Nonlinear Optimal STATCOM Controller for Power System Based on Hamiltonian Formalism

In this paper a nonlinear controller has been designed for Static Synchronous Compensator (STATCOM) in order to improve transient stability of a power system. The nonlinear model of the power system is exactly linearized via state feedback linearization technique. The optimal gain constants of the nonlinear controller are determined applying a special class of non-cooperative dynamic game theory. The performance of this proposed nonlinear STATCOM controller is compared with a fixed structure lead-lag based conventional STATCOM controller. The set of tuning parameters of the conventional controller are optimized through heuristic optimization technique, Genetic Algorithm (GA). The performance of both nonlinear and the conventional controllers are validated with application of a typical transient disturbance to a SMIB test power system. It has been revealed that the proposed nonlinear controller is more effective in the face of contingency in comparison to the GA based controller.

This paper presents a novel nonlinear control scheme for designing static synchronous compensators (STATCOM). A passivity-based approach is proposed for designing robust nonlinear STATCOM controller. The mathematical model of STATCOM will be represented by a Euler-Lagrange (EL) system corresponding to a set of EL parameters. By employing the Park's transformation, the differential geometry approach is used to investigate the power system dynamics with considering STATCOM under the synchronous d-q frame. The STATCOM controller based on passivity is obtained with a feedback control law from linear system models. Digital computer simulation for a large operation point variations have been studied the STATCOM controller design. Simulation results show that the proposed STATCOM controller can effectively enhance transient stability of the power system even in the presence of large operation point variations

Comparative analysis of controllers for stability enhancement for wind energy system with STATCOM in the grid connected environment

A Static Synchronous Compensator (STATCOM) is one of the Flexible AC Transmission System (FACTS) device which plays an vital role in power system network in alleviation of small and large transient disturbances and better voltage regulation. This paper proposed a self tuning Proportional-Integral (PI) controller for STATCOM which provided a voltage support at point of common coupling (PCC). Self tuning of PI controller was achieved by adapting PI controller gains with system parameters by using Bats Echolocation controller which mimics the Bats Echolocation behavior. In the proposed controller, the system voltage (parameter) at point of common coupling compared with reference voltage and then Bats Echolocation Controller updates the PI controller gains according to the variation obtained between them. This paper also proposed a Cascaded Multilevel Inverter (CMLI) instead of conventional Voltage Source Inverter (VSI) for STATCOM to obtain better voltage regulation at point of common coupling. The voltage imbalance between H-bridge cells in CMLI was rectified by prosing Multicarrier Pulse Width Modulation (PWM) techniques, The proposed controller was validated by comparing the simulation results with fixed gain PI controller and Self tuning PI controller using Neural controller and Particle Swarm Optimization.

Voltage stability assessment of isolated hybrid dish-stirling solar thermal-diesel microgrid with STATCOM using mine blast algorithm

This paper deals with the simultaneous tuning of proportional integral controller of static synchronous compensator (STATCOM) associated with lead-lag controller (LL) in order to improve the stability performance of combined wind farm (CWF). This type of farms has been developed to summarize the main benefits of Squirrel-Cage Induction Generator (SCIG) and doubly fed induction generators (DFIG). The performance of CWF with the tuned STATCOM is studied during line-to-line and three-phase faults. Multi-objective Lightning Attachment Procedure Optimization Algorithm (LAPO) is used as an intelligent optimization technique to determine the control parameters which can achieve the specified objective functions; minimizing the error signal and maximizing the output signal. The multi-objective LAPO is used to obtain the optimized values of AC voltage regulator, DC voltage regulator, current regulator, gains and time constant of LL. The ability of STATCOM tuned by multi-objective LAPO is examined by studying the performance of three wind farms. The first one is CWF and two other wind farms; one of them is based only on SCIG (SCIG-WF) and the other based only on DFIG (DFIG-WF) when they associated with the tuned STATCOM LAPO during grid fault. The results show that CWF associated with the tuned STATCOM LAPO has the best performance during grid faults compared with the other wind farms.

This paper aims to develop a coordinated controller to enhance the low voltage ride through (LVRT) performance of a permanent magnet synchronous generator (PMSG) based variable speed wind energy conversion system (WECS). This coordinated control comprises of a pitch angle control, a flux weakening control and a static synchronous compensator (STATCOM) control. The pitch angle control is adjusted to smooth the WECS output power fluctuations or to enhance the LVRT performance. The flux weakening controller is used to reduce the overvoltage of DC-link capacitor, and the STATCOM control is used to ensure continuous operation of WECS during symmetrical and asymmetrical grid faults. The proposed coordinated control method is compared with the conventional LVRT strategy based on the braking chopper (BC) via time series simulation results and effectiveness of the proposed control is verified.

Inter Area Oscillations amounting to a major portion of the class of low frequency oscillations, are detrimental to the dynamic stability of the present day power system. Power system stabilizer (PSS) installed throughout the system aids in mitigating such oscillations. Static synchronous compensator (STATCOM) based damping controllers installed in the system also provide oscillation damping apart from their intended purpose of reactive power compensation. Hence to improve the overall performance coordinated design of PSS and STATCOM is essential. The coordinated design of power system stabilizer (PSS) and static synchronous compensator (STATCOM) for mitigation of inter area oscillations is presented in this paper. The coordinated design is formulated as an optimization problem and particle swarm optimization (PSO) is employed for this design. Then the designed PSS and STATCOM are implemented in the test system and the response is analysed. The test system is simulated with and without Power system stabilizer and static synchronous compensator. The simulation results show that the coordinated design mitigates the inter area oscillations in an effective way.

1 A Survey on Computational Optimal Control.- Issues in the Direct Transcription of Optimal Control Problems to Sparse Nonlinear Programs.- Optimization in Control of Robots.- Large-scale SQP Methods and their Application in Trajectory Optimization.- Solving Optimal Control and Pursuit-Evasion Game Problems of High Complexity.- 2 Theoretical Aspects of Optimal Control and Nonlinear Programming.- Continuation Methods In Boundary Value Problems.- Second Order Optimality Conditions for Singular Extremals.- Synthesis of Adaptive Optimal Controls for Linear Dynamic Systems.- Control Applications of Reduced SQP Methods.- Time Optimal Control of Mechanical Systems.- 3 Algorithms for Optimal Control Calculations.- Second Order Algorithm for Time Optimal Control of a Linear System.- An SQP-type Solution Method for Constrained Discrete-Time Optimal Control Problems.- Numerical Methods for Solving Differential Games, Prospective Applications to Technical Problems.- Construction of the Optimal Feedback Controller for Constrained Optimal Control Problems with Unknown Disturbances.- Repetitive Optimization for Predictive Control of Dynamic Systems under Uncertainty.- Optimal Control of Multistage Systems Described by High-Index Differential-Algebraic Equations.- A New Class of a High Order Interior Point Method for the Solution of Convex Semiinfinite Optimization Problems.- A Structured Interior Point SQP Method for Nonlinear Optimal Control Problems.- 4 Software for Optimal Control Calculations.- Automated Approach for Optimizing Dynamic Systems.- ANDECS: A Computation Environment for Control Applications of Optimization.- Application of Automatic Differentiation to Optimal Control Problems.- OCCAL: A mixed symbolic-numeric Optimal Control CALculator.- 5 Applications of Optimal Control.- A Robotic Satellite with Simplified Design.- Nonlinear Control under Constraints of a Biological System.- An Object-Oriented Approach to Optimally Describe and Specify a SCADA System Applied to a Power Network.- Near-Optimal Flight Trajectories Generated by Neural Networks.- Performance of a Feedback Method with Respect to Changes in the Air-Density during the Ascent of a Two-Stage-To-Orbit Vehicle.- Linear Optimal Control for Reentry Flight.- Steady-State Modelling of Turbine Engine with Controllers.- Shortest Paths for Satellite Mounted Robot Manipulators.- Optimal Control of the Industrial Robot Manutec r3.

Adaptive control universality of STATCOM for efficient wind energy conversion systems

Improvement of synchronizing power and damping power by means of SSSC and STATCOM: A comparative study

The static synchronous compensator (STATCOM) is one of the flexible AC transmission system (FACTS) devices. The STATCOM and wide area measurement system (WAMS) are used in power systems. This paper describes the coordinated design of the wide area controllers and STATCOM controllers using a bacterial foraging algorithm (BFA). BFA is a new type of global optimization algorithm. The parameters of the controllers are optimized simultaneously by using the BFA to minimize the fitness function. The fitness function is the performance of the integral of the time-weighted squared error (ITSE). The fitness function is calculated by solving the differential equations. A 10-machine 39-bus new England system is a complex power system and is used to test the method of the coordinated design. The results show that the coordinated design of these controllers can improve the damping of the interconnected power system.

With the expansion of electric power systems, the size and complexity of the network is increased. One of the most important drawbacks of network expansion is the reduction in the damping torque of the whole system. The lack of damping torque can lead to fluctuations and instability in the power system. With regard to this problem, power system stabilizers (PSSs) have been widely utilized to improve power system stability. However, due to some drawbacks of the conventional PSSs, the need for finding a better substitution still remains. Therefore, in this paper, the application of a static synchronous compensator (STATCOM) to improve dynamic stability of a multimachine electric power system is presented and a supplementary stabilizer based on the STATCOM is incorporated. Intelligence optimization methods such as particle swarm optimization and genetic algorithms are considered for tuning the parameters of the proposed stabilizer. Several nonlinear time-domain simulation tests visibly show the ability of the STATCOM in damping power system oscillations.

In electromechanical oscillation damping within power system, power system stabilizers (PSSs) are often deployed. However, a PSS is less effective in damping interarea oscillation and is limited by changes in network configuration due to weak tie-lines and load variations. Consequently, this paper presents a wide-area coordination approach that damps interarea oscillations using FACTS devices and phasor measurement units. We selected a static synchronous compensator (STATCOM) and static series synchronous compensator (SSSC) for realistic power system interarea oscillation damping. The performance of the coordinated FACTS installed in a power system depends on their suitable locations, sizes, tuned parameters, and remote input signal selection. Hence, we formulated a multiobjective problem to provide the STATCOM and SSSC's optimal solutions using multiobjective particle swarm optimization. In addition, we employed a participation factor to select suitable generator speed deviations as the wide area stabilizing signal. The proposed approach was tested on different configurations of the Kundur $2$-area $4$-machine test system within MATLAB and Psat environments. The outcome of the nonlinear simulation proved that the multimachine power system stability was enhanced.

One of the technical solutions for improving the stability of power system is incorporation of Static Synchronous Compensators (STATCOM) and Static Synchronous Series Compensator (SSSC) controllers. However, the impact of hybridized STATCOM and SSSC on the generator damping stability of the power system to improve the post disturbance recovery voltages of the generator is necessary. Thus, in this study, hybridized model of STATCOM and SSSC controllers were incorporated on the Nigerian 31-bus power system to improve the system generator damping stability during disturbance. Transient stability of electrical power system with contingency was performed using swing equations technique. Line-Voltage Stability Index (L-VSI) technique was employed to determine the critical load bus for the placement of the controllers. Hybridized model of the STATCOM and SSSC was developed and incorporate into the selected load buses and its impact on stability of the generator oscillation damping was examined. Simulation was done in MATLAB R2023a. The generator damping ratio, total active power losses and total cost of controllers were determined. Results verified the effectiveness of hybridized model of STATCOM and SSSC controllers in improving the stability of power generator oscillation damping. Keywords : STATCOM, SSSC, Line-Voltage Stability Index, Contingency, Generator Oscillation Damping, Power Loss. DOI: 10.7176/NCS/15-04 Publication date: February 28 th 2025