scholarly journals Performance Comparison of Adaptive Estimation Techniques for Power System Small-Signal Stability Assessment

2010 ◽  
Vol 7 (2) ◽  
pp. 10
Author(s):  
E. A. Feilat
Keyword(s):  
Power System ◽  
Least Squares ◽  
Operating Conditions ◽  
Recursive Least Squares ◽  
Small Signal ◽  
Loading Conditions ◽  
Small Signal Stability ◽  
Signal Stability ◽  
Wide Range ◽  
Damping Torque

This paper demonstrates the assessment of the small-signal stability of a single-machine infinite- bus power system under widely varying loading conditions using the concept of synchronizing and damping torques coefficients. The coefficients are calculated from the time responses of the rotor angle, speed, and torque of the synchronous generator. Three adaptive computation algorithms including Kalman filtering, Adaline, and recursive least squares have been compared to estimate the synchronizing and damping torque coefficients. The steady-state performance of the three adaptive techniques is compared with the conventional static least squares technique by conducting computer simulations at different loading conditions. The algorithms are compared to each other in terms of speed of convergence and accuracy. The recursive least squares estimation offers several advantages including significant reduction in computing time and computational complexity. The tendency of an unsupplemented static exciter to degrade the system damping for medium and heavy loading is verified. Consequently, a power system stabilizer whose parameters are adjusted to compensate for variations in the system loading is designed using phase compensation method. The effectiveness of the stabilizer in enhancing the dynamic stability over wide range of operating conditions is verified through the calculation of the synchronizing and damping torque coefficients using recursive least square technique.

scholarly journals Improvement of Small Signal Stability of SMIB System with Optimized Power System Stabilizer

2020 ◽  
Vol 9 (7) ◽  
pp. 709-716
Keyword(s):  
Power System ◽  
Low Frequency ◽  
Power System Stabilizer ◽  
Small Signal ◽  
Small Signal Stability ◽  
Swarm Optimization ◽  
Signal Stability ◽  
System Stabilizer ◽  
Stability Issues ◽  
Damping Torque

As electrical power system is a complex system, there are more chances of stability issues may arise. One of the stability issues is Low Frequency Oscillations (LFOs) which makes the system unstable. As these oscillations are having low frequency i.e. large time constant with slowly increasing magnitude, they are referred to small signal stability. The main reason of these oscillations is due to lack of sufficient damping torque. Automatic Voltage Regulator (AVR) action in generator is providing sufficient synchronizing torque for system stability. This is possible with high gain and low time constant AVR which results in reduction of damping torque. Power System Stabilizer (PSS) is used together with AVR for providing necessary damping torque to minimize the LFOs. For effective damping, the PSS performance is improved by optimizing its parameters. In this paper, Single Machine Infinite Bus (SMIB) system is considered for studying the effect of LFOs. The SMIB system is simulated for a step disturbance in reference voltage and the results are carried out for different optimizing techniques Particle Swarm Optimization (PSO), Cat Swarm Optimization (CSO), Teaching and Learning based Optimization (TLBO)

scholarly journals Tuning of power system stabilizer for small signal stability improvement of interconnected power system

2017 ◽  
Vol 16 (1/2) ◽  
pp. 3-28 ◽  
Author(s):  
Prasenjit Dey ◽  
Aniruddha Bhattacharya ◽  
Priyanath Das
Keyword(s):  
Power System ◽  
Low Frequency ◽  
Operating Conditions ◽  
System Stability ◽  
Interconnected Systems ◽  
Small Signal ◽  
Small Signal Stability ◽  
Power System Stabilizers ◽  
Signal Stability ◽  
Low Frequency Oscillations

This paper reports a new technique for achieving optimized design for power system stabilizers. In any large scale interconnected systems, disturbances of small magnitudes are very common and low frequency oscillations pose a major problem. Hence small signal stability analysis is very important for analyzing system stability and performance. Power System Stabilizers (PSS) are used in these large interconnected systems for damping out low-frequency oscillations by providing auxiliary control signals to the generator excitation input. In this paper, collective decision optimization (CDO) algorithm, a meta-heuristic approach based on the decision making approach of human beings, has been applied for the optimal design of PSS. PSS parameters are tuned for the objective function, involving eigenvalues and damping ratios of the lightly damped electromechanical modes over a wide range of operating conditions. Also, optimal locations for PSS placement have been derived. Comparative study of the results obtained using CDO with those of grey wolf optimizer (GWO), differential Evolution (DE), Whale Optimization Algorithm (WOA) and crow search algorithm (CSA) methods, established the robustness of the algorithm in designing PSS under different operating conditions.

scholarly journals Enhancement of small signal stability of a DFIG-based wind power system using fuzzy logic control

1970 ◽  
Vol 8 (3) ◽  
pp. 48-63
Author(s):  
T. K. Renuka ◽  
P. Reji ◽  
Sasidharan Sreedharan
Keyword(s):  
Fuzzy Logic ◽  
Power System ◽  
Short Circuit ◽  
Test System ◽  
Operating Conditions ◽  
Small Signal ◽  
Small Signal Stability ◽  
Fuzzy Logic Controllers ◽  
Signal Stability ◽  
Logic Controllers

This paper proposes fuzzy logic controllers for enhancing the small signal stability of DFIG-based wind integrated power system. The test system used is single machine infinite bus system integrated with conventional proportional-integral controllers. The fuzzy logic controllers provide optimum proportional and integral gains under various operating conditions namely wind speed and grid strength. The effects of strong and weak grid strengths have been taken into account with short circuit level of 40 MVA and 16 MVA, respectively. The obtained result justifies that the damping ratio and there by the small signal stability of such a system have been enhanced considerably by the action of fuzzy logic controllers. The generalization can be enlarged to multi-machine systems in various dynamic conditions.Keywords : Doubly Fed Induction Generator, small signal stability, state space model, eigenvalue analysis, fuzzy logic based tuning circuits

Small signal stability analysis of power systems integrated with wind power using sensitivity-based index

2019 ◽  
pp. 0309524X1986842 ◽  
Author(s):  
Arghya Mitra
Keyword(s):  
Power System ◽  
Wind Power ◽  
Wind Farm ◽  
Operating Conditions ◽  
Sensitivity Index ◽  
Small Signal ◽  
Small Signal Stability ◽  
System Matrix ◽  
Signal Stability ◽  
Bus System

To know the inherent property of the power system connected with a wind farm along with its associated controllers, a small signal stability study is required. For this, a linearized system model has to be developed. The small signal model of the system with wind farm along with its controllers is discussed here. The eigenvalues of system matrix are computed from the linearized model of the power system. The absolute value of the real part of eigenvalues indicates distance from instability. The sensitivity of this minimum real part of eigenvalues with respect to small changes of wind power injection is used as an index to assess the small signal stability under various operating conditions. The optimum value of the wind power can also be determined with the help of the proposed eigenvalue sensitivity index. The systems used for the study are WSCC 3-machine 9-bus system and IEEE 16-machine 68-bus system.

scholarly journals Improved DE Algorithm for Power System Stabilizer for Damping Low Frequency Osci llations

2019 ◽  
Vol 9 (2S2) ◽  
pp. 606-611
Keyword(s):  
Power System ◽  
Low Frequency ◽  
Operating Conditions ◽  
Power System Stabilizer ◽  
Small Signal ◽  
Small Signal Stability ◽  
Interconnected Power System ◽  
Signal Stability ◽  
De Algorithm ◽  
System Stabilizer

In the large interconnected power system, maintaining the Small signal stability of the system is of more concern, for the stable, secure and reliable operation. This paper proposes an Improved Differential Evolution (DE) Algorithm based Optimal Power system stabilizer (PSS) for damping the low frequency oscillations. Enhancing the damping of system is formulated as the optimization problem. DE/Best Mutation Operator is adopted for producing the mutation vector, to augment the convergence rate of DE algorithm. The effectiveness of the proposed approach has been tested in Single Machine Infinite Bus (SMIB) system under different operating conditions. The time response evaluations has justified the superiority of the proposed approach for damping the oscillations and thereby improving the Small signal stability of the system.

Analyzing Small Signal Stability of Power System based on Online Data by Use of SMES

2009 ◽  
Vol 129 (11) ◽  
pp. 1290-1298
Author(s):  
Hiroyuki Ishikawa ◽  
Yasuyuki Shirai ◽  
Tanzo Nitta ◽  
Katsuhiko Shibata
Keyword(s):  
Power System ◽  
Small Signal ◽  
Small Signal Stability ◽  
Online Data ◽  
Signal Stability
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