Stability Enhancement in Multi-Machine Power Systems by Fuzzy-based Coordinated AVR-PSS

2015 ◽  
Vol 4 (2) ◽  
pp. 36-50 ◽  
Author(s):  
Rahmat Khezri ◽  
Hassan Bevrani
Keyword(s):  
Fuzzy Logic ◽  
Power Systems ◽  
Power System ◽  
Coordinated Control ◽  
System Stability ◽  
Test Case ◽  
Synchronous Generators ◽  
System Stabilizer ◽  
Stability Enhancement ◽  
Logic Unit

This paper presents performance of intelligent fuzzy-based coordinated control for Automatic Voltage Regulator (AVR) and Power System Stabilizer (PSS), to prevent losing synchronism after major sudden faults and to achieve appropriate post-fault voltage level in multi-machine power systems. The AVR and PSS gains can adaptively change to guarantee the power system stability after faults. For change in AVR and PSS gains, at least one significant generator in each area of a multi-area power system is equipped with fuzzy logic unit. The fuzzy logic unit accepts normalized deviations of terminal voltage and phase difference of synchronous generators as inputs and generates the desirable gains for AVR and PSS. The construction of appropriate fuzzy membership functions and rules for best tuning of gains is described. The proposed fuzzy control methodology is applied to 11-bus 4-generator power system test case. Simulation results illustrate the effectiveness and robustness of the proposed fuzzy-based coordinated control strategy.

Stability Enhancement in Multi-Machine Power Systems by Fuzzy-Based Coordinated AVR-PSS

Fuzzy Systems ◽  
2017 ◽  
pp. 235-249
Author(s):  
Rahmat Khezri ◽  
Hassan Bevrani
Keyword(s):  
Fuzzy Logic ◽  
Power Systems ◽  
Power System ◽  
Coordinated Control ◽  
System Stability ◽  
Test Case ◽  
Synchronous Generators ◽  
System Stabilizer ◽  
Stability Enhancement ◽  
Logic Unit

This paper presents performance of intelligent fuzzy-based coordinated control for Automatic Voltage Regulator (AVR) and Power System Stabilizer (PSS), to prevent losing synchronism after major sudden faults and to achieve appropriate post-fault voltage level in multi-machine power systems. The AVR and PSS gains can adaptively change to guarantee the power system stability after faults. For change in AVR and PSS gains, at least one significant generator in each area of a multi-area power system is equipped with fuzzy logic unit. The fuzzy logic unit accepts normalized deviations of terminal voltage and phase difference of synchronous generators as inputs and generates the desirable gains for AVR and PSS. The construction of appropriate fuzzy membership functions and rules for best tuning of gains is described. The proposed fuzzy control methodology is applied to 11-bus 4-generator power system test case. Simulation results illustrate the effectiveness and robustness of the proposed fuzzy-based coordinated control strategy.

scholarly journals An Accurate Method for Delay Margin Computation for Power System Stability

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3466 ◽  
Author(s):  
Ashraf Khalil ◽  
Ang Swee Peng
Keyword(s):  
Time Delay ◽  
Power Systems ◽  
Power System ◽  
System Stability ◽  
Area Measurement ◽  
Power System Stabilizer ◽  
Iteration Algorithm ◽  
Measurement Units ◽  
System Stabilizer ◽  
Delay Margin

The application of the phasor measurement units and the wide expansion of the wide area measurement units make the time delay inevitable in power systems. The time delay could result in poor system performance or at worst lead to system instability. Therefore, it is important to determine the maximum time delay margin required for the system stability. In this paper, we present a new method for determining the delay margin in the power system. The method is based on the analysis in the s-domain. The transcendental time delay characteristics equation is transformed to a frequency dependent equation. The spectral radius is used to find the frequencies at which the roots cross the imaginary axis. The crossing frequencies are determined through the sweeping test and the binary iteration algorithm. A single machine infinite bus system equipped with automatic voltage regulator and power system stabilizer is chosen as a case study. The delay margin is calculated for different values of the power system stabilizer (PSS) gain, and it is found that increasing the PSS gain decreases the delay margin. The effectiveness of the proposed method has been proved through comparing it with the most recent published methods. The method shows its merit with less conservativeness and fewer computations.

Under Frequency Load Shedding Techniques for Future Smart Power Systems

2019 ◽  
pp. 188-202
Author(s):  
H. H. Alhelou
Keyword(s):  
Power Systems ◽  
Power System ◽  
Active Power ◽  
Load Shedding ◽  
System Stability ◽  
Special Focus ◽  
Power Demand ◽  
Synchronous Generators ◽  
Smart Power ◽  
System Frequency

It is critical for today's power system to remain in a state of equilibrium under normal conditions and severe disturbances. Power imbalance between the load and the generation can severely affect system stability. Therefore, it is necessary that these imbalance conditions be addressed in the minimum time possible. It is well known that power system frequency is directly proportional to the speed of rotation of synchronous machines and is also a function of the active power demand. As a consequence, when active power demand is greater than the generation, synchronous generators tends to slow down and the frequency decreases to even below threshold if not quickly addressed. One of the most common methods of restoring frequency is the use of under frequency load shedding (UFLS) techniques. In this chapter, load shedding techniques are presented in general but with special focus on UFLS.

scholarly journals Water Cycle Algorithm Based Power System Stabilizer Robust Design for Power Systems

2015 ◽  
Vol 66 (2) ◽  
pp. 91-96 ◽  
Author(s):  
Navid Ghaffarzadeh
Keyword(s):  
Power Systems ◽  
Power System ◽  
Water Cycle ◽  
Computation Time ◽  
System Stability ◽  
Power System Stabilizer ◽  
Water Cycle Algorithm ◽  
Optimum Parameters ◽  
System Stabilizer ◽  
Power System Oscillations

Abstract Power System Stabilizers (PSSs) are used to enhance damping of power system oscillations. This paper presents a new fast algorithm to develop PSS. According to this regard, Water Cycle Algorithm (WCA) is used to detect optimum Power System Stabilizer parameters. For this purpose, the design problem of PSS is formulated as an optimization problem and WCA by forming three subsidiary objective functions is employed to search for optimal power system stabilizer’s parameters to minimize the maximum overshoot and settling time together. In order to show the efficiency of the proposed algorithm, a comparison between WCA and without PSS condition has been done, and the results of proposed algorithm show that it detects optimum parameters in reasonable computation time to increase the power system stability.

Improvement of Power System Dynamic Stability Based on Fuzzy Logic Power System Stabilizer (FLPSS)

2015 ◽  
Vol 793 ◽  
pp. 139-143
Author(s):  
Muhamad Irwanto ◽  
N. Gomesh ◽  
Y.M. Irwan ◽  
F. Malek ◽  
M.R. Mamat ◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Power System ◽  
Block Diagram ◽  
Electrical Power ◽  
System Stability ◽  
Power System Stabilizer ◽  
Dynamic Power ◽  
State Variable ◽  
Variable Equation ◽  
System Stabilizer

Generally this project is to improve the dynamic power system stability using fuzzy logic power system stabilizer (FLPSS) which applied to the excitation system. This research is started by electric power system mathematic modelling (state variable equation) and block diagram then set membership function of fuzzy logic power system stabilizer (FLPSS). Block diagram model (plant system) is formed from state variable equation. The plant is controlled by fuzzy logic power system stabilizer (FLPSS) which its input and output from the rotor speed and to excitation system, respectively. To observe the oscillation of dynamic power system stability, the electrical power is varied ± 0.1 pu (positive and negative value indicate an increasing and decreasing electrical power, respectively). The result shows that using FLPSS, the oscillation of dynamic power system can be improved. The overshoot of electric power and rotor speed change oscillation after the disturbance is smaller than the conventional, and also the time to reach the steady state is faster.

scholarly journals Solar PV Placement and Sizing for Line Stability Enhancement and Optimal Operating Cost

2019 ◽  
Vol 9 (1) ◽  
pp. 3585-3593
Keyword(s):  
Power Systems ◽  
Power System ◽  
Voltage Stability ◽  
Reactive Power ◽  
Cost Minimization ◽  
Operating Cost ◽  
System Stability ◽  
Total Power ◽  
Solar Pv ◽  
Stability Enhancement

Nowadays, many countries have started to implement and installed solar photovoltaic (PV). The initial designs of existing power systems were not integrating with any renewable energy (RE) including PV. So, the small scale PV may not have any effect on these power systems. However, integrating large scale PV might raise several power quality issues including power system stability. Power system stability has become major attention where the main focus is on voltage stability.Voltage stability is related on electrical grid capacity to balance the Total Power of Demand (PD) and Total Power generated by Generator (Pgtt). Instability of the voltage can cause inability of the power system to meet the demand of reactive power. The lack of reactive power will cause instability in the power system.This paper present optimal placement and sizing of PV for stability enhancement and operating cost minimization. In this research, reactive power has gradually increased and Fast Voltage Stability Index (FVSI) is applied to analyze voltage stability. PV is applied to stabilize voltage stability of the power system. Economic Load Dispatch (ELD) is conducted to determine the optimal cost and loss. DEIANT is conducted to optimize the total cost and the total loss after solar PV implementation. Simulation result indicates the effectiveness of the proposed technique for stability enhancement and operating cost minimization.

Sign in / Sign up

Export Citation Format

Share Document