scholarly journals Adaptive Armature Resistance Control of Virtual Synchronous Generators to Improve Power System Transient Stability

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2365
Author(s):  
Daniel Carletti ◽  
Arthur Eduardo Alves Amorim ◽  
Thiago Silva Amorim ◽  
Domingos Sávio Lyrio Simonetti ◽  
Jussara Farias Fardin ◽  
...  
Keyword(s):  
Adaptive Control ◽  
Power System ◽  
Transient Stability ◽  
Short Circuit ◽  
Stability Margin ◽  
Synchronous Generator ◽  
Synchronous Generators ◽  
Resistance Change ◽  
Clearing Time ◽  
Fault Current Limiters

The growing number of renewable energy plants connected to the power system through static converters have been pushing the development of new strategies to ensure transient stability of these systems. The virtual synchronous generator (VSG) emerged as a way to contribute to the system stabilization by emulating the behavior of traditional synchronous machines in the power converters operation. This paper proposes a modification in the VSG implementation to improve its contribution to the power system transient stability. The proposal is based on the virtualization of the resistive superconducting fault current limiters’ (SFCL) behavior through an adaptive control that performs the VSG armature resistance change in short-circuit situations. A theoretical analysis of the problem is done based on the equal-area criterion, simulation results are obtained using PSCAD, and experimental results are obtained in a Hardware-In-the-Loop (HIL) test bench to corroborate the proposal. Results show an increase in the system transient stability margin, with an increase in the fault critical clearing time (CCT) for all virtual resistance values added by the adaptive control to the VSG operation during the short-circuit.

Distributed Virtual Synchronous Generator approach versus Singular Virtual Synchronous Generator approach: A dynamic stability evaluation

2020 ◽  
pp. 0309524X2097546
Author(s):  
Abdul Waheed Kumar ◽  
Mairaj ud din Mufti ◽  
Mubashar Yaqoob Zargar
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Reactive Power ◽  
Magnetic Energy ◽  
Dynamic Performance ◽  
Synchronous Generator ◽  
Rate Of Change ◽  
Clearing Time ◽  
Magnetic Energy Storage ◽  
Virtual Synchronous Generator

This paper reports the modeling and dynamic performance of a wind penetrated multi-area power system incorporating a Singular Virtual Synchronous Generator (SVSG)/Distributed Virtual Synchronous Generator (DVSG). The active and reactive power controls are achieved by using Superconducting Magnetic Energy Storage (SMES) as Virtual Synchronous Generator (VSG). SMES based VSG control parameters are tuned offline using genetic algorithm (GA). Two topologies of VSGs are considered in this paper: SVSG at lowest inertia generator bus (SVSGGENBUS), SVSG at load bus (SVSGLOADBUS) and DVSG of comparatively smaller rating at three lowest inertia generator buses. A modified 18 machine, 70-bus power system is simulated in MATLAB/Simulink environment. System performance is assessed for two different types of disturbances: step wind disturbance and three-phase fault. The simulation results show that rate of change of frequency (ROCOF), deviations in frequency and voltage are minimized with DVSG. Transient stability measured in terms of critical clearing time (CCT) verifies that CCT is increased by DVSG topology.

scholarly journals Transient Stability Analysis of a System of Two Machines Connected to an Infinite Bus

2018 ◽  
Vol 3 (10) ◽  
pp. 81-89
Author(s):  
Aniagboso John Onah
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Synchronous Generator ◽  
Frequency Instability ◽  
First Case ◽  
System Collapse ◽  
Clearing Time ◽  
Steady State Stability ◽  
Two Machines ◽  
Large Disturbance

Abstract The term large disturbance is often used in place of system collapse. It is the process by which the series of events accompanying voltage instability, frequency instability, and transient instability leads to a blackout or abnormally low voltages in a significant part of the power system. Large disturbance may be due to tripping of the lines on an account of fault or increase in load than the available supply. Transient stability deals with the effect of large and sudden disturbances in the system, while steady-state Stability deals with the effect of small disturbances in the system. Small disturbance can be a change in the gain of the automatic voltage regulator in the excitation system of a large generating unit. This paper studies the effect of a large disturbance in a power system. The system is represented by a two-machine system connected to an infinite bus. This study involves the effects of the fault on the speed of the rotor of the synchronous generator. Two cases were investigated: firstly, when fault occurred on a bus, and secondly, when fault occurred on the middle of a line. The conditions of the network before, during and after the fault are established in this paper. The equal area criterion was applied to the swing curves obtained to predict the critical clearing time of the system. The critical clearing time was found to lie between 0.20s and 0.225s if the fault occurred on the bus, and lies between 0.245s and 0.355s if the fault occurred at the middle of a line. Thus the system is more transiently stable in the second case than in the first. Machine 1 was less stable in the first case, while machine 2 was less stable in the second case. The critical clearing time is essential to the design of proper relaying schemes for fault clearing.

scholarly journals Contribution of FACTS Devices to the Transient Stability Improvement of a Power System Integrated with a PMSG-based Wind Turbine

2019 ◽  
Vol 9 (6) ◽  
pp. 4893-4900 ◽  
Author(s):  
N. E. Akpeke ◽  
C. M. Muriithi ◽  
C. Mwaniki
Keyword(s):  
Power System ◽  
Wind Turbine ◽  
Energy Demand ◽  
Wind Farm ◽  
Transient Stability ◽  
Transient State ◽  
Synchronous Generator ◽  
Test System ◽  
Synchronous Generators ◽  
Facts Devices

The increasing penetration of wind energy to the conventional power system due to the rapid growth of energy demand has led to the consideration of different wind turbine generator technologies. In fault conditions, the frequency of the power system decreases and eventually leads to speed differences between the grid and the interconnected wind generator. This can result to power system problems such as transient instability (TS). This paper focuses on enhancing the TS of a permanent magnet synchronous generator (PMSG)-based power system during 3ph fault conditions using FACTS devices. The power system considered is connected to a large wind farm which is based on PMSG. Critical clearing time (CCT) is used as an index to evaluate the transient state of the system. Under the study of an IEEE-14 bus system using PSAT as a simulation tool, the integrated CCT with PMSG-based wind turbine is improved with three independent FACTS devices. One of the synchronous generators in the test system has been replaced at random with the PMSG-based wind turbine which is meant to generate an equivalent power. Time domain simulations (TDSs) were carried out considering four study cases. Simulation results show that the (CCT) of the system with the FACTS devices is longer than the CCT without them, which is an indication of TS improvement.

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.

A Simple Design Approach for Excitation Controller and Power System Stabilizer

2010 ◽  
Author(s):  
G. Fusco ◽  
M. Russo
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Short Circuit ◽  
Design Procedure ◽  
Voltage Regulation ◽  
Operating Conditions ◽  
Power System Stabilizer ◽  
Simple Design ◽  
Wide Range ◽  
System Stabilizer

This paper proposes a simple design procedure to solve the problem of controlling generator transient stability following large disturbances in power systems. A state-feedback excitation controller and power system stabilizer are designed to guarantee robustness against uncertainty in the system parameters. These controllers ensure satisfactory swing damping and quick decay of the voltage regulation error over a wide range of operating conditions. The controller performance is evaluated in a case study in which a three-phase short-circuit fault near the generator terminals in a four-bus power system is simulated.

scholarly journals Design of Optimal Power System Stabilizer Using ETAP

2012 ◽  
pp. 221-224
Author(s):  
Raja Nivedha. R ◽  
Sreevidya. L ◽  
V. Geetha ◽  
R. Deepa
Keyword(s):  
Power System ◽  
Optimal Power Flow ◽  
Transient Stability ◽  
Transient Behavior ◽  
Steel Plant ◽  
Power System Stabilizer ◽  
Optimal Power ◽  
Clearing Time ◽  
System Stabilizer ◽  
System Power

The main objective of this paper is to improve the critical clearing time of the Steel Plant 35 MW Turbo generator. In order to enhance the transient behavior of the system, Power System Stabilizer is added so that proper damping is done. Damping intra area and inter area oscillations are critical to optimal power flow and stability on a system. Power system stabilizer is an effective damping device, as they provide auxiliary control signals to the excitation system of the generator. Transient stability analysis was carried out for the Steel plant. The three phase to ground and line to ground fault was simulated. The critical clearing time was found to be more when Power System Stabilizer was added and when Power System Stabilizer was not added the critical clearing time has considerably reduced.

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