Mixed Controller

2021 ◽  
Vol 5 (4) ◽  
pp. 257
Author(s):  
Changjin Xu ◽  
Maoxin Liao ◽  
Peiluan Li ◽  
Lingyun Yao ◽  
Qiwen Qin ◽  
...  
Keyword(s):  
Time Delay ◽  
Fractional Order ◽  
Chaos Control ◽  
Chaotic Behavior ◽  
Control Strategies ◽  
Feedback Controller ◽  
Research Approach ◽  
Controlling Chaos ◽  
The Stability ◽  
Jerk System

In this study, we propose a novel fractional-order Jerk system. Experiments show that, under some suitable parameters, the fractional-order Jerk system displays a chaotic phenomenon. In order to suppress the chaotic behavior of the fractional-order Jerk system, we design two control strategies. Firstly, we design an appropriate time delay feedback controller to suppress the chaos of the fractional-order Jerk system. The delay-independent stability and bifurcation conditions are established. Secondly, we design a suitable mixed controller, which includes a time delay feedback controller and a fractional-order PDσ controller, to eliminate the chaos of the fractional-order Jerk system. The sufficient condition ensuring the stability and the creation of Hopf bifurcation for the fractional-order controlled Jerk system is derived. Finally, computer simulations are executed to verify the feasibility of the designed controllers. The derived results of this study are absolutely new and possess potential application value in controlling chaos in physics. Moreover, the research approach also enriches the chaos control theory of fractional-order dynamical system.

Droop Control Strategy for Voltage Source Converters Containing Renewable Power Sources

2020 ◽  
pp. 299-311
Author(s):  
Iván Andrade ◽  
Rubén Peña ◽  
Ramón Blasco-Gimenez ◽  
Javier Riedemann ◽  
Cristian Pesce
Keyword(s):  
Control Strategy ◽  
Voltage Source ◽  
Droop Control ◽  
Voltage Source Converters ◽  
Power Sources ◽  
Renewable Power

scholarly journals Fuzzy Logic Controlled Renewable Energy based DC Smart-Grid-System with Improved-Performance

2019 ◽  
Vol 8 (2S11) ◽  
pp. 3283-3289
Keyword(s):  
Smart Grid ◽  
Closed Loop ◽  
Harmonic Distortion ◽  
Grid System ◽  
Power Sources ◽  
Renewable Power ◽  
Voltage Quality ◽  
Pr Controller ◽  
Improved Performance ◽  
Smart Grid System

The DC smart-grid-system (DCSGS) becomes more and more popular and it is seen as an alternative to the AC. In DCSGS, voltage quality and harmonic distortion issues affects the performance of integrated renewable power sources. To improve the voltage quality, SEPIC converter is used to step up the output of PV cell. In DCSGS, output of PV is stepped-up using SEPIC. The output of wind generator is also rectified and stepped-up using SEPIC. This effort covenants with modeling&-simulation of CL(closed-loop)-DC-SGS (smart grid system) with PR controller and FLC in DCSGS. The performance of DCSGS with PR and FLC are compared and their results are presented. The results indicate that FLC controlled close-loop DCSGS gives superior response

scholarly journals Day-ahead renewable scenario forecasts based on generative adversarial networks

2020 ◽  
Author(s):  
Congmei Jiang ◽  
Yongfang Mao ◽  
Yi Chai ◽  
Mingbiao Yu
Keyword(s):  
Power Systems ◽  
Renewable Resources ◽  
Large Scale ◽  
Generative Adversarial Networks ◽  
Power Sources ◽  
Renewable Power ◽  
Adversarial Networks ◽  
Future Behavior ◽  
Large Scale Integration ◽  
Scale Integration

<p>With the increasing penetration of renewable resources such as wind and solar, the operation and planning of power systems, especially in terms of large-scale integration, are faced with great risks due to the inherent stochasticity of natural resources. Although this uncertainty can be anticipated, the timing, magnitude, and duration of fluctuations cannot be predicted accurately. In addition, the outputs of renewable power sources are correlated in space and time, and this brings further challenges for predicting the characteristics of their future behavior. To address these issues, this paper describes an unsupervised method for renewable scenario forecasts that considers spatiotemporal correlations based on generative adversarial networks (GANs), which have been shown to generate high-quality samples. We first utilized an improved GAN to learn unknown data distributions and model the dynamic processes of renewable resources. We then generated a large number of forecasted scenarios using stochastic constrained optimization. For validation, we used power-generation data from the National Renewable Energy Laboratory wind and solar integration datasets. The experimental results validated the effectiveness of our proposed method and indicated that it has significant potential in renewable scenario analysis.</p>

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