A new reinforcement learning based automatic generation controller for hydro-thermal power systems

Author(s):  
T.P.I. Ahamed ◽  
P.S. Sastry ◽  
P.S.N. Rao
2018 ◽  
Vol 8 (11) ◽  
pp. 2185 ◽  
Author(s):  
Linfei Yin ◽  
Lulin Zhao ◽  
Tao Yu ◽  
Xiaoshun Zhang

To reduce occurrences of emergency situations in large-scale interconnected power systems with large continuous disturbances, a preventive strategy for the automatic generation control (AGC) of power systems is proposed. To mitigate the curse of dimensionality that arises in conventional reinforcement learning algorithms, deep forest is applied to reinforcement learning. Therefore, deep forest reinforcement learning (DFRL) as a preventive strategy for AGC is proposed in this paper. The DFRL method consists of deep forest and multiple subsidiary reinforcement learning. The deep forest component of the DFRL is applied to predict the next systemic state of a power system, including emergency states and normal states. The multiple subsidiary reinforcement learning component, which includes reinforcement learning for emergency states and reinforcement learning for normal states, is applied to learn the features of the power system. The performance of the DFRL algorithm was compared to that of 10 other conventional AGC algorithms on a two-area load frequency control power system, a three-area power system, and the China Southern Power Grid. The DFRL method achieved the highest control performance. With this new method, both the occurrences of emergency situations and the curse of dimensionality can be simultaneously reduced.


2018 ◽  
Vol 26 (3) ◽  
pp. 11-24
Author(s):  
K. Jagatheesan ◽  
B. Anand

In this article, the optimal gain value of classical controller gain values is obtained by using different performance indices in Automatic Generation Control. These are interconnected by the three areas of a hydro-thermal power system. The thermal and hydro areas are incorporated with a reheat turbine and a mechanical governor, respectively. The current article was created to select a suitable technique for the tuning of controller gain, when 1% of a step load is given to the thermal area (Area 1). The performance of several controllers, such as Integral (I), Proportional-Integral (PI), and Integral-Derivative (ID) were evaluated and were compared to the cases of with and without Generation Rate Constraint (GRC) non-linearity. The classical controller gain value optimization was performed using the Integral Time Square Error (ITSE), Integral Square Error (ISE) and Integral Time Absolute Error (ITAE) performance indices. The minimum optimal value of controller gain normally offers better dynamic response. The obtained results established that the optimization based on the ITAE-PI controller always guarantees superior dynamic performances compared to other indices and controllers.


2018 ◽  
Vol 7 (4.5) ◽  
pp. 446
Author(s):  
V. Shanmugasundaram ◽  
. .

This work presents the Automatic generation control in an interconnected hydro-thermal power system to stabilize the frequency oscillations due to load changes. Advantage of facts devices are utilized here to improve the stability of the system. Thyristor controlled phase shifter (TCPS) is added in the tie line whose input is the area control error. The output of the phase shifter is the change in phase angle based on the error. The TCPS-RFB (Redox flow battery) and TCPS - SMES (Superconducting magnetic energy storage) combinations are compared against each other in terms of peak overshoot and settling time. The results proves that SMES is most effective than RFB. Then the LFC of hydrothermal plant with TCPS in tie line and SMES in one area is analyzed with different controllers like P, PI, PID and Fuzzy logic controller to find the best controller for these specific applications. The criterion for comparison remains to be the same. And finally fuzzy logic controller is found to best among the ones under consideration.  


This paper presents Automatic Generation Control (AGC) of a power system using integral controller. In the present day power systems, it has become absolutely essential to maintain the quality of the power generated indicating the need of a robust system that can handle parameter uncertainties neglecting disturbances. Although,extensive research has been done in thisarea, design of an efficient and robust system still remains one of the important issues that need to be addressed. Hence in this paperan integral controller has been designed for a singlearea thermal power system without reheat turbine. The optimum controller gain is obtained by Particle Swarm Optimization (PSO) based on Integral of Absolute Error (IAE) and Integral of Square Error (ISE) criterion. The second part of the investigation includes robustness testing of the designed controller against different load conditions and plant parameter variations. The results obtained are compared to those obtained by other control methodologies presented in the recent literature. The results of the simulation validate the superiority of the approach in terms of improvement in the transient response and robustness to plant parameter variations.


Author(s):  
Dillip Kumar Sahoo ◽  
Rabindra Kumar Sahu ◽  
Sidharth Panda

In this study, a Hybrid Adaptive Differential Evolution and Pattern Search (hADE-PS) tuned Fractional Order Fuzzy PID (FOFPID) structure is suggested for AGC of power systems. At first, a non-reheat type two-area thermal system is considered and the improvement of the proposed approach over Bacteria Foraging Optimization Algorithm (BFOA), Teaching Learning Based Optimization (TLBO), Jaya Algorithm (JA), Genetic Algorithm (GA) and Hybrid BFOA and Particle Swarm Optimization Algorithm (hBFOA-PSO) for the identical test systems has been demonstrated. The analysis was then extended to interconnected thermal power system of reheat type and two-area six-unit system. The results are compared with Firefly Algorithm (FA), Symbiotic Organism Search Algorithm (SOSA) and Artificial Bee colony (ABC) for second test system and TLBO, Hybrid Stochastic Fractal Search and Local Unimodal Sampling (hSFS-LUS), ADE and hADE-PS tuned PID for third test system. Finally, robustness of the suggested controller is examined under varied conditions.


2014 ◽  
Vol 492 ◽  
pp. 431-438
Author(s):  
Sathans Suhag ◽  
A. Swarup

In reality, load variations in power systems are random in nature. Therefore, the automatic generation control (AGC) performance of the power system needs to be investigated under random load disturbances so as to have a realistic evaluation of the control strategy. This paper reports results for one such investigation. The intelligent control strategy, based on fuzzy gain scheduling of a proportional-integral (PI) controller, is developed and implemented for a multi-area multi-unit thermal power system with reheat nonlinearity. The paper also investigates the effect of superconducting magnetic energy storage (SMES) system on the AGC performance. For the sake of comparison, the behavior of the system for the same load disturbance is also investigated with a conventional PI controller. Simulation studies indicate that the proposed intelligent control strategy is very effective under random load disturbances and provides significant improvement over the conventional PI controller.


2019 ◽  
Vol 41 (9) ◽  
pp. 2563-2581 ◽  
Author(s):  
Meysam Gheisarnejad ◽  
Mohammad Hassan Khooban

In this article, a novel fuzzy proportional integral derivative (PID) controller with filtered derivative action and fractional order integrator (fuzzy PIλDF controller) is proposed to solve automatic generation control (AGC) problem in power system. The optimization task for fine-tuning parameters of the proposed controller structure is accomplished by cuckoo optimization algorithm (COA). To appraise the usefulness and practicability of proposed COA optimized fuzzy PIλDF controller, four extensively used interconnected test systems, that is, two-area non-reheat thermal, two-area multi-source, three-area thermal and three-area hydro-thermal power plants, are considered. Different nonlinearity such as generation rate constraint (GRC) and governor dead band (GDB) as a source of physical constraints are taken into account in the model of the three-area power systems to examine the ability of the proposed technique to handle practical challenges. The acceptability and novelty of COA-based fuzzy PIλDF controller to solve aforesaid test systems are evaluated in comparison with some recently reported approaches. The consequences of time domain simulation reveal that designed secondary controllers provide a desirable level of performance and stability compared with other existing strategies. Additionally, to explore the robustness of the proposed technique, sensitivity analysis is conducted by varying the operating loading conditions and system parameters within a specific tolerable range.


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