scholarly journals Area-Based COI-Referred Rotor Angle Index for Transient Stability Assessment and Control of Power Systems

2012 ◽  
Vol 2012 ◽  
pp. 1-23 ◽  
Author(s):  
Noor Izzri Abdul Wahab ◽  
Azah Mohamed
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transient Stability ◽  
Stability Index ◽  
Test System ◽  
Emergency Control ◽  
Control Scheme ◽  
Rotor Angle ◽  
The Stability ◽  
And Control

This paper describes an index for judging the severity of transient events of power systems in simulation. The proposed transient stability index, known as the area-based COI-referred rotor angle index, is developed by considering the fact that a large-sized power system is divided into several areas according to the coherency of generators in a particular area. It can be assumed that an equivalent single large machine can represent all the generators in that area. Thus, the assessment of rotor angles for all generators can be simplified by only assessing the index of areas in a power system. The effectiveness of the proposed index in assessing the stability of power systems and its ability in pinpointing the weakest area in the power system is analyzed. Furthermore, this paper developed an emergency control scheme known as the combined UFLS and generator tripping in order to stabilize the system when unstable faults occurred in a power system. The proposed index is used to identify the generator to be tripped when the developed emergency control scheme operates. The performance of the proposed index and the combined UFLS and generator tripping scheme are evaluated on the IEEE 39-bus test system.

Transient stability analysis and control of power systems with considering flux decay by energy function approach

2012 ◽  
Vol 60 (1) ◽  
pp. 3-8
Author(s):  
D. Lu ◽  
X. Zhang
Keyword(s):  
Stability Analysis ◽  
Power Systems ◽  
Energy Function ◽  
Transient Stability ◽  
Stability Boundary ◽  
Function Approach ◽  
Fault System ◽  
Rotor Angle ◽  
And Control ◽  
Transient Stability Analysis

Transient stability analysis and control of power systems with considering flux decay by energy function approach In this paper, transient stability of power systems with structure preserving models is considered. A Hamiltonian function which can be regarded as a Lyapunov function for the system is proposed. Based on this, the influence of flux decay dynamics, especially during a fault, on transient stability is analyzed. With the increase of load power, the variation of stability boundary in the rotor angle/E'q plane is shown. The Energy-based excitation control, aiming at injecting additional damping into the post-fault system may reduce the critical clearing time (CCT). This can be demonstrated by the comparison of different flux decay dynamics in the fault-on condition, and the reason is illustrated by the relationship between rotor angle/E'q and the stability boundary. An improved control strategy is proposed and applied to increase the CCT. Simulation results verify that improvement is obtained both in transient stability and dynamic performance.

scholarly journals Nonlinear robust control for single-machine infinite-bus power systems with input saturation

2017 ◽  
Vol 65 (1) ◽  
pp. 3-9
Author(s):  
Y. Wan
Keyword(s):  
Power Systems ◽  
Power System ◽  
Single Machine ◽  
Input Saturation ◽  
Control Law ◽  
System A ◽  
Control Scheme ◽  
Single Machine Infinite Bus ◽  
The Stability ◽  
Nonlinear Robust

Abstract In this paper, a new control scheme is proposed to achieve stability for a single-machine infinite-bus power system. A power system model simultaneously considering input saturation and time-varying uncertainties is presented. A sufficient condition for the system convergence is given and based on this result, a switching excitation control law with auxiliary system is designed. The stability analysis and simulation results all show that the developed controller is effective.

scholarly journals Comparative Technical-Economical Analysis of Transient Stability Improvements in a Power System

2021 ◽  
Vol 11 (23) ◽  
pp. 11359
Author(s):  
Giuseppe Marco Tina ◽  
Giovanni Maione ◽  
Sebastiano Licciardello ◽  
Domenico Stefanelli
Keyword(s):  
Stability Analysis ◽  
Power Systems ◽  
Power System ◽  
Transient Stability ◽  
Short Circuit ◽  
Software Tool ◽  
Frequency Stability ◽  
Sensitivity Analyses ◽  
Worst Case ◽  
Rotor Angle

Power systems are rapidly evolving to face the increasing penetration of renewable inverter-based generation units and to improve their reliability and safety. A power system is constantly exposed to sudden changes or disturbances that may affect its stability. In this paper, a comparative analysis of solutions to improve transient stability, both rotor angle and frequency stability, is performed. These solutions are SVC, STATCOM, a fast excitation system, and an additional parallel transmission line. Sensitivity analyses were performed to evaluate the effects of the location of the three-phase fault line and the most effective SVC or STATCOM installation bus. Based on these analyses, the worst-case fault is considered, and the critical fault clearing time is determined as an engineering parameter for comparing the different solutions. For the numerical analysis, the IEEE 9 bus system is considered, and the PowerWorld software tool is used. Rotor angle and frequency stability analyses were performed. Moreover, specifically for SVC and STATCOM, the effects of different values of short-circuit ratios were considered in the context of rotor angle stability analysis. As part of the frequency stability analysis, the use of the remuneration for load shedding service in Italy was considered to perform an economic analysis for SVC and STATCOM.

Novel Real-Time Stability Assessment Algorithm Based on Synchro-Phasors Measurement and Parallel Algorithms for Multi-Machine Networks.

2012 ◽  
Vol 13 (3) ◽  
Author(s):  
Mohamed Abdelwahhab Ali ◽  
Wagdy Mohamed Mansour ◽  
Wael Refaat Anis ◽  
Fahmy Metwally Bendary
Keyword(s):  
Power Systems ◽  
Parallel Algorithms ◽  
Real Time ◽  
Transient Stability ◽  
Test System ◽  
System Stability ◽  
Stability Assessment ◽  
Varying Coefficients ◽  
Rotor Angle ◽  
Time Varying Coefficients

Abstract The introduction of wide area measurements has brought a need for real time assessment methods of power systems, which are accurate and fast. The time varying coefficients in synchronous machine equations make it difficult to find solutions to obtain machine voltages, currents and flux linkages when expressed in phase quantities under transient conditions. The paper presents an approach to design power system transient stability assessment using direct methods for a multi-machine network based on multiple synchronized phasors, measured from Phasor Measurement Units (PMUs) and generator parameters. The generator rotor angle was derived from phasor measurements of voltage and current, and generator parameters using direct algorithm . The method assumes that a temporary fault is applied to the system therefore the pre-fault and post-fault conditions are similar. The multi-machine system was reduced to groups denoted Single Machine to Equivalent Bus (SMEB) models and another groups denoted Load Equivalent Bus (LEB) using Parallel Algorithms (PAs) [1]. The use of these PAs eliminates the SPMUs at each bus in the system, and it is required number of SPMUs only equals the number of generator buses. So that, the Equal Area Criterion in both rotor angle domain and time domain can be applicable for the SMEBs groups to assess the system stability in real-time through the Synchro-Phasors Measurements Units (SPMUs). A temporary three phase fault was simulated at test system comprises 2-machine, 8-bus network for validating the novel algorithm.

scholarly journals Enhancement of Power System Transient Stability by the Coordinated Control between an Adjustable Speed Pumping Generator and Battery

2020 ◽  
Vol 10 (24) ◽  
pp. 9034
Author(s):  
Junji Tamura ◽  
Atsushi Umemura ◽  
Rion Takahashi ◽  
Atsushi Sakahara ◽  
Fumihito Tosaka ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Wind Farm ◽  
Transient Stability ◽  
Wind Farms ◽  
System Stability ◽  
Synchronous Generators ◽  
Adjustable Speed ◽  
The Stability ◽  
Network Fault

The penetration level of large-scale wind farms into power systems has been increasing significantly, and the frequency stability and transient stability of the power systems during and after a network fault can be negatively affected. This paper proposes a new control method to improve the stability of power systems that are composed of large wind farms, as well as usual synchronous generators. The new method is a coordinated controlling method between an adjustable-speed pumping generator (ASG) and a battery. The coordinated system is designed to improve power system stability during a disconnection in a fixed-rotor-speed wind turbine with a squirrel cage-type induction generator (FSWT-SCIG)-based wind farm due to a network fault, in which a battery first responds quickly to the system frequency deviation due to a grid fault and improves the frequency nadir, and then the ASG starts to supply compensatory power to recover the grid frequency to the rated frequency. The performance of the proposed system was confirmed through simulation studies on a power system model consisting of usual synchronous generators (SGs), an ASG, a battery, and an SCIG-based wind farm. Simulation results demonstrated that the proposed control system can enhance the stability of the power system effectively.

scholarly journals Transient Stability Improvement of IEEE 9-Bus System Using Static Var Compensator

2021 ◽  
Vol 4 (4) ◽  
pp. 98-102
Author(s):  
Manish Shrivastava ◽  
Vinay Prakash ◽  
Vishal Kaushik ◽  
Vivek Kumar Upadhyay
Keyword(s):  
Power Systems ◽  
Transient Stability ◽  
Reactive Power ◽  
Test System ◽  
Limiting Factor ◽  
Static Var Compensator ◽  
Voltage Profile ◽  
Matlab Simulation ◽  
The Stability ◽  
Stability Limits

With increase in power demand over the last few decades, there has been a great expansion in power generation & transmission. But due to various disturbances, improper loading and environmental conditions the power systems are working near their stability limits which have become a power-transfer limiting factor. This in turn poses a threat to the stability of the system. Transient stability has been considered as one of the most important stability for a power system. In this paper Static VAR Compensator (SVC) has been discussed for reactive power control and hence improvement of transient stability and voltage profile. This paper incorporates IEEE-9 BUS test system with SVC controller using MATLAB Simulation.

scholarly journals A dynamical multi-input/multi-output network formulation for stability analysis in AC microgrids

2019 ◽  
Author(s):  
Chrysovalantis Spanias ◽  
Petros Aristidou ◽  
Michalis Michaelides
Keyword(s):  
Stability Analysis ◽  
Power System ◽  
Test System ◽  
Power Grids ◽  
Rotational Inertia ◽  
Numerical Application ◽  
Medium Voltage ◽  
Output System ◽  
The Stability ◽  
And Control

Nowadays, we have witnessed a significant increaseof renewable sources across the existing power grids, as aresult of the undeniable need to mitigate the effects of environmental pollution and assist the economic development of countries around the globe. However, due to the lack of rotational inertia and their intermittent nature, renewables have also increased the severity of the occurring disturbances and instability phenomena, which in turn place a demand for more accurate modeling of the network and the power system components. In this paper, we propose a novel network formulation for AC microgrids that allows the consideration of less conservative conditions for the network, while allowing the adoption of higher order inverter-based generation dynamicsand facilitating the stability analysis and control. In particular, we formulate the network as a dynamical multi-input/multi-output system, which we show is both stable and passive, even if the network’s dynamic and lossy nature is taken into account. We then briefly discuss the opportunities and the advantages offered by the proposed approach and provide useful guidelines for a more accurate modeling of power system components.Finally, we verify the proposed network formulation through a numerical application on the Four Machine Two Area Kundur test system and several simulations on typical Medium Voltage (MV) distribution lines.

scholarly journals Transient Stability Improvement of the Power Systems

2018 ◽  
Vol 12 (3) ◽  
pp. 916
Author(s):  
Zaid H. Al-Tameemi ◽  
Hayder H. Enawi ◽  
Karrar M. Al-Anbary ◽  
Hussam M. Almukhtar
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Transient Stability ◽  
Electrical Power ◽  
Limiting Factor ◽  
Stable Operation ◽  
Electric Power Networks ◽  
Matlab Package ◽  
The Stability

<p>During the last few decades, electrical power demand enlarged significantly whereas power production and transmission expansions has been brutally restricted as a result of restricted resources as well as ecological constrains. Consequently, many transmission lines have been profoundly loading so the stability of power system became as Limiting factor for transferring electrical power. So, maintaining a secure and stable operation of the electric power networks is deemed an imporatant and challenge issue.transient stability of a power system has been gained a considerable attention from researchers dute to it importance . Therefore,this paper sheds light on A substantial number of the adopted techniques, including an inclease in  inertia constant of generator, shunt capacitor, reduction reactance of the transmission line to acheive this purpose. A 7-Machine CIGRE system has been considered a case study. Matlab package has been employed to implement this study. The simulation results show that the transient stability of the repective system enhanced considerably with these techniques.</p>

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