scholarly journals Coordinated Control of Multiple Virtual Synchronous Generators in Mitigating Power Oscillation

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2788 ◽  
Author(s):  
Pan Hu ◽  
Hongkun Chen ◽  
Kan Cao ◽  
Yuchuan Hu ◽  
Ding Kai ◽  
...  

Virtual synchronous generators (VSGs) present attractive technical advantages and contribute to enhanced system operation and reduced oscillation damping in dynamic systems. Traditional VSGs often lack an interworking during power oscillation. In this paper, a coordinated control strategy for multiple VSGs is proposed for mitigating power oscillation. Based on a theoretical analysis of the parameter impact of VSGs, a coordinated approach considering uncertainty is presented by utilizing polytopic linear differential inclusion (PLDI) and a D-stable model to enhance the small-signal stability of system. Subsequently, the inertia and damping of multiple VSGs are jointly exploited to reduce oscillation periods and overshoots during transient response. Simulation, utilizing a two-area four-machine system and a typical microgrid test system, demonstrates the benefits of the proposed strategy in enhancing operation stability and the anti-disturbing ability of multiple VSGs. The results conclusively confirm the validity and applicability of the method.

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7372
Author(s):  
Nikolay Nikolaev ◽  
Kiril Dimitrov ◽  
Yulian Rangelov

This paper focuses on the methods that ensure the rotor angle stability of electric power systems, which is most frequently analyzed with small-signal models. Over the past several decades, power system stabilizers (PSSs) for conventional excitation systems were the main tools for improving the small-signal stability of electromechanical oscillatory modes. In the last decade, power oscillation damping (POD) control implemented in photovoltaic (PV) inverters has been considered an alternative to PSSs. As PV generation undergoes massive rollout due to policy directions and renewable energy source integration activities, it could potentially be used as a source of damping, which is crucial for sustaining the rotor angle stability of the remaining in-service synchronous generators. Several studies have already been dedicated to the development of different damping strategies. This paper contributes to the existing research in power system stability by providing a comprehensive review of the effects of PV generation on small-signal stability, as well as the recent evolution of POD control through PV inverters. The features and impacts of the various ways to realize POD controllers are assessed and summarized in this paper. Currently, detailed information and discussions on the practical application of PV inverter PODs are not available. This paper is, thus, intended to initiate a relevant discussion and propose possible implementation approaches concerning the topic under study.


Author(s):  
Ohnmar Swe

This paper presents the small signal stability of multi-machine power system over the 58-Bus, 26-Machine, Yangon Distribution Network and is validated with MATLAB software under various disturbance conditions. Time-domain solution analysis is employed to determine the small signal dynamic behavior of test system. Transtability model is used to perform time-domain simulation in SIMULINK. The simulation is carried out for normal condition, reference voltage of regulator (Vref) disturbance, mechanical torque (Tm)disturbance and network (fault) disturbance and the conditions of change in center of inertia for rotor angle (delta COI),  slip for center of inertia (slip COI), field current and mechanical torque are observed. According to the simulation results, perturbation of Vref shows only instability on the system. But ramping of Tm and network disturbance can cause large disturbance on the system and unstable conditions can be observed.


2019 ◽  
Vol 217 ◽  
pp. 01017
Author(s):  
Nikita Tomin ◽  
Daniil Panasetsky ◽  
Alexey Iskakov

The state of the art of transient stability and steady-state (small signal) stability in power grids are reviewed. Transient stability concepts are illustrated with simple examples; in particular, we consider two machine learning-based methods for computing region of attraction: ROA produced by Neural Network Lyapunov Function; estimation of the ROA of IEEE 39-bus system using Gaussian process and Converse Lyapunov function. We discuss steady state stability in power systems, and using Prony’s modal analysis for evaluating small signal stability for the 7 Bus Test system and real French power system.


Author(s):  
SAMUNDRA GURUNG ◽  
SUMATE NAETILADDANON ◽  
ANAWACH SANGSWANG

Currently, large-scale solar farms are being rapidly integrated in electrical grids all over the world. However, the photovoltaic (PV) output power is highly intermittent in nature and can also be correlated with other solar farms located at different places. Moreover, the increasing PV penetration also results in large solar forecast error and its impact on power system stability should be estimated. The effects of these quantities on small-signal stability are difficult to quantify using deterministic techniques but can be conveniently estimated using probabilistic methods. For this purpose, the authors have developed a method of probabilistic analysis based on combined cumulant and Gram– Charlier expansion technique. The output from the proposed method provides the probability density function and cumulative density function of the real part of the critical eigenvalue, from which information concerning the stability of low-frequency oscillatory dynamics can be inferred. The proposed method gives accurate results in less computation time compared to conventional techniques. The test system is a large modified IEEE 16-machine, 68-bus system, which is a benchmark system to study low-frequency oscillatory dynamics in power systems. The results show that the PV power fluctuation has the potential to cause oscillatory instability. Furthermore, the system is more prone to small-signal instability when the PV farms are correlated as well as when large PV forecast error exists.


Author(s):  
Shalom Lim Zhu Aun ◽  
Marayati Bte Marsadek ◽  
Agileswari K. Ramasamy

This paper primarily focuses on the small signal stability analysis of a power system integrated with solar photovoltaics (PV). The test system used in this study is the IEEE 39-bus. The small signal stability of the test system are investigated in terms of eigenvalue analysis, damped frequency, damping ratio and participation factor. In this study, various conditions are analyzed which include the increase in solar PV penetration into the system and load variation. The results obtained indicate that there is no significant impact of solar PV penetration on the small signal stability of large scaled power system.


2013 ◽  
Vol 765-767 ◽  
pp. 2579-2585
Author(s):  
Min Jing Yang ◽  
Yan Li ◽  
Jin Yu Wen ◽  
Chun Fang Liu ◽  
Min Jie Zhu ◽  
...  

The high penetration of doubly-fed induction generators (DFIGs) entails a change in dynamics and operational characteristics of the power system, thus this paper investigates the small signal stability of the large-scale wind farm with DFIGs. The GE 1.5MW DFIG is modeled in power system analysis software package (PSASP), and a large-scale wind farm with DFIGs is established. Then, the two-area test system with four generators is applied to assess the effect of the large wind farm on power system inter-area oscillatory mode in which the penetration and the installation site of the wind farm are considered. Finally, the simulation results indicate that abundant penetration of DFIG-based wind power will improve the inter-area oscillatory, and the integration of wind farms with DFIGs in the receiving area makes the inter-area mode highly damped.


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