scholarly journals Transient Stability Analysis of the Two-Area With AC/DC Paralleled Interconnected Power System in Different Operation

2021 ◽  
Vol 9 ◽  
Author(s):  
Hongbo Liu ◽  
Shuyu Zhang ◽  
Li Sun ◽  
Chong Zhang ◽  
Xiaoyu Peng
Keyword(s):  
Hybrid System ◽  
Transient Stability ◽  
Stability Margin ◽  
Operating Conditions ◽  
Control Cost ◽  
Parallel Transmission ◽  
Transient Characteristics ◽  
Interconnected Power System ◽  
Angle Stability ◽  
Rotor Angle Stability

In order to deeply explore the transient stability mechanism of the AC/DC hybrid system, this paper analyzes the rotor angle stability of the two-area AC/DC hybrid system. The system is analyzed after subjecting it to large disturbances in the AC system and for different operating conditions, qualitatively and quantitatively. The influence of factors, such as the AC operating point of the system and the proportion of DC transmission power, have been considered for improving the rotor motion equation. Subsequently, the transient characteristics of the hybrid system are analyzed after being subjected to disturbances. The power angle stability margin index is obtained, based on which the transient characteristics after DC blocking are analyzed, and the coordinated control strategy with the least control cost is proposed. The results are verified using the two-area AC/DC parallel transmission system network model. The study provides the reference for ensuring the security and stability of the hybrid AC/DC power grid.

scholarly journals Enhancement of Power System Transient Stability By Fractional Order Controlled STATCOM Tuned By PSO

2018 ◽  
Vol 7 (4.24) ◽  
pp. 163
Author(s):  
R.S. Srinivas ◽  
P.V.Ramana Rao
Keyword(s):  
Power System ◽  
Fractional Order ◽  
Transient Stability ◽  
Stability Margin ◽  
Computational Effort ◽  
Static Synchronous Compensator ◽  
Facts Controllers ◽  
Angle Stability ◽  
Rotor Angle Stability ◽  
The Stability

This paper discusses the application of Fractional order PI controlled Static synchronous compensator for improvement rotor angle stability of inter connected power system. FACTS Controllers plays important role in enhancing the power system stability.Besides improving the stability margin of the power system it also aids the damping of inter area power oscillations. In the present work STATCOM is connected in multimachine power system .The dynamic response of the STATCOM is controlled by using fractional order controllers.The controller gains of the fractional controller are tuned by using PSO algorithm.It gives acceptable solutions to continuous non-linear systems with less computational effort. The performance of the proposed controller has been compared with integer order PI controllers at different locations of fault. In this paper a 3 machine 9 bus WSSC test power system is considered and simulated in MATLAB/SIMULINK.

scholarly journals The Transient Stability Study of a Synchronous Generator Based on the Rotor Angle Stability

2015 ◽  
Vol 5 (6) ◽  
pp. 1319 ◽  
Author(s):  
Selwa Fetissi ◽  
Djamel Labed ◽  
Imen Labed
Keyword(s):  
Transient Stability ◽  
Electrical Power ◽  
Circuit Breaker ◽  
Stability Study ◽  
Electrical Power System ◽  
Step Method ◽  
Clearing Time ◽  
Angle Stability ◽  
Rotor Angle ◽  
Rotor Angle Stability

Transient stability is an important aspect in the operation of electrical power system. In case of fault occurs in the system, the determining of fault clearing time of circuit breaker is considered one of the main factors to ensure power transfer of the system. This paper is aim to study the transient stability of single machine infinite bus system (SMIB), based on the rotor angle stability. The study is performed to determine the influence of the critical clearing time of the circuit breakers on the rotor angle stability of the generator in the case of three phase fault. For obtaining and determining numerically the nature of the rotor angle of machine, we applied the Step-by-step method for different values of fault clearing time. The results of simulation indicate that determine of critical clearing time is a major evaluation in stability studies. The system model is created in MATLAB/ SIMULINK software.

scholarly journals Qualitative and Quantitative Transient Stability Assessment of Stand-Alone Hybrid Microgrids in a Cluster Environment

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1286
Author(s):  
Kishan Veerashekar ◽  
Halil Askan ◽  
Matthias Luther
Keyword(s):  
Transient Stability ◽  
System Stability ◽  
Stability Assessment ◽  
Large Signal ◽  
Operating Modes ◽  
Stability Point ◽  
Cluster Environment ◽  
Angle Stability ◽  
Rotor Angle ◽  
Rotor Angle Stability

Neighboring stand-alone hybrid microgrids with diesel generators (DGs) as well as grid-feeding photovoltaics (PV) and grid-forming battery storage systems (BSS) can be coupled to reduce fuel costs and emissions as well as to enhance the security of supply. In contrast to the research in control and small-signal rotor angle stability of microgrids, there is a significant lack of knowledge regarding the transient stability of off-grid hybrid microgrids in a cluster environment. Therefore, the large-signal rotor angle stability of pooled microgrids was assessed qualitatively and also quantitatively in this research work. Quantitative transient stability assessment (TSA) was carried out with the help of the—recently developed and validated—micro-hybrid method by combining time-domain simulations and transient energy function analyses. For this purpose, three realistic dynamic microgrids were modelled regarding three operating modes (island, interconnection, and cluster) as well as the conventional scenario “classical” and four hybrid scenarios (“storage”, “sun”, “sun & storage”, and “night”) regarding different instants of time on a tropical partly sunny day. It can be inferred that, coupling hybrid microgrids is feasible from the voltage, frequency, and also transient stability point of view. However, the risk of large-signal rotor angle instability in pooled microgrids is relatively higher than in islanded microgrids. Along with critical clearing times, new stability-related indicators such as system stability degree and corrected critical clearing times should be taken into account in the planning phase and in the operation of microgrids. In principle, a general conclusion concerning the best operating mode and scenario of the investigated microgrids cannot be drawn. TSA of pooled hybrid microgrids should be performed—on a regular basis especially in the grid operation—for different loading conditions, tie-line power flows, topologies, operating modes, and scenarios.

Automatic Gain Controller for Variable Speed Wind Turbines

2008 ◽  
Vol 9 (1) ◽  
Author(s):  
Mohamed S ElMoursi
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Reactive Power ◽  
Stability Margin ◽  
Voltage Regulation ◽  
Primary Control ◽  
Voltage Reference ◽  
Voltage Profile ◽  
Frequency Model ◽  
Interconnected Power System

This paper presents a novel controller for DFIG based wind parks, designed to achieve more efficient voltage regulation, reactive power compensation and to enhance the transient stability margin of the interconnected power system. The supervisory-secondary voltage control is used to generate the local voltage reference, providing an improved overall voltage profile, while combining an automatic gain controller (AGC) to improve the transient response of the primary control loop. The controller is implemented and tested with a power system comprising of a lumped, fundamental frequency model of a DFIG based wind park, and hydro and diesel generators connected to the electric grid. The performance of the controller was investigated for both steady-state improvements as well as under extreme contingencies to demonstrate its benefits.

scholarly journals Parametric Sensitivity Analysis of Rotor Angle Stability Indicators

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5023
Author(s):  
Ashish Shrestha ◽  
Francisco Gonzalez-Longatt
Keyword(s):  
Sensitivity Analysis ◽  
Power Systems ◽  
Power System ◽  
Transient Stability ◽  
Damping Ratio ◽  
Parametric Sensitivity ◽  
Parametric Sensitivity Analysis ◽  
Angle Stability ◽  
Rotor Angle ◽  
Rotor Angle Stability

With the increasing penetration rate of Power Electronic Converter (PEC) based technologies, the electrical power systems are facing the problem of transient stability since the PEC based technologies do not contribute to the system inertia, and the proportion of synchronous generators (i.e., the source of inertia) is in decreasing rate. In addition, PEC based technologies’ components have poor inherent damping. It is very important to analyze the system characteristics of a power system to minimize the potential instabilities during the contingencies. This paper presents the parametric sensitivity analysis of the rotor angle stability indicators for the 39-bus New England power system. The indicators of rotor angle stability analysis such as critical fault clearing time (CCT), Eigenvalue points, damping ratio, frequency deviation, voltage deviation, and generator’s speed deviation are identified and analyzed for three case scenarios; each scenario has six sub-cases with different inertia constants. The results show that the CCTs for each component will be reduced if the inertia reduces at any section of a multi-machine power system. Although the applied three scenarios with six sub-cases are identified to be stable in this analysis, the decreasing inertia constant has significant impact on the power system dynamics.

scholarly journals Hybrid Power System Design for Damping Electromechanical Modes of Oscillation in Grid Connected Machines

2020 ◽  
pp. 1-12
Author(s):  
Syed Sanjar Ul Islam ◽  
Santosh kumar
Keyword(s):  
Renewable Energy ◽  
Hybrid System ◽  
Solar Pv ◽  
Pv Systems ◽  
Electromechanical Modes ◽  
Maximum Stability ◽  
Angle Stability ◽  
Rotor Angle ◽  
Rotor Angle Stability ◽  
Two Machines

Due to the natural intermittent nature of wind and solar PV, autonomous wind/PV systems for renewable energy typically require energy storage or other sources of production to form a hybrid system. in this paper objective of the designing of a grid dynamics controller equipped with IGBT based bridge structure for stabilizing various electrical parameters on the grid system while its renewable energy-based grid integration. And the controller has to be designed with modulation technique, for both voltage and current at particular frequency following stabilization which is both simple in implementation and operation. And the comparative analysis of techniques used has to be carried out with AI-based optimization algorithms for studying its effectiveness. The results of the THD % of voltage in the system having no controller was found to be 3.32 %.  in the system having adaptive neural PSO switching of grid dynamics controller, the distortion level came down to 1.96%. The hybrid system with solar wind energy was further integrated with the grid and was analyzed for the rotor angle stability in the two machines. It was concluded that out of the three controls for grid dynamics controller the artificial intelligence-based adaptive neural PSO switching was found to be best with maximum stability of machines.

A New Control Method to Mitigate Power Fluctuations for Grid Integrated PV/Wind Hybrid Power System Using Ultracapacitors

2016 ◽  
Vol 17 (4) ◽  
pp. 451-461 ◽  
Author(s):  
N. S. Jayalakshmi ◽  
D. N. Gaonkar
Keyword(s):  
Solar Wind ◽  
Output Power ◽  
Hybrid System ◽  
Transient Stability ◽  
Control Method ◽  
Storage System ◽  
Operating Conditions ◽  
Solar Irradiation ◽  
Power Fluctuations ◽  
Utility Grid

Abstract The output power obtained from solar-wind hybrid system fluctuates with changes in weather conditions. These power fluctuations cause adverse effects on the voltage, frequency and transient stability of the utility grid. In this paper, a control method is presented for power smoothing of grid integrated PV/wind hybrid system using ultracapacitors in a DC coupled structure. The power fluctuations of hybrid system are mitigated and smoothed power is supplied to the utility grid. In this work both photovoltaic (PV) panels and the wind generator are controlled to operate at their maximum power point. The grid side inverter control strategy presented in this paper maintains DC link voltage constant while injecting power to the grid at unity power factor considering different operating conditions. Actual solar irradiation and wind speed data are used in this study to evaluate the performance of the developed system using MATLAB/Simulink software. The simulation results show that output power fluctuations of solar-wind hybrid system can be significantly mitigated using the ultracapacitor based storage system.

scholarly journals Power System Transient Stability Assessment Based on Snapshot Ensemble LSTM Network

2021 ◽  
Vol 13 (12) ◽  
pp. 6953
Author(s):  
Yixing Du ◽  
Zhijian Hu
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transient Stability ◽  
Short Term Memory ◽  
Risk Function ◽  
Stability Margin ◽  
Risk Level ◽  
Stability Assessment ◽  
Lstm Network ◽  
Hierarchical Assessment

Data-driven methods using synchrophasor measurements have a broad application prospect in Transient Stability Assessment (TSA). Most previous studies only focused on predicting whether the power system is stable or not after disturbance, which lacked a quantitative analysis of the risk of transient stability. Therefore, this paper proposes a two-stage power system TSA method based on snapshot ensemble long short-term memory (LSTM) network. This method can efficiently build an ensemble model through a single training process, and employ the disturbed trajectory measurements as the inputs, which can realize rapid end-to-end TSA. In the first stage, dynamic hierarchical assessment is carried out through the classifier, so as to screen out credible samples step by step. In the second stage, the regressor is used to predict the transient stability margin of the credible stable samples and the undetermined samples, and combined with the built risk function to realize the risk quantification of transient angle stability. Furthermore, by modifying the loss function of the model, it effectively overcomes sample imbalance and overlapping. The simulation results show that the proposed method can not only accurately predict binary information representing transient stability status of samples, but also reasonably reflect the transient safety risk level of power systems, providing reliable reference for the subsequent control.

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