Damping inter-area oscillations using virtual generator based power system stabilizer

Robust design and best control channel selection of FACTs-based WADC for improving power system stability using Grey Wolf Optimizer

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.

The interarea oscillation is one of the main challenges for the secure and stable operation of a large-scale interconnected AC/DC power system. As the voltage source converter high voltage direct current (VSC-HVDC) transmission system features the fast and flexible power regulation capability, supplementary damping controller (SDC) can be designed for VSC-HVDC to suppress interarea oscillation in a large-scale AC/DC power system. In this paper, an innovative adaptive dynamic programming approach, namely the goal representation heuristic dynamic programming (GrHDP), is proposed to design SDC for VSC-HVDC. The GrHDP based SDC consists of three neural networks, which can automatically form an internal adaptive reward signal to facilitate better mapping between the system state and the control action. Therefore, the GrHDP based SDC can significantly improve the dynamic performance of the power system. Without knowing the exact mathematic model of the power system, the GrHDP based SDC still conducts the quick learning and universal control characteristics and has strong adaptability, which is superior to the conventional lead-lag SDC. Case study is undertaken based on a two-area four machine power system with one VSC-HVDC transmission line. The conventional lead-lag SDC has also been studied for comparison. Simulation results show that the proposed GrHDP based SDC has better performance in damping interarea oscillation than that of the conventional lead-lag SDC in a wide range of system operating conditions.

This study presents coordinate control tuning of power system stabilizer (PSS) with series and shunt FACTS controllers. Here thyristor controlled series compensator (TCSC) and static synchronous compensator (STATCOM) based controllers are coordinated to enhance the damping of power system inter area oscillations. The design of proposed damping controller is formulated as an optimization problem and the controller gains of a linearized power system are optimized instantaneously using genetic algorithm (GA). Here the power system employed with PSS and STATCOM as well as TCSC. The coordinated tuning among the damping controllers is performed on the linearized power system model. Finally, the proposed coordinated controller performance is tested with both eigen value analysis and time domain simulations. Three different control schemes are employed on the test system and the simulation results are compared.

The rapid growth of energy demand in the recent years mandated exploiting energy resources alternative to the conventional fossil fuel-based resources. Nowadays, the renewable energy resources became a fundamental component of the current power systems. Numerous challenges are induced by these recent bulk systems such as low-frequency inter-area oscillations. This paper investigates three methods to damp inter-area oscillation in power systems with deep penetration of wind energy, which are: incorporating power system stabilizers in the automatic voltage regulator controls of the conventional generator, implementing a static var compensator in one of the system busbars, and implementing a high voltage dc transmission system to connect weakly-tied areas within the system. These methods helped increase inter-area oscillation damping when implemented in a modified system based on the classical two-area system.

Self Tuning Wide Area Damping Control for Distributed Power Systems

Due to power system oscillations induced by complex interconnections, power system stability has been a major concern and will continue to be a major concern in power system operations. For improving power system stability, efforts have been directed toward damping power system oscillations. The small signal stability is the instability that has been influenced by complex interconnections. Small signal stability can be dampened with power system stabilisers (PSS). PSS, on the other hand, have certain disadvantages, such as significant variations in voltage profiles and the potential for leading power factor operations, which may reduce system stability in the face of severe disturbances. In wide multi machine power systems, using only traditional PSS can not be enough to dampen inter-area oscillations and the effect of voltage profile variation. Power electronic devices known as Flexible Alternating Current Transmission System (FACTS) devices, on the other hand, are good at damping inter-area oscillations and can handle voltage variations. As a result, based on computational intelligence techniques, this paper provides a thorough analysis and evaluation of PSS and FACTS power oscillation damping (POD) controllers in reducing low frequency oscillations. The importance of technical paper publications on PSS and FACTS-based controller design, optimum location, and parameter tuning is highlighted. Finally, the potential future research directions for novel PSS and FACTS devices is proposed as a reference for interested researchers.

In this paper, control of inter-area oscillation in power systems with high wind power penetration is achieved via doubly fed induction generator (DFIG). The DFIG is modeled in Matlab <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">reg</sup> /Simulink. A two-area system is investigated with a wind farm connected in the area that exports power. Control schemes for active power and reactive power regulation are designed firstly. The paper finds that without active power and reactive power regulation, it is impossible to design an effective inter-area oscillation damping controller through DFIG machine side inverter. An auxiliary control loop for oscillation damping that adjusts the active power command can help damp the inter-area oscillation. Time domain simulations demonstrate the effectiveness of the control.

Electromechanical oscillations are the major stability limits which constrain the power transfer in the interconnected system and influence the transmission line capacity. Power System Stabilizer (PSS) and Flexible AC Transmission Systems (FACTS) devices can be deploy to overcome these oscillations. In this paper the focus has been made on the damping of the inter-area oscillations and Unified Power Flow Controller (UPFC) which has been chosen to be installed at the midpoint of the tie-line between Pakistan and Iran. The region has been experiencing extensive blackouts due to oscillation. A comprehensive analysis for the control of power transmission and damping of inter-area oscillations has been performed with UPFC and PSS based on a dynamic control scheme. The complete system has been simulated in the Matlab/Simulink Environment for different fault conditions. The results verify the potency of the suggested control strategy.

The damping of inter-area oscillations is a major concern for many power system operators. This paper presents a novel method for monitoring of inter-area oscillations based on system identification using subspace techniques and modal analysis. The method enables the detection of oscillatory modes as well as the damping and frequency of those from ambient data recorded during normal operation of the power system. Through modal observability which is also estimated, the parts of the grid participating in an oscillation mode can be determined. The method is suitable for real-time implementation. The paper demonstrates application of the method to measurements from the Nordic power system and to synthetic data. The technique can be used to increase operator situational awareness and provide early warning in case of potential for unstable inter-area mode oscillations.

Scope of this paper is to present a design process of a supervisory control scheme that optimally coordinates a parallel operation of FACTS devices and an HVDC link to synchronously counteract inter-area oscillations in a power system. The control system is based on Linear Quadratic Gaussian (LQG) optimal control theory. The scheme provides coordinating control signals to the power electronic devices to coherently damp electromechanical oscillations inherent in the system. The scenarios considered involve transient disturbances, signal time delays and reduced system inertia. The feasibility of the proposed scheme is validated on a two-area network incorporating HVDC link, TCSC and SVC devices. The modelling was performed in MATLAB and DIgSILENT simulation environments. Main outcome from this research is the demonstration of improved performance and robustness measures achieved by the novel control scheme, utilizing flexible transmission assets to effectively damp power oscillations in inter-connected power systems.

This paper studies the impact of wind generation on generator rotor angle and inter-area oscillation stability. A comparative simulation study is conducted based on a U.S. Eastern Interconnection (EI) planning model for year 2030. The wind penetration level is 17% of the total generation. Generator critical clearing time (CCT) and inter-area oscillation damping ratio are evaluated. It is observed that rotor angle stability is barely affected while inter-area oscillation damping shows discernible improvement due to wind generation. Possible explanations are then explored.

The utilization of renewable energy sources for energy transition is gaining significant popularity due to pollution control and other environmental benefits. To move toward green energy generation, the integration of renewable energy sources with the existing conventional grid plays a key role. The performance of a modern interconnected power system, particularly with a high penetration of renewable energy sources, is significantly impacted by power system oscillations. Flexible Alternating Current Transmission System (FACTS) devices are recommended to improve control framework performance, and the power system stabilizer is the customary controller for damping such oscillations. FACTS offer a powerful strategy as they can control transport voltage, transmission line impedance, and power flows. This paper presents an efficient control scheme that combines four FACTS controllers: the static VAR compensator for controlling reactive power in control frameworks, the unified power flow controller for managing active and reactive power flows on transmission lines, the static synchronous compensator for maintaining system voltage stability, and the static synchronous series compensator for controlling transmission line impedance. To address the challenges posed by the variability of renewable energy sources such as wind and solar, the ant colony optimization algorithm is employed to optimally tune the controllers&amp;rsquo; parameters. By generating controlled voltage and interfacing with the transmission line, these controllers enhance system stability, even under fluctuating renewable energy inputs. The IEEE 30-Bus system was used for simulation and control design, demonstrating the effectiveness of this approach in damping inter-area oscillations and improving the stability and resilience of a renewable-energy-integrated power system.

This paper presents a study of the application of a STATCOM to enhance the damping of an inter-area oscillation exhibited by a two-area four-machine interconnected power system. The adaptive fuzzy controller, of which the parameters art tuned by orthogonal least squares (OLS) training algorithm, is incorporated into the supplementary control of STATCOM. Comparing to gradient descent algorithm, which may get trapped at a local minimum of the chosen optimization criterion during the learning procedure, the use of OLS algorithm give a faster and more robust parameter estimation. The inter-area oscillation damping is improved more by the STATCOM. The simulation results show that the designed fuzzy controller is efficient in damping power oscillations, and has better performance than the linear counterpart when operating condition changes.

Dominant inter-area oscillation mode identification using local measurement and modal energy for large-scale power systems with high grid-tied VSCs penetration