Stability Of Interconnected Power System Research Articles

Enhancing Load Frequency Control of Interconnected Power System Using Hybrid PSO-AHA Optimizer

The integration of nonconventional energy sources such as solar, wind, and fuel cells into electrical power networks introduces significant challenges in maintaining frequency stability and consistent tie-line power flows. These fluctuations can adversely affect the quality and reliability of power supplied to consumers. This paper addresses this issue by proposing a Proportional–Integral–Derivative (PID) controller optimized through a hybrid Particle Swarm Optimization–Artificial Hummingbird Algorithm (PSO-AHA) approach. The PID controller is tuned using the Integral Time Absolute Error (ITAE) as a fitness function to enhance control performance. The PSO-AHA-PID controller’s effectiveness is evaluated in two networks: a two-area thermal tie-line interconnected power system (IPS) and a one-area multi-source power network incorporating thermal, solar, wind, and fuel cell sources. Comparative analyses under various operational conditions, including parameter variations and load changes, demonstrate the superior performance of the PSO-AHA-PID controller over the conventional PSO-PID controller. Statistical results indicate that in the one-area multi-source network, the PSO-AHA-PID controller achieves a 76.6% reduction in overshoot, an 88.9% reduction in undershoot, and a 97.5% reduction in settling time compared to the PSO-PID controller. In the dual-area system, the PSO-AHA-PID controller reduces the overshoot by 75.2%, reduces the undershoot by 85.7%, and improves the fall time by 71.6%. These improvements provide a robust and reliable solution for enhancing the stability of interconnected power systems in the presence of diverse and variable energy sources.

Event-based [formula omitted] load frequency control for fuzzy Markov-jump IPS with wind power under hybrid attacks

This paper addresses the H∞ load frequency control problem of interconnected power systems that incorporate high-permeability wind power and face a mixed attack of deception and denial of service. The interconnected power system is modeled as a Takagi–Sugeno (T–S) fuzzy Markov jump system. Given the involvement of wind power, optimizing the utilization of already in-demand communication resources becomes imperative. Thus, a new event-triggering mechanism is adopted to reduce data transmission traffic. Simultaneously, in response to the general network’s vulnerability to network attacks in power systems, a closed-loop system with Markov jump, modeled using the T–S fuzzy approach, is studied. A novel multi-agent Event-Triggering Strategy (ETS) composed of membership functions is proposed to address the mismatch between the membership functions of fuzzy systems and fuzzy controllers, and ensure the consistency of multi-agent systems. Subsequently, employing Lyapunov–Krasovskii theory and stochastic analysis techniques, conditions sufficient to ensure the asymptotic stability of interconnected power systems are derived from linear matrix inequalities. Finally, simulation verification is provided to ensure the accuracy and feasibility of the obtained theory.

Security load frequency control model of interconnected power system based on deception attack.

The interconnected power system connects the power grids of different regions through transmission lines, achieving power interconnection and resource sharing. However, data is transmitted through open power networks and is more susceptible to network attacks. To improve the stability of interconnected power systems under deception attacks, three scenarios of system security load frequency control were studied. Based on the construction of a dynamic model of load frequency control, an event-triggered strategy was used to reduce the communication frequency between nodes, resulting in a reduction in the amount of network transmission data. A sliding mode controller was constructed to solve the problem of event-triggered sliding mode security load frequency control. Elastic event-triggered sliding mode load frequency control for interconnected power systems under mixed attacks. The simulation results showed that using the load frequency control model triggered by events, the load frequency deviation of the interconnected power system can be stabilized at around 12 seconds, effectively saving the cost of network resources. Under the regulation of the load frequency control model based on sliding mode control, the interconnected power system stabilized in 10 seconds, reducing the load of network transmission. The elastic event-triggered sliding mode load frequency control model can ensure stable transmission of power data under various attacks and has good anti-interference performance. The results of this study have played an important role in achieving the stability of power resource supply. Compared with previous studies on individual power systems, this study solves the attack problem of interconnected power systems and considers the frequency control problem of system security loads under mixed attacks, enabling the system to recover stability faster.

HVDC Transmission Placement Study to Increase Critical Clearing Time Using Sensitivity Analysis

Stability is the ability to go back to ordinary conditions after an interruption. Power transfer using an AC transmission system has some stability issues. Fast modulation of the HVDC transmission can escalate the transient stability of interconnected power systems thereby increasing the CCT. To calculate load flow sensitivity, use the load flow sensitivity analysis command in Powerfactory 15.1. The variable considered in this research is dφ/dP. In this paper, we will discuss the use of sensitivity analysis to specify the location of the HVDC transmission to increase the CCT value. By taking several samples that have high sensitivity values,namely channels 8-9 to 7-8 with an average cct change value of 0.555 s, mediumvalues, channels 5-8 to 9-6 have an average cct change of 0.234 s, and low fromchannels 6-4 to 9-4 with an average change of 0.109 s. The data above shows thata channel with a large sensitivity value will provide a higher increase in cct valuecomparedwith a low sensitivityvaluewhen paired with an HVDC.

Fractional-Order Sliding Mode Load Frequency Control and Stability Analysis for Interconnected Power Systems With Time-Varying Delay

The universal use of open communication networks in interconnected power systems has changed the constant delay in the formerly dedicated channels into time-varying delay. The delay will deteriorate the dynamic performance of the load frequency control and lead to system frequency instability. This paper presents a fractional-order sliding mode controller for interconnected power systems with time-varying delay and performs stability analysis based on the Lyapunov direct method. Firstly, fractional-order integral sliding mode control is used to improve the stability of interconnected power systems containing time-varying delay. This expands the delay margin by taking advantage of the scalability of the fractional-order to the sliding mode surface. Then, the Riemann-Liouville fractional-order Lyapunov functional is introduced to stability analysis. This reduced the conservatism of the stability analysis by adjusting the upper limit of the functional integral. Lastly, combining Lyapunov's theory and integral inequality to obtain the stability conditions of the time-varying delay power system described by linear matrix inequality, and bring the stability margin of the system. The simulation results show that the designed controller can guarantee that the maximum delay time of the system is less than a predefined upper limit. The proposed control strategy obtains a larger stability margin than the other four scenarios. Additional simulation study was also conducted to verify its robustness to load variations and wind fluctuations.

Enhancing the transient stability of interconnected power systems by designing an adaptive fuzzy-based fractional order PID controller

The reliable and efficient operation of the electrical energy transmission system heavily relies on maintaining stability as a key requirement. Interconnected power systems often experience low-frequency oscillations (LFOs), which have the potential to initiate instability and, subsequently, necessitate careful attention and investigation. To tackle this issue, researchers have focused on various controllers, including Fractional-Order Proportional-Integral-Derivative (FOPID) controllers. The FOPID controller, with its increased number of design parameters, has proven to be more successful than the traditional PID controller in various engineering applications. However, determining the optimal parameters for the controller becomes more challenging due to the increased design space. Moreover, the performance of fixed-gain FOPID controllers may be degraded when confronted with highly nonlinear and uncertain controlled objects such as power systems. This issue is primarily attributed to the static nature of fixed-gain FOPID controllers. To overcome these challenges associated with fixed-gain FOPID controllers and to instill an adaptive quality, this article introduces a novel power system control methodology. This adaptive approach combines a FOPID control strategy with a fuzzy logic system and is denoted as EOA-AFFOPID. The proposed adaptive controller dynamically tunes its coefficients through a fuzzy block, which significantly improves the overall performance of the control system. To establish a performance benchmark, we have also created an alternative controller, named EOA-FOPID, a version of the optima FOPID controller with fixed coefficients. The proposed methodology is applied to multi-machine interconnected power systems equipped with Static Synchronous Series Compensators (SSSCs), and comparative evaluations are conducted with other popular recent control strategies. The comparisons demonstrate the effectiveness of the EOA-AFFOPID control strategy in damping system fluctuations and achieving significant performance improvements in terms of different metrics including overshoot, undershoot, and settling time.

Utilization of superconducting magnetic energy storage and doubly fed induction generator for enhancing stability of interconnected power system

SummaryAs the share of wind power keeps on increasing, the interaction between synchronous and wind generators pose a challenging issue on power system stability. In order to investigate the impact of wind penetration on stability of power system, appropriate modeling of wind energy conversion systems (WECSs) is necessary. Moreover, it is needed to comprehensively study the impact of wind penetration on power system oscillations. This paper presents a didactic approach for integrating a doubly fed induction generator (DFIG)‐based wind farm from SimPower Systems library to a five‐area 68‐bus power system modeled in Simulink. Inter‐area oscillations with and without wind power penetration are investigated for their characteristics. Renewable energy sources are connected to the grid via power electronics converters at the cost of a reduction in inertia. The concept of virtual synchronous generator (VSG) produces virtual inertia by exchanging active power with the power system. The impact of superconducting magnetic energy storage (SMES) and DFIG on enhancing damping performance of inter‐area is investigated. The increase in damping ratios of inter‐area oscillatory modes verifies the enhancement in small signal stability by connecting SMES and DFIG to the power system. The usage of SMES operating in VSG mode to improve the dynamic stability with highly erratic wind profile is also investigated. The developed MATLAB/SIMULINK‐based DFIG model is simple to use and can be expanded to build efficient controllers. The fidelity of the DFIG model and VSG technology is verified in real time by Opal‐RT (OP4510).

Two-Layer Robust Distributed Predictive Control for Load Frequency Control of a Power System under Wind Power Fluctuation

The frequency stability of interconnected power systems becomes quite challenging when incorporating renewable energy sources (mostly wind power). Distributed model predictive control (DMPC) is an effective method to maintain stable grid frequency and realize power system load frequency control (LFC). This paper proposes a two-layer robust DMPC for the LFC of an interconnected power system. In the scheme, the wind power penetrating the power grid is largely affected by the environment condition, and it is taken as an uncertain disturbance to the power system. The two-layer robust DMPC consists of a nominal DMPC controller and an ancillary DMPC controller. The nominal DMPCs coordinate with each other in achieving the systemwide LFC objective, where the systemwide objective is a strict convex combination of the local LFC objectives. The nominal optimization problems are solved supposing the wind power fluctuation is zero. The ancillary DMPC generates the actual control signal for each generation unit based on signals which are transmitted from the nominal DMPC controller. The simulation on a four-area interconnected power system demonstrates the effectiveness of the proposed algorithm in alleviating the frequency deviation caused by varying the load and uncertain wind power fluctuation.

Frequency stability of interconnected power systems using atom search optimization algorithm

This paper explores the dynamic controller design issue for load frequency control (LFC) of a practical interconnected power system model. In view of this, the three-degree-of-freedom proportional-integral-derivative (3DOF-PID) controller architecture and LFC performance analysis for the proposed atom search optimization (ASO) is presented. The consistency of the form and acceptability of the well-known PID controller’s responses ultimately enforces to use in this work. The proposed ASO algorithm efficiently combines search space discovery and exploitation that yield promising solutions at the termination condition. The test system investigated is a four-area model with each region consisting of identical thermal unit. The system is also connected in one area with an interline power flow controller. The simulation results presented showed the superiority of ASO based 3DOF-PID controller in terms of settling time, peak variance, and magnitude of oscillation.

Wind Inertial Response Based on the Center of Inertia Frequency of a Control Area

As a result of the increased integration of power converter-connected variable speed wind generators (VSWG), which do not provide rotational inertia, concerns about the frequency stability of interconnected power systems permanently arise. If the inertia of a power system is insufficient, wind power plants’ participation in the inertial response should be required. A trendy solution for the frequency stability improvement in low inertia systems is based on utilizing so-called “synthetic” or “virtual” inertia from modern VSWG. This paper presents a control scheme for the virtual inertia response of wind power plants based on the center of inertia (COI) frequency of a control area. The PSS/E user written wind inertial controller based on COI frequency is developed using FORTRAN. The efficiency of the controller is tested and applied to the real interconnected power system of Southeast Europe. The performed simulations show certain conceptual advantages of the proposed controller in comparison to traditional schemes that use the local frequency to trigger the wind inertial response. The frequency response metrics, COI frequency calculation and graphical plots are obtained using Python.

Renewable Energy-Based Load Frequency Stabilization of Interconnected Power Systems Using Quasi-Oppositional Dragonfly Algorithm

It is already established that the renewable integration effects to the power system are nonzero and become more important with large penetrations. Thereby, the impacts of renewable energy sources (RESs) after integration are studied in this work to stabilize grid frequency of the studied test power system model. Initially, the two-area power system model is studied as the test system. The purpose is to show the tuning efficiency of non-conventional quasi-oppositional dragonfly algorithm (QODA) algorithm as compared to conventional way of tuning technique. It is showed that QODA algorithm is quite effective to find the optimal parameters of proportional–integral–derivative (PID) controller in load frequency control performance. Further, the three-area power system model integrated with RESs is studied. The work done here is to study the impacts of wind turbine generation, solar thermal power generation and solar photovoltaic on system frequency oscillations. The PID controller is employed as the supplementary control task, and its parameters are tuned by QODA algorithm. The integral of time absolute error is chosen as the objective function, and further performance indices are determined at the end of the execution of the program to examine the performance of the designed QODA-based PID controller. Following the integration of RESs, the impacts on frequency deviation through simulation results are also presented. The simulation results showed that the RESs are quite effective in regulating the power system frequency deviation understudied.

OPTIMUM LOCATION OF PSS AND ITS PARAMETERS BY USING PARTICLE SWARM OPTIMIZATION

This paper deals with stability of interconnected power system using optimum power system stabilizer (PSS) present at generators. Tuning of PSS parameters has been done using particle swarm optimization (PSO) algorithm. This can be achieved by the modal analysis of IEEE 10 machine 39 bus New England system in Matlab-Simulink. A comparative analysis of IEEE 10 machine 39 bus system has been carried out for investigating the effectiveness of PSS at all generators and with PSS only at generators which were having modal analysis based higher participation factor. Tuning of PSS is an important issue in wide area control system, hence we can tune only the PSS at optimal locations of generators and tuning time got decreased however system was still stable. Investigation shows that the optimum PSS increases the damping of the electromechanical modes and stabilizes the entire system disturbance.

A robust damping controller for DFIG based on variable-gain sliding mode and Kalman filter disturbance observer

This paper proposes a sliding mode based inter-area oscillation damping control strategy for the Doubly Fed Induction Generator (DFIG) to enhance the stability of interconnected power systems. The synthesized damping controller is designed based on the variable-gain super-twisting algorithm to deal with the inherent nonlinear behavior in the DFIG and the power system. A Derivative-free nonlinear Kalman Filter is also developed as a disturbance estimator to accurately estimate the disturbance terms in the represented system. Such estimated results make the gains of super-twisting algorithm more efficient. The proposed controller is insensitive to the presence of unmolded system dynamics and the external disturbances acting on the system, and has a fast response speed and robustness with respect to the power system uncertainties. The stability property of the proposed damping controller is proved via the Lyapunov method, and its performance has been verified through numerical simulations considering detailed system model, external disturbances and operation point uncertainty.

Virtual Inertia Control Application to Enhance Frequency Stability of Interconnected Power Systems with High Renewable Energy Penetration

Due to a rapid increase in the utilization of power converter-based renewable energy sources (RESs), the overall system inertia in an interconnected power system might be significantly reduced, increasing the vulnerability of the interconnected power system to the system instability. To overcome problems caused by the significant reduction in system inertia, this paper proposes a new application of virtual inertia control to improve frequency stability of the interconnected power system due to high penetration level of RESs. The derivative control technique is introduced for higher-level applications of virtual inertia emulation. Thus, the proposed virtual inertia control loop has a second-order characteristic, which provides a simultaneous enabling of damping and inertia emulations into the interconnected power system, enhancing frequency stability and resiliency. System modeling and simulation results are carried out using MATLAB/Simulink® (R2016b, MathWorks, Natick, MA, USA). Trajectory sensitivities are also performed to analyze the dynamic effects of virtual inertia control’s parameters on the system stability. The effectiveness of the virtual inertia control concept on stability improvement is verified through a multi-area test system with high RESs penetration level for different contingencies.

Partition‐composition method for online detection of interconnected power system transient stability

A new partition-composition method for online detection of transient stability of interconnected power system with the data from wide area measurement system (WAMS) is proposed. It consists of two parts: partition and composition. In the partition step, interconnected grids are divided into several local areas according to their geographical locations or ownership. Each area is modelled as an adjoint power system (APS) to determine its own synchronism. In the composition step, transient stability of entire grid is evaluated by the APS model of entire system composed with several key parameters of local areas, which can be directly derived from local WAMS. The proposed method only uses WAMS data, hence it is independent from the offline data, such as network topology, device model and system parameters. Another outstanding feature of the proposed method is that only a few key parameters are required to be transferred from the local control centres to the global control centre. These features are helpful for the interconnected grid with different owners since exhaustive data are unnecessary for the global control centre. Case studies on the 10-generator New England system and one of 2007 operation cases of North China Power Grid validate its correctness and effectiveness.

EFFICIENT POWER OSCILLATION DAMPING CONTROL BY ADAPTIVE NEURO FUZZY CONTROLLER BASED POWER SYSTEM STABILIZER

Low frequency Inter-area oscillations are undesirable which affects the goals of maximum power transfer and optimal power flow. Power system stabilizers can be added to the automatic voltage regulators on the generators to reduce the effect of low frequency inter area oscillation. Different types of power system stabilizers are developed to reduce low frequency inter area oscillations inter but the area is still open for the efficient power stabilizer, for handling the power oscillations without increasing the system controller complexity. This paper presents a way to improve the dynamic stability of interconnected power systems by damping of inter area oscillations in two area four machine power system by designing of Adaptive Neuro Fuzzy Inference System based controller. The implementation is done with the Simulink of MATLAB 2012(b).The obtained results shows that ANIFS-PSS is capable of damping power oscillations in multi area system.

Simulation and Hardware Implementation of Multilevel STATCOM for Smart Grid

The increase in penetration of intermittent renewable energy source has created the need to investigate problems encountered with grid connection. Flexible AC Transmission Systems (FACTS) controllers have proved to be effective in improving system stability of interconnected power system. This paper investigates the improvement of system stability in smart grid using Multi Level STATic COMpensator (MLS) with penetration of Wind Turbines. The control algorithm for improving the dynamic response of the system is implemented using FPGA processor. The Hardware-In-Loop (HIL) testing facility of MATLAB combined with xilinx FPGA was used to represent a real time STATCOM control. The designed hardware for multilevel STATCOM was tested on an IEEE 13 Bus system using the HIL feature, for various operating conditions.

Robust wide‐area damping controller design for inter‐area oscillations with signals' delay

A new wide‐area damping control strategy is investigated for flexible AC transmission systems (FACTS) device using wide‐area measurement system (WAMS) signals. The purpose is to design a dynamic output wide‐area damping controller (WADC) for improving the stability of interconnected power systems. The time‐varying delay of wide‐area signal is incorporated into the design process, which can effectively reduce the delay effect on the damping performance. First, a discrete‐time plant model with time‐varying delay is established for power systems; then by using the proposed improved free‐weighting matrices (IFWMs) approach and a convex optimization algorithm, a new and less conservative delay‐dependent stability criterion, expressed in the terms of linear matrix inequalities (LMIs), is obtained without ignoring any useful terms on the difference of a Lyapunov function. Detailed case studies on a 4‐machine two‐area benchmark test system and 16‐machine five‐area NETS‐NYPS interconnected system show that the designed WADC can not only maintain effective damping performance under the condition of time‐varying delay but also get the maximum wide‐area time delay. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Modeling and Dynamic Behavior of Battery Energy Storage: A Simple Model for Large-Scale Time-Domain Stability Studies

With the continued development and proliferation of renewable energy systems worldwide, particularly wind and photovoltaic (PV) generation, computer simulation models for these technologies to be used in large interconnected power-system stability analyses have been a key focus over the past several years. Such computer simulation models are used by power-system planners and operators to simulate various scenarios of large interconnected systems?e.g., continental Europe and the western or eastern North American grid?to assess the stability and reliability of the bulk electric power system. In Europe, much of this work has been led by efforts within the International Electrotechnical Commission, while in North America, most of the major efforts in modeling has gone through the Renewable Energy Modeling Task Force (REMTF) of the Western Electricity Coordinating Council (WECC). The total nameplate capacity of wind generation installed worldwide has surpassed 360,000 MW, and PV generation has surpassed 130,000 MW, with the top three countries in terms of cumulative total capacity being China, the United States, and Germany.

Устойчивость объединенных энергосистем в условиях меняющихся нагрузок и структуры сети

Random dynamic processes in power systems are of great practical importance for the reliability and stability of interconnected power systems (IPS), but not well under-stood. In the analysis of the stability of the weak links of the IPS have to consider load-and outages of generating units. As a rule, the calculation of the trip being the most powerful unit, and the dynamic state of the IPS is not considered. The article carried algorithmic union action of various kinds of disturbances to unify and accelerate the analysis of the stability of the weak links in the IPS respect to the definition of probability of stable parallel operation of the association. For this purpose, the method of canonical orthogonal expansions developed in the theory of stochastic processes, together with the method of statistical tests.